Coil component and mounting board

Abstract

To improve adhesion between a coil component and a substrate, enabling high-density mounting.SOLUTION: A coil component according to an embodiment includes a magnetic base containing metal magnetic particles, having a first surface and a second surface adjacent to each other as outer surfaces, and having a first ridge extending between the first surface and the second surface, a conductor provided inside or on the surface of the magnetic base, an insulating layer provided on the surface of the magnetic base and extending from the first surface to the second surface via the first ridge, and an external electrode electrically connected to the conductor, spaced apart from the first ridge, and provided on the first surface.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a coil component and a mounting board. [Background technology]

[0002] As digital electronic devices become increasingly smaller and more powerful, there is a growing need for higher density electronic circuits. This has led to a demand for surface-mount electronic components that can accommodate the reduction of the board's land area by providing external electrodes only on the bottom surface, which corresponds to the mounting surface of the component. External electrodes that are provided only on the bottom surface are also called single-surface electrodes.

[0003] For example, Patent Document 1 discloses a multilayer electronic component in which a part of the element body, which is a magnetic material, fits into a concave wedge portion of an external electrode to improve adhesion between the external electrode and the element body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-061409 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of surface-mounted electronic components equipped with external electrodes as described in Patent Document 1, it has been found that the surface area of ​​the external electrodes shrinks as electronic components become smaller, resulting in a decrease in adhesion between the external electrodes and the substrate, and a decrease in mechanical reliability. In particular, in coil components, the solder fillet wets and rises to the surface of the magnetic substrate during mounting, reducing adhesion.

[0006] In view of the above circumstances, an object of the present invention is to improve the adhesion between a coil component and a substrate, thereby enabling high-density mounting. [Means for solving the problem]

[0007] In order to solve the above problem, a coil component according to one embodiment of the present invention comprises: a magnetic base containing metal magnetic particles, having a first surface and a second surface adjacent to each other as outer surfaces, and having a first ridge extending between the first surface and the second surface; a conductor provided inside or on the surface of the magnetic base; an insulating layer provided on the surface of the magnetic base and extending from the first surface to the second surface via the first ridge; and an external electrode electrically connected to the conductor, spaced apart from the first ridge, and provided on the first surface.

[0008] In a coil component according to one aspect of the present invention, the distance from the first surface to the farthest position of the external electrode in a direction perpendicular to the first surface is greater than the distance from the first surface to the farthest position of the insulating layer. According to a coil component according to one embodiment of the present invention, in a direction perpendicular to the first surface, the distance between the farthest position of the insulating layer and the farthest position of the external electrode is smaller than the distance from the first surface to the farthest position of the insulating layer.

[0009] In the coil component according to one aspect of the present invention, the insulating layer covers the second surface. In a coil component according to one aspect of the present invention, the insulating layer is made of resin and ceramic particles. In a coil component according to one aspect of the present invention, the external electrode has a base electrode layer and a plating layer provided on the outside of the base electrode layer, and the plating layer is in contact with the insulating layer.

[0010] In a coil component according to one aspect of the present invention, a part of the outer periphery of the base electrode layer is covered with an insulating layer, and the plating layer is provided inside the outer periphery of the base electrode layer. In a coil component according to one aspect of the present invention, the base electrode layer has a flat portion on the same surface as the first surface or at a position recessed from the first surface. A mounting board according to one embodiment of the present invention comprises the coil component, a substrate having lands to which the external electrodes are soldered, and solder that connects the lands and the external electrodes and forms a fillet spaced apart from the second surface. Furthermore, a mounting board according to one aspect of the present invention includes the coil component, a substrate having lands to which the external electrodes are soldered, and solder that connects the lands and the external electrodes and forms a fillet spaced apart from the second surface. [Effects of the Invention]

