Coil parts

Abstract

To provide a coil component capable of improving bonding strength between an internal conductor and an external electrode.SOLUTION: A coil component 1 includes: an element body 2; a coil 3 disposed in the element body 2 and having a plurality of coil conductors 21 to 25 electrically connected to each other; a first external electrode 4 disposed in the element body 2; and a first connection conductor 8 for connecting the coil 3 and the first external electrode 4. The first connection conductor 8 is exposed from an end surface 2a of the element body 2 and has a shape extending outward over an entire circumference in a first end portion 8a connected to the first external electrodes 4.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 describes a laminated inductor that includes a magnetic part formed by stacking multiple magnetic layers, 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] An object of the present disclosure is to provide a coil component that can improve the bonding strength between an internal conductor and an external electrode. [Means for solving the problem]

[0005] A coil component according to one aspect of the present disclosure comprises a base body, a coil having a plurality of coil conductors disposed within the base body and electrically connected to each other, an external electrode disposed on the base body, and a connecting conductor connecting the coil and the external electrode, the connecting conductor being exposed from the outer surface of the base body and having a shape that extends outward around the entire circumference at the end connected to the external electrode.

[0006] In a coil component according to an embodiment of the present disclosure, the connecting conductor has a shape that expands outward over the entire circumference at the end portion, thereby increasing the bonding area between the connecting conductor and the external electrode, thereby improving the bonding strength between the connecting conductor, which is an internal conductor, and the external electrode.

[0007] A coil component according to another aspect of the present disclosure comprises a base body, a coil having a plurality of coil conductors disposed within the base body and electrically connected to each other, an external electrode disposed on the base body, and a connecting conductor connecting the coil and the external electrode, the connecting conductor having an end exposed from the outer surface of the base body and connected to the external electrode, the end having a shape in which the cross-sectional area gradually widens as it approaches the external electrode.

[0008] In a coil component according to another aspect of the present disclosure, the end of the connecting conductor has a shape in which the cross-sectional area gradually increases toward the external electrode, thereby increasing the bonding area between the connecting conductor, which is an internal conductor, and the external electrode, thereby improving the bonding strength between the connecting conductor, which is an internal conductor, and the external electrode.

[0009] The element body may have a plurality of element body layers stacked in a first direction, and the element body layers may include a plurality of soft magnetic metal particles.

[0010] A coil component according to yet another aspect of the present disclosure comprises a coil having a plurality of coil conductors arranged within a base body and electrically connected to each other, an external electrode arranged on the base body, and a connecting conductor connecting the coil and the external electrode, wherein the base body has a plurality of base body layers stacked in a first direction, the base body layers including a plurality of soft magnetic metal particles, the connecting conductor having an end exposed from the outer surface of the base body and connected to the external electrode, the length of the end in the first direction being longer than the length of the coil conductor in the first direction, and two or more soft magnetic metal particles are arranged along the first direction between adjacent coil conductors and connecting conductors in the first direction.

[0011] In a coil component according to yet another aspect of the present disclosure, the length of the end of the connection conductor in the first direction is longer than the length of the coil conductor in the first direction. This increases the bonding area between the connection conductor and the external electrode. This improves the bonding strength between the connection conductor, which is an internal conductor, and the external electrode. Furthermore, two or more soft magnetic metal particles are arranged along the first direction between the connection conductor and the coil conductor. This improves the interlayer voltage resistance between the connection conductor and the coil conductor.

[0012] When viewed from the first direction, the width of the end portion may be larger than the width of the coil conductor, which reliably increases the bonding area between the connecting conductor and the external electrode, thereby reliably improving the bonding strength between the connecting conductor and the external electrode.

[0013] The external electrodes may be conductive resin layers, which have a lower density of metal particles than sintered metal layers, thereby reducing stray capacitance between the external electrodes and the coil conductors.

[0014] The length of the end of the connecting conductor in the longitudinal direction may be equal to or less than half the distance between the coil conductor and the external electrode, in which case the withstand voltage between the end and the coil conductor can be ensured.

[0015] The outer surface of the end portion may be curved so as to be recessed inward of the connecting conductor in a cross section perpendicular to the outer surface where the end portion is exposed, which makes it easier to ensure a withstand voltage between the end portion and the coil conductor.

[0016] The distance between the coil conductor and the external electrode may be longer than the distance between adjacent coil conductors, in which case the voltage applied between the coil conductor and the external electrode is greater than the voltage applied between adjacent coil conductors, making it easier to ensure the withstand voltage of the coil.

