Coil component

Abstract

To provide a coil component that can suppress peeling of external electrodes, stray capacitance, and solder erosion.SOLUTION: A coil component 1 includes an element body 2 containing soft magnetic metal particles P, a coil 5 disposed within the element body 2, and external electrodes 3 and 4 connected to the coil 5. The external electrodes 3 and 4 have a plated conductor 8 at least partially embedded in the element body 2, and a plating layer 9 covering the plated conductor 8. The plating layer 9 is thicker than the plated conductor 8.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] A coil component is known that includes an element body, a coil disposed within the element body, and external electrodes connected to the coil (see, for example, Patent Document 1). Patent Document 1 describes that the external electrodes of the passive component are soldered to land patterns, thereby mounting the passive component on a circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-141079 Summary of the Invention [Problem to be solved by the invention]

[0004] To prevent the external electrodes from peeling off from the element body, it is possible to embed the external electrodes in the element body. However, this configuration shortens the distance between the external electrodes and the coil, which can increase stray capacitance. Furthermore, if the external electrodes are made thin, there is a risk of solder erosion.

[0005] An object of the present disclosure is to provide a coil component that can suppress peeling of external electrodes, stray capacitance, and solder erosion. [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 an external electrode connected to the coil, wherein the external electrode has a plated conductor at least partially embedded in the base body and a plating layer covering the plated conductor, and the plating layer is thicker than the plated conductor.

[0007] In the coil component, at least a portion of the plated conductor is embedded in the element body containing soft magnetic metal particles, increasing the contact area between the external electrode and the element body. This prevents the external electrode from peeling off from the element body. Furthermore, the external electrode includes, in addition to the plated conductor, a plating layer that is thicker than the plated conductor. This allows the thickness of the plated conductor to be reduced, thereby increasing the distance between the plated conductor and the coil. This reduces stray capacitance. Furthermore, the thick plating layer prevents solder erosion when the coil component is soldered.

[0008] (2) In the coil component of (1), the plating layer may have a laminated structure in which a plurality of plating layers are stacked, and each of the plurality of plating layers may be thicker than the plated conductor. In this case, peeling of the external electrodes, stray capacitance, and solder erosion can be further suppressed.

[0009] (3) In the coil component of (2) above, the plating layer may include a Ni layer and a Sn layer disposed on the Ni layer as the plurality of plating layers, and the Sn layer may be thicker than the Ni layer. In this case, the thick heat-resistant Ni layer can effectively suppress solder erosion. Furthermore, the Sn layer, which has high solder bonding strength, can be thicker than the Ni layer, thereby reliably improving mounting strength.

[0010] (4) In the coil component of any one of (1) to (3) above, the plated conductor may be entirely embedded in the element body, which can further suppress peeling of the external electrodes.

[0011] (5) In any one of the coil components (1) to (4) above, the external electrodes may be provided only on the mounting surface. In this case, preventing peeling of the external electrodes is more important than in a configuration in which the external electrodes are provided across multiple surfaces of the element body. Therefore, a configuration in which the plated conductor is embedded in the element body is particularly effective.

[0012] (6) In the coil component of any one of (1) to (5) above, the plating layer may be provided on the outside of the element body, which can further reduce stray capacitance. [Effects of the Invention]

[0013] According to the present disclosure, a coil component is provided that can suppress peeling of external electrodes, stray capacitance, and solder erosion. [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 an exploded perspective view of the coil component shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the coil device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[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 or a laminated coil component). 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 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 a plurality of element layers (magnetic layers) 10a-10h in a first direction D1. That is, the stacking direction of the element body 2 is the first direction D1. The specific stacking configuration will be described later. In the actual element body 2, the plurality of element layers 10a-10h 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. 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, the soft magnetic alloy may include 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.

[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] The external electrodes 3 and 4 are provided on the element body 2 and connected to the coil 5. The external electrodes 3 and 4 are so-called bottom electrodes and are provided only on the mounting surface (principal surface 2d). The external electrodes 3 and 4 have the same shape. The external electrodes 3 and 4 are provided on the mounting surface (principal surface 2d) spaced apart 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.