[0011] According to the present invention, the adhesion between the coil component and the substrate can be improved, enabling high-density mounting. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view showing a coil component according to an embodiment of the present invention; [Figure 2] FIG. 2 is a bottom perspective view of the coil device shown in FIG. [Figure 3] FIG. 2 is a schematic cross-sectional view of the coil component shown in FIG. [Figure 4] FIG. 10 is a partially enlarged view showing the shape of a solder fillet in a comparative example. [Figure 5] FIG. 4 is a partially enlarged view showing the shape of a solder fillet in the present embodiment. [Figure 6] 10A and 10B are diagrams showing modified examples corresponding to a reduction in the thickness of the solder; [Figure 7] 10 is a graph showing the results of an impact test for a comparative example and the present embodiment. [Figure 8] 10A and 10B are diagrams showing modified examples in which the number of external electrodes is different. [Figure 9] FIG. 10 is a cross-sectional view showing a modified example in which the structure of the external electrode is different. [Figure 10] FIG. 10 is a bottom view showing a modified example in which the structure of the external electrodes is different. [Figure 11] 10A and 10B are diagrams showing a modified example in which the insulating layer is formed over a wide area. [Figure 12]FIG. 10 is a diagram showing a modified example in which the insulating layer is formed over a narrow area. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the configuration of the present invention. The configuration of the embodiments may be modified or changed as appropriate depending on the specifications of the device to which the present invention is applied and various conditions (such as usage conditions and usage environment).

[0014] The technical scope of the present invention is defined by the claims and is not limited by the individual embodiments described below. The drawings used in the following description may differ in scale and shape from the actual structure to make each configuration easier to understand. The correspondence between the drawings may also differ in some places to simplify the description. Components shown in previously described drawings may be referenced as appropriate in the description of subsequent drawings.

[0015] <One embodiment of the coil component> FIG. 1 is a perspective view showing a coil device 100 according to one embodiment of the present invention. The coil component 100 is mounted on a substrate 200. The substrate 200 is provided with, for example, two land portions 201. The coil component 100 has, for example, two external electrodes 12. The coil component 100 is mounted on the substrate 200 by joining each external electrode 12 and the land portion 201 with solder.

[0016] The circuit board 10 includes a coil component 100 and a substrate 200 on which the coil component 100 is mounted. The circuit board 10 is included in a variety of electronic devices. Examples of electronic devices that include the circuit board 10 include automotive electrical components, servers, board computers, and various other electronic devices.

[0017] The coil component 100 may be an inductor, a transformer, a filter, a reactor, or any of various other coil components. The coil component 100 may be a coupled inductor, a choke coil, or any of various other magnetically coupled coil components. The coil component 100 may be, for example, an inductor used in a DC / DC converter. The uses of the coil component 100 are not limited to those explicitly described in this specification.

[0018] In this specification, unless otherwise understood in the context, the directions will be described based on the "L axis" direction, the "W axis" direction, and the "H axis" direction in Figure 1, which will be referred to as the "length" direction, the "width" direction, and the "height" direction, respectively. The coil device 100 has, for example, a rectangular parallelepiped outer shape. That is, the coil device 100 has outer surfaces at both ends in the length direction L, both ends in the height direction H, and both ends in the width direction W.

[0019] The rectangular parallelepiped coil device 100 has sides with a length L dimension in the range of 1.0 to 4.5 mm, a width W dimension in the range of 0.5 to 3.2 mm, and a height H dimension in the range of 0.5 to 2.0 mm. The height H dimension is smaller than the length L dimension, and further, the height H dimension is smaller than the width W dimension.

[0020] The outer surfaces of the coil device 100 may be flat, curved, or have a stepped portion. The eight corners and twelve ridges of the coil device 100 may be rounded. In this specification, even when the outer surface of the coil device 100 is partially curved or has steps, or when the corners or ridges of the coil device 100 are rounded, such a shape may be referred to as a "rectangular parallelepiped shape." In other words, in this specification, when we refer to a "rectangular parallelepiped" or a "rectangular parallelepiped shape," it does not mean a "rectangular parallelepiped" in the strict mathematical sense.

[0021] <Coil component structure> Fig. 2 is a bottom perspective view of the coil device 100 shown in Fig. 1, and Fig. 3 is a schematic cross-sectional view of the coil device 100. Fig. 3 shows a cross section taken along line AA shown in Fig. 1. The following description will be made with reference to Figs. 1 to 3.

[0022] The coil device 100 has a magnetic substrate 11 , external electrodes 12 and an insulating layer 13 , and has a conductor 14 inside the magnetic substrate 11 . The magnetic base 11 has, for example, a hexahedral shape, such as a rectangular parallelepiped shape. That is, the magnetic base 11 has a bottom surface 101 at one end in the height direction H and a top surface 102 at the other end in the height direction H. The magnetic base 11 also has side surfaces 103 at both ends in the length direction L. Furthermore, the magnetic base 11 has a front surface 104 at one end in the width direction W and a rear surface 105 at the other end in the width direction W.

