JP2018156992A - Coil component and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a coil component which can suppress the worsening of DC superposing characteristics while it enables the downsizing; and a method for manufacturing the coil component.SOLUTION: A coil component 10 comprises a magnetic substrate 11 including a Ni-Zn based ferrite material in which a NiO content accounts for 24-30 mol%. The inventors newly found that a high effective saturated magnetic flux density (Bms) can be achieved by adopting the ferrite material like this. That is, a magnetic substrate 11 which the ferrite material is adopted for is less prone to go into a magnetic saturation state, the worsening of the DC superposing characteristic of the coil component when thinning a magnetic substrate can be suppressed effectively.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a coil component and a manufacturing method thereof.

  As a conventional coil component, for example, Patent Document 1 discloses a coil component having a configuration in which a coil and an upper cover layer made of a composite of a metal magnetic powder and a polymer are provided on the magnetic substrate. It is disclosed.

JP 2013-140939 A

  The coil components as described above can be employed in power supply circuits of electronic devices such as smartphones. However, in order to cope with recent downsizing, high functionality, and multi-functionality of electronic devices, the coil components themselves can be reduced in size and characteristics. There is a need for improvement.

  To reduce the size of the coil component itself, it is conceivable to make the magnetic substrate thinner. However, simply reducing the thickness of the magnetic substrate lowers the DC superimposition characteristics of the coil component, making it difficult to achieve both reduction in size and improvement in characteristics.

  In view of the above, an object of the present invention is to provide a coil component in which a reduction in direct current superposition characteristics is suppressed and a method for manufacturing the same, while achieving downsizing.

  A coil component according to an aspect of the present invention includes a magnetic substrate having a main surface and made of a Ni—Zn-based ferrite material, and a NiO content in the ferrite material of 24 to 30 mol%, and a magnetic substrate. A coil having a coil axis along the normal direction of the main surface, and a magnetic resin layer provided on the main surface of the magnetic substrate and covering the coil from the main surface side.

  In the coil component, the NiO content in the Ni—Zn ferrite material constituting the magnetic substrate is 24 to 30 mol%, and by adopting such a ferrite material, a high effective saturation magnetic flux density (Bms) can be obtained. The inventors have newly found that this is possible. That is, the magnetic substrate employing the above ferrite material is unlikely to be in a magnetic saturation state, and the situation where the DC superimposition characteristics of the coil component are reduced when the magnetic substrate is thinned is effectively suppressed.

  In the coil component according to another aspect of the present invention, the magnetic substrate has a complex permeability (μ ″) of less than 35 at 10 MHz or less. According to such a magnetic substrate, a high effective saturation magnetic flux density can be obtained.

  In the coil component according to another aspect of the present invention, the magnetic resin layer has a layered coating layer portion facing the magnetic substrate with the coil interposed therebetween, and the thickness of the magnetic substrate is equal to that of the coating layer portion of the magnetic resin layer. Thicker than the thickness. In this case, the magnetic substrate is more likely to be in a magnetic saturation state than the magnetic resin layer, but the magnetic saturation state in the magnetic substrate is less likely to occur by configuring the magnetic substrate with the ferrite material.

  A method of manufacturing a coil component according to one aspect of the present invention includes a step of preparing a magnetic substrate that is made of a Ni—Zn-based ferrite material and that has a NiO content of 24 to 30 mol% in the ferrite material; A step of disposing a coil having a coil axis along the normal direction of the main surface on the main surface of the substrate, and a step of forming a magnetic resin layer covering the coil from the main surface side on the main surface of the magnetic substrate Including.

  In the coil component manufacturing method, the magnetic substrate prepared in the step of preparing the magnetic substrate is made of a Ni—Zn-based ferrite material having a NiO content of 24 to 30 mol%. The inventors newly found that a high effective saturation magnetic flux density (Bms) can be obtained by employing such a ferrite material. That is, the magnetic substrate employing the above ferrite material is unlikely to be in a magnetic saturation state, and the situation where the DC superimposition characteristics of the coil component are reduced when the magnetic substrate is thinned is effectively suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, while aiming at size reduction, the coil component by which the fall of the direct current | flow superimposition characteristic was suppressed, and its manufacturing method are provided.

