Coil component

Abstract

This 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 external electrodes (3, 4) connected to the coil (5). The external electrodes (3, 4) have: a base metal layer (8) provided on the outer surface (2s) of the element body (2); and a plating layer (9) covering the base metal layer (8). The plating layer (9) has a protruding portion (9b) which is provided on an outer edge portion (9a) of the plating layer (9) and which enters the interior of the element body (2).

Description

Technical Field

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

[0002] A coil component is known that includes a body, a coil disposed within the body, and an external electrode connected to the coil (see, for example, Japanese Patent Application Publication No. 2020-141079). Japanese Patent Application Publication No. 2020-141079 describes mounting a passive component on a circuit board by soldering the external electrode of the passive component to a land pattern. Summary of the Invention

[0003] An object of the present disclosure is to provide a coil component capable of improving the bonding strength between an external electrode and solder.

[0004] (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 an external electrode connected to the coil, the external electrode comprising: a base metal layer provided on the outer surface of the body; and a plating layer covering the base metal layer, the plating layer comprising: a protrusion provided on the outer edge of the plating layer and extending into the interior of the body.

[0005] In the coil component, the plating layer has protrusions that penetrate into the element body, thereby increasing the surface area of ​​the plating layer bonded to the solder compared to a structure without the protrusions. This can improve the bonding strength between the external electrode and the solder.

[0006] (2) In the coil component of (1) above, the outer surface may have a mounting surface, and the external electrode may be provided only on the mounting surface. In this case, compared with a structure in which the external electrode is provided across multiple surfaces, it is important to improve the bonding strength between the external electrode and the solder. Therefore, a structure in which the plating layer has a protrusion is particularly effective.

[0007] (3) In the coil component of (1) or (2) above, the base metal layer may include an embedded portion embedded in the element body. In this case, the external electrode is difficult to separate from the element body. Therefore, the mounting strength when the coil component is mounted on the circuit board by solder can be improved.

[0008] (4) In the coil component of (3) above, the outer surface may have a peripheral portion of the external electrode, and the embedded portion may have: an exposed surface exposed from the outer surface; and a side surface adjacent to the exposed surface, wherein the angle formed between the peripheral portion and the side surface is less than 90 degrees. In this case, the gap between the soft magnetic metal particles and the side surface of the embedded portion tends to become larger. By forming a protrusion of the plating layer in a larger gap, the surface area of ​​the plating layer fixed to the solder is further increased. As a result, the bonding strength between the external electrode and the solder can be further improved.

[0009] (5) In the coil component of any one of (1) to (4) above, the base metal layer may not contain a glass component. In this case, the base metal material area on the surface of the base metal layer becomes larger than that in a structure in which the base metal layer contains a glass component. Therefore, plating can be easily performed.

[0010] (6) In the coil component according to any one of (1) to (5) above, the protrusion may be provided over the entire periphery of the outer edge of the plating layer. In this case, the surface area of ​​the plating layer increases over the entire periphery of the outer edge of the plating layer, thereby further improving the bonding strength between the external electrode and the solder.

[0011] (7) In the coil component of any one of (1) to (6) above, the outer surface may have: a mounting surface; and a pair of end surfaces adjacent to and opposite to the mounting surface, a pair of external electrodes being provided on the mounting surface separated from each other in relative directions of the pair of end surfaces, and the mounting surface having: a central region disposed between the pair of external electrodes when viewed from a direction orthogonal to the mounting surface, the protrusion being provided on an outer edge of the plating layer adjacent to the central region. In this case, when the coil component is mounted on a circuit substrate, stress is easily applied between the central region and the external electrodes. By providing the protrusion along the central region, the bonding strength between the external electrode and the solder can be improved in the portion where stress is easily applied when the coil component is mounted.

[0012] (8) In the coil component according to any one of (1) to (7) above, the element body may include a first region provided in contact with the external electrode and a second region provided in contact with the coil, wherein the average particle size of the soft magnetic metal particles contained in the first region is larger than the average particle size of the soft magnetic metal particles contained in the second region. In this case, the protrusions can be easily formed while maintaining the characteristics of the coil.

[0013] (9) In the coil component according to any one of (1) to (8) above, the average depth of the protrusions penetrating the element body may be at least 1 / 2 the average particle size of the soft magnetic metal particles. In this case, the bonding strength between the external electrode and the solder can be reliably improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a perspective view of the coil component according to the first embodiment.

[0015] Figure 2 yes Figure 1 A perspective perspective view of the coil assembly is shown.

[0016] Figure 3 yes Figure 1 An exploded perspective view of the coil assembly is shown.

[0017] Figure 4 Viewed from the mounting surface Figure 1 Figure of the coil assembly shown.

[0018] Figure 5 yes Figure 1 A cross-sectional view of the coil component is shown.

[0019] Figure 6 It is a perspective view of a coil component according to a second embodiment.

