Coil component

Abstract

A coil component (1) is provided with: an element body (2) containing soft magnetic metal particles (P); a coil (5) disposed within the element body (2); and an external electrode (3) which is embedded in the element body (2) so as to be exposed only from the main surface (2d) of the element body (2), and which is connected to the coil (5). The external electrode (3) includes: a first electrode portion (21) having an exposed surface (21a) exposed from the main surface (2d); and a second electrode portion (22) that protrudes from the first electrode portion (21) into the element body (2) and is separated from the coil (5). The entirety of the second electrode portion (22) is provided inside the element body (2).

Description

Technical Field

[0001] The present disclosure relates to coil components. Background Art

[0002] There is known a coil component including an element body, a coil arranged in the element body, and an external electrode provided only on a mounting surface of the element body (for example, see International Publication No. 2011 / 135936). Summary of the Invention

[0003] In the coil component described above, since the external electrodes are provided only on the mounting surface of the element body, the external electrodes are more likely to be separated from the element body than in a configuration in which the external electrodes are provided over multiple surfaces of the element body.

[0004] An object of the present disclosure is to provide a coil component capable of suppressing separation of an external electrode.

[0005] (1) A coil component according to one embodiment of the present invention comprises: a body containing soft magnetic metal particles; a coil arranged in the body; and a first external electrode embedded in the body so as to be exposed only from the mounting surface of the body and connected to the coil, wherein the first external electrode comprises: a first electrode portion having an exposed surface exposed from the mounting surface; and a second electrode portion protruding from the first electrode portion toward the interior of the body and separated from the coil, wherein the entirety of the second electrode portion is arranged inside the body.

[0006] In the coil component described above, the first external electrode includes a second electrode portion that protrudes from the first electrode portion toward the interior of the element body and is disposed entirely within the element body. Therefore, compared to a configuration in which the first external electrode does not include the second electrode portion, the contact area between the first external electrode and the element body is increased. This prevents the first external electrode from peeling off from the element body.

[0007] (2) The coil component of (1) above may further include: a second external electrode embedded in the element body so as to be exposed only from the mounting surface of the element body and connected to the coil, wherein the first external electrode and the second external electrode are separated from each other, the first electrode portion has an edge portion proximate to the second external electrode, and the second electrode portion protrudes from the edge portion toward the second external electrode when viewed in a first direction perpendicular to the mounting surface. In this case, the second electrode portion can suppress the development of cracks originating from the portion between the edge portion of the first electrode portion and the element body due to flexural stress when the coil component is soldered and mounted on a circuit board.

[0008] (3) In the coil component of (2) above, the angle formed between the second electrode portion and the mounting surface may be greater than 0 degrees and less than 90 degrees. In this case, the second electrode portion can effectively suppress the progress of the crack.

[0009] (4) In the coil component according to any one of (1) to (3) above, the element body may include an element body portion that includes a portion of the mounting surface and covers the second electrode portion, and the element body portion may contain a glass component. In this case, plating extension can be suppressed.

[0010] (5) In the coil component of (4) above, the element body may further contain the soft magnetic metal particles. In this case, the characteristics of the coil can be improved.

[0011] (6) In the coil component according to any one of (1) to (5) above, the second electrode portion may have protrusions that penetrate between the soft magnetic metal particles. In this case, peeling of the external electrode can be further suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a perspective view of a coil component according to one embodiment.

[0013] Figure 2 yes Figure 1 A perspective perspective view of the coil assembly is shown.

[0014] Figure 3 Viewed from the mounting surface Figure 1 Figure of the coil assembly shown.

[0015] Figure 4 yes Figure 1 A cross-sectional view of the coil component is shown.

[0016] Figure 5 Yes Figure 1 A cross-sectional view illustrating the flexural stress and cracks of a coil component is shown. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements will be denoted by the same reference numerals, and duplicate descriptions will be omitted.

[0018] Reference Figures 1 to 4 , a coil component 1 according to an embodiment of the present invention is described. Figures 1 to 4 As shown in FIG. 1 , the coil component 1 includes: an element body 2, an external electrode 3, an external electrode 4, a coil 5, a first connection conductor 6, and a second connection conductor 7. The coil component 1 is a laminated coil component. Figure 2 In FIG, for the sake of convenience, the element body 2 is represented by a dotted line.

