Coil component

Abstract

To achieve reduction of the size of a coil component including an insulation layer.SOLUTION: A coil component according to one embodiment includes: a magnetic base body containing a magnetic metal material; a conductor disposed inside the magnetic base body; external electrodes connected to the conductor and extending along a first surface of the magnetic base body, each of the external electrodes having a first electrode portion embedded in the magnetic base body and a second electrode portion exposed from the magnetic base body; and an insulation layer covering an area of the first surface that excludes areas on which the external electrodes are disposed.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] As electronic devices become smaller and more functional, there is a demand for higher density mounting of electronic components on boards. However, even with high density mounting, there is a limit to the number of electronic components that can be mounted on the surface of a board, so smaller, higher performance electronic components are required. This increases the number of electronic components that can be mounted on a board, and electronic devices become smaller and more functional.

[0003] As a means of miniaturizing electronic components, the magnetic material in coil components is being changed from ferrite magnetic material to metallic magnetic material. By using metallic magnetic material with high magnetic saturation characteristics, the volume occupied by the magnetic material required for magnetic saturation is reduced. Coil components that use metal magnetic materials have low resistance, so it is necessary to ensure insulation on the surfaces on which external electrodes are provided, and a structure in which the outside of the component body is covered with an insulating layer may be adopted.

[0004] For example, Patent Document 1 proposes an electronic component using an insulator containing metal magnetic powder, the electronic component having a resin coating film on the insulator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-178282 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, whether the coil component is mounted on the surface of a substrate or embedded inside the substrate, the external electrodes need to be thick to a certain extent. Therefore, if an insulating layer is provided on the component body, the thickness of both the external electrodes and the insulating layer increases, which causes the external dimensions of the coil component to increase.

[0007] Conversely, when the outer dimensions are fixed, the component body including the magnetic portion will be reduced by the thickness of the insulating layer, which will reduce the performance of the coil component and hinder miniaturization of the coil component. In view of the above circumstances, an object of the present invention is to reduce the size of a coil component having an insulating layer. [Means for solving the problem]

[0008] In order to solve the above problem, a coil component according to one embodiment of the present invention includes a magnetic base containing a metal magnetic material, a conductor provided inside the magnetic base, an external electrode connected to the conductor and extending along a first surface of the magnetic base, the external electrode having a first electrode portion embedded in the magnetic base and a second electrode portion exposed to the outside of the magnetic base, and an insulating layer covering an area of ​​the first surface excluding the external electrode.

[0009] In addition, in the coil component according to one aspect of the present invention, the second electrode portion is located inside the outer periphery of the first electrode portion when viewed in a direction perpendicular to the first surface. In addition, in a coil component according to an aspect of the present invention, the first electrode portion is externally covered with the second electrode portion and the insulating layer.

[0010] In addition, in the coil component according to one aspect of the present invention, the first electrode portion has a thickness greater than the thickness of the second electrode portion in a direction perpendicular to the first surface. Furthermore, in a coil component according to an aspect of the present invention, the distance from the first surface to the surface of the external electrode in a direction perpendicular to the first surface is greater than the distance from the first surface to the surface of the insulating layer.

[0011] In addition, in a coil component according to an aspect of the present invention, the insulating layer has, on at least a portion of its surface, an inclined surface that approaches the first surface with increasing distance from the external electrode. In the coil component according to an aspect of the present invention, the insulating layer has a larger area than the second electrode portion in terms of the proportion of the first surface.

[0012] Furthermore, in a coil component according to one embodiment of the present invention, the magnetic base has a plurality of surfaces including the first surface and a surface different from the first surface, and the external electrode is provided only on the first surface of the plurality of surfaces. In addition, in the coil component according to one aspect of the present invention, the insulating layer has a surface roughness smaller than that of the magnetic base.

[0013] In addition, in the coil component according to one aspect of the present invention, the insulating layer is made of at least one insulating material selected from the group consisting of resin, glass, and metal oxide. Furthermore, in a coil component according to an aspect of the present invention, the distance from the first surface to the surface of the insulating layer in a direction perpendicular to the first surface is greater than the distance from the first surface to the surface of the external electrode.

[0014] In addition, in the coil component according to one aspect of the present invention, the first electrode portion contains the same metal element as the conductor as a main component. In addition, in the coil component according to one aspect of the present invention, the second electrode portion includes Cu on the surface.

