Multilayer coil components

Abstract

To provide a laminated coil component which allows improvement in L-value of a coil while ensuring a withstand voltage between coil conductors.SOLUTION: A laminated coil component 1 comprises: an element assembly in which a plurality of magnetic layers containing soft magnetic metal particles M are laminated in a first direction D1; and a coil disposed in the element assembly. The coil has a plurality of coil conductors which are electrically connected to one another. The plurality of magnetic layers has a first magnetic layer 11 and a second magnetic layer 12 which are laminated between two of the coil conductors adjacent to each other in the first direction D1. Soft magnetic metal particles M2 contained in the second magnetic layer 12 have an average particle diameter greater than that of soft magnetic metal particles M1 contained in the first magnetic layer 11.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent document 1 describes a laminated inductor that includes a magnetic part formed by stacking layers containing soft magnetic alloy particles, a coil disposed within the magnetic part, and external terminals provided at both ends of the magnetic part and connected to the coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-38263 Summary of the Invention [Problem to be solved by the invention]

[0004] Increasing the particle size of the soft magnetic alloy particles makes it possible to increase the L value of the coil, but makes it difficult to ensure the withstand voltage between the coil conductors.On the other hand, decreasing the particle size of the soft magnetic alloy particles makes it possible to ensure the withstand voltage between the coil conductors, but makes it difficult to increase the L value of the coil.

[0005] An object of the present disclosure is to provide a laminated coil component that can increase the L value of the coil while ensuring the withstand voltage between the coil conductors. [Means for solving the problem]

[0006] A laminated coil component according to one aspect of the present disclosure includes a base body formed by stacking a plurality of magnetic layers containing soft magnetic metal particles in a first direction, and a coil disposed within the base body, wherein the coil has a plurality of coil conductors electrically connected to each other, the plurality of magnetic layers having a first magnetic layer and a second magnetic layer stacked between two coil conductors adjacent to each other in the first direction, and the average particle diameter of the soft magnetic metal particles contained in the second magnetic layer is larger than the average particle diameter of the soft magnetic metal particles contained in the first magnetic layer.

[0007] In a laminated coil component according to one embodiment of the present disclosure, a first magnetic layer and a second magnetic layer are disposed between adjacent coil conductors. The average particle diameter of the soft magnetic metal particles contained in the first magnetic layer is different from the average particle diameter of the soft magnetic metal particles contained in the second magnetic layer. Therefore, at least two soft magnetic metal particles are likely to be disposed along the first direction between adjacent coil conductors. This ensures a high withstand voltage between adjacent coil conductors compared to when a single magnetic layer is disposed. Furthermore, compared to when two magnetic layers with smaller average particle diameters are disposed, the magnetic permeability is improved, resulting in an increased L value of the coil.

[0008] The first magnetic layer may be thinner than the second magnetic layer, which can reliably increase the L value of the coil.

[0009] The first magnetic layer may be thicker than the second magnetic layer, in which case the withstand voltage between the coil conductors can be reliably ensured.

[0010] The plurality of magnetic layers may further include a plurality of third magnetic layers disposed around the corresponding coil conductors when viewed from the first direction and constituting the same layer as the corresponding coil conductors, and the average particle diameter of the soft magnetic metal particles contained in the plurality of third magnetic layers may be larger than the average particle diameter of the soft magnetic metal particles contained in the first magnetic layer, which can further increase the L value of the coil.

[0011] The first and second magnetic layers may overlap the coil conductors and have a line width wider than that of the coil conductors when viewed from the first direction, and the magnetic layers may further include a third magnetic layer that is disposed around the first and second magnetic layers and that forms the same layer as the first and second magnetic layers when viewed from the first direction, and the average particle diameter of the soft magnetic metal particles contained in the third magnetic layer may be larger than that of the soft magnetic metal particles contained in the first magnetic layer. In this case, the L value of the coil can be further increased compared to a configuration in which the average particle diameter of the soft magnetic metal particles contained in the third magnetic layer is equal to or smaller than that of the soft magnetic metal particles contained in the first magnetic layer.

[0012] The average particle size of the soft magnetic metal particles contained in the third magnetic layer may be larger than the average particle size of the soft magnetic metal particles contained in the second magnetic layer, which can further increase the L value of the coil.

[0013] The laminated coil component may further include a high-resistance portion disposed between the two coil conductors and having an electrical resistivity higher than that of the first magnetic layer and the second magnetic layer, the high-resistance portion overlapping the plurality of coil conductors when viewed from the first direction and having a line width wider than that of the plurality of coil conductors. In this case, it is possible to reliably ensure a withstand voltage between the coil conductors.

[0014] The high resistance portion may be provided so as to be in contact with one of the two coil conductors. In this case, when an AC current flows through the coil conductor, the magnetic flux generated in the element body is larger closer to the coil conductor. This can further reduce AC loss.

[0015] A mixed region containing both small and large soft magnetic metal particles may be present between the first and second magnetic layers, further ensuring the withstand voltage between the coil conductors. [Effects of the Invention]

[0016] According to one aspect of the present invention, it is possible to provide a laminated coil component that can increase the L value of the coil while ensuring the withstand voltage between the coil conductors. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view showing the laminated coil component according to the first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the laminated coil component shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the laminated coil component shown in FIG. [Figure 4] FIG. 4 is a perspective view showing a first end portion of a first connecting conductor. [Figure 5] FIG. 5 is a partially enlarged view of FIG. [Figure 6] FIG. 6 is a partially enlarged cross-sectional view of the laminated coil component according to the second embodiment. [Figure 7] FIG. 7 is a plan view of the laminated coil component shown in FIG. [Figure 8] FIG. 8 is a partially enlarged cross-sectional view of the laminated coil component according to the third embodiment. [Figure 9] FIG. 9 is a partially enlarged cross-sectional view of the laminated coil component in accordance with the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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.