[0023] The bottom surface 101 corresponds to an example of the "first surface" according to the present invention, and the side surface 103 corresponds to an example of the "second surface" according to the present invention. The top surface 102 and the bottom surface 101 are positioned back to back. "Back to back" means that the surfaces face outward in opposite directions. The top surface 102 is adjacent to the side surface 103, the front surface 104, and the rear surface 105, and the bottom surface 101 is adjacent to the side surface 103, the front surface 104, and the rear surface 105. "Adjacent" means that there is no other surface between the surfaces, but rather a ridge line between them. In the example shown here, the adjacent surfaces are positioned so that they intersect at right angles.

[0024] The ridge 31 extending between the bottom surface 101 and the side surface 103 of the magnetic base 11 is, for example, an R-surface. The magnetic base 11 in this embodiment is a magnetic body made of a metal magnetic material and a binder. The magnetic base 11 may be formed by a lamination method, a powder pressing method, or a molding method.

[0025] The binder serves to bond the metal magnetic materials together and also has high insulating properties to prevent electrical conduction. 6For example, a binder with a specific resistance of 10 8 For the purpose of increasing the mechanical strength, resin, glass, or metal oxide can be selected as the binder. 5 A resistance of Ω / sq. or more may be used.

[0026] Since the metal magnetic material, whose main component is Fe, itself has low resistance, it is desirable to adjust the components and mixing ratio of the binder to match the metal magnetic material. 8 A material having a resistivity of Ωcm or more is selected, and in order to enhance the insulating properties, a resin is included as a binder, and glass or metal oxide can be selected as a component other than resin.

[0027] The magnetic substrate 11 has a very high internal resistivity, as well as a surface that also contains a binder. The metal magnetic material is metal magnetic particles containing one or more of Fe, Ni, and Co. In addition to the metal magnetic particles, the metal magnetic material may also contain ceramic magnetic particles of one or more of Mg, Mn, and Ni, or non-magnetic particles such as silica. The metal magnetic particles may contain one or more of Si, Cr, Al, B, and P in addition to Fe, Ni, and Co, or multiple types of metal magnetic particles may be combined.

[0028] The particle size of the metal magnetic material is 1 μm or more and 60 μm or less. Furthermore, when the metal magnetic material further contains other materials such as metal fine particles, metal oxides, or ceramic materials in addition to the metal magnetic particles, the particle size of the other materials is 0.01 to 1 μm on average, which is smaller than that of the metal magnetic particles. When materials other than metal magnetic particles are contained, rather than improving the magnetic function, it is possible to, for example, reduce voids or compensate for mechanical strength. The magnetic base 11 has a filling rate of metal magnetic material of 80 vol% or more and 88 vol% or less, with the remainder being materials other than the metal magnetic material and including insulators or voids.

[0029] The conductor 14 is made of a metal material with excellent conductivity. Examples of the metal material for the conductor 14 include one or more of Cu, Al, Ni, and Ag, or an alloy containing any of these metals. The conductor 14 may be a wound metal wire with an insulating film on its surface, or may be formed on the surface of a substrate, sheet, or the like by plating or printing.

[0030] The conductor 14 of this embodiment has a winding portion that is wound one or more times. FIGS. 2 and 3 show the winding portion of the conductor 14. The number of turns of the winding portion is, for example, 1.5 turns or more and 10.5 turns or less. The shape of the winding portion may be planar or spiral. The winding portion may have, for example, two turns facing each other on the upper and lower sides to form a single assembly. FIGS. 2 and 3 show an example of a so-called horizontally wound winding portion in which the conductor wire is wound along the bottom surface 101 and the top surface 102 of the magnetic base 11. The conductor 14 may have a so-called vertically wound winding portion in which the conducting wire is wound around the side surface 103 of the magnetic base 11. The magnetic base 11 may also be a drum core type, in which case the conductor 14 winds around the surface of the magnetic base 11.

[0031] The conductor 14 has an extension portion (not shown) for electrical conduction with the outside. The extension portion connects the external electrode 12 to the conductor 14. Therefore, the external electrode 12 is electrically coupled to the conductor 14. The conductor 14 can be manufactured by any of the processes of winding, thin film, and lamination, and there are no particular limitations on the method.