[0015] In addition, in a coil component according to an aspect of the present invention, three or more external electrodes are provided. Moreover, a coil component according to one aspect of the present invention includes a plurality of the conductors, each of which is an inductor element. Effect of the Invention

[0016] According to the present invention, it is possible to reduce the size of a coil component having an insulating layer. [Brief description of the drawings]

[0017] [Figure 1] 1 is a perspective view showing a coil component according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II in FIG. [Diagram 3] 6A to 6C are diagrams illustrating a first step in a manufacturing method of a coil component according to a comparative example. [Figure 4] 11 is a diagram illustrating a second step in the manufacturing method of the coil component of the comparative example. [Diagram 5] 11 is a diagram illustrating a third step in the manufacturing method of the coil component of the comparative example. [Figure 6] 13 is a diagram illustrating a fourth step in the manufacturing method of the coil component of the comparative example. [Figure 7] 3A to 3C are diagrams illustrating a first step in a manufacturing method of the coil component according to the first embodiment. [Figure 8] 5A to 5C are diagrams illustrating a second step in the manufacturing method of the coil component according to the first embodiment. [Figure 9] 5A to 5C are diagrams illustrating a third step in the manufacturing method of the coil component according to the first embodiment. [Figure 10] 5A to 5C are diagrams illustrating a fourth step in the manufacturing method of the coil component according to the first embodiment. [Figure 11] FIG. 13 is a diagram showing a first modified example of the coil component. [Figure 12] FIG. 13 is a diagram showing a second modified example of the coil component. [Figure 13] FIG. 13 is a diagram showing a third modified example of the coil component. [Figure 14] FIG. 13 is a diagram showing a fourth modified example of the coil component. [Figure 15] FIG. 11 is a perspective view showing a coil component according to a second embodiment of the present invention. [Figure 16] FIG. 16 is a cross-sectional view taken along line II-II in FIG. [Figure 17] FIG. 16 is a cross-sectional view taken along line III-III in FIG. [Figure 18] FIG. 11 is a cross-sectional view showing a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the 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 appropriately modified or changed depending on the specifications of the device to which the present invention is applied and various conditions (such as usage conditions and usage environment).

[0019] The technical scope of the present invention is defined by the claims and is not limited by the following individual embodiments. The drawings used in the following description may differ in scale and shape from the actual structure in order to make each configuration easier to understand. The components shown in the drawings described above may be appropriately referenced in the description of the drawings that follow.

[0020] First Embodiment FIG. 1 is a perspective view showing a coil component according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II in FIG. The coil component 10 of the first embodiment includes a magnetic base 11 made of a metal magnetic material, two external electrodes 12 provided on a first surface 11a of the magnetic base 11, a conductor provided on a part of the magnetic base 11, and an insulating layer 14 provided between the two external electrodes 12. For example, an example of the conductor is an internal conductor 13 provided inside the magnetic base 11. Note that "provided on a surface" means that the conductor is provided at a location that is visible when the surface is viewed, and may be provided protruding outward from the surface or recessed inward from the surface. As described later, the external electrode 12 is partially protruding from the first surface 11a and partially embedded in the first surface 11a. The range of the first surface 11a of the magnetic base 11 is the entire range up to the outer periphery, including the area where the external electrode 12 is provided. In addition, the position of the first surface 11a in the area where the external electrode 12 is provided is a flat extended position ignoring unevenness caused by the provision of the external electrode 12.

[0021] The coil component 10 is mounted on the surface of a substrate, or embedded in a resin inside the substrate. Alternatively, the coil component 10 is packaged in resin as a package component. When embedded in a substrate or packaged, the coil component 10 is sealed with resin. For example, soft magnetic metal particles are used as the magnetic material of the magnetic substrate 11. The magnetic substrate 11 is formed by employing any known technique.

[0022] In this specification, unless otherwise understood in the context, the directions are described based on the "L axis" direction, the "W axis" direction, and the "H axis" direction in Figure 1, and are referred to as the "length" direction, the "width" direction, and the "height" direction, respectively. The coil component 10 has a rectangular parallelepiped outer shape. That is, the coil component 10 has outer surfaces at both ends in the length direction L, at both ends in the height direction H, and at both ends in the width direction W. All of the outer surfaces of the coil component 10 may be flat or curved. Furthermore, the eight corners and 12 ridges of the coil component 10 may be rounded.