[0019] (First embodiment) As shown in FIG. 1, the laminated coil component 1 according to the first embodiment includes an element body 2, a first external electrode 4, a second external electrode 5, a first electrode portion 6, and a second electrode portion 7.

[0020] The element body 2 has a substantially rectangular parallelepiped shape. 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 element body 2 has, as its outer surfaces, a pair of end faces 2a, 2b facing each other, a pair of main faces 2c, 2d facing each other, and a pair of side faces 2e, 2f facing each other. The facing direction in which the pair of main faces 2c, 2d face each other is the first direction D1. The facing direction in which the pair of end faces 2a, 2b face each other is the second direction D2. The facing direction in which the pair of side faces 2e, 2f face each other is the third direction D3. In this embodiment, the first direction D1 is the height direction of the element body 2. The second direction D2 is the longitudinal direction of the element body 2 and is perpendicular to the first direction D1. The third direction D3 is the width direction of the element body 2 and is perpendicular to the first direction D1 and the second direction D2.

[0021] The pair of end faces 2a, 2b extend in a first direction D1 so as to connect the pair of principal faces 2c, 2d together. The pair of end faces 2a, 2b also extend in a third direction D3 (the direction of the short sides of the pair of principal faces 2c, 2d). The pair of side faces 2e, 2f extend in the first direction D1 so as to connect the pair of principal faces 2c, 2d together. The pair of side faces 2e, 2f also extend in a second direction D2 (the direction of the long sides of the pair of end faces 2a, 2b). The principal face 2d can be defined as a mounting surface that faces another electronic device (for example, a circuit board or an electronic component) when the laminated coil component 1 is mounted on the other electronic device.

[0022] As shown in FIG. 2, the element body 2 has a plurality of magnetic layers 10a-10p stacked in a first direction D1. The element body 2 is formed by stacking a plurality of magnetic layers 10a-10p in the first direction D1. The magnetic layers 10a-10p are stacked in this order in the first direction D1. In other words, the first direction D1 is the stacking direction. In an actual element body 2, the magnetic layers 10a-10p are integrated to the extent that the boundaries between the layers are not visible. Although FIG. 2 shows each of the magnetic layers 10a-10p as one layer, multiple magnetic layers 10a and multiple magnetic layers 10o are stacked. The main surface 2c is formed by the main surface of the magnetic layer 10a located at the end of the stack. The main surface 2d is formed by the main surface of the magnetic layer 10p.

[0023] The magnetic layers 10a-10p have thicknesses (lengths in the first direction D1) of, for example, 1 μm or more and 100 μm or less. While the magnetic layers 10a-10p are shown as having the same thickness in FIG. 2, the magnetic layers 10b, 10d, 10f, 10h, 10j, 10l, and 10n, on which coil conductors 21-25, first connecting conductors 8, and second connecting conductors 9 (described later) are provided, are thicker than the magnetic layers 10c, 10e, 10g, 10i, 10k, 10m, and 10o, on which through-hole conductors 31-36 (described later) are provided. In this embodiment, the magnetic layers 10b, 10d, 10f, 10h, 10j, 10l, and 10n have the same thickness, for example, 15 μm or more and 100 μm or less. In this embodiment, the magnetic layers 10c, 10e, 10g, 10i, 10k, 10m, and 10o have the same thickness, for example, between 1 μm and 15 μm.

[0024] Each of the magnetic layers 10a to 10p includes a plurality of soft magnetic metal grains M (see FIG. 5). The soft magnetic metal grains M are made of a soft magnetic alloy (soft magnetic material). The soft magnetic alloy is, for example, an Fe-Si alloy. When the soft magnetic alloy is an Fe-Si alloy, it may contain P. The soft magnetic alloy may be, for example, an Fe-Ni-Si-M alloy. "M" includes one or more elements selected from Co, Cr, Mn, P, Ti, Zr, Hf, Nb, Ta, Mo, Mg, Ca, Sr, Ba, Zn, B, Al, and rare earth elements.

[0025] In the magnetic layers 10a to 10p, the soft magnetic metal particles M are bonded to one another. The bond between the soft magnetic metal particles M is realized, for example, by bonding between oxide films formed on the surfaces of the soft magnetic metal particles M. In the magnetic layers 10a to 10p, the soft magnetic metal particles M are electrically insulated from one another by the bonding between the oxide films. The thickness of the oxide film is, for example, 5 nm or more and 60 nm or less. The oxide film may be composed of one or more layers.

[0026] The element body 2 contains a resin. The resin is present among the soft magnetic metal particles M. The resin is a resin having electrical insulation properties (insulating resin). The insulating resin includes, for example, a silicone resin, a phenol resin, an acrylic resin, or an epoxy resin.

[0027] 3, a step is formed in part of the main surface 2d of the element body 2. Specifically, the end surface 2a side and the end surface 2b side of the main surface 2d are recessed closer to the main surface 2c than the central portion.

[0028] 1 and 3, the first external electrode 4 and the second external electrode 5 are arranged on the element body 2. The first external electrode 4 and the second external electrode 5 are arranged on the outer surface of the element body 2. The first external electrode 4 is arranged at one end of the element body 2 in the second direction D2. The second external electrode 5 is arranged at the other end of the element body 2 in the second direction D2. The first external electrode 4 and the second external electrode 5 are spaced apart from each other in the second direction D2.