[0032] As an example, the coil device 100 includes two external electrodes 12. The external electrodes 12 shown in FIGS. 1 to 3 are electrodes of a type called a one-surface electrode, and are provided on the bottom surface 101 of the magnetic base 11, for example. Note that "provided on the surface" means that the electrode is provided at a location that is visible when the surface is viewed, and may be provided so as to protrude outward from the surface or so as to recess inward from the surface. As will be described later, the external electrode 12 is partially protruding from the bottom surface 101 and partially embedded in the bottom surface 101. The range of the bottom surface 101 of the magnetic base 11 is the entire range up to the outer periphery, including the area where the external electrode 12 is provided. Furthermore, the position of the bottom surface 101 in the area where the external electrode 12 is provided is a flat extension position, ignoring any unevenness caused by the provision of the external electrode 12.

[0033] The external electrode 12 has a base electrode layer 21 and a plating layer 22 on the outside of the base electrode layer 21. The thickness of the base electrode layer 21 is, for example, 2 to 10 μm, and the thickness of the plating layer 22 is, for example, 2 to 10 μm. The outer surface of the base electrode layer 21 is flush with the bottom surface 101 and has a flat portion. Alternatively, the outer surface of the base electrode layer 21 is recessed from the plane flush with the bottom surface 101 and has a flat portion in the center. When the outer surface of the base electrode layer 21 and the bottom surface 101 have such a relationship, the thickness of the plating layer 22 becomes larger than the thickness of the base electrode layer 21, or the thickness of the plating layer 22 becomes smaller than the thickness of the base electrode layer 21.

[0034] Furthermore, the plating layer 22 is provided inside the outer periphery of the base electrode layer 21. This allows the plating layer 22 to have a stable overall thickness. The external electrode 12 may have a metal layer between the base electrode layer 21 and the plating layer 22. The total thickness of the external electrode 12 including the metal layer is, for example, 5 to 20 μm. In FIG. 3, for convenience of illustration, the thicknesses of the base electrode layer 21 and the plating layer 22 are shown to be thicker than they actually are.

[0035] Furthermore, the external electrode 12 may have a base electrode layer 21, a plating layer 22, and a conductive resin layer partially containing resin. The thickness of the conductive resin layer is, for example, 5 to 20 μm, and the thicknesses of the base electrode layer 21 and the plating layer 22 may be smaller than the thickness of the conductive resin layer. The total thickness of the external electrode 12 including the conductive resin layer is, for example, 10 to 30 μm. The external electrode 12 is made up of one or both of a layer made of the same component as the conductor 14 and a layer made of a component having a higher resistance than the conductor 14. The external electrode 12 is also made up of one or both of a layer having the same filling rate as the conductor 14 and a layer having a lower filling rate than the conductor 14.

[0036] The base electrode layer 21 is made of a metal material such as Ag, Cu, Ti, or Ni. The base electrode layer 21 is provided on the surface of the magnetic base 11 by plating, coating or printing of a metal material, sputtering, or vapor deposition. The base electrode layer 21 may be formed integrally with the magnetic base 11 during a lamination-type manufacturing process for the magnetic base 11. Alternatively, a portion of the base electrode layer 21 may be separated from other portions. The base electrode layer 21 is in close contact with the surface of the magnetic base 11 and the lead-out portion of the conductor 14, thereby integrating the external electrode 12 with the magnetic base 11 and establishing electrical continuity between the external electrode 12 and the conductor 14.

[0037] The plating layer 22 is made of a metal material with excellent conductivity. Examples of metal materials that can be used include Cu and Ag, and alternatively, Ni, Pd, and Sn. The plating layer 22 is formed in a layered structure, with layers made primarily of the respective metal materials or layers that are partially alloyed with each other. The plating layer 22 is provided to increase the strength of soldering to the external electrode 12.

[0038] When the external electrode 12 has the above-mentioned metal layer, the metal layer is made of the same metal material as the base electrode layer 21 and is formed so as to have a higher metal filling rate than the base electrode layer 21. The metal layer has a lower resistance and a higher static strength than the base electrode layer 21. When the external electrode 12 has the above-described conductive resin layer, the conductive resin layer uses the same metal material as the base electrode layer 21, and the metal material is mixed with resin. By including resin, the conductive resin layer has higher resistance and impact strength than the base electrode layer 21.