[0017] The connecting conductor may be a plated conductor, which can increase the density of the connecting conductor compared to a sintered metal conductor, thereby further increasing the bonding area between the connecting conductor and the external electrode. [Effects of the Invention]

[0018] According to one aspect of the present invention, the bonding strength between the internal conductor and the external electrode can be improved. [Brief explanation of the drawings]

[0019] [Figure 1]FIG. 1 is a perspective view showing a coil component according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the coil component shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the 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. DETAILED DESCRIPTION OF THE INVENTION

[0020] 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.

[0021] As shown in FIG. 1, a coil component 1 according to the 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 .

[0022] 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.

[0023] The pair of end faces 2a, 2b extend in a first direction D1 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 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 coil device 1 is mounted on the other electronic device.

[0024] As shown in FIG. 2, the element body 2 has a plurality of element layers 10a to 10p stacked in a first direction D1. The coil component 1 is a laminated coil component. The element layers 10a to 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 plurality of element layers 10a to 10p are integrated to the extent that the boundaries between the layers are not visible. Although FIG. 2 shows each of the element layers 10a to 10p as one layer, multiple element layers 10a and multiple element layers 10o are stacked. The main surface 2c is formed by the main surface of the element layer 10a located at the end of the stack. The main surface 2d is formed by the main surface of the element layer 10p.

[0025] The thicknesses of the element layers 10a-10p (length in the first direction D1) are, for example, 1 μm or more and 100 μm or less. While the element layers 10a-10p are shown as having the same thickness in FIG. 2, the element 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 element layers 10c, 10e, 10g, 10i, 10k, 10m, and 10o, on which through-hole conductors 31-36 (described later) are provided. In this embodiment, the element 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 thicknesses of the element layers 10c, 10e, 10g, 10i, 10k, 10m, and 10o are equal to one another, for example, not less than 1 μm and not more than 15 μm.

[0026] Each of the base layers 10a-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.

[0027] In the element 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 element 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, not less than 5 nm and not more than 60 nm. The oxide film may be composed of one or more layers.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 have a rectangular shape 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.

[0037] 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.

[0038] As shown in FIG. 2, the first electrode portion 6 and the second electrode portion 7 are arranged to sandwich the element layer 10p in the second direction D2. The first electrode portion 6, the second electrode portion 7, and the element 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 include a conductive material. The conductive material is, for example, Ag, Pd, Cu, Al, or Ni.

[0039] As shown in FIGS. 2 and 3, the coil device 1 further includes a coil 3, a first connecting conductor 8, and a second connecting conductor 9.

[0040] 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.

[0041] 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, plated conductors. 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.

[0042] 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.

[0043] Each of the ends 21a to 25a and 21b to 25b of the coil conductors 21 to 25 is circular 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 W1 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 line width W1 is, for example, 5 μm or more and 300 μm or less. 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, for example, 10 μm or more and 300 μm or less.

[0044] Coil conductor 21 is provided in element layer 10d. Coil conductor 22 is provided in element layer 10f. Coil conductor 23 is provided in element layer 10h. Coil conductor 24 is provided in element layer 10j. Coil conductor 25 is provided in element layer 10l. Each of coil conductors 21 to 25 is provided to penetrate corresponding element layer 10d, 10f, 10h, 10j, 10l in its thickness direction (first direction D1).

[0045] In this embodiment, the lengths L1 in the first direction D1 of the multiple coil conductors 21 to 25 are equal to each other and are equal to the thicknesses of the corresponding element layers 10d, 10f, 10h, 10j, and 10l.

[0046] The through-hole conductor 31 is provided in the element body layer 10c. The through-hole conductor 32 is provided in the element body layer 10e. The through-hole conductor 33 is provided in the element body layer 10g. The through-hole conductor 34 is provided in the element body layer 10i. The through-hole conductor 35 is provided in the element body layer 10k. The through-hole conductor 36 is provided in the element body layer 10m. Each of the through-hole conductors 31 to 36 is provided to penetrate the corresponding element body layer 10c, 10e, 10g, 10i, 10k, and 10m in its thickness direction (first direction D1).