[0029] The first external electrode 4 includes a first electrode portion 4a located on the end face 2a, a second electrode portion 4b located on the principal surface 2c, a third electrode portion 4c located on the principal surface 2d, a fourth electrode portion 4d located on the side face 2e, and a fifth electrode portion 4e located on the side face 2f. The first electrode portion 4a extends along the first direction D1 and the third direction D3 and has a rectangular shape when viewed from the second direction D2. The second electrode portion 4b extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The third electrode portion 4c extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The fourth electrode portion 4d extends along the first direction D1 and the second direction D2 and has a rectangular shape when viewed from the third direction D3. The fifth electrode portion 4e extends along the first direction D1 and the second direction D2 and has a rectangular shape when viewed from the third direction D3.

[0030] The first electrode portion 4a, the second electrode portion 4b, the third electrode portion 4c, the fourth electrode portion 4d, and the fifth electrode portion 4e are connected and electrically connected to each other at the ridge portions of the element body 2. The first external electrode 4 is formed on five surfaces: one end face 2a, a pair of main surfaces 2c and 2d, and a pair of side surfaces 2e and 2f. The first electrode portion 4a, the second electrode portion 4b, the third electrode portion 4c, the fourth electrode portion 4d, and the fifth electrode portion 4e are integrally formed.

[0031] The second external electrode 5 includes a first electrode portion 5a located on the end face 2b, a second electrode portion 5b located on the principal face 2c, a third electrode portion 5c located on the principal face 2d, a fourth electrode portion 5d located on the side face 2e, and a fifth electrode portion 5e located on the side face 2f. The first electrode portion 5a extends along the first direction D1 and the third direction D3 and has a rectangular shape when viewed from the second direction D2. The second electrode portion 5b extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The third electrode portion 5c extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The fourth electrode portion 5d extends along the first direction D1 and the second direction D2 and has a rectangular shape when viewed from the third direction D3. The fifth electrode portion 5e extends along the first direction D1 and the second direction D2 and has a rectangular shape when viewed from the third direction D3.

[0032] The first electrode portion 5a, the second electrode portion 5b, the third electrode portion 5c, the fourth electrode portion 5d, and the fifth electrode portion 5e are connected and electrically connected to each other at the ridge portions of the element body 2. The second external electrode 5 is formed on five surfaces: one end face 2b, a pair of main faces 2c and 2d, and a pair of side faces 2e and 2f. The first electrode portion 5a, the second electrode portion 5b, the third electrode portion 5c, the fourth electrode portion 5d, and the fifth electrode portion 5e are integrally formed.

[0033] The first external electrode 4 and the second external electrode 5 are conductive resin layers. The conductive resin is a mixture of a thermosetting resin with a conductive material and an organic solvent. The conductive material is, for example, a conductive filler. The conductive filler is metal powder. The metal powder is, for example, Ag powder. The thermosetting resin is, for example, a phenol resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0034] The first electrode portion 6 and the second electrode portion 7 are arranged on the main surface 2d and spaced apart from each other in the second direction D2. The first electrode portion 6 and the second electrode portion 7 are rectangular when viewed from the first direction and extend along the second direction D2 and the third direction D3. The first electrode portion 6 and the second electrode portion 7 are provided over the entire main surface 2d in the third direction D3. The first electrode portion 6 is covered by the third electrode portion 4c and is electrically connected to the first external electrode 4. A portion of the first electrode portion 6 closer to the second electrode portion 7 is exposed from the third electrode portion 4c. The second electrode portion 7 is covered by the third electrode portion 5c and is electrically connected to the second external electrode 5. A portion of the second electrode portion 7 closer to the first electrode portion 6 is exposed from the third electrode portion 5c.

[0035] The first electrode portion 6 is provided so as to fill in a step provided on the end face 2a side of the main surface 2d. The first electrode portion 6 is flush with the main surface 2d, the end face 2a, the side face 2e, and the side face 2f. It can be said that the first electrode portion 6 is embedded in the element body 2 so as to be exposed from the main surface 2d, the end face 2a, the side face 2e, and the side face 2f. The second electrode portion 7 is provided so as to fill in a step provided on the end face 2b side of the main surface 2d. The second electrode portion 7 is flush with the main surface 2d, the end face 2b, the side face 2e, and the side face 2f. It can be said that the second electrode portion 7 is embedded in the element body 2 so as to be exposed from the main surface 2d, the end face 2b, the side face 2e, and the side face 2f.

[0036] As shown in FIG. 2, the first electrode portion 6 and the second electrode portion 7 are arranged to sandwich the magnetic layer 10p in the second direction D2. The first electrode portion 6, the second electrode portion 7, and the magnetic layer 10p have the same thickness (length in the first direction D1). The first electrode portion 6 and the second electrode portion 7 are, for example, a printing paste or a plated conductor. The first electrode portion 6 and the second electrode portion 7 contain a conductive material. The conductive material is, for example, Ag, Pd, Cu, Al, or Ni.

[0037] As shown in FIGS. 2 and 3, the laminated coil component 1 further includes a coil 3, a first connecting conductor 8, and a second connecting conductor 9.

[0038] The coil 3 is disposed within the element body 2. In this embodiment, the coil 3 is disposed at the center of the element body 2 in both the second direction D2 and the third direction D3. That is, the distance between the coil 3 and the end face 2a is equal to the distance between the coil 3 and the end face 2b. The distance between the coil 3 and the side face 2e is equal to the distance between the coil 3 and the side face 2f. In this specification, the distance means the shortest distance.

[0039] The coil 3 includes a plurality of coil conductors 21-25 electrically connected to each other and a plurality of through-hole conductors 31-36. The coil conductors 21-25 and the through-hole conductors 31-36, together with the first connecting conductor 8 and the second connecting conductor 9, are internal conductors arranged inside the coil 3. The internal conductors are, for example, printing paste or plated conductor. The internal conductors contain a conductive material. The conductive material is, for example, Ag, Pd, Cu, Al, or Ni. The internal conductors are, for example, made of the same material as each other. The internal conductors are, for example, made of the same material as the first electrode portion 6 and the second electrode portion 7.