[0039] The insulating layer 13 is provided on the surface of the magnetic base 11, and extends from the side surface 103, over the ridge line 31, to the bottom surface 101. The insulating layer 13 extends partway up the side surface 103, and covers a portion of the side surface 103 adjacent to the bottom surface 101. The insulating layer 13 is made of resin and ceramic particles, for example. The insulating layer 13 has a melting point higher than the melting point of solder and the reflow temperature during mounting. The insulating layer 13 may be formed by printing, transferring, or dipping.

[0040] The insulating layer 13 may be formed before or after the formation of the plating layer 22. Forming the insulating layer 13 before the formation of the plating layer 22 is preferable because it suppresses the plating from extending toward the ridge line 31 when the plating layer 22 is formed. In this case, the thickness of the insulating layer 13 is set to be thin. Furthermore, the insulating layer 13 is set over a narrow range.

[0041] 1 to 3, the insulating layer 13 and the external electrode 12 are in contact with each other at their edges 12a, 13a. The edge 12a of the external electrode 12 here refers to the edge 12a of the plating layer 22 of the external electrode 12 that is closer to the side surface 103. There may be a gap between the insulating layer 13 and the external electrode 12.

[0042] The insulating layer 13 is in contact with the plating layer 22. The insulating layer 13 covers a portion of the outer surface of the base electrode layer 21, and the plating layer 22 is provided inside the outer periphery of the base electrode layer 21. With this relationship, the edge 13a of the insulating layer 13 does not extend beyond the extension of the edge 12a of the external electrode 12. Furthermore, it is preferable that the insulating layer 13 does not extend beyond the position of the edge 12a of the external electrode 12 in the length direction L. In other words, the insulating layer 13 is not present, for example, between the two external electrodes 12, on the front surface 104 and rear surface 105 of the magnetic base 11, or on the top surface 102 of the magnetic base 11. This reduces the volume occupied by the insulating layer 13, allowing the coil device 100 to be miniaturized while maintaining its magnetic properties, thereby enabling high-density packaging.

[0043] Comparing positions H2 and H3 on the external electrode 12 and the insulating layer 13 that are farthest from position H1 on the bottom surface 101 in the height direction H perpendicular to the bottom surface 101, the distance from position H1 on the bottom surface 101 to the farthest position H2 on the external electrode 12 is greater than the distance from position H1 on the bottom surface 101 to the farthest position H3 on the insulating layer 13. In other words, in the direction from the magnetic base 11 toward the substrate 200, the external electrode 12 protrudes outward more than the insulating layer 13.

[0044] Therefore, the cream solder applied to the surface of the external electrode 12 comes into contact with the land portion 201 of the substrate 200, ensuring reliable soldering. Furthermore, by providing the insulating layer 13, damage to the ridges 31 of the magnetic base 11 where no external electrodes 12 are present is suppressed.

[0045] FIG. 4 is a partially enlarged view showing the shape of a solder fillet in a comparative example, and FIG. 5 is a partially enlarged view showing the shape of a solder fillet in this embodiment. The coil device 1000 of the comparative example shown in FIG. 4 is the coil device 100 shown in FIGS. 1 to 3 without the insulating layer 13.

[0046] When coil component 1000 of the comparative example is soldered to land portion 201 of substrate 200, solder 40 extends upward onto the rounded surface of ridge line 31 of magnetic base 11. As a result, apex 41 of the fillet made of solder 40 reaches above the position of external electrode 12, and stress when substrate 200 is distorted is concentrated and applied to ridge line 31 of magnetic base 11.

[0047] For this reason, in the coil device 1000 of the comparative example, peeling of the solder 40 and chipping of the ridge line 31 are likely to occur near the apex 41 of the fillet, reducing the adhesion between the land portion 201 and the external electrode 12. Also, in the substrate 200, the tip of the fillet and the outer periphery of the land portion 201 coincide with each other, so peeling from the substrate 200 is likely to occur starting from the outer periphery of the land portion 201. Furthermore, as shown by the dotted line, the position of the plating layer 22 of the external electrode 12 may exceed the ridge line 31 due to plating elongation or the like, and extend to the side surface 103. In this case, the fillet of the solder 40 exceeds the range of the external dimensions of the coil component 1000.