[0020] Figure 7 yes Figure 6 A cross-sectional view of the coil component is shown.

[0021] Figure 8 yes Figure 6 An exploded perspective view of the coil assembly is shown.

[0022] Figure 9 It is a cross-sectional view of a coil component according to a first modification of the first embodiment.

[0023] Figure 10 It is a cross-sectional view of a coil component according to a second modified example of the first embodiment. DETAILED DESCRIPTION

[0024] 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.

[0025] (First embodiment)

[0026] Reference Figures 1 to 5 , the coil component 1 of the first embodiment is described. Figures 1 to 5As 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.

[0027] 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.

[0028] 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.

[0029] 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 (not shown) (e.g., a circuit substrate or a laminated coil component). 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.

[0030] 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, 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.

[0031] 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.

[0032] The element body 2 is composed of multiple element layers (magnetic layers) 10a to 10h stacked in a first direction D1. That is, the stacking direction of the element body 2 is the first direction D1. The specific stacking structure will be described later. In the actual element body 2, the multiple element layers 10a to 10h are integrated to the extent that the boundaries between the layers are not discernible.

[0033] The element body 2 includes a plurality of soft magnetic metal particles P (refer to Figure 5 ). 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.

[0034] 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.

[0035] like Figure 5 As shown, the element body 2 has: a first region R1 provided in contact with the external electrodes 3 and 4, and a second region R2 provided in contact with the coil 5. In this embodiment, the first region R1 is a region that includes the entire main surface 2d and is thicker than the embedded portion 8b in the first direction D1. The second region R2 is all regions other than the first region R1 in the element body 2. The size (volume) of the gaps between the soft magnetic metal particles P, P in the first region R1 is larger than the size (volume) of the gaps between the soft magnetic metal particles P, P in the second region R2. For example, the first region R1 includes the element body layer 10h (refer to Figure 3 ) and an element layer 10g adjacent to the element layer 10h (refer to Figure 3 ). The second region R2 includes the remaining element body layer.

[0036] 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 (main surface 2d). The external electrodes 3 and 4 have the same shape. The external electrodes 3 and 4 are provided on the mounting surface (main surface 2d) separated from each other in the second direction D2. Specifically, the external electrode 3 is provided on the end surface 2a side of the element body 2. The external electrode 4 is provided on the end surface 2b side of the element body 2.

[0037] The coil 5 is arranged in the element body 2. Figure 3 As shown, 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 inside 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.

[0038] like Figure 2 As shown, the first connecting conductor 6 is disposed 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 connects 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 Figure 3 In this embodiment, the first connecting conductor 6 has a rectangular cross section (a cross section along the second direction D2 and the third direction D3) perpendicular to the extending direction (the first direction D1). That is, the first connecting conductor 6 has a prismatic shape.

[0039] 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 connects 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 16a, 16b, 16c, 16d, and 16e (see Figure 3 In this embodiment, the second connecting conductor 7 has a rectangular cross section (a cross section along the second direction D2 and the third direction D3) perpendicular to the extending direction (the first direction D1). That is, the second connecting conductor 7 has a prismatic shape.

[0040] like Figure 3As shown, the coil component 1 includes multiple layers La, Lb, Lc, Ld, Le, Lf, Lg, and Lh. The coil component 1 is constructed by, for example, stacking layers La to Lh in order from the main surface 2c side. In the coil component 1 of this embodiment, each layer includes multiple layers Lc and Lg.

[0041] The layer La is composed of the element body layer 10 a and constitutes the principal surface 2 c of the element body 2 .

[0042] Layer Lb is composed of a combination of element layer 10b and coil conductor layer 12a. The element layer 10b has a cutout (not shown) corresponding in shape to the coil conductor layer 12a, into which the coil conductor layer 12a fits. The element layer 10b and coil conductor layer 12a are complementary to each other.

[0043] Layer Lc is formed by combining the element layer 10c, the coil conductor layer 12b, and the second connecting conductor layer 16a. The element layer 10c has a cutout (not shown) corresponding in shape to the coil conductor layer 12b and the second connecting conductor layer 16a, into which the coil conductor layer 12b and the second connecting conductor layer 16a fit. The element layer 10c and the coil conductor layer 12b and the second connecting conductor layer 16a complement each other.

[0044] Layer Ld is composed of a combination of the element layer 10d, the coil conductor layer 12c, and the second connecting conductor layer 16b. The element layer 10d has a cutout (not shown) corresponding in shape to the coil conductor layer 12c and the second connecting conductor layer 16b, into which the coil conductor layer 12c and the second connecting conductor layer 16b fit. The element layer 10d and the coil conductor layer 12c and the second connecting conductor layer 16b complement each other.

[0045] Layer Le is composed of a combination of the element layer 10e, the coil conductor layer 12d, and the second connecting conductor layer 16c. The element layer 10e has a cutout (not shown) corresponding in shape to the coil conductor layer 12d and the second connecting conductor layer 16c, into which the coil conductor layer 12d and the second connecting conductor layer 16c fit. The element layer 10e, the coil conductor layer 12d, and the second connecting conductor layer 16c complement each other.