[0040] The coil axis of the coil 3 is arranged along the first direction D1. The coil conductors 21 to 25 are arranged so that at least a portion of each of them overlaps with one another when viewed from the first direction D1. One end 21a of the coil conductor 21 constitutes one end 3a of the coil 3. The other end 21b of the coil conductor 21 is connected to one end 22a of the coil conductor 22 by a through-hole conductor 32. The other end 22b of the coil conductor 22 is connected to one end 23a of the coil conductor 23 by a through-hole conductor 33. The other end 23b of the coil conductor 23 is connected to one end 24a of the coil conductor 24 by a through-hole conductor 34. The other end 24b of the coil conductor 24 is connected to one end 25a of the coil conductor 25 by a through-hole conductor 35. The other end 25b of the coil conductor 25 constitutes the other end 3b of the coil 3.

[0041] Each of the ends 21a to 25a and 21b to 25b of the coil conductors 21 to 25 is formed in a circular shape when viewed from the first direction D1. When viewed from the first direction D1, the diameter of each of the ends 21a to 25a and 21b to 25b is larger than the line width of the coil conductors 21 to 25 (the line width of the portions of the coil conductors 21 to 25 other than the ends 21a to 25a and 21b to 25b). The enlarged ends 21a to 25a and 21b to 25b facilitate connection between the ends 21a to 25a and 21b to 25b and the through-hole conductors 31 to 36. The diameter of each of the ends 21a to 25a and 21b to 25b is equal to the diameter of the through-hole conductors 31 to 36.

[0042] The coil conductor 21 is provided on the magnetic layer 10d. The coil conductor 22 is provided on the magnetic layer 10f. The coil conductor 23 is provided on the magnetic layer 10h. The coil conductor 24 is provided on the magnetic layer 10j. The coil conductor 25 is provided on the magnetic layer 10l.

[0043] In this embodiment, the lengths in the first direction D1 of the multiple coil conductors 21 to 25 are equal to each other. The lengths in the first direction D1 of the multiple coil conductors 21 to 25 are equal to the thicknesses of the corresponding magnetic layers 10d, 10f, 10h, 10j, and 10l.

[0044] The through-hole conductor 31 is provided in the magnetic layer 10c. The through-hole conductor 32 is provided in the magnetic layer 10e. The through-hole conductor 33 is provided in the magnetic layer 10g. The through-hole conductor 34 is provided in the magnetic layer 10i. The through-hole conductor 35 is provided in the magnetic layer 10k. The through-hole conductor 36 is provided in the magnetic layer 10m. Each of the through-hole conductors 31 to 36 is provided to penetrate the corresponding magnetic layer 10c, 10e, 10g, 10i, 10k, and 10m in its thickness direction (first direction D1).

[0045] In this embodiment, the lengths in the first direction D1 of the through-hole conductors 31 to 36 are equal to each other and are equal to the thicknesses of the corresponding magnetic layers 10c, 10e, 10g, 10i, 10k, and 10m.

[0046] The first connecting conductor 8 connects one end 3a of the coil 3 and the first electrode portion 4a of the first external electrode 4. The first connecting conductor 8 extends in the second direction D2. The first connecting conductor 8 has a first end 8a and a second end 8b. The first end 8a is exposed from the end face 2a and is connected to the first electrode portion 4a. The first end 8a includes a connection surface 8c that contacts the first electrode portion 4a.

[0047] The second end 8b is connected to one end 3a of the coil 3 by a through-hole conductor 31. The second end 8b is formed in a circular shape when viewed from the first direction D1. When viewed from the first direction D1, the diameter of the second end 8b is larger than the line width of the first connecting conductor 8 other than the two end portions 8a, 8b. By enlarging the second end 8b in this manner, it becomes easier to connect the second end 8b to the through-hole conductor 31.

[0048] The second connecting conductor 9 connects the other end 3b of the coil 3 and the first electrode portion 5a of the second external electrode 5. The second connecting conductor 9 extends in the second direction D2. The second connecting conductor 9 has a first end 9a and a second end 9b. The first end 9a is exposed from the end surface 2b and is connected to the first electrode portion 5a. The first end 9a includes a connection surface 9c that contacts the first electrode portion 5a.

[0049] The second end 9b is connected to the other end 3b of the coil 3 by a through-hole conductor 36. The second end 9b is formed in a circular shape when viewed from the first direction D1. When viewed from the first direction D1, the diameter of the second end 9b is larger than the line width of the portion of the second connecting conductor 9 other than the two end portions 9a, 9b. By enlarging the second end 9b in this manner, it becomes easier to connect the second end 9b to the through-hole conductor 36.

[0050] As shown in Fig. 2, a magnetic layer 10e is arranged between the coil conductors 21 and 22 that are adjacent to each other in the first direction D1. A magnetic layer 10g is arranged between the coil conductors 22 and 23 that are adjacent to each other in the first direction D1. A magnetic layer 10i is arranged between the coil conductors 23 and 24 that are adjacent to each other in the first direction D1. A magnetic layer 10k is arranged between the coil conductors 24 and 25 that are adjacent to each other in the first direction D1. Each of the magnetic layers 10e, 10g, 10i, and 10k has a multilayer structure.