1 is a perspective view showing a power supply circuit unit according to an embodiment of the present invention. It is a figure which shows the equivalent circuit of the power supply circuit unit of FIG. It is a perspective view of the coil component which concerns on one Embodiment of this invention. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. It is a disassembled perspective view of a coil component. It is a figure explaining the manufacturing process of coil components. It is a figure explaining the manufacturing process of coil components. It is a figure explaining the manufacturing process of coil components. It is a table | surface which shows the experimental result which concerns on an Example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  First, with reference to FIG.1 and FIG.2, the whole structure of the power supply circuit unit 1 which concerns on one Embodiment is demonstrated. The power supply circuit unit described in the present embodiment is, for example, a switching power supply circuit unit that performs voltage conversion (step-down) of a DC voltage. As shown in FIGS. 1 and 2, the power supply circuit unit 1 includes a circuit board 2 and electronic components 3, 4, 5, 6, and 10. Specifically, the power supply IC 3, the diode 4, the capacitor 5, the switching element 6, and the coil component 10 are mounted on the circuit board 2.

  The configuration of the coil component 10 will be described with reference to FIGS. FIG. 3 is a perspective view of the coil component 10. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is an exploded perspective view of the coil component. In the exploded perspective view of FIG. 5, the illustration of the magnetic resin layer 18 of FIG. 3 is omitted.

  As shown in FIG. 3, the coil component 10 includes an element body 7 (magnetic element body) in which a coil 12 described later is provided, and an insulating layer 30 provided on the main surface 7 a of the element body 7. I have. The element body 7 has a rectangular parallelepiped outer shape. The rectangular parallelepiped shape includes a rectangular parallelepiped shape in which corners and ridge lines are chamfered and a rectangular parallelepiped shape in which corners and ridge lines are rounded. The element body 7 has a main surface 7a, and the main surface 7a has a rectangular shape having a long side and a short side. The rectangular shape includes a rectangle with rounded corners.

  Terminal electrodes 20 </ b> A and 20 </ b> B are provided on the main surface 7 a via an insulating layer 30. The terminal electrode 20A is along one short side of the main surface 7a, and the terminal electrode 20B is along the other short side of the main surface 7a. The terminal electrodes 20A and 20B are separated from each other in the direction along the long side of the main surface 7a.

  The element body 7 is made of, for example, a magnetic material. Specifically, the element body 7 includes a magnetic substrate 11 and a magnetic resin layer 18.

  The magnetic substrate 11 is a substantially flat substrate made of a magnetic material (see FIG. 5). The magnetic substrate 11 is located on the opposite side of the element body 7 from the main surface 7a. On the main surface 11a of the magnetic substrate 11, a magnetic resin layer 18 and a coil 12 described later are provided.

Specifically, the magnetic substrate 11 is made of a Ni—Zn ferrite material. In the present embodiment, the ferrite material constituting the magnetic substrate 11 includes a _F e _2O 3, NiO and ZnO as a main material, and includes TiO, _CoO, and _{Bi 2 O 3, Ca 2 O} 3 as an additive. Further, in the ferrite material according to the present embodiment, _Fe 2 _{O 3} content of from 45~49.5mol%, 24~30mol the content of NiO%, the content of ZnO is in the 19~25mol%. Furthermore, in the ferrite material according to the present embodiment, the purity of Fe ₂ O ₃ is 99.3% or more.

  The magnetic resin layer 18 is formed on the magnetic substrate 11 and includes a coil 12 (see FIGS. 4 and 5) to be described later. A surface 18 a opposite to the surface 18 b on the magnetic substrate 11 side of the magnetic resin layer 18 constitutes a main surface 7 a of the element body 7. The magnetic resin layer 18 is a mixture of magnetic powder and binder resin, and the constituent material of the magnetic powder is, for example, iron, carbonyl iron, silicon, cobalt, chromium, nickel, or boron, and the constituent material of the binder resin is, for example, It is an epoxy resin. 90% or more of the entire magnetic resin layer 18 may be made of magnetic powder, for example. The magnetic resin layer 18 has a magnetic permeability of 10 to 100 (as an example, 35).

  The magnetic resin layer 18 includes an air core portion 18c positioned in an air core portion (inner diameter side portion) of the coil 12, which will be described later, an outer peripheral portion 18d positioned in an outer peripheral portion (outer diameter side portion) of the coil 12, and a coil 12 includes a layered covering layer portion 18e facing the magnetic substrate 11 with 12 interposed therebetween. The thickness t1 of the coating layer portion 18e of the magnetic resin layer 18 is designed to be thinner than the thickness t2 of the magnetic substrate 11. The thickness t1 of the covering layer portion 18e and the thickness t2 of the magnetic substrate 11 can be determined within a range of 50 to 200 μm. As an example, the thickness t1 of the covering layer portion 18e is 110 μm, and the thickness t2 of the magnetic substrate 11 is 145 μm.