[0046] Layer Lf is composed of a combination of element layer 10f, coil conductor layer 12e, and second connecting conductor layer 16d. The element layer 10f has a cutout (not shown) corresponding in shape to the coil conductor layer 12e and second connecting conductor layer 16d, into which the coil conductor layer 12e and second connecting conductor layer 16d fit. The element layer 10f and the coil conductor layer 12e and second connecting conductor layer 16d complement each other.

[0047] Layer Lg is formed by combining the element body layer 10g, the first connecting conductor layer 14a, and the second connecting conductor layer 16e. The element body layer 10g is provided with a notch (not shown) having a shape corresponding to the first connecting conductor layer 14a and the second connecting conductor layer 16e, into which the first connecting conductor layer 14a and the second connecting conductor layer 16e fit. The element body layer 10g and the first connecting conductor layer 14a and the second connecting conductor layer 16e are complementary to each other.

[0048] Layer Lh is formed by combining the element body layer 10h, the base metal layer 8 of the external electrode 3, and the base metal layer 8 of the external electrode 4. The element body layer 10h is provided with a notch (not shown) corresponding to the shape of each base metal layer 8, into which each base metal layer 8 is inserted. The element body layer 10h, the base metal layer 8 of the external electrode 3, and the base metal layer 8 of the external electrode 4 are complementary to each other. Layer Lh constitutes the main surface 2d of the element body 2.

[0049] Next, the external electrodes 3 and 4 are described in detail. Figure 4 As shown, 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 arranged apart from the outer edge of the main surface 2d.

[0050] When viewed from a first direction D1 perpendicular to the mounting surface, 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. The outer surface 2s has a pair of peripheral portions 2h surrounding the external electrode 3 and the external electrode 4, respectively. The peripheral portions 2h are rectangular rings.

[0051] like Figure 5 As shown, the external electrodes 3 and 4 each include a base metal layer 8 and a plating layer 9. The base metal layer 8 is provided on the outer surface 2s. The base metal layer 8 is provided only on the mounting surface (main surface 2d). The base metal layer 8 has an exposed surface 8a that is exposed from the element body 2. In this embodiment, the exposed surface 8a is flush with the main surface 2d.

[0052] The base metal layer 8 includes an embedded portion 8b embedded within the element body 2. The embedded portion 8b is located further inward of the element body 2 than the outer surface 2s (here, the main surface 2d). In this embodiment, the entire base metal layer 8 constitutes the embedded portion 8b. The embedded portion 8b includes an opposing surface 8c that opposes the exposed surface 8a, and four side surfaces 8d adjacent to the exposed surface 8a. The side surfaces 8d extend toward the interior of the element body 2, connecting the exposed surface 8a and the opposing surfaces 8c. The angle formed between the side surfaces 8d and the peripheral portion 2h is, for example, less than 90 degrees. If the side surfaces 8d and the peripheral portion 2h are separated from each other, the angle formed between an imaginary plane containing the side surfaces 8d and an imaginary plane containing the peripheral portion 2h may be the same as the angle formed between the side surfaces 8d and the peripheral portion 2h. Alternatively, the angle formed between the side surfaces 8d and the exposed surface 8a may be, for example, greater than 90 degrees. The angle formed between the side surfaces 8d and the peripheral portion 2h may also be greater than 90 degrees.

[0053] The base metal layer 8 is formed of a conductive material such as Ag, Cu, Ni, Sn, or Au. The base metal layer 8 contains substantially no glass. The glass content of the base metal layer 8 is, for example, less than 0.5%. Therefore, compared to base metal layers containing glass, the surface area of ​​the base metal material on the base metal layer 8 is larger. This facilitates plating.

[0054] The plating layer 9 covers the base metal layer 8. The plating layer 9 covers the entire exposed surface 8a. The plating layer 9 includes a protrusion 9b provided at the outer edge 9a of the plating layer 9 and extending into the interior of the element body 2. The protrusion 9b covers the end of the side surface 8d near the exposed surface 8a. The protrusion 9b is provided, for example, at the outer edge 9a adjacent to the central region 2g. The protrusion 9b is provided, for example, along the entire circumference of the outer edge 9a.

[0055] The protrusions 9b are formed by plating into the gaps between the soft magnetic metal particles P and the embedded portions 8b. The average depth of the protrusions 9b into the element body 2 is, for example, 1 / 2 or more of the average particle size of the soft magnetic metal particles P.