[0051] 4, the magnetic body layer 10k includes a first magnetic body layer 11 and a second magnetic body layer 12 stacked in the first direction D1. Although not shown, each of the magnetic body layers 10e, 10g, and 10i has a similar configuration to the magnetic body layer 10k and includes the first magnetic body layer 11 and the second magnetic body layer 12. Each of the magnetic body layers 10e, 10g, 10i, and 10k has a two-layer structure in which the first magnetic body layer 11 and the second magnetic body layer 12 are stacked. In this embodiment, in each of the magnetic body layers 10e, 10g, 10i, and 10k, the second magnetic body layer 12 is disposed closer to the main surface 2d than the first magnetic body layer 11; however, the first magnetic body layer 11 may be disposed closer to the main surface 2d than the second magnetic body layer 12. Which of the first magnetic layer 11 and the second magnetic layer 12 is disposed closer to the main surface 2d may differ for each of the magnetic layers 10e, 10g, 10i, and 10k.

[0052] The first magnetic layer 11 and the second magnetic layer 12 are provided with the same size as the element body 2 when viewed in the first direction D1. The thickness t1 of the first magnetic layer 11 (length in the first direction D1) is, for example, 1 μm or more and 20 μm or less. The thickness t2 of the second magnetic layer 12 (length in the first direction D1) is, for example, 1 μm or more and 20 μm or less. In this embodiment, the first magnetic layer 11 is thinner than the second magnetic layer 12.

[0053] 5, the soft magnetic metal particles M contained in the first magnetic layer 11 are soft magnetic metal particles M1. The soft magnetic metal particles M contained in the second magnetic layer 12 are soft magnetic metal particles M2. Between the coil conductors 24 and 25 adjacent to each other in the first direction D1, two or more soft magnetic metal particles M, each including one soft magnetic metal particle M1 and one soft magnetic metal particle M2, are arranged along the first direction D1. In FIG. 5, the resin present between the multiple soft magnetic metal particles M is not shown.

[0054] The average particle size of the soft magnetic metal particles M2 is larger than that of the soft magnetic metal particles M1. The average particle size of the soft magnetic metal particles M1 is, for example, 0.5 μm or more and 5 μm or less. The average particle size of the soft magnetic metal particles M2 is, for example, 1 μm or more and 10 μm or less. The average particle size of the soft magnetic metal particles M2 is, for example, 1.1 times or more and 20 times or less than the average particle size of the soft magnetic metal particles M1.

[0055] The average particle diameter of each of the soft magnetic metal particles M1 and M2 can be obtained, for example, as follows. A cross-sectional photograph of the laminated coil component 1 including the element body 2, the first external electrode 4, and the second external electrode 5 is obtained. The cross-sectional photograph is obtained, for example, by photographing a cross section of the laminated coil component 1 cut along a plane parallel to the pair of side surfaces 2e and 2f and spaced a predetermined distance from the pair of side surfaces 2e and 2f. In this case, the plane may be equidistant from the pair of side surfaces 2e and 2f. The obtained cross-sectional photograph is subjected to image processing using software. The boundaries of the soft magnetic metal particles M1 and M2 are identified through image processing, and the areas of the soft magnetic metal particles M1 and M2 are determined. From the determined areas of the soft magnetic metal particles M1 and M2, the particle diameters converted into circle-equivalent diameters are determined. Here, the particle diameters of 100 or more particles of each of the soft magnetic metal particles M1 and M2 are calculated, and a particle size distribution is determined. The particle diameter (d50) at 50% of the cumulative value in the determined particle size distribution is defined as the “average particle diameter.” There are no particular limitations on the particle shape of the soft magnetic metal particles M1 and M2.

[0056] A mixed region R, in which soft magnetic metal particles M with small particle diameters (i.e., soft magnetic metal particles M1) and soft magnetic metal particles M with large particle diameters (i.e., soft magnetic metal particles M2) are mixed, exists between the first magnetic layer 11 and the second magnetic layer 12. The first magnetic layer 11 and the second magnetic layer 12 are arranged to sandwich the mixed region R in the first direction D1. The thicknesses t1 and t2 described above do not include the thickness of the mixed region R.

[0057] The magnetic layers 10d, 10f, 10h, 10j, and 10l are disposed around the corresponding coil conductors 21 to 25 when viewed from the first direction D1, and constitute the same layer as the corresponding coil conductors 21 to 25. The corresponding coil conductors 21 to 25 are disposed in the magnetic layers 10d, 10f, 10h, 10j, and 10l so as to penetrate the magnetic layers 10d, 10f, 10h, 10j, and 10l in the thickness direction (first direction D1). The soft magnetic metal particles M contained in the magnetic layers 10d, 10f, 10h, 10j, and 10l are soft magnetic metal particles M3. The average particle diameter of the soft magnetic metal particles M3 is larger than the average particle diameter of the soft magnetic metal particles M1 and larger than the average particle diameter of the soft magnetic metal particles M2. The average particle diameter of the soft magnetic metal particles M3 is, for example, 5 μm or more and 50 μm or less. The average particle size of the soft magnetic metal particles M3 can be obtained, for example, in the same manner as the average particle sizes of the soft magnetic metal particles M1 and M2. There are no particular limitations on the particle shape of the soft magnetic metal particles M3.

[0058] In this embodiment, each of the magnetic layers 10d, 10f, 10h, 10j, and 10l has a single-layer structure, but may have a multilayer structure including multiple magnetic layers stacked in the first direction D1. Even in the case of a multilayer structure, the soft magnetic metal particles M included in the multiple magnetic layers of each of the magnetic layers 10d, 10f, 10h, 10j, and 10l are all soft magnetic metal particles M3.