[0048] 5 according to this embodiment, when the coil component 100 is soldered to the land portion 201 of the substrate 200, the solder 40 is formed at a position away from the side surface 103 of the magnetic base 11. The solder 40 is also formed at a position away from the ridge line 31 of the magnetic base 11. In other words, the area where the solder 40 is provided is limited to the bottom surface 101. As a result, the stress from the substrate 200 is dispersed to the bottom surface 101. Therefore, in the coil component 100 of this embodiment, the adhesion between the land portion 201 and the external electrode 12 can be improved.

[0049] Also, in the substrate 200, the insulating layer 13 prevents the solder 40 from wetting up, so the fillet made of the solder 40 has a shape that widens along the land portion 20, and the solder 40 does not reach the bottom surface 101 of the magnetic base 11. Therefore, the area where the fillet is formed is small, and the tip of the fillet is located inside and away from the outer periphery of the land portion 201, so that stress from the substrate 200 is concentrated inside the land portion 201, resulting in high adhesion between the substrate 200 and the land portion 201. In other words, the stress originating from the outer periphery of the land portion 201 is alleviated, making it less likely to peel off from the substrate 200. To further improve the adhesion between the land portion 201 and the external electrode 12, it is desirable that the thickness of the solder 40 be made smaller.

[0050] FIG. 6 shows a modified example corresponding to a reduction in the thickness of the solder. In the modification shown in Fig. 6, the farthest position H3 of the insulating layer 13 is positioned lower than in the case shown in Fig. 3. As a result, the distance in the height direction H between the farthest position H2 of the external electrode 12 and the farthest position H3 of the insulating layer 13 is smaller than the distance in the height direction H between the position H1 of the bottom surface 101 and the farthest position H3 of the insulating layer 13.

[0051] That is, the farthest position H3 of the insulating layer 13 is located between the position H1 on the bottom surface 101 and the farthest position H2 of the external electrode 12, and is closer to the farthest position H2 of the external electrode 12. By providing the insulating layer 13 at such a position, it becomes possible to accommodate a reduction in the thickness of the solder 40, and the solder fillet shape is also reduced, further improving the adhesion between the land portion 201 and the external electrode 12.

[0052] FIG. 7 is a graph showing the results of impact tests on the comparative example and this embodiment. The horizontal axis of the graph in Fig. 7 represents the number of tests, and the vertical axis represents the pass rate. In the graph in Fig. 7, the black triangles (▲) and the solid line represent the impact test results of this embodiment, and the white triangles (△) and the dashed line represent the impact test results of the comparative example. In the impact test results, a total of 30 impacts were applied, with the impact energy applied to the center of the mounting substrate 10 being increased stepwise every 10 impacts. The impact energy started from an impact energy equivalent to a drop from a height of 1.0 m, then increased to an impact energy equivalent to a drop from a height of 1.2 m, and further increased to an impact energy equivalent to a drop from a height of 1.4 m.

[0053] In the comparative example, parts fell off within 10 times of an impact equivalent to a drop height of 1.0 m, reducing the pass rate to about 30%.The remaining parts in the comparative example all fell off within 10 times of an impact equivalent to a drop height of 1.2 m, reducing the pass rate to 0%.

[0054] In contrast, in the case of this embodiment, the pass rate was 100% even after 10 impacts equivalent to a drop height of 1.0 m. After 10 impacts equivalent to a drop height of 1.2 m, some parts fell off, but the pass rate was still over 80%. Furthermore, even after 10 impacts equivalent to a drop height of 1.4 m, no additional parts fell off and the pass rate of over 80% was maintained. In this way, it was confirmed that the provision of the insulating layer 13 improves the adhesion between the land portion 201 and the external electrode 12.

[0055] <Modification> Next, modified examples of the coil component will be described. In the following, duplicated explanations of elements that are the same as elements that have already been explained will be omitted. FIG. 8 shows modified examples in which the number of external electrodes is different. 8 is a composite component such as a transformer, and includes, for example, two pairs of external electrodes 12, for a total of four external electrodes 12. In the modified coil component 300, the edge 13a of the insulating layer 13 does not extend beyond the extension of the edge 12a of the external electrode 12. Therefore, the volume occupied by the insulating layer 13 is small, and the coil component 300 can be mounted at a high density.