[0047] In this embodiment, the lengths L2 in the first direction D1 of the multiple through-hole conductors 31 to 36 are equal to one another. The lengths L2 in the first direction D1 of the multiple through-hole conductors 31 to 36 are equal to the thicknesses of the corresponding element layers 10c, 10e, 10g, 10i, 10k, and 10m. The length L2 is equal to the spacing between adjacent coil conductors 21 to 25, the spacing between the first connecting conductor 8 and the coil conductor 21, and the spacing between the second connecting conductor 9 and the coil conductor 25. The length L1 is longer than the length L2.

[0048] 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.

[0049] 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 its end portions 8a, 8b. By expanding the second end 8b in this manner, it becomes easier to connect the second end 8b to the through-hole conductor 31. When viewed from the first direction D1, the line width of the first connecting conductor 8 other than its end portions 8a, 8b is equal to the line width W1 of the coil conductors 21-25.

[0050] 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.

[0051] 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 second connecting conductor 9 other than its end portions 9a, 9b. By expanding the second end 9b in this manner, it becomes easier to connect the second end 9b to the through-hole conductor 36. When viewed from the first direction D1, the line width of the second connecting conductor 9 other than its end portions 9a, 9b is equal to the line width W1 of the coil conductors 21-25.

[0052] As shown in FIGS. 2 to 4, the first end 8a of the first connecting conductor 8 has a shape in which the cross-sectional area of ​​the first end 8a (the area of ​​a cross section parallel to the end face 2a or the area of ​​a cross section perpendicular to the second direction D2, which is the length direction of the first connecting conductor 8) gradually increases toward the first electrode portion 4a. The first connecting conductor 8 has a shape that expands outward over the entire circumference at the first end 8a. The first end 8a has a tapered shape that gradually expands outward over the entire circumference toward the first electrode portion 4a. The outer surface 8d (see FIG. 5) of the first end 8a has a tapered shape in all cross sections perpendicular to the end face 2a. The outer surface 8d is curved inward of the first connecting conductor 8 in a cross section perpendicular to the end face 2a, forming an R-shape. The first end 8a has a tapered shape over the entire second direction D2.

[0053] The length (maximum length) L3 of the first end 8a in the first direction D1 is longer than the length L1 of the coil conductors 21 to 25 in the first direction D1. The length L3 is, for example, not less than 5 μm and not more than 150 μm. When viewed from the first direction D1, the line width W2 of the first end 8a (the maximum length of the first end 8a in the third direction D3) is larger than the line width W1 of the coil conductors 21 to 25. The line width W2 is, for example, not less than 10 μm and not more than 400 μm.

[0054] The length L4 of the first end 8a of the first connecting conductor 8 in the longitudinal direction (second direction D2) is equal to or less than half the separation distance L5 between the coil conductors 21 to 25 and the first external electrode 4. The first end 8a does not overlap the coil conductors 21 to 25 when viewed from the first direction D1. The length L4 is, for example, equal to the radius of curvature of the outer surface 8d in a cross section perpendicular to the end face 2a. The length L4 is, for example, not less than 5 μm and not more than 30 μm. The separation distance L5 is, for example, not less than 30 μm and not more than 150 μm.

[0055] Length L2 is shorter than separation distance L5. As described above, length L2 is the length of the multiple through-hole conductors 31-36 in the first direction D1, and is equivalent to the thickness of element body layers 10c, 10e, 10g, 10i, 10k, and 10m. Therefore, length L2 is equivalent to the separation distance between any two adjacent internal conductors among the multiple coil conductors 21-25, first connecting conductor 8, and second connecting conductor 9.

[0056] Although a perspective view of the second connecting conductor 9 is omitted, the first end 9a of the second connecting conductor 9 has the same shape as the first end 8a of the first connecting conductor 8. The first end 9a has a shape in which the cross-sectional area of ​​the first end 9a (the area of ​​a cross section parallel to the end face 2b or the area of ​​a cross section perpendicular to the second direction D2, which is the length direction of the second connecting conductor 9) gradually increases toward the first electrode portion 5a. The second connecting conductor 9 has a shape that expands outward over the entire circumference at the first end 9a. The first end 9a has a tapered shape that gradually expands outward over the entire circumference toward the first electrode portion 5a. The outer surface of the first end 9a has a tapered shape in all cross sections perpendicular to the end face 2b. The outer surface of the first end 9a is curved inward of the second connecting conductor 9 in a cross section perpendicular to the end face 2b, forming an R-shape. The first end 9a has a tapered shape over the entire second direction D2.