[0059] The magnetic layers 10a, 10b, 10c, 10m, 10n, 10o, and 10p are arranged outside the coil 3 in the first direction D1. The magnetic layers 10a, 10b, and 10c are provided on one side (main surface 2c side) of the coil 3 in the first direction D1. The magnetic layers 10m, 10n, 10o, and 10p are provided on the other side (main surface 2d side) of the coil 3 in the first direction D1. The magnetic layers 10a, 10b, and 10c and the magnetic layers 10m, 10n, 10o, and 10p are arranged to sandwich the coil 3 in the first direction D1. The soft magnetic metal particles M contained in the magnetic layers 10a, 10b, 10c, 10m, 10n, 10o, and 10p are all soft magnetic metal particles M3.

[0060] Next, a method for manufacturing the laminated coil component 1 will be described.

[0061] A first slurry containing soft magnetic metal particles M1, a second slurry containing soft magnetic metal particles M2, and a third slurry containing soft magnetic metal particles M3 are prepared. Each slurry is obtained by mixing the soft magnetic metal particles M1, M2, and M3 with an insulating resin, a solvent, and the like.

[0062] The third slurry is applied to a substrate (such as a PET film) by screen printing or doctor blade, thereby forming green sheets that will become the magnetic layers 10a on the substrate. Green sheets that will become the magnetic layers 10o are also formed on the substrate in the same manner.

[0063] A conductor pattern that will become the first connecting conductors 8 is formed on the substrate by screen printing or plating. Next, a third slurry is applied to the substrate by screen printing, for example, so as to fill in the periphery of the conductor pattern. This forms green sheets that will become the multiple magnetic layers 10b on the substrate. The green sheets that will become the multiple magnetic layers 10c, 10d, 10f, 10h, 10j, 10l, 10m, and 10n are also formed by forming the corresponding conductor patterns on the substrate and then applying the third slurry to fill in the periphery.

[0064] A conductive pattern that will become the through-hole conductors 32 is formed on the substrate by screen printing or plating. Next, the second slurry and the first slurry are applied to the substrate in this order, for example, by screen printing, so as to fill in the periphery of the conductive pattern. This forms a green sheet that will become the multiple magnetic layers 10e on the substrate. The green sheets that will become the multiple magnetic layers 10g, 10i, and 10k are also formed by forming the corresponding conductive patterns on the substrate, and then applying the second slurry and the first slurry in this order to fill in the periphery.

[0065] Next, the green sheets that will become the multiple magnetic layers 10a to 10p are transferred and stacked in this order, each with its conductor pattern. The green sheets are pressed in the stacking direction to form a laminate. The green sheet laminate is then fired to form a laminate substrate. The laminate substrate is then cut into chips of a predetermined size using a cutting machine equipped with a rotary blade, forming individual laminates.

[0066] Next, the laminate is immersed in a resin liquid to impregnate the laminate with the resin, thereby forming the element body 2. Resin electrode layers that will become the first external electrodes 4 and the second external electrodes 5 are formed on both ends of the element body 2 by, for example, a dipping method. In this way, the laminated coil component 1 is formed.

[0067] As described above, in the laminated coil component 1 according to this embodiment, the first magnetic layer 11 and the second magnetic layer 12 are disposed between adjacent coil conductors among the coil conductors 21 to 25, i.e., between the coil conductors 21 and 22, between the coil conductors 22 and 23, between the coil conductors 23 and 24, and between the coil conductors 24 and 25. The average particle diameter of the soft magnetic metal particles M1 contained in the first magnetic layer 11 is different from the average particle diameter of the soft magnetic metal particles M2 contained in the second magnetic layer 12. Therefore, two or more soft magnetic metal particles M, including at least one soft magnetic metal particle M1 and one soft magnetic metal particle M2, are likely to be disposed along the first direction D1 between adjacent coil conductors among the coil conductors 21 to 25. This ensures a high withstand voltage between adjacent coil conductors compared to when a single magnetic layer is disposed. Furthermore, compared to when a single first magnetic layer 11 having a small average particle diameter is disposed, the magnetic permeability is improved, thereby increasing the L value of the coil 3.

[0068] The thickness t1 of the first magnetic layer 11 is greater than the thickness t2 of the second magnetic layer 12. This makes it possible to reliably ensure a withstand voltage between adjacent coil conductors.

[0069] Each of the magnetic layers 10d, 10f, 10h, 10j, and 10l is disposed around a corresponding one of the coil conductors 21 to 25 when viewed from the first direction D1, and constitutes the same layer as the corresponding coil conductor. The average particle diameter of the soft magnetic metal particles M3 contained in each of the magnetic layers 10d, 10f, 10h, 10j, and 10l is larger than the average particle diameter of the soft magnetic metal particles M1. Therefore, the L value of the coil 3 can be further increased compared to when the average particle diameter of the soft magnetic metal particles M3 is smaller than the average particle diameter of the soft magnetic metal particles M1. The average particle diameter of the soft magnetic metal particles M3 is larger than the average particle diameter of the soft magnetic metal particles M2. Therefore, the L value of the coil 3 can be further increased compared to when the average particle diameter of the soft magnetic metal particles M3 is smaller than the average particle diameter of the soft magnetic metal particles M2.

[0070] A mixed region R containing soft magnetic metal particles M1 with small particle diameters and soft magnetic metal particles M2 with large particle diameters exists between the first magnetic layer 11 and the second magnetic layer 12. Three layers, namely the first magnetic layer 11, the second magnetic layer 12, and the mixed region R, exist between adjacent coil conductors, so that the withstand voltage between adjacent coil conductors can be more reliably ensured.

[0071] Second Embodiment A laminated coil component 1A according to a second embodiment will be described with reference to Fig. 6 and Fig. 7. The first external electrodes 4 and the second external electrodes 5 are not shown in Fig. 7. As shown in Fig. 6 and Fig. 7, in the laminated coil component 1A, the first magnetic layers 11 and the second magnetic layers 12 overlap the coil 3 (i.e., the coil conductors 21 to 25) when viewed from the first direction D1, and have a line width w2 that is wider than the line width w1 of the coil 3 (i.e., the coil conductors 21 to 25). Here, the line width w1 is the line width of the coil conductors 21 to 25 other than the ends 21a to 25a and 21b to 25b when viewed from the first direction D1.