[0023] In this specification, even when the outer surface of the coil component 10 is partially curved or uneven, or when the corners or ridges of the coil component 10 are rounded, such a shape may be referred to as a "rectangular parallelepiped shape." In other words, in this specification, the terms "rectangular parallelepiped" or "rectangular parallelepiped shape" do not mean "rectangular parallelepiped" in the strict mathematical sense.

[0024] In the first embodiment, the first surface of the magnetic base 11 is the main surface of the coil component 10. The main surface of the coil component 10 becomes the mounting surface when the coil component 10 is mounted on, for example, the surface of a substrate. Furthermore, in the first embodiment, the external electrodes 12 are provided only on the first surface 11a of the magnetic base 11, so that the effect of the thickness of the external electrodes 12 on the dimensions of the coil component 10 is limited only in the direction perpendicular to the first surface 11a, which contributes to miniaturization of the coil component 10.

[0025] The coil component 10 of the first embodiment includes two external electrodes 12 provided on a first surface 11a of a magnetic base 11 at positions spaced apart from each other in the longitudinal direction L, for example. A plating layer is provided on the surface of the external electrodes 12 for the purpose of connection to a substrate. The plating layer preferably contains Cu, which provides high connectivity with the substrate.

[0026] Each external electrode 12 extends in a length direction L and a width direction W along the first surface 11a. In addition, in the height direction H, each external electrode 12 has a first electrode portion 12a embedded in the magnetic base 11 and a second electrode portion 12b exposed to the outside from the magnetic base 11. The first electrode portion 12a and the second electrode portion 12b are made of, for example, Ag or Cu. The first electrode portion 12a and the second electrode portion 12b may be made of the same material or different materials. Each of the external electrodes 12 is electrically connected to one end of the internal conductor 13 via the first electrode portion 12a. The internal conductor 13 may be any conductor that generates inductance, and may be wound, for example, a predetermined number of turns around a coil axis (not shown).

[0027] The coil component 10 is a small electronic component, and the area and volume occupied by each component is small. For example, in the first embodiment, there is one electrically connected element made up of one internal conductor 13 and two external electrodes 12, and the area of ​​the first surface 11a is 0.5 mm 2 More than 1.5mm 2 The following is the result.

[0028] In addition, for example, when there are two elements, the area of ​​the first surface 11a is limited to 2.0 mm because the spacing between the external electrodes 12 is a constraint. 2 More than 3.5mm 2 The external electrodes 12 are provided at intervals of, for example, 0.5 mm or less. The insulating layer 14 is formed from an insulating material with excellent insulating properties, and covers the area sandwiched between the external electrodes 12. The insulating layer 14 has a higher electrical resistivity than the magnetic base 11. The material of the insulating layer 14 is, for example, a resin material such as a silicon resin, an epoxy resin, or a phenolic resin, a glass such as a borosilicate glass, or a metal oxide such as an oxide containing P. The material of the insulating layer 14 is preferably a thermosetting material.

[0029] In the coil component 10 of the first embodiment, the regions of the first surface 11a of the magnetic base 11 between the external electrodes 12 are entirely covered with the insulating layer 14. In terms of the proportion of the first surface 11a, the insulating layer 14 is larger than the second electrode portions 12b. In other words, the total area of ​​the insulating layers 14 is larger than the total area of ​​the second electrode portions 12b.

[0030] A magnetic base 11 using a metal magnetic material may have a portion with a lower surface resistance than a magnetic base using, for example, ferrite, and an insulating layer 14 is provided on the magnetic base 11. The insulating layer 14 prevents the occurrence of a short circuit due to a decrease in insulation resistance between the external electrodes 12 of the coil component, even when a plating layer is provided on the external electrodes 12. Meanwhile, since the first electrode portion 12a of the external electrode 12 is embedded in the magnetic base 11, the thickness of the insulating layer 14 is restricted to a thickness corresponding to the second electrode portion 12b of the external electrode 12. Therefore, the coil component 10 including the insulating layer 14 can be made smaller in size.

[0031] In forming the insulating layer 14, the steps of applying the insulating material that will become the insulating layer 14 to the surface of the magnetic base 11, curing it by heat, and surface processing are carried out, and as a result of these steps, an insulating layer 14 of the required thickness is obtained. Note that for the surface processing, processing means such as sandblasting, polishing, barrel, laser, and solvent etching are used.