[0056] 9 and 10 are diagrams showing modified examples with different structures of the external electrodes, with Fig. 9 showing a cross-sectional view and Fig. 10 showing a bottom view. 9 and 10 , a coil device 400 according to a modified example has a flat portion 21a provided on the base electrode layer 21. The flat portion 21a extends beyond the plating layer 22 and spreads along the bottom surface 101. The flat portion 21a also extends between the insulating layer 13 and the magnetic base 11. The insulating layer 13 extends over the bottom surface 101, covers the surface of the flat portion 21a, and reaches adjacent to the plating layer 22.

[0057] Since the base electrode layer 21 has a flat portion 21a, in the modified coil component 400, the stress applied to the plating layer 22 via the solder 40 is dispersed without concentrating on the outer edge of the base electrode layer 21, thereby further improving the adhesion between the land portion 201 and the external electrode 12.

[0058] FIG. 11 shows a modified example in which the insulating layer is formed over a wide area. In a modified coil device 500 shown in FIG. 11, the insulating layer 13 covers the entire side surface 103 of the magnetic base 11. Portions of the insulating layer 13 reach the bottom surface 101, the top surface 102, the front surface 104, and the rear surface 105, but the insulating layer 13 does not extend beyond the position of the edge 12a of the external electrode 12 in the length direction L on any surface. The insulating layer 13 shown in FIG. 11 has high adhesion to the magnetic base 11. Furthermore, the insulating layer 13 shown in FIG. 11 can be easily formed by a dipping method or the like.

[0059] FIG. 12 shows a modified example in which the insulating layer is formed over a narrow area. In a modified coil device 600 shown in Fig. 12, the insulating layer 13 is provided along the ridge line 31 between the bottom surface 101 and the side surface 103. The insulating layer 13 does not extend in a planar manner on either the bottom surface 101 or the side surface 103, but extends linearly along the ridge line 31. This type of insulating layer 13 is the minimum insulating layer 13 that covers the ridge line 31, and the volume occupied by the insulating layer 13 is also minimized. Therefore, the presence of the insulating layer 13 does not affect the magnetic properties of the coil device 600 shown in Fig. 12, which particularly contributes to high-density packaging. [Explanation of symbols]

[0060] 10 Circuit Board 11 Magnetic substrate 12 External electrode 12a Edge 13 Insulating layer 13a Edge 14 Conductors 21 Base electrode layer 21a Flat part 22 plating layer 31 Ridgeline 40 Solder 100, 300, 400, 500, 600 coil parts 101 bottom 102 Top surface 103 Side 104 Front 105 Rear 200 boards 201 Land Club

Claims

1. a magnetic substrate including metal magnetic particles, having a first surface and a second surface adjacent to each other as outer surfaces, and a first ridge line extending between the first surface and the second surface; a conductor provided inside or on the surface of the magnetic substrate; an insulating layer provided across the first ridge line from the first surface to the second surface; an external electrode electrically connected to the conductor, spaced apart from the first ridge line, and provided on the first surface; A coil component comprising:

2. The coil component according to claim 1 , wherein in a direction perpendicular to the first surface, the distance from the first surface to the farthest position of the external electrode is greater than the distance from the first surface to the farthest position of the insulating layer.

3. The coil component according to claim 2 , wherein the distance between the farthest position of the insulating layer and the farthest position of the external electrode in a direction perpendicular to the first surface is smaller than the distance from the first surface to the farthest position of the insulating layer.

4. The coil component according to claim 1 , wherein the insulating layer covers the second surface.

5. The coil component according to claim 1 , wherein the insulating layer is made of a resin and ceramic particles.

6. The coil component according to claim 1 , wherein the external electrodes each have a base electrode layer and a plating layer provided on the outside of the base electrode layer, the plating layer being in contact with the insulating layer.

7. The coil component according to claim 6 , wherein the outer periphery of the base electrode layer of the external electrode is partially covered with an insulating layer, and the plating layer is provided inside the outer periphery of the base electrode layer.

8. The coil component according to claim 7 , wherein the base electrode layer has a flat portion on the same surface as the first surface or at a position recessed from the first surface.

9. The coil component according to claim 1; a substrate having lands to which the external electrodes are soldered; solder connecting the land and the external electrode and spaced from the second surface to form a fillet; A mounting board comprising:

10. The coil component according to claim 1; a substrate having lands to which the external electrodes are soldered; solder that connects the land and the external electrode and forms a fillet within the range of the outer dimensions of the coil component; A mounting board comprising:

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