[0072] The first magnetic layer 11 and the second magnetic layer 12 have a rectangular frame shape with a line width w2 when viewed from the first direction D1. The first magnetic layer 11 and the second magnetic layer 12 have the same shape when viewed from the first direction D1. The first magnetic layer 11 and the second magnetic layer 12 are provided spaced apart from the pair of end faces 2a, 2b and the pair of side faces 2e, 2f.

[0073] The magnetic layer 10k further includes a third magnetic layer 13 that is provided around the first magnetic layer 11 and the second magnetic layer 12 and that forms the same layer as the first magnetic layer 11 and the second magnetic layer 12 when viewed from the first direction D1. The third magnetic layer 13 is provided both outside and inside the first magnetic layer 11 and the second magnetic layer 12 when viewed from the first direction D1. The soft magnetic metal particles M contained in the third magnetic layer 13 are soft magnetic metal particles M3. The average particle diameter of the soft magnetic metal particles M3 is larger than the average particle diameter of the soft magnetic metal particles M1. Therefore, in the laminated coil component 1A, the L value of the coil 3 can be further increased compared to a configuration in which the soft magnetic metal particles M contained in the third magnetic layer 13 are soft magnetic metal particles M1.

[0074] The average particle size of the soft magnetic metal particles M3 is larger than the average particle size of the soft magnetic metal particles M2. Therefore, in the laminated coil component 1A, the L value of the coil 3 can be further increased compared to the laminated coil component 1 in which the first magnetic layer 11 and the second magnetic layer 12 are provided on the entire surface.

[0075] In the laminated coil component 1A, the first magnetic layer 11 and the second magnetic layer 12 have a rectangular frame shape with a line width w2 when viewed from the first direction D1, but are not limited to this. For example, the first magnetic layer 11 and the second magnetic layer 12 may be provided with a line width w2 in a region overlapping both adjacent coil conductors when viewed from the first direction D1. In this case, the shapes of the first magnetic layer 11 and the second magnetic layer 12 differ depending on the magnetic layers 10e, 10g, 10i, and 10k. Compared to when the first magnetic layer 11 and the second magnetic layer 12 are provided in a rectangular frame shape, the region in which the soft magnetic metal particles M3 are provided is increased, thereby further increasing the L value of the coil 3.

[0076] (Third embodiment) A laminated coil component 1B according to a third embodiment will be described with reference to FIG. 8. As shown in FIG. 8, the laminated coil component 1B further includes a high resistance portion 40 having an electrical resistivity higher than that of each of the first magnetic layer 11 and the second magnetic layer 12. The high resistance portion 40, together with the first magnetic layer 11 and the second magnetic layer 12, is disposed between adjacent coil conductors. The high resistance portion 40 is provided so as to be in contact with one of two adjacent coil conductors. In the magnetic layer 10k, the high resistance portion 40 is provided so as to be in contact with the coil conductor 24, for example, but may also be provided so as to be in contact with the coil conductor 25.

[0077] Although not shown in a plan view, the high resistance portion 40 overlaps the coil 3 (i.e., the coil conductors 21 to 25) when viewed from the first direction D1, and has a line width w3 that is wider than the line width w1 of the coil 3 (i.e., the coil conductors 21 to 25). When viewed from the first direction D1, the high resistance portion 40 has a rectangular frame shape with the line width w3. The high resistance portion 40 is spaced apart from the pair of end faces 2a, 2b and the pair of side faces 2e, 2f. The thickness of the high resistance portion 40 is, for example, thinner than the thickness t1 of the first magnetic layer 11 and the thickness t2 of the second magnetic layer 12. The thickness of the high resistance portion 40 (the length in the first direction D1) is, for example, 0.1 μm or more and 5 μm or less.

[0078] The high resistance portion 40 is made of, for example, ZrO2. The high resistance portion 40 may also be a void. When the high resistance portion 40 is a void, a resin that disappears when fired is placed at the intended position for forming the high resistance portion 40, and a laminate of green sheets is formed. By firing the laminate of green sheets, the resin disappears and the void is formed.

[0079] The laminated coil component 1B includes the high-resistance portions 40, which can reliably ensure the withstand voltage between the coil conductors. In the laminated coil component 1B, the high-resistance portions 40 have a rectangular frame shape with a line width w3 when viewed from the first direction D1, but this is not limited to this. For example, the high-resistance portions 40 may be provided with a line width w3 in a region that overlaps with both adjacent coil conductors when viewed from the first direction D1. In this case, the shape of the high-resistance portions 40 differs depending on the magnetic layers 10e, 10g, 10i, and 10k. Compared to when the high-resistance portions 40 are provided in a rectangular frame shape, the region in which the soft magnetic metal particles M are provided is increased, thereby further increasing the L value of the coil 3.

[0080] (Fourth embodiment) A laminated coil component 1C according to a fourth embodiment will be described with reference to Fig. 9. As shown in Fig. 9, in the laminated coil component 1C according to the fourth embodiment, similar to the laminated coil component 1A, each of the first magnetic layer 11 and the second magnetic layer 12 overlaps with the coil 3 when viewed from the first direction D1, and has a line width w2 wider than the line width w1 of the coil 3. In addition, similar to the laminated coil component 1B, the laminated coil component 1C further includes a high resistance portion 40 having an electrical resistivity higher than the electrical resistivity of each of the first magnetic layer 11 and the second magnetic layer 12. The high resistance portion 40 overlaps with the coil 3 when viewed from the first direction D1, and has a line width w3 wider than the line width w1 of the coil 3.

