Coil component

Abstract

To provide a coil component capable of suppressing detachment of external electrodes.SOLUTION: A coil component 1 includes a base body 2 containing soft magnetic metal particles P, a coil 5 disposed within the base body 2, and an external electrode 3 embedded in the base body 2 so as to be exposed only from a principal surface 2d of the base body 2 and connected to the coil 5. The external electrode 3 includes a first electrode portion 21 having an exposed surface 21a exposed from the principal surface 2d, and a second electrode portion 22 protruding inward from the first electrode portion 21 into the base body 2 and spaced apart from the coil 5. The entire second electrode portion 22 is provided inside the base body 2.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] BACKGROUND ART A coil component is known that includes an element body, a coil disposed within the element body, and external electrodes provided only on the mounting surface of the element body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2011 / 135936 Summary of the Invention [Problem to be solved by the invention]

[0004] In the coil component described above, the external electrodes are provided only on the mounting surface of the element body, and therefore the external electrodes are more likely to peel off from the element body than in a configuration in which the external electrodes are provided across multiple surfaces of the element body.

[0005] An object of the present disclosure is to provide a coil component that can suppress peeling of external electrodes. [Means for solving the problem]

[0006] (1) A coil component according to one aspect of the present disclosure comprises a base body containing soft magnetic metal particles, a coil disposed within the base body, and a first external electrode embedded in the base body so as to be exposed only from a mounting surface of the base body and connected to the coil, wherein 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 into the base body and spaced apart from the coil, and the entire second electrode portion is provided inside the base body.

[0007] In the coil component described above, the first external electrode has a second electrode portion that protrudes from the first electrode portion into the element body and is entirely provided inside the element body, which increases the contact area between the first external electrode and the element body compared to a configuration in which the first external electrode does not have the second electrode portion, thereby preventing the first external electrode from peeling off from the element body.

[0008] (2) The coil component of (1) above may further include a second external electrode connected to the coil and embedded in the element body so as to be exposed only from the mounting surface of the element body, the first external electrode and the second external electrode being spaced apart from each other, the first electrode portion having an edge closer to the second external electrode, and the second electrode portion protruding from the edge toward the second external electrode as viewed in a first direction perpendicular to the mounting surface. In this case, the second electrode portion can suppress the propagation of cracks originating from a portion between the edge of the first electrode portion and the element body due to deflection stress when the coil component is soldered mounted on a circuit board.

[0009] (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 smaller than 90 degrees. In this case, the second electrode portion can effectively suppress the propagation of the crack.

[0010] (4) In the coil component of any one of (1) to (3), the element body may have an element body portion that includes a part of the mounting surface and covers the second electrode portion, and the element body portion may contain a glass component. In this case, plating spread can be suppressed.

[0011] (5) In the coil component of (4) above, the body portion may further contain the soft magnetic metal particles, which can improve the characteristics of the coil.

[0012] (6) In the coil component of any one of (1) to (5) above, the second electrode portion may have protrusions that penetrate into the spaces between the soft magnetic metal particles, which further suppresses peeling of the external electrode. [Effects of the Invention]

[0013] According to the present disclosure, a coil component capable of suppressing peeling of an external electrode is provided. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of a coil component according to one embodiment. [Figure 2] FIG. 2 is a see-through perspective view of the coil component shown in FIG. [Figure 3] FIG. 3 is a view of the coil component shown in FIG. 1 as seen from the mounting surface side. [Figure 4] FIG. 4 is a cross-sectional view of the coil device shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view illustrating the bending stress and cracks in the coil component shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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 equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0016] A coil component 1 according to a first embodiment will be described with reference to Figures 1 to 4. As shown in Figures 1 to 4, the coil component 1 includes an element body 2, external electrodes 3 and 4, a coil 5, a first connecting conductor 6, and a second connecting conductor 7. The coil component 1 is a laminated coil component. For ease of explanation, the element body 2 is indicated by a dashed line in Figure 2.

[0017] The element body 2 has a 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 outer surface 2s of the element body 2 has a pair of end faces 2a and 2b, a pair of main faces 2c and 2d, and a pair of side faces 2e and 2f. The end faces 2a and 2b face each other. The main faces 2c and 2d face each other. The side faces 2e and 2f face each other. In this embodiment, the opposing direction of the main faces 2c and 2d is defined as a first direction D1, the opposing direction of the end faces 2a and 2b is defined as a second direction D2, and the opposing direction of the side faces 2e and 2f is defined as a third direction D3. The first direction D1, the second direction D2, and the third direction D3 are substantially perpendicular to each other.