[0019] The element body 2 is in the shape of a rectangular parallelepiped. The rectangular parallelepiped shape includes the shape of a rectangular parallelepiped with chamfered corners and ridges, and the shape of a rectangular parallelepiped with rounded corners and ridges. The outer surface 2s of the element body 2 has a pair of end faces 2a, 2b, a pair of main faces 2c, 2d, and a pair of side faces 2e, 2f. The end faces 2a, 2b are opposite to each other. The main faces 2c, 2d are opposite to each other. The side faces 2e, 2f are opposite to each other. In this embodiment, the relative direction of the main faces 2c, 2d is set to a first direction D1, the relative direction of the end faces 2a, 2b is set to a second direction D2, and the relative direction of the side faces 2e, 2f is set to a third direction D3. The first direction D1, the second direction D2, and the third direction D3 are substantially orthogonal to each other.

[0020] End surfaces 2a and 2b extend in a first direction D1, connecting principal surfaces 2c and 2d. End surfaces 2a and 2b also extend in a third direction D3, connecting side surfaces 2e and 2f. Principal surfaces 2c and 2d extend in a second direction D2, connecting end surfaces 2a and 2b. Principal surfaces 2c and 2d also extend in a third direction D3, connecting side surfaces 2e and 2f. Side surfaces 2e and 2f extend in the first direction D1, connecting principal surfaces 2c and 2d. Side surfaces 2e and 2f also extend in the second direction D2, connecting end surfaces 2a and 2b.

[0021] The main surface 2d is the mounting surface, for example, the surface facing the other electronic device when the coil component 1 is mounted on another electronic device (e.g., a circuit board) not shown. The end surfaces 2a and 2b are surfaces that are continuous from the mounting surface (i.e., the main surface 2d). The end surfaces 2a and 2b are also surfaces adjacent to the mounting surface.

[0022] The length of the element body 2 in the second direction D2 is longer than the length of the element body 2 in the first direction D1 and the length of the element body 2 in the third direction D3. The second direction D2 is the longitudinal direction of the element body 2. The length of the element body 2 in the third direction D3 is longer than the length of the element body 2 in the first direction D1. That is, in this embodiment, the end faces 2a, 2b, the main faces 2c, 2d, and the side faces 2e, 2f are rectangular. The length of the element body 2 in the first direction D1 may be equal to or longer than the length of the element body 2 in the third direction D3.

[0023] In the description of the embodiments, "equivalent" may refer to values ​​that are equal, in addition to being equal, within a predetermined range of slight differences or manufacturing errors. For example, if multiple values ​​are within a range of ±5% of the average value of the multiple values, the multiple values ​​are considered equivalent.

[0024] The element body 2 is formed by stacking a plurality of element layers (magnetic layers) (not shown) in a first direction D1. That is, the stacking direction of the element body 2 is the first direction D1. In the actual element body 2, the plurality of element layers are integrated to such an extent that the boundaries between the layers cannot be discerned.

[0025] The element body 2 includes a plurality of soft magnetic metal particles P (refer to Figure 4 ). The soft magnetic metal particles P are composed 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, the soft magnetic alloy may also contain P. The soft magnetic alloy may also be, for example, an Fe-Ni-Si-M alloy. "M" contains 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.

[0026] In the element body 2, the soft magnetic metal particles P and P are bonded to each other. The bonding of the soft magnetic metal particles P and P is achieved, for example, by bonding of an oxide film (not shown) formed on the surface of the soft magnetic metal particles P. The thickness of the oxide film is, for example, not less than 5 nm and not more than 60 nm. The oxide film may also be composed of one or more layers. A resin is present in at least a portion of the gaps between the soft magnetic metal particles P and P. The resin has electrical insulating properties and may be, for example, a silicone resin, a phenolic resin, an acrylic resin, or an epoxy resin.

[0027] like Figure 4 As shown, the element body 2 includes a first element body portion 15 and a second element body portion 16. The first element body portion 15 is arranged between the external electrodes 3 and 4 in the second direction D2. The first element body portion 15 includes a portion of the mounting surface (main surface 2d). The first element body portion 15 is provided so as to contact the external electrodes 3 and 4, respectively, and connect the external electrodes 3 and 4. The second element body portion 16 is the portion of the element body 2 other than the first element body portion 15.

[0028] like Figure 3 As shown, the mounting surface (main surface 2d) has a central region 2g disposed between the external electrode 3 and the external electrode 4. The central region 2g is rectangular with the second direction D2 as the short side direction and the third direction D3 as the long side direction. The central region 2g extends in the second direction D2 and connects the exposed surfaces 21a of the external electrodes 3 and 4. Figure 3 In the figure, for the convenience of illustration, the central area 2g and the exposed surface 21a of the external electrodes 3 and 4 are separated in the second direction D2, but they are actually in contact. Figure 3 In the figure, for convenience of illustration, the length of the central region 2g in the third direction D3 is longer than the length of the exposed surface 21a of the external electrodes 3 and 4 in the third direction D3, but in reality, they are the same.