[0056] The average particle size of the soft magnetic metal particles P is 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 by software. Through image processing, the boundaries of the soft magnetic metal particles P are determined, and the area of ​​the soft magnetic metal particles P is obtained. Based on the obtained area of ​​the soft magnetic metal particles P, the particle size converted into the equivalent circle diameter is obtained. Here, the particle size of more than 100 soft magnetic metal particles P is calculated, and the particle size distribution of these soft magnetic metal particles P is obtained. The particle size (d50) at 50% of the cumulative value in the obtained particle size distribution is taken as the "average particle size". There is no particular restriction on the particle shape of the soft magnetic metal particles P.

[0057] The average depth of the protrusion 9b is 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 when the coil component 1 is cut along a plane parallel to the side surfaces 2e and 2f and passing through the external electrodes 3 and 4. The position of the third direction D3 is changed and a plurality of cross-sectional photographs are obtained. In the obtained cross-sectional photograph, the plane including the main surface 2d is used as the reference plane, and the length of the first direction D1 from the reference plane to the front end of the protrusion 9b is calculated as the depth of the protrusion 9b. Based on one cross-sectional photograph, the depth of a maximum of four protrusions 9b is calculated. Here, for example, the depth of the protrusion 9b is calculated based on five or more cross-sectional photographs, and the average value of these depths is used as the "average depth" of the protrusion 9b.

[0058] Next, a method for manufacturing the coil component 1 is described. Soft magnetic metal particles P are mixed with an insulating resin and a solvent to prepare a slurry containing the soft magnetic metal particles P. For example, the slurry is applied to a substrate (e.g., a PET film) by screen printing or a doctor blade method, forming a green sheet to become the element layer 10a on the substrate.

[0059] A conductive pattern is formed on a substrate by plating or screen printing. Next, a slurry is applied to the substrate, for example, by screen printing, so as to fill the area surrounding the conductive pattern. This forms a green sheet of multiple element layers 10b, 10c, 10d, 10e, 10f, 10g, and 10h on the substrate.

[0060] In this embodiment, a first slurry for forming the first region R1 and a second slurry for forming the second region R2 are prepared as the aforementioned slurries. The first slurry contains a greater amount of insulating resin and solvent than the second slurry. For example, the first slurry is used to form the element layer 10h and one element layer 10g adjacent to the element layer 10h. The second slurry is used to form the remaining element layers.

[0061] Next, the green sheets that will become the multiple element layers 10a to 10h are transferred and stacked in sequence for each conductor pattern. Punching is performed in the stacking direction to form a laminate substrate of the green sheets. Next, a cutting machine equipped with a rotary blade is used to cut the laminate substrate into chips of a specified size to form a single-piece laminate. Next, the single-piece laminate is fired to form a laminate. By firing, the insulating resin and solvent of the slurry are burned off, thereby forming gaps between the soft magnetic metal particles P, P. The content of the insulating resin and solvent in the first slurry is greater than the content of the insulating resin and solvent in the second slurry, so the size of the gap in the first region R1 is greater than the size of the gap in the second region R2.

[0062] Next, the laminate is immersed in a resin solution to impregnate the laminate with the resin, which is then cured using heat. This forms the element body 2. Next, the plating layer 9 is formed using a plating method. At this time, the protrusion 9b is easily formed in the first region R1 due to the larger volume of the gap. Through the above, the coil component 1 is formed.

[0063] As described above, in the coil component 1 of this embodiment, since the plating layer 9 has the protrusion 9b that penetrates into the interior of the element body 2, the surface area of ​​the plating layer 9 bonded to the solder increases compared to a structure without the protrusion 9b. This improves the bonding strength between the external electrodes 3 and 4 and the solder.

[0064] Since the external electrodes 3 and 4 are provided only on the main surface 2d, which serves as the mounting surface, it is important to improve the bonding strength between the external electrodes 3 and 4 and the solder, compared to a structure in which the external electrodes 3 and 4 are provided across multiple surfaces of the element body 2. Therefore, a structure in which the plating layer 9 has the protrusions 9b is particularly effective.

[0065] The base metal layer 8 has an embedded portion 8b embedded in the element body 2. Therefore, the external electrodes 3 and 4 are less likely to be separated from the element body 2. Therefore, the mounting strength when the coil component 1 is mounted on the circuit board by solder can be improved.

[0066] The angle formed between the peripheral edge 2h of the element body 2 and the side surface 8d of the embedded portion 8b is less than 90 degrees. Therefore, the gap between the soft magnetic metal particles P and the side surface 8d is easily increased. Since the protrusions 9b of the plating layer 9 are formed in the larger gap, the surface area of ​​the plating layer 9 bonded to the solder is further increased. This further enhances the bonding strength between the external electrodes 3 and 4 and the solder.

[0067] Since the base metal layer 8 does not contain a glass component, the area of ​​the base metal material on the surface of the base metal layer 8 becomes larger than that of a structure in which the base metal layer 8 contains a glass component. Therefore, plating formation can be facilitated.

[0068] The protrusions 9b are provided over the entire circumference of the outer edge 9a of the plating layer 9. This increases the surface area of ​​the plating layer 9 over the entire circumference of the outer edge 9a, thereby further improving the bonding strength between the external electrodes 3 and 4 and the solder.