[0018] The end faces 2a, 2b extend in the first direction D1 to connect the principal faces 2c, 2d. The end faces 2a, 2b also extend in the third direction D3 to connect the side faces 2e, 2f. The principal faces 2c, 2d extend in the second direction D2 to connect the end faces 2a, 2b. The principal faces 2c, 2d also extend in the third direction D3 to connect the side faces 2e, 2f. The side faces 2e, 2f extend in the first direction D1 to connect the principal faces 2c, 2d. The side faces 2e, 2f also extend in the second direction D2 to connect the end faces 2a, 2b.

[0019] The main surface 2d is a mounting surface, and is the surface that faces another electronic device (not shown) when the coil component 1 is mounted on the other electronic device (for example, a circuit board). The end surfaces 2a and 2b are surfaces that are continuous with the mounting surface (i.e., the main surface 2d). The end surfaces 2a and 2b are also surfaces that are adjacent to the mounting surface.

[0020] 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, main faces 2c, 2d, and side faces 2e, 2f have a rectangular shape. The length of the element body 2 in the first direction D1 may be equal to or shorter than the length of the element body 2 in the third direction D3.

[0021] In the description of the embodiments, "equivalent" may mean not only equal but also values ​​that include slight differences or manufacturing errors within a preset range. For example, if multiple values ​​are within a range of ±5% of the average value of the multiple values, the multiple values ​​are defined as equivalent.

[0022] The element body 2 is formed by stacking multiple 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 multiple element layers are integrated to the extent that the boundaries between the layers are not visible.

[0023] The element body 2 includes a plurality of soft magnetic metal particles P (see FIG. 4). The soft magnetic metal particles P 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 also include P. The soft magnetic alloy may also 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.

[0024] In the element body 2, the soft magnetic metal particles P, P are bonded to each other. The bond between the soft magnetic metal particles P, P is realized, for example, by bonding between oxide films (not shown) formed on the surfaces of the soft magnetic metal particles P. The thickness of the oxide film is, for example, 5 nm to 60 nm. The oxide film may be composed of one or more layers. Resin is present in at least some of the gaps between the soft magnetic metal particles P, P. The resin has electrical insulating properties and may be, for example, silicone resin, phenol resin, acrylic resin, or epoxy resin.

[0025] As shown in FIG. 4, the element body 2 has a first element body portion 15 and a second element body portion 16. The first element body portion 15 is disposed between the external electrodes 3 and 4 in the second direction D2. The first element body portion 15 includes part of the mounting surface (main surface 2d). The first element body portion 15 is in contact with each of the external electrodes 3 and 4 and is provided so as to connect the external electrodes 3 and 4 together. The second element body portion 16 is the portion of the element body 2 other than the first element body portion 15.

[0026] As shown in FIG. 3, the mounting surface (principal surface 2d) has a central region 2g disposed between the external electrode 3 and the external electrode 4. The central region 2g has a rectangular shape with its short sides aligned in the second direction D2 and its long sides aligned in the third direction D3. The central region 2g extends in the second direction D2 and connects the exposed surfaces 21a of the external electrodes 3 and 4 to each other. In FIG. 3, for convenience of illustration, the central region 2g and the exposed surfaces 21a of the external electrodes 3 and 4 are shown separated from each other in the second direction D2, but in reality they are in contact. In FIG. 3, for convenience of illustration, the length of the central region 2g in the third direction D3 is longer than the length of the exposed surfaces 21a of the external electrodes 3 and 4 in the third direction D3, but in reality they are the same.

[0027] The first element body portion 15 includes the central region 2g as part of the mounting surface. The first element body portion 15 includes the entire central region 2g. When viewed from the first direction D1, the first element body portion 15 and the central region 2g completely overlap each other. The length of the first element body portion 15 in the third direction D3 may be longer than the length of the central region 2g in the third direction D3.

[0028] In this embodiment, the first element portion 15 contains a glass component. The second element portion 16 does not contain a glass component. Therefore, it can be said that the glass component content of the first element portion 15 is greater than the glass component content of the second element portion 16. The first element portion 15 further contains soft magnetic metal particles P (see FIG. 4). Note that the second element portion 16 may contain a glass component, but in this case too, the glass component content of the first element portion 15 is greater than the glass component content of the second element portion 16. The first element portion 15 may, for example, be made only of a glass component and not contain soft magnetic metal particles P. The first element portion 15 may, for example, be made only of soft magnetic metal particles P and not contain a glass component.

[0029] 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 (principal surface 2d). The external electrodes 3 and 4 are so-called bottom electrodes. The external electrodes 3 and 4 have the same shape. The external electrodes 3 and 4 are spaced apart from each other in the second direction D2. Specifically, the external electrode 3 is disposed on the end surface 2a side of the element body 2. The external electrode 4 is disposed 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.