[0029] The first body portion 15 includes the central region 2g as part of the mounting surface. The first body portion 15 encompasses the entire central region 2g. When viewed from the first direction D1, the first body portion 15 and the central region 2g completely overlap. The length of the first body portion 15 in the third direction D3 may be longer than the length of the central region 2g in the third direction D3.

[0030] In this embodiment, the first element body portion 15 contains a glass component. The second element body portion 16 does not contain a glass component. Therefore, it can be said that the content of the glass component in the first element body portion 15 is greater than the content of the glass component in the second element body portion 16. The first element body portion 15 also contains soft magnetic metal particles P (see Figure 4 ). In addition, the second element body portion 16 may also contain a glass component, but in this case, the content of the glass component in the first element body portion 15 is also greater than the content of the glass component in the second element body portion 16. For example, the first element body portion 15 may also be composed only of a glass component without containing the soft magnetic metal particles P. For example, the first element body portion 15 may also be composed only of soft magnetic metal particles P without containing a glass component.

[0031] The external electrodes 3 and 4 are connected to the coil 5. The external electrodes 3 and 4 are embedded in the element body 2 so as to be exposed only from the mounting surface (main surface 2d). The external electrodes 3 and 4 are so-called bottom electrodes. The external electrodes 3 and 4 have the same shape as each other. The external electrodes 3 and 4 are separated from each other in the second direction D2. Specifically, the external electrode 3 is arranged on the end surface 2a side of the element body 2. The external electrode 4 is arranged on the end surface 2b side of the element body 2. The external electrodes 3 and 4 are formed of a conductive material such as Ag, Cu, Ni, Sn, or Au.

[0032] The coil 5 is arranged in the element body 2. The coil 5 is composed of a plurality of coil conductor layers 12a to 12e. The plurality of coil conductor layers 12a to 12e are electrically connected to each other to form the coil 5 in the element body 2. The coil axis of the coil 5 is arranged along the first direction D1. When viewed from the first direction D1, the coil conductor layers 12a to 12e are arranged so as to at least partially overlap each other. The plurality of coil conductor layers 12a to 12e are composed of a conductive material (for example, Ag or Pd). In this embodiment, the plurality of coil conductor layers 12a, 12c, and 12e are plated conductors. The coil conductor layers 12a to 12e are arranged separately from the end faces 2a, 2b, the main faces 2c, 2d, and the side faces 2e, 2f.

[0033] The first connecting conductor 6 is arranged in the element body 2. The first connecting conductor 6 connects the external electrode 3 and the coil 5. The first connecting conductor 6 is a through-hole conductor. The first connecting conductor 6 extends in the first direction D1 and is connected to the external electrode 3 and one end of the coil 5. The first connecting conductor 6 is composed of a plurality of first connecting conductor layers not shown. In this embodiment, the cross section of the first connecting conductor 6 that is orthogonal to the extension direction (first direction D1) (the cross section along the second direction D2 and the third direction D3) is rectangular. That is, the first connecting conductor 6 is prismatic.

[0034] The second connecting conductor 7 is arranged in the element body 2. The second connecting conductor 7 connects the external electrode 4 and the coil 5. The second connecting conductor 7 is a through-hole conductor. The second connecting conductor 7 extends in the first direction D1 and is connected to the other end of the external electrode 4 and the coil 5. The second connecting conductor 7 is composed of a plurality of second connecting conductor layers not shown. In this embodiment, the cross section of the second connecting conductor 7 that is orthogonal to the extension direction (first direction D1) (the cross section along the second direction D2 and the third direction D3) is rectangular. That is, the second connecting conductor 7 is prismatic.

[0035] Next, the external electrodes 3 and 4 are described in detail. When viewed from the first direction D1, the external electrodes 3 and 4 are rectangular, with the second direction D2 as the short side and the third direction D3 as the long side. The external electrodes 3 and 4 are spaced apart from the outer edge of the main surface 2d.

[0036] The external electrodes 3 and 4 respectively include a first electrode portion 21 and a second electrode portion 22. The first electrode portion 21 is buried in the element body 2. The first electrode portion 21 has an exposed surface 21a exposed from the mounting surface (main surface 2d). The exposed surface 21a and the main surface 2d constitute the same plane. The first electrode portion 21 of the external electrode 3 is connected to one end of the coil 5 through the first connecting conductor 6. The first electrode portion 21 of the external electrode 4 is connected to the other end of the coil 5 through the second connecting conductor 7. In this embodiment, the second electrode portion 22 of each of the external electrodes 3 and 4 has a curved shape that bends toward the inside of the element body 2.