[0081] In the present embodiment, the line width w3 is wider than the line width w2, but the line width w3 may be equal to or narrower than the line width w2. In the magnetic layer 10k, the high resistance portion 40 is provided so as to be in contact with the coil conductor 25, for example, but may also be provided so as to be in contact with the coil conductor 24. The first magnetic layer 11, the second magnetic layer 12, and the high resistance portion 40 have, for example, a rectangular frame shape when viewed from the first direction D1. The laminated coil component 1C includes the high resistance portion 40, so that the withstand voltage between the coil conductors can be reliably ensured.

[0082] When viewed from the first direction D1, a third magnetic layer 13 is provided around the first magnetic layer 11, the second magnetic layer 12, and the high resistance section 40. The third magnetic layer 13 forms the same layer as the first magnetic layer 11, the second magnetic layer 12, and the high resistance section 40. The average particle diameter of the soft magnetic metal particles M3 contained in the third magnetic layer 13 is larger than the average particle diameters of the soft magnetic metal particles M1 and the soft magnetic metal particles M2. Therefore, in the laminated coil component 1C, the L value of the coil 3 can be further increased.

[0083] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0084] The second end 8b of the first connecting conductor 8, the second end 9b of the second connecting conductor 9, and the ends 21a to 25a, 21b to 25b of the coil conductors 21 to 25 are enlarged when viewed from the first direction D1, but they do not have to be enlarged.

[0085] The first connecting conductor 8 is exposed at the end face 2a, and the second connecting conductor 9 is exposed at the end face 2b, but the first connecting conductor 8 and the second connecting conductor 9 may also be exposed at the main face 2d. In this case, the first external electrode 4 and the second external electrode 5 may be bottom electrodes provided on the main face 2d. The stacking direction of the magnetic layers may be the second direction D2 or the third direction D3.

[0086] The above-described embodiments and modifications may be combined as appropriate. [Explanation of symbols]

[0087] 1, 1A, 1B, 1C... multilayer coil component, 2... element body, 3... coil, 10a to 10p... magnetic layer, 11... first magnetic layer, 12... second magnetic layer, 13... third magnetic layer, 21 to 25... coil conductor, 40... high resistance portion, M, M1, M2, M3... soft magnetic metal particles.

Claims

1. an element body formed by stacking a plurality of magnetic layers containing soft magnetic metal particles in a first direction; a coil disposed within the element body, the coil has a plurality of coil conductors electrically connected to each other; the plurality of magnetic layers include a first magnetic layer and a second magnetic layer stacked between two coil conductors adjacent to each other in the first direction, the average particle size of the soft magnetic metal particles contained in the second magnetic layer is larger than the average particle size of the soft magnetic metal particles contained in the first magnetic layer, The first magnetic layer is thicker than the second magnetic layer. Multilayer coil components.

2. an element body formed by stacking a plurality of magnetic layers containing soft magnetic metal particles in a first direction; a coil disposed within the element body, the coil has a plurality of coil conductors electrically connected to each other; the plurality of magnetic layers include a first magnetic layer and a second magnetic layer stacked between two coil conductors adjacent to each other in the first direction, the average particle size of the soft magnetic metal particles contained in the second magnetic layer is larger than the average particle size of the soft magnetic metal particles contained in the first magnetic layer, each of the first magnetic layer and the second magnetic layer overlaps with the plurality of coil conductors when viewed from the first direction and has a line width wider than a line width of the plurality of coil conductors; the plurality of magnetic layers further include a third magnetic layer that is provided around the first magnetic layer and the second magnetic layer when viewed from the first direction and that forms the same layer as the first magnetic layer and the second magnetic layer; the average particle size of the soft magnetic metal particles contained in the third magnetic layer is larger than the average particle size of the soft magnetic metal particles contained in the first magnetic layer; Multilayer coil components.

3. an element body formed by stacking a plurality of magnetic layers containing soft magnetic metal particles in a first direction; a coil disposed within the element body, the coil has a plurality of coil conductors electrically connected to each other; the plurality of magnetic layers include a first magnetic layer and a second magnetic layer stacked between two coil conductors adjacent to each other in the first direction, the average particle size of the soft magnetic metal particles contained in the second magnetic layer is larger than the average particle size of the soft magnetic metal particles contained in the first magnetic layer, a high resistance portion disposed between the two coil conductors and having an electrical resistivity higher than that of the first magnetic layer and the second magnetic layer, the high resistance portion overlaps the plurality of coil conductors when viewed from the first direction and has a line width wider than a line width of the plurality of coil conductors. Multilayer coil components.

4. the high resistance portion is provided so as to be in contact with one of the two coil conductors. The laminated coil component according to claim 3 .

5. the first magnetic layer is thinner than the second magnetic layer; The laminated coil component according to any one of claims 1 to 4.

6. the plurality of magnetic layers further include a plurality of third magnetic layers that are provided around the corresponding coil conductors when viewed from the first direction and that constitute the same layer as the corresponding coil conductors, the average particle size of the soft magnetic metal particles contained in the third magnetic layers is larger than the average particle size of the soft magnetic metal particles contained in the first magnetic layer; The laminated coil component according to any one of claims 1 to 4.

7. the average particle size of the soft magnetic metal particles contained in the third magnetic layer is larger than the average particle size of the soft magnetic metal particles contained in the second magnetic layer; The laminated coil component according to claim 2 or 6.

8. Between the first magnetic layer and the second magnetic layer, there is a mixed region in which soft magnetic metal particles having small particle sizes and soft magnetic metal particles having large particle sizes are mixed. The laminated coil component according to any one of claims 1 to 7.

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