[0032] The surface roughness of the insulating layer 14 is smaller than the surface roughness of the first surface 11a of the magnetic base 11. In other words, the surface of the insulating layer 14 is smoother than the first surface 11a of the magnetic base 11. By forming the surface of the insulating layer 14 smoothly, the flow of the sealing resin is promoted, and the formation of voids during resin encapsulation is suppressed.

[0033] The surface roughness of the insulating layer 14 and the surface roughness of the first surface 11a of the magnetic base 11 can be expressed as an arithmetic surface roughness Sa calculated using a measuring instrument conforming to, for example, ISO 25178. The arithmetic surface roughness Sa is measured using a commercially available instrument capable of measuring the arithmetic surface roughness Sa, such as a shape analysis laser microscope (VK-X250) manufactured by Keyence Corporation.

[0034] <Manufacturing method of coil parts> 3 to 6 are diagrams showing a method for manufacturing a coil component of a comparative example, and FIGS. 7 to 10 are diagrams showing a method for manufacturing coil component 10 of the present embodiment. In the comparative example, a magnetic base portion 21 using a metal magnetic material and an internal conductor portion 23 made of a conductor are formed in the first step shown in Fig. 3. Note that Figs. 3 to 10 diagrammatically show only the end portions of the internal conductor portion.

[0035] The magnetic base 21 and the internal conductor 23 are formed by a combination of printing or plating a conductor pattern on a sheet made of a metal magnetic material and laminating a plurality of sheets. The internal conductor 23 is formed with one end exposed on the surface of the magnetic base 21.

[0036] 4, an insulating layer 24 is formed on the surface (the surface where one end of the internal conductor 23 is exposed) of the magnetic base 21. Since the thickness D1 of the insulating layer 24 is required to be equivalent to the thickness of the external electrode 12, the insulating layer 24 is formed to have a sufficient thickness.

[0037] 5, a hole H is formed in the insulating layer 24. That is, a part of the insulating layer 24 is removed to expose the internal conductor portion 23. 6, the external electrodes 22 are formed by, for example, plating at the locations of the holes H in the insulating layer 24. Since the external electrodes 22 are required to have a certain thickness, the aforementioned thickness D1 of the insulating layer 24 also becomes thick, making it difficult to miniaturize the coil component. In addition, the thick thickness D1 of the insulating layer 24 makes it easy for voids to occur during resin sealing.

[0038] In contrast, in the coil component 10 of this embodiment, the magnetic base portion 31 using a metal magnetic material, the internal conductor portion 33 made of a conductor, and the first electrode portion 32a are formed in the first step shown in Fig. 7. The magnetic base portion 31, the internal conductor portion 33, and the first electrode portion 32a are also formed by combining printing or plating of a conductor pattern on a sheet using a metal magnetic material and laminating a plurality of sheets. Therefore, if the internal conductor portion 33 and the first electrode portion 32a are the same type of conductor (i.e., mainly composed of the same metal element), they are easily formed.

[0039] The magnetic base portion 31, the internal conductor portion 33, the first electrode portion 32a, etc. are formed, for example, as a laminate corresponding to a plurality of coil components 10 and then separated into individual pieces, thereby making it possible to efficiently manufacture the coil components 10.

[0040] 8, an insulating layer 34 is formed on the first surface 31a of the magnetic base portion 31. The thickness D2 of this insulating layer 34 corresponds to the thickness of the second electrode portion 12b of the external electrode 12, and is therefore thinner than the thickness D1 of the insulating layer 24 in the comparative example, which contributes to miniaturization of the coil component. The insulating layer 34 may be formed when the laminate is formed, or may be formed after singulation.

[0041] 9, a part of the insulating layer 34 is removed to form a hole H, and the first electrode portion 32a is exposed. Since the hole H is within the outer periphery of the first electrode portion 32a, damage to the surface of the magnetic base portion 31 around the first electrode portion 32a is avoided. Note that the insulating layer 34 may be formed in the formation stage excluding the exposed portion of the first electrode portion 32a, rather than removing a part of it.