[0069] Since the protrusion 9b is arranged on the outer edge portion 9a adjacent to the central area 2g, the bonding strength between the external electrodes 3 and 4 and the solder can be improved in the portion where stress is easily applied when the coil component 1 is installed, that is, the portion between the central area 2g and the external electrodes 3 and 4.

[0070] The average depth of the protrusions 9b penetrating into the element body 2 is equal to or greater than 1 / 2 of the average particle size of the soft magnetic metal particles P. This ensures that the bonding strength between the external electrodes 3 and 4 and the solder is increased.

[0071] The average particle size of the soft magnetic metal particles P contained in the first region R1 is larger than the average particle size of the soft magnetic metal particles P contained in the second region R2. In the first region R1, the gaps between the soft magnetic metal particles P tend to be larger, thereby facilitating the formation of protrusions 9b. In the second region R2, the gaps between the soft magnetic metal particles P tend to be smaller, thereby maintaining the characteristics of the coil 5.

[0072] (Second embodiment)

[0073] Reference Figures 6 to 8 , a coil component 20 according to a second embodiment will be described. Figure 6 It is a perspective view of a coil component according to a second embodiment. Figure 7 yes Figure 6 A cross-sectional view of the coil component is shown. Figure 8 yes Figure 6 The exploded perspective view of the coil component is shown in FIG. Figures 6 to 8 As shown, the coil component 20 includes an element body 22, an external electrode 23, an external electrode 24, a coil 25, a first connection conductor 26, and a second connection conductor 27. The coil component 20 is a laminated coil component.

[0074] The element body 22 has, for example, the same shape as the element body 2 of the coil component 1. The outer surface 22s of the element body 22 has a pair of end faces 22a, 22b, a pair of main faces 22c, 22d, and a pair of side faces 22e, 22f. The end faces 22a, 22b are opposite to each other. The main faces 22c, 22d are opposite to each other. The side faces 22e, 22f are opposite to each other. In this embodiment, the relative direction of the main faces 22c, 22d is set to a first direction D1, the relative direction of the end faces 22a, 22b is set to a second direction D2, and the relative direction of the side faces 22e, 22f 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.

[0075] The end surfaces 22a and 22b extend in the first direction D1, connecting the main surfaces 22c and 22d. The end surfaces 22a and 22b also extend in the third direction D3, connecting the side surfaces 22e and 22f. The main surfaces 22c and 22d extend in the second direction D2, connecting the end surfaces 22a and 22b. The main surfaces 22c and 22d also extend in the third direction D3, connecting the side surfaces 22e and 22f. The side surfaces 22e and 22f extend in the first direction D1, connecting the main surfaces 22c and 22d. The side surfaces 22e and 22f also extend in the second direction D2, connecting the end surfaces 22a and 22b.

[0076] The main surface 22d is a mounting surface, for example, the surface facing the other electronic device when the coil component 1 is mounted on another electronic device (not shown) (e.g., a circuit substrate or a laminated coil component). The end surfaces 22a and 22b are surfaces that are continuous from the mounting surface (i.e., the main surface 22d). The end surfaces 22a and 22b are surfaces adjacent to the mounting surface.

[0077] End surfaces 22a and 22b have, for example, the same shape as end surfaces 2a and 2b of coil component 1. Main surfaces 22c and 22d have, for example, the same shape as main surfaces 2c and 2d of coil component 1. Side surfaces 22e and 22f have, for example, the same shape as side surfaces 2e and 2f of coil component 1.

[0078] The element body 22 is formed by stacking a plurality of element body layers (magnetic layers) 30 in a first direction D1. That is, the stacking direction of the element body 22 is the first direction D1. The specific stacking structure will be described later. In the actual element body 22, the plurality of element body layers 30 are integrated to the extent that the boundaries between the layers cannot be identified. The element body 22 is made of the same material as the element body 2 of the coil component 1, and contains a plurality of soft magnetic metal particles P (see Figure 5 A resin is present in at least a portion of the gaps between the soft magnetic metal particles P, 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.

[0079] The external electrodes 23 and 24 are provided on the element body 22 and connected to the coil 25. The external electrodes 23 and 24 are provided at both ends of the element body 22 in the second direction D2 and are separated from each other in the second direction D2. The external electrodes 23 and 24 have the same shape.

[0080] The external electrode 23 is arranged on the end face 22a side of the element body 22. The external electrode 23 includes five electrode portions: a first electrode portion 23a located on the end face 22a, a second electrode portion 23b located on the principal face 22c, a third electrode portion 23c located on the principal face 22d, a fourth electrode portion 23d located on the side face 22e, and a fifth electrode portion 23e located on the side face 22f. The first electrode portion 23a, the second electrode portion 23b, the third electrode portion 23c, the fourth electrode portion 23d, and the fifth electrode portion 23e are connected at the ridges of the element body 22 and are electrically connected to each other. The external electrode 23 is formed on five surfaces: one end face 22a, a pair of principal faces 22c and 22d, and a pair of side faces 22e and 22f. The first electrode portion 23a, the second electrode portion 23b, the third electrode portion 23c, the fourth electrode portion 23d, and the fifth electrode portion 23e are integrally formed.