[0057] The length (maximum length) L6 of the first end 9a in the first direction D1 is longer than the length L1. The length L6 is equivalent to the length L3. When viewed from the first direction D1, the line width W3 of the first end 9a (the maximum length of the first end 9a in the third direction D3) is greater than the line width W1 of the coil conductors 21 to 25. The length L7 of the first end 9a in the length direction (second direction D2) of the second connecting conductor 9 is equal to or less than half the separation distance L8 between the coil conductors 21 to 25 and the second external electrode 5. The length L7 is equivalent to the length L4. The separation distance L8 is equivalent to the separation distance L5. When viewed from the first direction D1, the first end 9a does not overlap with the coil conductors 21 to 25. The length L7 is equivalent to, for example, the radius of curvature of the outer surface of the first end 9a in a cross section perpendicular to the end face 2b.

[0058] As shown in Fig. 5, two or more soft magnetic metal particles M are arranged along the first direction D1 between the coil conductor 21 and the first connecting conductor 8 that are adjacent in the first direction D1. In Fig. 5, the hatching of the resin present between the soft magnetic metal particles M is omitted. Although a partial enlarged view of the second connecting conductor 9 is not shown, two or more soft magnetic metal particles M are also arranged along the first direction D1 between the coil conductor 25 and the second connecting conductor 9 that are adjacent in the first direction D1.

[0059] Next, a method for manufacturing the coil device 1 will be described.

[0060] A slurry is prepared by mixing soft magnetic metal particles M, an insulating resin, a solvent, etc. The prepared slurry is applied to a substrate (e.g., a PET film) by, for example, screen printing or doctor blade, to form green sheets that will become the plurality of element layers 10a on the substrate. Green sheets that will become the plurality of element layers 10o are also formed on the substrate in the same manner.

[0061] A conductor pattern that will become the first connecting conductors 8 is formed on the substrate by screen printing or plating. Next, a slurry is applied to the substrate by, for example, screen printing so as to fill in the periphery of the conductor pattern. In this way, green sheets that will become the multiple element layers 10b are formed on the substrate. After the corresponding conductor patterns are formed on the substrate, the green sheets that will become the multiple element layers 10c to 10n, 10p are also formed so as to fill in the periphery of the conductor patterns.

[0062] Next, the green sheets that will become the multiple element layers 10a-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.

[0063] In the above-described step of forming the conductor patterns, the conductor patterns that will become the first connecting conductors 8 and the second connecting conductors 9 are formed so as to overlap the portions that will become the cutting margins in the step of cutting the laminate substrate. For example, one of the adjacent conductor patterns may be inverted, so that the conductor patterns that will become the first connecting conductors 8 are continuous through the portions that will become the cutting margins, and the conductor patterns that will become the second connecting conductors 9 are continuous through the portions that will become the cutting margins. The conductor in the cutting margins is removed with a rotating blade, so that the first end portions 8a and the first end portions 9a can be formed into the desired shapes. The shapes of the first end portions 8a and the first end portions 9a are adjusted as appropriate depending on cutting conditions such as the materials of the element body 2 and the conductors and the rotational speed of the rotating blade.

[0064] 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 electrode 4 and the second external electrode 5 are formed on both ends of the element body 2 by, for example, a dipping method. In this way, the coil component 1 is formed.

[0065] As described above, in the coil component 1 according to this embodiment, the first connecting conductor 8 has a shape that spreads outward over the entire circumference at the first end portion 8a. This increases the bonding area between the first connecting conductor 8 and the first external electrode 4. This can improve the bonding strength between the first connecting conductor 8 and the first external electrode 4. The second connecting conductor 9 has a shape that spreads outward over the entire circumference at the first end portion 9a. This increases the bonding area between the second connecting conductor 9 and the second external electrode 5. This can improve the bonding strength between the second connecting conductor 9 and the second external electrode 5.

[0066] The first end 8a has a shape in which the cross-sectional area gradually increases toward the first external electrode 4. This increases the bonding area between the first connecting conductor 8 and the first external electrode 4. This improves the bonding strength between the first connecting conductor 8 and the first external electrode 4. The first end 9a has a shape in which the cross-sectional area gradually increases toward the second external electrode 5. This increases the bonding area between the second connecting conductor 9 and the second external electrode 5. This improves the bonding strength between the second connecting conductor 9 and the second external electrode 5.

[0067] The element body 2 contains a plurality of soft magnetic metal particles M.