[0042] 10, the second electrode portion 32b is formed on the exposed portion of the first electrode portion 32a by, for example, plating. As a result, an external electrode 32 consisting of the first electrode portion 32a and the second electrode portion 32b is formed. Although the external electrode 32 has a predetermined thickness, the first electrode portion 32a, which is a part of the external electrode 32, is embedded in the magnetic base portion 31, so that the thickness of the insulating layer 34 is suppressed, which contributes to miniaturization of the coil component 10.

[0043] <Modification> Next, a description will be given of modified examples of the coil device 10. In the following, a duplicated description of the configuration similar to that of the first embodiment will be omitted.

[0044] Figures 11 to 13 are diagrams showing first to third modified examples which have different structures for the external electrode 12, and Figure 14 is a diagram showing a fourth modified example which has a different structure for the insulating layer 14. Figures 11 to 14 show cross-sectional views similar to Figure 2.

[0045] In the first modified example shown in Fig. 11, the second electrode portion 12b is thinner and smaller than the first electrode portion 12a. That is, in the thickness direction perpendicular to the first surface, the thickness of the first electrode portion 12a is greater than the thickness of the second electrode portion 12b, and the second electrode portion 12b is located inside the outer periphery of the first electrode portion 12a when viewed from the direction toward the first surface 11a. The second electrode portion 12b is thinner than the first electrode portion 12a, which suppresses the thickness of the insulating layer 14, and the first electrode portion 12a is wider and thicker than the second electrode portion 12b, which increases the adhesion with the magnetic base 11 and improves the strength of the external electrode 12.

[0046] Since the second electrode portion 12b is smaller than the first electrode portion 12a, for example, in the third step shown in Fig. 9, the outer periphery of the hole H is formed inside the outer periphery of the first electrode portion 12a. Therefore, when the hole H is formed, the periphery of the first electrode portion 32a is not damaged, and the first surface 11a of the magnetic base 11 is not damaged. As a result, the first electrode portion 32a is covered on the outside with the second electrode portion 12b and the insulating layer 14.

[0047] 12, a part of the first electrode portion 12a is wedge-shaped. At the wedge-shaped portion, the outer edge of the first electrode portion 12a widens as it moves away from the first surface 11a, which further increases the adhesion between the first electrode portion 12a and the magnetic base 11. Therefore, even if the area of ​​the external electrode 12 is small, the electrode is prevented from peeling off.

[0048] 13, the outer periphery of the first electrode portion 12a is located inside the side surface 11b of the magnetic base 11. This structure also increases the adhesion between the first electrode portion 12a and the magnetic base 11, thereby improving the strength of the external electrode 12. In the third modified example, in the thickness direction perpendicular to the first surface 11a, the insulating layer 14 extends outside the external electrodes 12. Therefore, the smooth insulating layer 14 improves the handleability of the coil device 10.

[0049] In a fourth modified example shown in Fig. 14, the thickness of the insulating layer 14, with the first surface 11a as the reference surface, is large in a portion close to the external electrode 12 and is small in a central portion. For example, the insulating layer 14 has an inclined surface 14a that approaches the first surface 11a with increasing distance from the external electrode 12. By providing the insulating layer 14 with such a shape, the flow of the sealing resin is prevented from being hindered during resin sealing, and the occurrence of voids and the like is prevented. Furthermore, in the fourth modified example, the external electrode 12 extends outside the insulating layer 14 in the thickness direction perpendicular to the first surface 11a, so that the flow of the sealing resin is further prevented from being hindered.

[0050] The thickness of the insulating layer 14 at the center is preferably, for example, 0.2 times or less the thickness of the second electrode portion 12b (i.e., the distance protruding from the first surface 11a). If the thickness is 0.2 times or less the thickness of the second electrode portion 12b, a large space is secured between the magnetic base 11 and the ground surface of the coil component 10 during resin encapsulation, so that the sealing resin is likely to flow along the surface of the insulating layer 14. In order to secure a larger space for the resin to flow during resin encapsulation, the thickness of the insulating layer 14 at the center is more preferably 0.1 times or less the thickness of the second electrode portion 12b, and may further be so thin that it is difficult to measure.

[0051] The insulating layer 14, which has a smaller thickness in the center portion, is formed, for example, by surface processing. The surface processing of the insulating layer 14 is performed by sandblasting, polishing, barrel processing, and other known surface processing means. In barrel processing, media with a diameter larger than the distance between the external electrodes 12 is used, so that the media comes into contact with the center portion of the insulating layer 14, while the media does not come into contact with the region of the insulating layer 14 that is in the vicinity of the external electrodes 12. By such surface processing, the upper surface of the insulating layer 14 is formed into a curved surface that is concave toward the center.