[0026] The coil 5 is disposed within the element body 2. As shown in FIG. 3, 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 spaced apart from the end faces 2a and 2b, the main faces 2c and 2d, and the side faces 2e and 2f.

[0027] As shown in FIG. 2, 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 14a (see FIG. 3). 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.

[0028] 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 multiple second connecting conductor layers 16a, 16b, 16c, 16d, and 16e (see FIG. 3). 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). That is, the second connecting conductor 7 has a prismatic shape.

[0029] 3, the coil component 1 includes multiple layers La, Lb, Lc, Ld, Le, Lf, Lg, and Lh. The coil component 1 is configured, for example, by stacking the layers La to Lh in order from the main surface 2c side. The coil component 1 according to this embodiment includes multiple layers Lc and multiple layers Lg.

[0030] The layer La is composed of the element body layer 10a. The layer La forms the main surface 2c of the element body 2.

[0031] Layer Lb is formed by combining an element layer 10b and a coil conductor layer 12a. The element layer 10b has a shape corresponding to the coil conductor layer 12a and is provided with a recess (not shown) into which the coil conductor layer 12a is fitted. The element layer 10b and the coil conductor layer 12a have a complementary relationship.

[0032] The layer Lc is formed by combining an element layer 10c, a coil conductor layer 12b, and a second connecting conductor layer 16a. The element layer 10c has shapes corresponding to the coil conductor layer 12b and the second connecting conductor layer 16a, and is provided with recesses (not shown) into which the coil conductor layer 12b and the second connecting conductor layer 16a are fitted. The element layer 10c, the coil conductor layer 12b, and the second connecting conductor layer 16a have a mutually complementary relationship.

[0033] The layer Ld is formed by combining an element layer 10d, a coil conductor layer 12c, and a second connecting conductor layer 16b. The element layer 10d has shapes corresponding to the coil conductor layer 12c and the second connecting conductor layer 16b, and is provided with recesses (not shown) into which the coil conductor layer 12c and the second connecting conductor layer 16b are fitted. The element layer 10d, the coil conductor layer 12c, and the second connecting conductor layer 16b have a complementary relationship with each other.

[0034] The layer Le is formed by combining an element layer 10e, a coil conductor layer 12d, and a second connecting conductor layer 16c. The element layer 10e has recesses (not shown) that have shapes corresponding to the coil conductor layer 12d and the second connecting conductor layer 16c and into which the coil conductor layer 12d and the second connecting conductor layer 16c are fitted. The element layer 10e, the coil conductor layer 12d, and the second connecting conductor layer 16c have a complementary relationship with each other.

[0035] The layer Lf is formed by combining an element layer 10f, a coil conductor layer 12e, and a second connecting conductor layer 16d. The element layer 10f has cutouts (not shown) that have shapes corresponding to the coil conductor layer 12e and the second connecting conductor layer 16d and into which the coil conductor layer 12e and the second connecting conductor layer 16d are fitted. The element layer 10f, the coil conductor layer 12e, and the second connecting conductor layer 16d have a complementary relationship.

[0036] The layer Lg is formed by combining an element layer 10g, a first connecting conductor layer 14a, and a second connecting conductor layer 16e. The element layer 10g has shapes corresponding to the first connecting conductor layer 14a and the second connecting conductor layer 16e, and is provided with recesses (not shown) into which the first connecting conductor layer 14a and the second connecting conductor layer 16e are fitted. The element layer 10g, the first connecting conductor layer 14a, and the second connecting conductor layer 16e have a mutually complementary relationship.

[0037] The layer Lh is formed by combining an element body layer 10h, the plated conductors 8 of the external electrode 3, and the plated conductors 8 of the external electrode 4. The element body layer 10h has a shape corresponding to each of the plated conductors 8, and is provided with cutouts (not shown) into which each of the plated conductors 8 is fitted. The element body layer 10h, the plated conductors 8 of the external electrode 3, and the plated conductors 8 of the external electrode 4 are complementary to each other. The layer Lh forms the main surface 2d of the element body 2.