[0081] In this embodiment, the edges (end faces) of the second electrode portion 23b and the third electrode portion 23c of the external electrode 23 are, for example, along the third direction D3. The edge of the second electrode portion 23b is formed linearly on the main surface 22c. The edge of the third electrode portion 23c is formed linearly on the main surface 22d. The edges of the fourth electrode portion 23d and the fifth electrode portion 23e of the external electrode 23 are along the first direction D1. The edge of the fourth electrode portion 23d is formed linearly on the side surface 22e. The edge of the fifth electrode portion 23e is formed linearly on the side surface 22f. In addition, the shape of the edges of the second electrode portion 23b, the third electrode portion 23c, the fourth electrode portion 23d, and the fifth electrode portion 23e can also be curved or formed into a concave-convex shape.

[0082] The external electrode 24 is arranged on the end face 22b side of the element body 22. The external electrode 24 includes five electrode portions: a first electrode portion 24a located on the end face 22b, a second electrode portion 24b located on the principal face 22c, a third electrode portion 24c located on the principal face 22d, a fourth electrode portion 24d located on the side face 22e, and a fifth electrode portion 24e located on the side face 22f. The first electrode portion 24a is connected to the second electrode portion 24b, the third electrode portion 24c, the fourth electrode portion 24d, and the fifth electrode portion 24e at the ridgeline of the element body 22 and are electrically connected to each other. The external electrode 24 is formed on five surfaces: one end face 22b, a pair of principal faces 22c and 22d, and a pair of side faces 22e and 22f. The first electrode portion 24a, the second electrode portion 24b, the third electrode portion 24c, the fourth electrode portion 24d, and the fifth electrode portion 24e are integrally formed.

[0083] In this embodiment, the edges of the second electrode portion 24b and the third electrode portion 24c of the external electrode 24 are, for example, along the third direction D3. The edge of the second electrode portion 24b is formed linearly on the main surface 22c. The edge of the third electrode portion 24c is formed linearly on the main surface 22d. The edges of the fourth electrode portion 24d and the fifth electrode portion 24e of the external electrode 24 are along the first direction D1. The edge of the fourth electrode portion 24d is formed linearly on the side surface 22e. The edge of the fifth electrode portion 24e is formed linearly on the side surface 22f. In addition, the shape of the edges of the second electrode portion 24b, the third electrode portion 24c, the fourth electrode portion 24d, and the fifth electrode portion 24e can also be curved or formed into a concave-convex shape.

[0084] The external electrodes 23 and 24 each include a base metal layer 28 and a plating layer 29. The base metal layer 28 is provided on the outer surface 22s. The base metal layer 28 of the external electrode 23 is provided on five surfaces: one end surface 22a, a pair of main surfaces 22c and 22d, and a pair of side surfaces 22e and 22f. The base metal layer 28 of the external electrode 24 is provided on five surfaces: one end surface 22b, a pair of main surfaces 22c and 22d, and a pair of side surfaces 22e and 22f. The base metal layer 28 is provided on the outside of the element body 22, for example, and is not embedded within the element body 22. The base metal layer 28 is formed of a conductive material such as Ag, Cu, Ni, Sn, or Au. The base metal layer 28 may contain a glass component, for example, but may also be substantially free of glass.

[0085] The plating layer 29 covers the base metal layer 28. The plating layer 29 covers the entire outer surface of the base metal layer 28. The plating layer 29 includes a protrusion 29b provided on the outer edge 29a of the plating layer 29 and extending into the interior of the element body 2. The protrusion 29b is provided, for example, along the entire circumference of the outer edge 29a. Alternatively, the protrusion 29b may be provided only on the outer edge 29a, on the principal surface 22d (mounting surface) of the principal surfaces 22c, 22d and the side surfaces 22e, 22f.

[0086] The protrusions 29b are plated into the soft magnetic metal particles P (see Figure 5 The average depth of the protrusions 29b entering the element body 22 is, for example, 1 / 2 or more of the average particle size of the soft magnetic metal particles P.

[0087] The coil 25 is arranged in the element body 22. The coil 25 is composed of a plurality of coil conductors 32a to 32h (see Figure 8 ). Multiple coil conductors 32a to 32h are electrically connected to each other, forming the coil 25 within the element body 22. The coil axis of the coil 25 is arranged along the first direction D1. Adjacent coil conductors 32a to 32h are electrically connected via through-hole conductors (not shown). The coil conductors 32a to 32h are arranged separately from the end faces 22a, 22b, the main faces 22c, 22d, and the side faces 22e, 22f.