[0052] <Second embodiment> Next, a coil component according to a second embodiment of the present invention will be described. FIG. 15 is a perspective view showing a coil component according to a second embodiment of the present invention, FIG. 16 is a cross-sectional view taken along line II-II in FIG. 15, and FIG. 17 is a cross-sectional view taken along line III-III in FIG. 15.

[0053] A coil component 40 according to the second embodiment includes a magnetic base 41 using a metallic magnetic material, an external electrode 42 provided on a first surface 41a of the magnetic base 41, an internal conductor 43 provided inside the magnetic base 41, and an insulating layer 44 provided between the external electrodes 42. The magnetic base 41, the external electrode 42, the internal conductor 43, and the insulating layer 44 in the second embodiment correspond to the magnetic base 11, the external electrode 12, the internal conductor 13, and the insulating layer 14 in the first embodiment, respectively.

[0054] The coil component 40 according to the second embodiment is an array-type electronic component including a plurality of elements, each of which is electrically connected to two external electrodes 42 and one internal conductor 43. In an array-type electronic component, a plurality of elements are packaged as a single component, thereby reducing the mounting space for the plurality of elements. The coil component 40 includes a plurality of internal conductors 43, each of which is, for example, an inductor element.

[0055] A coil component 40 including multiple elements has three or more (eight in the example of FIG. 15) external electrodes 42. In the coil component 40 of the second embodiment, the eight external electrodes 42 are arranged, for example, along the first surface 41a and spaced apart from each other in both the length direction L and the width direction W. That is, four external electrodes 42 are arranged in the length direction L and two in the width direction W.

[0056] The multiple elements included in the coil component 40 are, for example, elements that have the same characteristics and are independent of each other on the circuit. The coil component 40 may include multiple elements with different characteristics, or may include a combination of multiple elements that interact magnetically or electrically (for example, a transformer or an LC filter).

[0057] In the coil component 40 of the second embodiment, the external electrodes 42 also have a first electrode portion 42a embedded in the magnetic base 41 and a second electrode portion 42b exposed from the magnetic base 41, so that the thickness of the insulating layer 44 provided between the external electrodes 42 is reduced, contributing to miniaturization of the coil component 40.

[0058] 14, the insulating layer 44 in the second embodiment has a thickness greater in a vicinity of the external electrode 42 and smaller in a central portion. Moreover, the insulating layer 44 in the second embodiment has a curved surface in the length direction L and also in the width direction W. The total area of ​​the insulating layer 44 on the first surface 41a is larger than the total area of ​​the eight external electrodes 42 on the first surface 41a. Therefore, the insulating layer 44 maintains the insulation between the external electrodes 42.

[0059] 17 shows an example in which the dimension L1 of the external electrode 42 in the length direction L is larger than the dimension L2 of the insulating layer 44 in the length direction L (i.e., the mutual spacing of the external electrodes 42 in the length direction L). However, the dimension L2 of the insulating layer 44 in the length direction L may be larger than the dimension L1 of the external electrodes 42 in the length direction L.

[0060] When the dimension L2 of the insulating layer 44 in the length direction L is smaller than the dimension L1 of the external electrode 42 in the length direction L, as shown in Fig. 16, the dimension W2 of the insulating layer 44 in the width direction W is larger than the dimension W1 of the external electrode 42 in the width direction W. As a result, as described above, the total area of ​​the insulating layer 44 on the first surface 41a is larger than that of the external electrode 42. In particular, when two external electrodes 42 are arranged in the width direction W as shown in Fig. 16, the dimension W2 of the insulating layer 44 in the width direction W is larger than the sum of the dimensions W1 of the external electrodes 42 in the width direction W (i.e., the dimension W1+W1 of two electrodes), thereby making the insulating layer 44 sufficiently wide.

[0061] Conversely, when the dimension W2 of the insulating layer 44 in the width direction W is smaller than the dimension W1 of the external electrode 42 in the width direction W, the dimension L2 of the insulating layer 44 in the length direction L becomes larger than the dimension L1 of the external electrode 42 in the length direction L, and the insulating layer 44 remains wider than the external electrode 42. In other words, the spacing between the external electrodes 42 in the width direction W and the spacing between the external electrodes 42 in the length direction L are in a relationship such that as one becomes smaller, the other becomes larger.