[0030] The coil 5 is disposed within 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 within the element body 2. The coil axis of the coil 5 is provided along the first direction D1. The coil conductor layers 12a to 12e are disposed so as to at least partially overlap each other when viewed from the first direction D1. The plurality of coil conductor layers 12a to 12e are made 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 disposed apart from the end faces 2a and 2b, the main faces 2c and 2d, and the side faces 2e and 2f.

[0031] The first connecting conductor 6 is disposed within 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 a 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 first connecting conductor 6 has a rectangular cross section (cross section along the second direction D2 and the third direction D3) perpendicular to the extension direction (first direction D1). That is, the first connecting conductor 6 has a prismatic shape.

[0032] The second connecting conductor 7 is disposed within 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 external electrode 4 and the other end of the coil 5. The second connecting conductor 7 is composed of a plurality of second connecting conductor layers (not shown). In this embodiment, the second connecting conductor 7 has a rectangular cross section (cross section along the second direction D2 and the third direction D3) perpendicular to the extension direction (first direction D1). In other words, the second connecting conductor 7 has a prismatic shape.

[0033] Next, the external electrodes 3 and 4 will be described in detail. When viewed from the first direction D1, the external electrodes 3 and 4 have a rectangular shape with their short sides extending in the second direction D2 and their long sides extending in the third direction D3. The external electrodes 3 and 4 are arranged apart from the outer edge of the main surface 2d.

[0034] Each of the external electrodes 3, 4 includes a first electrode portion 21 and a second electrode portion 22. The first electrode portion 21 is embedded in the element body 2. The first electrode portion 21 has an exposed surface 21a exposed from the mounting surface (principal surface 2d). The exposed surface 21a is flush with the principal surface 2d. The first electrode portion 21 of the external electrode 3 is connected to one end of the coil 5 by a first connecting conductor 6. The first electrode portion 21 of the external electrode 4 is connected to the other end of the coil 5 by a second connecting conductor 7. In this embodiment, each of the external electrodes 3, 4 has a bent shape in which the second electrode portion 22 is bent toward the inside of the element body 2.

[0035] The first electrode portion 21 has an edge 21b closer to the center in the second direction D2 of the element body 2. The external electrodes 3 and 4 are arranged so that the edge portions 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 21b closer to the external electrode 4. It can also be said that the first electrode portion 21 of the external electrode 4 has an edge 21b closer to the external electrode 3.

[0036] The second electrode portion 22 protrudes from the edge 21b of the first electrode portion 21 into the element body 2. The second electrode portion 22 is separated 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. In other words, 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. Furthermore, 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.

[0037] When viewed from the first direction D1, the second electrode portion 22 protrudes so as to overlap with the central region 2g. When viewed from the first direction D1, the tip 22b of the second electrode portion 22 is positioned closer to the center of the element body 2 in the second direction D2 than the edge 21b of the first electrode portion 21.

[0038] The angle θ formed between 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 that is 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 region 2g. Specifically, the angle θ is the angle formed between the side surface 22a of the second electrode portion 22 and the central region 2g. The angle (180-θ) formed between 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).

[0039] The second electrode portion 22 has protrusions 22c that get into spaces between the soft magnetic metal particles P. The protrusions 22c are formed, for example, by a plurality of soft magnetic metal particles P biting into the external electrodes 3, 4 through press working during the manufacture of the coil component 1. Specifically, the protrusions 22c are portions of the second electrode portion 22 that are not bitten by the soft magnetic metal particles P. The protrusions 22c may be formed on the side surface 22a. A plurality of protrusions 22c may be formed on the surface of the second electrode portion 22.

[0040] The external electrodes 3, 4 may further include a plating layer (not shown) covering the exposed surface 21a. The plating layer is not embedded in the element body 2, but is disposed outside the mounting surface (main surface 2d). The plating layer is, for example, a Ni plating layer or a Sn plating layer. The plating layer may have a single-layer structure or a multi-layer structure.

[0041] The bent shape of the external electrodes 3, 4 can be obtained, for example, by the following method. First, multiple green sheets including element patterns and conductor patterns are stacked to form a laminate. At this point, the conductor patterns that will become the external electrodes 3, 4 are flat. Next, a green sheet that will become the first element portion 15 is stacked on top of the portions of the conductor patterns that will become the second electrode portions 22 of the external electrodes 3, 4, and pressed in the stacking direction. As a result, the portions of the conductor patterns that will become the second electrode portions 22 of the external electrodes 3, 4 are pressed and bent toward the inside of the laminate.