[0088] The first connection conductor 26 is disposed in the element body 22. The first connection conductor 26 connects the external electrode 23 and the coil 25. The first connection conductor 26 connects the external electrode 23 and one end of the coil 25. The first connection conductor 26 is formed integrally with the coil conductor 32a.

[0089] The second connection conductor 27 is disposed in the element body 22. The second connection conductor 27 connects the external electrode 24 and the coil 25. The second connection conductor 27 is connected to the external electrode 24 and the other end of the coil 25. The second connection conductor 27 is formed integrally with the coil conductor 32h.

[0090] Coil conductors 32a-32h, first connecting conductor 26, and second connecting conductor 27 are made of a conductive material commonly used as a coil conductor. Examples of conductive materials include Ag, Cu, Au, Al, Pd, and Pd / Ag alloys. In this embodiment, the conductive material is Ag. Coil conductors 32a-32h, first connecting conductor 26, and second connecting conductor 27 are formed as a sintered body of a conductive paste containing any of these conductive materials.

[0091] In the method of manufacturing the coil component 20 , the contents of the insulating resin and solvent in the slurry may be adjusted to increase the volume of the gap in the region of the element body 22 that contacts the outer edge portion 29 a of the plating layer 29 .

[0092] As described above, in the coil component 20 of this embodiment, the plating layer 29 also has the protrusion 29b that penetrates into the interior of the element body 22. Therefore, compared with a structure in which the plating layer 29 does not have the protrusion 29b, the surface area of ​​the plating layer 29 bonded to the solder increases. This can improve the bonding strength between the external electrodes 23 and 24 and the solder.

[0093] The average particle size of the soft magnetic metal particles P in the vicinity of the main surface 22d of the element body 22 can, for example, be larger than the average particle size of the soft magnetic metal particles P in other areas. In this case, the protrusions 29b provided on the main surface 22d are larger than the protrusions 29b provided on the main surface 22c and the side surfaces 22e and 22f. This further increases the surface area of ​​the plating layer 29 fixed to the solder on the main surface 22d. As a result, the mounting strength can be improved.

[0094] As mentioned above, although embodiment of this disclosure was described, this disclosure is not necessarily limited to the above-mentioned embodiment, Various changes can be made without departing from the scope of the present disclosure.

[0095] In the above embodiment, coil components 1 and 20 are used as an example of coil components. However, the coil components are not limited to coil components 1 and 20, and other coil components may be used. For example, the number and shape of coil conductors constituting coils 5 and 25 are not limited.

[0096] Figure 9 This is a cross-sectional view of a coil component according to a first variation of the first embodiment. As shown in this figure, coil component 1A of the first variation differs from coil component 1 in that first region R1 includes a third region R3. The average particle size of the soft magnetic metal particles P in third region R3 is larger than the average particle size of the soft magnetic metal particles P in the remainder of first region R1 and the average particle size of the soft magnetic metal particles in second region R2. The volume of the gaps in third region R3 is equal to the volume of the gaps in the remainder of first region R1 and larger than the volume of the gaps in second region R2.

[0097] The third region R3 is, for example, provided between the embedded portions 8b of the external electrodes 3 and 4. The third region R3 includes the central region 2g as its outer surface. For example, the third region R3 includes the region of the element layer 10h corresponding to the central region 2g. The thickness (length in the first direction D1) of the third region R3 is, for example, equal to the thickness (length in the first direction D1) of the external electrodes 3 and 4.

[0098] When manufacturing coil component 1A, a third slurry is prepared as a slurry in addition to the first and second slurries for forming third region R3. The insulating resin and solvent contents of the third slurry are equivalent to those of the first slurry and greater than those of the second slurry. The average particle size of the soft magnetic metal particles P in the third slurry is larger than both the average particle size of the soft magnetic metal particles P in the first slurry and the average particle size of the soft magnetic metal particles P in the second slurry.

[0099] In coil component 1A, plating layer 9 also has protrusions 9b, achieving the same effects as coil component 1. In third region R3, the average particle size of soft magnetic metal particles P is large. Therefore, on side surface 8d in contact with third region R3, the gap between side surface 8d and soft magnetic metal particles P is more likely to increase. By forming protrusions 9b of plating layer 9 in a larger gap, the surface area of ​​plating layer 9 bonded to the solder is further increased. This further enhances the bonding strength between external electrodes 3 and 4 and the solder.

[0100] Because the third region R3 includes the central region 2g as its outer surface, the protrusions 9b provided on the outer edge 9a adjacent to the central region 2g are likely to be larger than the protrusions 9b provided on the outer edge 9a distal to the central region 2g. Consequently, the average depth of the protrusions 9b provided on the outer edge 9a adjacent to the central region 2g can be made deeper than the average depth of the protrusions 9b provided on the outer edge 9a distal to the central region 2g. In this way, even if the average particle size of the soft-magnetic metal particles P varies depending on the location of the protrusions 9b, the average depth of the protrusions 9b penetrating into the element body 2 is at least half the average particle size of the soft-magnetic metal particles P provided proximate to the protrusions 9b.