[0038] 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.

[0039] As shown in FIG. 4, each of the external electrodes 3, 4 has a plated conductor 8 and a plating layer 9. At least a portion of the plated conductor 8 is embedded in the element body 2 and is located inside the outer surface 2s (here, the main surface 2d). In this embodiment, the entire plated conductor 8 is embedded in the element body 2. The plated conductor 8 does not have a portion located outside the outer surface 2s (here, the main surface 2d). The plated conductor 8 has an exposed surface 8a exposed from the element body 2. In this embodiment, the exposed surface 8a of the plated conductor 8 forms the same plane as the main surface 2d. The plated conductor 8 has a single-layer structure.

[0040] The plated conductor 8 is formed of a conductive material such as Ag, Cu, Ni, Sn, or Au. The plated conductor 8 is substantially free of glass components. The glass component content of the plated conductor 8 is, for example, less than 0.5%. Therefore, the area of ​​the base metal material on the surface of the plated conductor 8 is larger than that of a base metal layer containing glass components. This makes plating formation easier.

[0041] The plating layer 9 covers the plated conductor 8. The plating layer 9 is not embedded in the element body 2, but is disposed on the outside of the outer surface 2s, for example. The plating layer 9 has a laminated structure in which a plurality of plating single layers are stacked. The plating layer 9 has a Ni layer 21 and a Sn layer 22 as the plurality of plating single layers. The Ni layer 21 is disposed on the plated conductor 8. The Ni layer 21 is in contact with the exposed surface 8a and covers the entire exposed surface 8a. The Sn layer 22 is disposed on the Ni layer 21. The Sn layer 22 is disposed in contact with the outer surface of the Ni layer 21.

[0042] Each of the multiple plated single layers is thicker than the plated conductor 8. That is, the thickness t2 of the Ni layer 21 (the length of the Ni layer 21 in the first direction D1) is thicker than the thickness t1 of the plated conductor 8 (the length of the plated conductor 8 in the first direction D1). Furthermore, the thickness t3 of the Sn layer 22 (the length of the Sn layer 22 in the first direction D1) is thicker than the thickness t1. The thickness t3 is, for example, thicker than the thickness t2. The plated layer 9 is thicker than the plated conductor 8. That is, the total thickness of the plated layer 9 (the length of the entire plated layer 9 in the first direction D1) is thicker than the thickness t1.

[0043] The thickness t1 may be thinner than the average particle diameter of the soft magnetic metal particles P, for example. The thickness t1 is, for example, 0.01 μm or more and 5 μm or less. The average particle diameter of the soft magnetic metal particles P is, for example, 1 μm or more and 20 μm or less. The thickness t2 is, for example, 0.5 μm or more and 5 μm or less. The thickness t3 is, for example, 1 μm or more and 10 μm or less. The total thickness of the plating layer 9 is, for example, 1.5 μm or more and 15 μm or less.

[0044] The thicknesses t1, t2, and t3 are obtained, for example, as follows: A cross-sectional photograph of the coil component 1 is obtained. The cross-sectional photograph is obtained, for example, by photographing a cross section of the coil component 1 cut along a plane parallel to the side surfaces 2e and 2f and passing through the external electrodes 3 and 4. In the obtained cross-sectional photograph, the maximum thicknesses of the plated conductor 8, the Ni layer 21, and the Sn layer 22 are determined. The position in the third direction D3 is changed, and cross-sectional photographs are similarly obtained, and the determination of each maximum thickness is repeated multiple times. The average values ​​of the obtained maximum thicknesses are designated as thicknesses t1, t2, and t3.