[0037] The first electrode portion 21 has an edge portion 21b located near the center of the element body 2 in the second direction D2. The external electrodes 3 and 4 are arranged so that the edges 21b of the first electrode portions 21 face each other in the second direction D2. It can be said that the first electrode portion 21 of the external electrode 3 has an edge portion 21b located near the external electrode 4. Similarly, it can be said that the first electrode portion 21 of the external electrode 4 has an edge portion 21b located near the external electrode 3.

[0038] The second electrode portion 22 protrudes from the edge portion 21b of the first electrode portion 21 toward the interior of the element body 2. The second electrode portion 22 is separate from the coil 5 and is not directly connected to the coil 5. The entire second electrode portion 22 is provided inside the element body 2. The second electrode portion 22 is not exposed from the element body 2. When viewed from the first direction D1, the second electrode portion 22 protrudes toward the center of the element body 2 in the second direction D2. That is, when viewed from the first direction D1, the second electrode portion 22 of the external electrode 3 protrudes in the second direction D2 toward the external electrode 4. In addition, when viewed from the first direction D1, the second electrode portion 22 of the external electrode 4 protrudes in the second direction D2 toward the external electrode 3.

[0039] The second electrode portion 22 protrudes to overlap the central region 2g when viewed from the first direction D1. The front end 22b of the second electrode portion 22 is located closer to the center of the element body 2 in the second direction D2 than the edge 21b of the first electrode portion 21 when viewed from the first direction D1.

[0040] The angle θ formed by the second electrode portion 22 and the mounting surface (main surface 2d) is, for example, greater than 0 degrees and less than 90 degrees (0<θ<90). The second electrode portion 22 has a side surface 22a covered by the first element body portion 15. The side surface 22a is a surface adjacent to the exposed surface 21a. The side surface 22a is also a surface adjacent to the central area 2g. Specifically, the angle θ is the angle formed by the side surface 22a of the second electrode portion 22 and the central area 2g. The angle (180-θ) formed by the exposed surface 21a and the side surface 22a is, for example, greater than 90 degrees and less than 180 degrees (90<180-θ<180).

[0041] The second electrode portion 22 has a protrusion 22c that penetrates between the soft magnetic metal particles P. The protrusion 22c is formed, for example, by punching during the manufacture of the coil component 1 so that a plurality of soft magnetic metal particles P penetrate the external electrodes 3 and 4. Specifically, the portion of the second electrode portion 22 where the soft magnetic metal particles P do not penetrate becomes the protrusion 22c. The protrusion 22c can also be formed on the side surface 22a. Multiple protrusions 22c can also be formed on the surface of the second electrode portion 22.

[0042] The external electrodes 3 and 4 may further include a plating layer (not shown) covering the exposed surface 21a. For example, the plating layer is not embedded in the element body 2 but is disposed outside the mounting surface (main surface 2d). Examples of the plating layer include Ni plating and Sn plating. The plating layer may have a single-layer structure or a multi-layer structure.

[0043] The curved shape of the external electrodes 3 and 4 is achieved, for example, by the following method. First, multiple green sheets containing element body patterns or conductor patterns are stacked to form a laminate. At this point, the conductor patterns that will become the external electrodes 3 and 4 are flat. Next, a green sheet that will become the first element body portion 15 is stacked on the portion of the conductor patterns that will become the second electrode portion 22, and the sheets are pressed in the stacking direction. This bends the portion of the conductor patterns that will become the external electrodes 3 and 4 that will become the second electrode portion 22 toward the inside of the laminate.

[0044] As described above, in coil component 1, external electrodes 3 and 4 include second electrode portions 22 that protrude from first electrode portions 21 into element body 2 and are entirely disposed within element body 2. Therefore, compared to a configuration in which external electrodes 3 and 4 do not include second electrode portions 22, the contact area between external electrodes 3 and 4 and element body 2 increases. This prevents external electrodes 3 and 4 from peeling off (falling off) from element body 2.

[0045] Reference Figure 5 , a coil component 100 of a comparative example will be described. Figure 5 As shown, in the coil component 100, the external electrodes 103 and 104 do not have a second electrode portion 22 (see Figure 4 ) The coil component 100 is mounted on the pad electrodes 31 and 32 of the circuit board 30 by solder 33. The external electrode 103 is connected to the pad electrode 31. The external electrode 104 is connected to the pad electrode 32.