[0042] As described above, in the coil device 1, the external electrodes 3, 4 have second electrode portions 22 that protrude from the first electrode portions 21 into the element body 2 and are entirely provided inside the element body 2. This increases the contact area between the external electrodes 3, 4 and the element body 2 compared to a configuration in which the external electrodes 3, 4 do not have the second electrode portions 22. This prevents the external electrodes 3, 4 from peeling off (falling off) from the element body 2.

[0043] A coil component 100 according to a comparative example will be described with reference to Fig. 5. As shown in Fig. 5, in the coil component 100, the external electrodes 103 and 104 do not have a configuration corresponding to the second electrode portion 22 (see Fig. 4). The coil component 100 is mounted to land electrodes 31 and 32 of a circuit board 30 with solder 33 when in use. The external electrode 103 is connected to the land electrode 31. The external electrode 104 is connected to the land electrode 32.

[0044] For example, when the circuit board 30 bends, bending stresses F1, F2, and F3 are generated in the circuit board 30. As a result, tensile stresses F4 and F5 are applied to the external electrodes 103 and 104. As a result, cracks C1 and C2 originating from the portion between the edge 21b of the first electrode portion 21 of the external electrodes 103 and 104 and the element body 2 propagate obliquely outward in the second direction D2 of the element body 102 and toward the main surface 2c. If the cracks C1 and C2 cause the coil 105 or the connecting conductor (not shown) to break, the function of the coil 105 may be lost.

[0045] In contrast, in the coil device 1, the external electrodes 3 and 4 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 portions 22 are arranged so as to intersect with the direction in which the cracks C1 and C2 propagate. Furthermore, the external electrodes 3 and 4 are harder than the element body 2. Therefore, the second electrode portions 22 can suppress the propagation of the cracks C1 and C2.

[0046] 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 is likely to intersect with the direction in which the cracks C1 and C2 propagate. Therefore, the second electrode portion 22 can effectively suppress the propagation of the cracks C1 and C2.

[0047] The first element body portion 15 of the element body 2 includes a central region 2g that is part of the mounting surface (main surface 2d), and covers the second electrode portion 22. The first element body portion 15 contains a glass component, which can suppress plating spread in the central region 2g. The first element body portion 15 further contains soft magnetic metal particles P, which can improve the characteristics of the coil component 1.

[0048] The second electrode portion 22 has protrusions 22c that get into the spaces between the soft magnetic metal particles P, P. This further suppresses the external electrodes 3, 4 from peeling off.

[0049] Although the embodiments 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.

[0050] In the above embodiment, the coil component 1 has been described as an example of a coil component. However, the coil component is not limited to the coil component 1, and may be other coil components. For example, the number and shape of the coil conductors constituting the coil 5 are not limited.

[0051] In the coil device 1, the exposed surface 21a is flush with the main surface 2d, but the exposed surface 21a may be located closer to the inside of the element body 2 than the main surface 2d, or may be located closer to the outside of the element body 2. Furthermore, the exposed surface 21a is not limited to being flat, and may be curved.

[0052] The external electrodes 3, 4 may have different shapes. If one of the external electrodes 3, 4 has the second electrode portion 22, the other does not necessarily have to have the second electrode portion 22.

[0053] The second electrode portion 22 may protrude from a portion other than the edge portion 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 between an imaginary plane including the side surface 22a of the second electrode portion 22 and an imaginary plane including the central region 2g. [Explanation of symbols]

[0054] 1...coil component, 2...element body, 2d...main surface (mounting surface), 3, 4...external electrode, 5...coil, 21...first electrode portion, 21a...exposed surface, 21b...edge portion, 22...second electrode portion, 22c...protrusion, D1...first direction, P...soft magnetic metal particle, θ...angle

Claims

1. an element body including soft magnetic metal particles; a coil disposed within the element body; a first external electrode that is embedded in the element body so as to be exposed only from the mounting surface of the element body and is 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 into the element body and spaced apart from the coil, the second electrode portion is entirely provided inside the element body; Coil parts.

2. a second external electrode that is embedded in the element body so as to be exposed only from the mounting surface of the element body and is connected to the coil; the first external electrode and the second external electrode are spaced apart from each other; the first electrode portion has an edge closer to the second external electrode, When viewed from a first direction perpendicular to the mounting surface, the second electrode portion protrudes from the edge portion toward the second external electrode. The coil component according to claim 1 .

3. an angle formed between the second electrode portion and the mounting surface is greater than 0 degrees and smaller than 90 degrees; The coil component according to claim 2 .

4. the element body has an element body portion that includes a part of the mounting surface and covers the second electrode portion, The element portion contains a glass component. The coil component according to any one of claims 1 to 3.

5. The element portion further includes the soft magnetic metal particles. The coil component according to claim 4 .

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

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