[0045] The average particle diameter of the soft magnetic metal particles P can be obtained, for example, as follows: A cross-sectional photograph of the coil component 1 is obtained. The obtained cross-sectional photograph is subjected to image processing using software. The boundaries of the soft magnetic metal particles P are identified through image processing, and the area of ​​the soft magnetic metal particles P is determined. From the determined area of ​​the soft magnetic metal particles P, the particle diameter converted into a circle-equivalent diameter is determined. Here, the particle diameters of 100 or more soft magnetic metal particles P are calculated, and the particle size distribution of these soft magnetic metal particles P is determined. The particle diameter at 50% of the integrated value (d50) in the determined particle size distribution is defined as the "average particle diameter." The particle shape of the soft magnetic metal particles P is not particularly limited.

[0046] As described above, in the coil component 1 according to this embodiment, the entire plated conductor 8 is embedded in the element body 2 containing soft magnetic metal particles P, thereby increasing the contact area between the external electrodes 3, 4 and the element body 2. This makes it possible to prevent the external electrodes 3, 4 from peeling off from the element body 2. The external electrodes 3, 4 have, in addition to the plated conductor 8, a plating layer 9 that is thicker than the plated conductor 8. This makes it possible to reduce the thickness t1 of the plated conductor 8. Because the plating layer 9 is provided on the outside of the element body 2, it is possible to increase the distance between the plated conductor 8 and the coil 5. This makes it possible to reduce stray capacitance. This makes it possible to increase the self-resonant frequency (SRF) of the coil component 1. Furthermore, the thick plating layer 9 makes it possible to prevent solder erosion when the coil component 1 is mounted by soldering.

[0047] The plating layer 9 includes a Ni layer 21 and a Sn layer 22, and the thickness t2 of the Ni layer 21 and the thickness t3 of the Sn layer 22 are both greater than the thickness t1 of the plated conductor 8. The thick heat-resistant Ni layer 21 can effectively suppress solder erosion. Furthermore, the Sn layer 22, which has high solder bonding strength, is even thicker than the Ni layer 21, thereby reliably improving mounting strength.

[0048] Because the external electrodes 3, 4 are provided only on the main surface 2d, which is the mounting surface, they are more likely to peel off from the element body 2 than in a configuration in which the external electrodes 3, 4 are provided across multiple surfaces of the element body 2, making it important to prevent peeling of the external electrodes 3, 4. Therefore, a configuration in which the plated conductor 8 is embedded in the element body 2 is particularly effective.

[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 above embodiment, the entire plated conductor 8 is embedded in the element body 2, but the plated conductor 8 may have a portion that protrudes from the outer surface 2s of the element body 2. In this case, it becomes easier to form the plating layer 9. The external electrodes 3, 4 may be L-shaped when viewed from the third direction D3, and may be provided on the end surfaces 2a, 2b in addition to the main surface 2d. [Explanation of symbols]

[0052] 1... coil component, 2... element body, 2d... main surface (mounting surface), 3, 4... external electrodes, 5... coil, 8... plated conductor, 9... plated layer, 21... Ni layer, 22... Sn layer, P... soft magnetic metal particles.

Claims

1. an element body including soft magnetic metal particles; a coil disposed within the element body; an external electrode connected to the coil, the external electrode has a plated conductor at least a portion of which is embedded in the element body, and a plating layer covering the plated conductor; The plating layer is thicker than the plated conductor. Coil parts.

2. the plating layer has a laminated structure in which a plurality of plating single layers are laminated, Each of the plurality of plated monolayers is thicker than the plated conductor. The coil component according to claim 1 .

3. The plating layer has, as the plurality of plating single layers, a Ni layer and a Sn layer disposed on the Ni layer, The Sn layer is thicker than the Ni layer. The coil component according to claim 2 .

4. the entire plated conductor is embedded in the element body; The coil component according to any one of claims 1 to 3.

5. the element body has a mounting surface, the external electrodes are provided only on the mounting surface; The coil component according to any one of claims 1 to 3.

6. The plating layer is provided on the outside of the element body. The coil component according to any one of claims 1 to 3.

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