[0046] For example, when the circuit board 30 bends, flexural stresses F1, F2, and F3 are generated in the circuit board 30. Consequently, tensile stresses F4 and F5 are applied to the external electrodes 103 and 104. As a result, cracks C1 and C2 originating between the edge 21b of the first electrode portion 21 of the external electrodes 103 and 104 and the element body 102 propagate obliquely outward in the second direction D2 and toward the main surface 2c of the element body 102. If the coil 105 or the connecting conductor (not shown) breaks due to cracks C1 and C2, the coil 105 may lose its function.

[0047] In contrast, the external electrodes 3 and 4 of the coil component 1 have second electrode portions 22. The second electrode portion 22 of the external electrode 3 protrudes from the edge 21b of the first electrode portion 21 toward the external electrode 4. Furthermore, the second electrode portion 22 of the external electrode 4 protrudes from the edge 21b of the first electrode portion 21 toward the external electrode 3. The second electrode portion 22 is arranged so as to intersect the direction in which the cracks C1 and C2 progress. Furthermore, the external electrodes 3 and 4 are harder than the element body 2. Therefore, the second electrode portion 22 can suppress the progress of the cracks C1 and C2.

[0048] The angle θ formed between the second electrode portion 22 and the mounting surface (main surface 2d) is greater than 0 degrees and less than 90 degrees. Therefore, the second electrode portion 22 easily intersects the direction of propagation of cracks C1 and C2. Consequently, the second electrode portion 22 can more effectively suppress the propagation of cracks C1 and C2.

[0049] The first element body portion 15 of the element body 2 includes a central region 2g, which is part of the mounting surface (main surface 2d), and covers the second electrode portion 22. Because the first element body portion 15 contains a glass component, plating extension in the central region 2g can be suppressed. Because the first element body portion 15 also contains soft magnetic metal particles P, the characteristics of the coil component 1 can be improved.

[0050] The second electrode portion 22 has the protrusions 22 c that penetrate between the soft magnetic metal particles P, P. This can further suppress the peeling of the external electrodes 3, 4.

[0051] As mentioned above, although embodiment was demonstrated, this disclosure is not necessarily limited to the said embodiment, Various changes are possible within the range which does not deviate from the summary.

[0052] In the above embodiment, the coil component 1 is used as an example of a coil component. However, the coil component is not limited to the coil component 1, and other coil components may be used. For example, the number and shape of the coil conductors constituting the coil 5 are not limited.

[0053] In coil component 1, exposed surface 21a and main surface 2d are flush with each other, but exposed surface 21a may be located inside or outside element body 2. Furthermore, exposed surface 21a is not limited to a flat surface but may be curved.

[0054] The external electrodes 3 and 4 may have different shapes. As long as one of the external electrodes 3 and 4 has the second electrode portion 22 , the other may not have the second electrode portion 22 .

[0055] The second electrode portion 22 may protrude beyond the edge 21b of the first electrode portion 21. In this case, the side surface 22a of the second electrode portion 22 is not directly adjacent to the central region 2g. Therefore, the angle θ may be the angle formed by an imaginary plane including the side surface 22a of the second electrode portion 22 and an imaginary plane including the central region 2g.

Claims

1. A coil component comprising: A body containing soft magnetic metal particles; a coil disposed in the body; and a first external electrode embedded in the element body so as to be exposed only from the mounting surface of the element body and connected to the coil; The first external electrode includes: a first electrode portion having an exposed surface exposed from the mounting surface; and a second electrode portion protruding from the first electrode portion toward the interior of the element body and separated from the coil. The entire second electrode portion is disposed inside the element body.

2. The coil component according to claim 1, wherein It further comprises: a second external electrode embedded in the element body so as to be exposed only from the mounting surface of the element body and connected to the coil; The first external electrode and the second external electrode are separated from each other, The first electrode portion has an edge portion close to the second external electrode, The second electrode portion protrudes from the edge portion toward the second external electrode when viewed from a first direction perpendicular to the mounting surface.

3. The coil component according to claim 2, wherein An angle formed between the second electrode portion and the mounting surface is greater than 0 degrees and less than 90 degrees.

4. The coil component according to any one of claims 1 to 3, wherein The element body includes an element body portion that includes a portion of the mounting surface and covers the second electrode portion. The element body portion contains a glass component. The coil component according to claim 4 , wherein The element body portion further contains the soft magnetic metal particles.

6. The coil component according to any one of claims 1 to 3, wherein The second electrode portion has protrusions that penetrate between the soft magnetic metal particles.

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