[0101] In the coil component 1A, the third region R3 is a portion of the first region R1 , but the third region R3 may be provided in the entire first region R1 . In this case, it is not necessary to prepare the first slurry.

[0102] Figure 10This is a cross-sectional view of a coil component according to a second variant of the first embodiment. As shown in the figure, the coil component 1B according to the second variant differs from the coil component 1 in that the base metal layer 8 has a bent portion 8e. The bent portion 8e bends toward the inside of the element body 2. When viewed from the third direction D3, the bent portion 8e protrudes from the end portion on the side of the central area 2g of the exposed surface 8a toward the center of the second direction D2 of the element body 2 and the center of the first direction D1 of the element body 2. When viewed from the first direction D1, the bent portion 8e overlaps with the central area 2g. The bent portion 8e is buried inside the element body 2. The entire base metal layer 8 including the bent portion 8e constitutes the buried portion 8b.

[0103] In the coil component 1B, the plating layer 9 also has a protrusion 9b, so the same effect as the coil component 1 can be obtained. In the coil component 1B, the base metal layer 8 has a bent portion 8e embedded in the interior of the element body 2, so the external electrodes 3 and 4 are more difficult to peel off from the element body 2. Therefore, the installation strength when the coil component 1B is mounted on the circuit board by solder can be further improved. Due to the flexural stress during installation, cracks starting from the portion between the central area 2g and the external electrodes 3 and 4 are likely to occur in the element body 2. In the coil component 1B, a bent portion 8e is provided at a location where cracks are likely to occur. Therefore, cracks can be suppressed.

[0104] The curved portion 8e includes one of the four side surfaces 8d. The angle formed between the side surface 8d of the curved portion 8e and the peripheral edge 2h is, for example, smaller than the angles formed between the other three side surfaces 8d and the peripheral edge 2h. This facilitates increasing the gap between the side surface 8d of the curved portion 8e and the soft-magnetic metal particles P. By forming the protrusions 9b of the plating layer 9 in a relatively large gap, the surface area of ​​the plating layer 9 bonded to the solder is further increased. This further enhances the bonding strength between the external electrodes 3 and 4 and the solder.

[0105] Since the curved portion 8e is provided adjacent to the end portion of the exposed surface 8a on the central region 2g side, the protrusion 9b provided on the outer edge portion 9a adjacent to the central region 2g is likely to be larger than the protrusion 9b provided on the outer edge portion 9a away from the central region 2g. Therefore, similar to the coil component 1A, the average depth of the protrusion 9b provided on the outer edge portion 9a adjacent to the central region 2g can be made deeper than the average depth of the protrusion 9b provided on the outer edge portion 9a away from the central region 2g.

Claims

1. A coil component comprising: A body containing soft magnetic metal particles; a coil disposed in the body; and an external electrode connected to the coil, The external electrode includes: a base metal layer provided on the outer surface of the element body; and a plating layer covering the base metal layer. The plating layer includes a protrusion provided at an outer edge of the plating layer and penetrating into the element body.

2. The coil component according to claim 1, wherein The outer surface has a mounting surface, The external electrodes are only provided on the mounting surface.

3. The coil component according to claim 1 or 2, wherein The base metal layer has an embedded portion embedded in the element body. The coil component according to claim 3 , wherein: The outer surface has a peripheral edge portion of the external electrode, The embedded portion has: an exposed surface exposed from the outer surface; and a side surface adjacent to the exposed surface, An angle formed between the peripheral portion and the side surface is smaller than 90 degrees.

5. The coil component according to claim 1 or 2, wherein The base metal layer does not contain glass components.

6. The coil component according to claim 1 or 2, wherein The protrusion is provided over the entire circumference of the outer edge of the plating layer.

7. The coil component according to claim 1 or 2, wherein The outer surface has: a mounting surface; and a pair of end surfaces adjacent to and opposite to the mounting surface, The pair of external electrodes are provided on the mounting surface so as to be separated from each other in the opposing direction of the pair of end surfaces. The mounting surface has a central region disposed between the pair of external electrodes when viewed from a direction perpendicular to the mounting surface. The protrusion is provided at an outer edge portion of the plating layer adjacent to the central region.

8. The coil component according to claim 1 or 2, wherein The element body includes: a first region provided in contact with the external electrode; and a second region provided in contact with the coil. An average particle size of the soft magnetic metal particles contained in the first region is larger than an average particle size of the soft magnetic metal particles contained in the second region.

9. The coil component according to claim 1 or 2, wherein The average depth of the protrusions penetrating into the element body is equal to or greater than 1 / 2 of the average particle size of the soft magnetic metal particles.

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