[0062] When the dimension of the coil component 40 is longer in the length direction L than in the width direction W, it is preferable from a design perspective that more external electrodes 42 are arranged in the length direction L than in the width direction W. For this reason, it is preferable that the spacing between the external electrodes 42 in the short direction of the coil component 40 is greater than the spacing between the external electrodes 42 in the long direction of the coil component 40. In this case, sufficient insulation can be obtained by making the spacing between the external electrodes 42 in the short direction of the coil component 40 greater than the dimension of the external electrodes 42 in the short direction.

[0063] <Third embodiment> Next, a third embodiment of the present invention will be described. FIG. 18 is a cross-sectional view showing a third embodiment of the present invention. In the third embodiment, the coil component 40 of the second embodiment described above is used to configure a substrate 50 with built-in electronic components.

[0064] The substrate 50 includes a coil component 40 , an insulating layer 52 , a first resin layer 53 , a second resin layer 54 , and a wiring pattern 55 . The insulating layers 52 are part of a multi-layer printed circuit board and are made of an insulating material such as glass epoxy. The coil components 40 are disposed between the insulating layers 52.

[0065] The first resin layer 53 is formed around the coil components 40 disposed between the insulating layers 52. The first resin layer 53 is formed of, for example, a thermosetting resin. The second resin layer 54 is formed so as to cover the insulating layer 44 side of the coil component 40. The second resin layer 54 may be made of the same thermosetting resin as the first resin layer 53. The coil component 40 is sealed within the substrate 50 by the second resin layer 54. Since the surface of the insulating layer 44 is curved, the flow of the resin is promoted. Therefore, the generation of voids in the second resin layer 54 that seals the coil component 40 can be suppressed.

[0066] The wiring pattern 55 is formed by forming via holes in the second resin layer 54, plating, and etching, and is connected to the external electrodes 42. By embedding the coil component 40 in the substrate 50, the component mounting density on the substrate 50 is improved, which contributes to miniaturization of electronic devices. [Explanation of symbols]

[0067] 10,40 Coil parts 11,41 Magnetic substrate 11a,41a 1st page 12,42 External electrode 13,43 Inner conductor 14,44 Insulating layer 50 Substrates

Claims

1. A magnetic substrate including a metal magnetic material; A conductor provided inside the magnetic base; an external electrode connected to the conductor, extending along a first surface of the magnetic base, and having a first electrode portion embedded in the magnetic base and a second electrode portion exposed to the outside of the magnetic base; an insulating layer covering an area of ​​the first surface excluding the external electrodes; A coil component comprising:

2. The coil component according to claim 1 , wherein the second electrode portion is located inside an outer periphery of the first electrode portion when viewed in a direction perpendicular to the first surface.

3. The coil component according to claim 1 , wherein the first electrode portion is covered on the outside with the second electrode portion and the insulating layer.

4. The coil component according to claim 1 , wherein a thickness of the first electrode portion is greater than a thickness of the second electrode portion in a direction perpendicular to the first surface.

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

6. The coil component according to claim 1 , wherein the insulating layer has, on at least a portion of its surface, an inclined surface that approaches the first surface as it moves away from the external electrode.

7. The coil component according to claim 1 , wherein the insulating layer has a larger area than the second electrode portion in terms of the proportion of the first surface.

8. 2. The coil component according to claim 1, wherein the magnetic base has a plurality of surfaces including the first surface and a surface different from the first surface, and the external electrode is provided only on the first surface among the plurality of surfaces.

9. 2. The coil component according to claim 1, wherein the insulating layer has a surface roughness smaller than that of the magnetic base.

10. 2. The coil component according to claim 1, wherein the insulating layer is made of at least one insulating material selected from the group consisting of resin, glass, and metal oxide.

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

12. The coil component according to claim 1 , wherein the first electrode portion is mainly composed of the same metal element as the conductor.

13. The coil component according to claim 1 , wherein the second electrode portion includes Cu on a surface thereof.

14. The coil component according to claim 1 , wherein the number of the external electrodes provided is three or more.

15. 2. The coil component according to claim 1, comprising a plurality of the conductors, each of the conductors being an inductor element.

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