[0068] The length L3 of the first end 8a in the first direction D1 is longer than the length L1 of the coil conductors 21 to 25 in the first direction D1. This increases the bonding area between the first connecting conductor 8 and the first external electrode 4. This improves the bonding strength between the first connecting conductor 8 and the first external electrode 4. Two or more soft magnetic metal particles M are arranged along the first direction D1 between the first connecting conductor 8 and the coil conductor 21. This improves the interlayer withstand voltage between the first connecting conductor 8 and the coil conductor 21. The length L6 of the first end 9a in the first direction D1 is longer than the length L1. This increases the bonding area between the second connecting conductor 9 and the second external electrode 5. This improves the bonding strength between the second connecting conductor 9 and the second external electrode 5. Two or more soft magnetic metal particles M are arranged along the first direction D1 between the second connecting conductor 9 and the coil conductor 25. This improves the interlayer withstand voltage between the second connecting conductor 9 and the coil conductor 26.

[0069] When viewed from the first direction D1, the line width W2 of the first end 8a is larger than the line width W1 of the coil conductors 21 to 25. This reliably increases the bonding area between the first connecting conductor 8 and the first external electrode 4. This reliably improves the bonding strength between the first connecting conductor 8 and the first external electrode 4. When viewed from the first direction D1, the line width W3 of the first end 9a is larger than the line width W1 of the coil conductors 21 to 25. This reliably increases the bonding area between the second connecting conductor 9 and the second external electrode 5. This reliably improves the bonding strength between the second connecting conductor 9 and the second external electrode 5.

[0070] The first external electrode 4 and the second external electrode 5 are conductive resin layers. Therefore, the density of metal particles in the first external electrode 4 and the second external electrode 5 is lower than in a configuration in which the first external electrode 4 and the second external electrode 5 are sintered metal layers. This makes it possible to suppress stray capacitance between the first external electrode 4 and the second external electrode 5 and the coil conductors 21 to 25.

[0071] The length L4 of the first end 8a is equal to or less than half the distance L5 between the coil conductor 21 and the first external electrode 4. This ensures a sufficient withstand voltage between the first end 8a and the coil conductor 21. The length L7 of the first end 9a is equal to or less than half the distance L8 between the coil conductor 25 and the second external electrode 5. This ensures a sufficient withstand voltage between the first end 9a and the coil conductor 25.

[0072] The outer surface 8d of the first end 8a is curved so as to be recessed inward of the first connecting conductor 8 in a cross section perpendicular to the end face 2a. This makes it easy to ensure a withstand voltage between the first end 8a and the coil conductor 21. The outer surface of the first end 9a is curved so as to be recessed inward of the second connecting conductor 9 in a cross section perpendicular to the end face 2b. This makes it easy to ensure a withstand voltage between the first end 9a and the coil conductor 25.

[0073] The distance between adjacent coil conductors 21-25 is equal to length L2. The distance L5 between the coil conductors 21-25 and the first external electrode 4 is longer than length L2. The voltage applied between the coil conductors 22-25 and the first external electrode 4 is greater than the voltage applied between adjacent coil conductors 21-25. Because the distance L5 is longer than length L2, it is easy to ensure the withstand voltage of the coil 3. The distance L8 between the coil conductors 21-25 and the second external electrode 5 is longer than length L2. The voltage applied between the coil conductors 21-24 and the second external electrode 5 is greater than the voltage applied between adjacent coil conductors 21-25. Because the distance L8 is longer than length L2, it is easy to ensure the withstand voltage of the coil 3.

[0074] The first connecting conductor 8 and the second connecting conductor 9 may be plated conductors. In the case of plated conductors, the density of the first connecting conductor 8 and the second connecting conductor 9 can be increased compared to when the first connecting conductor 8 and the second connecting conductor 9 are sintered metal conductors. This allows the bonding area between the first connecting conductor 8 and the first external electrode 4 to be further increased. Also, the bonding area between the second connecting conductor 9 and the second external electrode 5 to be further increased. The coil conductors 21 to 25 may also be plated conductors. In the case of plated conductors, for example, the density of the conductor can be increased and the electrical resistivity of the conductor can be reduced. This allows the characteristics of the coil 3 to be improved.

[0075] 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.

[0076] The element body 2 does not necessarily need to be composed of soft magnetic metal particles, and may be composed of ferrite (for example, Ni-Cu-Zn ferrite, Ni-Cu-Zn-Mg ferrite, or Cu-Zn ferrite), a dielectric material, etc. The coil conductors 21 to 25, the through-hole conductors 31 to 36, the first connecting conductor 8, the second connecting conductor 9, the first electrode portion 6, and the second electrode portion 7 may be sintered metal conductors.

[0077] 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. In this case, the first connecting conductor 8, the second connecting conductor 9, and the coil conductors 21 to 25, including their ends, are formed to have a line width W1.

[0078] The first connecting conductor 8 is arranged on a different element body layer from the coil conductor 21, but may be arranged on the same element body layer. In this case, the first connecting conductor 8 and the coil conductor 21 are directly connected to each other so as to be continuous within the same element body layer, without the through-hole conductor 31 interposed therebetween. The second connecting conductor 9 is arranged on a different element body layer from the coil conductor 25, but may be arranged on the same element body layer. In this case, the second connecting conductor 9 and the coil conductor 25 are directly connected to each other so as to be continuous within the same element body layer, without the through-hole conductor 36 interposed therebetween.

[0079] 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 element layers may be the second direction D2 or the third direction D3.

[0080] The first end portion 8a and the first end portion 9a may have different shapes. At least one of the first end portion 8a and the first end portion 9a may have a shape that widens outward over the entire periphery toward the first external electrode 4 and the second external electrode 5. [Explanation of symbols]

[0081] 1...coil component, 2...element body, 3...coil, 4...first external electrode, 5...second external electrode, 8...first connecting conductor, 8a...first end, 8d...outer surface, 9...second connecting conductor, 9a...first end, 10a to 10p...element body layer, 21 to 25...coil conductor, M...soft magnetic metal particle.

Claims

1. The base body and a coil having a plurality of coil conductors disposed within the element body and electrically connected to one another, the plurality of coil conductors being stacked so that at least a portion of the coil conductors overlap one another when viewed from the stacking direction; an external electrode disposed on the element body; a connecting conductor connecting the coil and the external electrode, the connecting conductor is exposed from the outer surface of the element body, and has a shape that spreads outward over the entire periphery at the end connected to the external electrode; the external electrode and the connecting conductor are made of different materials; Coil parts.

2. The base body and a coil having a plurality of coil conductors disposed within the element body and electrically connected to one another, the plurality of coil conductors being stacked so that at least a portion of the coil conductors overlap one another when viewed from the stacking direction; an external electrode disposed on the element body; a connecting conductor connecting the coil and the external electrode, the connecting conductor has an end exposed from the outer surface of the element body and connected to the external electrode, the entire region of the end portion has a shape in which the cross-sectional area increases uniformly and monotonically toward the external electrode; the external electrode and the connecting conductor are made of different materials; Coil parts.

3. the element body has a plurality of element body layers stacked in a first direction, the base layer includes a plurality of soft magnetic metal particles; The coil component according to claim 1 or 2.

4. The base body and a coil having a plurality of coil conductors disposed within the element body and electrically connected to one another, the plurality of coil conductors being stacked so that at least a portion of the coil conductors overlap one another when viewed from the stacking direction; an external electrode disposed on the element body; a connecting conductor connecting the coil and the external electrode, the element body has a plurality of element body layers stacked in a first direction, the element layer includes a plurality of soft magnetic metal particles, the connecting conductor is exposed from the outer surface of the element body, and has a shape that spreads outward over the entire periphery at the end connected to the external electrode; a length of the end portion in the first direction is longer than a length of the coil conductor in the first direction; Two or more of the soft magnetic metal particles are arranged along the first direction between the coil conductor and the connection conductor adjacent to each other in the first direction. Coil parts.

5. When viewed from the first direction, the line width of the end portion is larger than the line width of the coil conductor. The coil component according to claim 3 or 4.

6. The external electrodes are conductive resin layers. The coil component according to any one of claims 1 to 5.

7. the length of the end of the connecting conductor in the longitudinal direction is equal to or less than half the distance between the coil conductor and the external electrode; The coil component according to any one of claims 1 to 6.

8. an outer surface of the end portion is curved so as to be recessed inward of the connection conductor in a cross section perpendicular to the outer surface where the end portion is exposed; The coil component according to any one of claims 1 to 7.

9. a distance between the coil conductor and the external electrode is longer than a distance between adjacent coil conductors; The coil component according to any one of claims 1 to 8.

10. The connecting conductor is a plated conductor. The coil component according to any one of claims 1 to 9.

Images