  Each of the pair of terminal electrodes 20A, 20B provided on the main surface 7a of the element body 7 has a film shape and has a substantially rectangular shape in plan view. The areas of the terminal electrodes 20A and 20B are substantially the same. The terminal electrodes 20A and 20B are made of a conductive material such as Cu, for example. The terminal electrodes 20A and 20B are plating electrodes formed by plating. The terminal electrodes 20A and 20B may have a single layer structure or a multilayer structure.

  As shown in FIGS. 4 and 5, the element body 7 of the coil component 10 includes the coil 12, the covering portion 17, and the lead conductors 19 </ b> A and 19 </ b> B inside (specifically, in the magnetic resin layer 18). Have.

  The coil 12 is wound in a rectangular shape in plan view. The coil 12 is made of, for example, a metal material such as Cu, and its axis (coil axis) is in the normal direction of the main surface 11a of the magnetic substrate 11 and the main surface 7a of the element body 7 (the main surface 11a and the element body). 7 in a direction perpendicular to the main surface 7a). The coil 12 includes two coil conductor layers. The coil 12 includes a lower coil portion 13 and an upper coil portion 14 as the coil conductor layer, and includes connecting portions 15 and 16. The lower coil portion 13 and the upper coil portion 14 are arranged in a direction orthogonal to the main surface 7a (the axial center direction of the coil 12), and the upper coil portion 14 is located on the main surface 7a side with respect to the lower coil portion 13. ing. The lower coil part 13 and the upper coil part 14 have the same winding direction. The connecting portion 15 is interposed between the lower coil portion 13 and the upper coil portion 14 to connect the innermost winding portion of the lower coil portion 13 and the innermost winding portion of the upper coil portion 14. Yes. The connecting portion 16 extends from the lower coil portion 13 to the main surface 7a side, and connects the lower coil portion 13 and the lead conductor 19B.

  The coating | coated part 17 has insulation and is comprised with insulating resin. Examples of the insulating resin used for the covering portion 17 include polyimide and polyethylene terephthalate. The covering portion 17 integrally covers the lower coil portion 13 and the upper coil portion 14 of the coil 12 in the element body 7. The covering portion 17 individually covers the lower coil portion 13, the upper coil portion 14, and the connecting portion 15. The covering portion 17 has a laminated structure, and in the present embodiment, the covering portion 17 includes five insulating resin layers 17a, 17b, 17c, 17d, and 17e (see FIG. 5). The insulating resin layer 17a is located below the lower coil portion 13 (on the magnetic substrate 11 side), and is formed in substantially the same region as the formation region of the coil 12 in plan view. The insulating resin layer 17b fills the periphery of the lower coil portion 13 in the same layer and the space between the winding portions, and an area corresponding to the inner diameter of the coil 12 is open. The insulating resin layer 17 b extends along a direction orthogonal to the magnetic substrate 11. The insulating resin layer 17 c is located between the lower coil portion 13 and the upper coil portion 14, and an area corresponding to the inner diameter of the coil 12 is open. The insulating resin layer 17d fills the periphery of the upper coil portion 14 in the same layer and the space between the winding portions, and an area corresponding to the inner diameter of the coil 12 is open. The insulating resin layer 17 e is located on the upper side (main surface 7 a side) of the upper coil portion 14, and an area corresponding to the inner diameter of the coil 12 is open.

  The pair of lead conductors 19A and 19B are made of Cu, for example, and extend from both end portions E1 and E2 of the coil 12 in a direction orthogonal to the main surface 7a.

  The lead conductor 19 </ b> A is connected to one end E <b> 1 of the coil 12 provided at the outermost winding portion of the upper coil portion 14. The lead conductor 19A extends from the end E1 of the coil 12 to the main surface 7a of the element body 7 so as to penetrate the magnetic resin layer 18, and is exposed to the main surface 7a. A terminal electrode 20A is provided at a position corresponding to the exposed portion of the lead conductor 19A. The lead conductor 19A is connected to the terminal electrode 20A by a conductor portion 31 in the through hole 31a of the insulating layer 30. Thus, the end E1 of the coil 12 and the terminal electrode 20A are electrically connected via the lead conductor 19A and the conductor portion 31.

  The lead conductor 19 </ b> B is connected to the other end E <b> 2 of the coil 12 provided at the outermost winding portion of the lower coil portion 13. The lead conductor 19B extends from the end E2 of the coil 12 to the main surface 7a of the element body 7 so as to penetrate the magnetic resin layer 18, and is exposed to the main surface 7a. A terminal electrode 20B is provided at a position corresponding to the exposed portion of the lead conductor 19B. The lead conductor 19B is connected to the terminal electrode 20B by a conductor portion 32 in the through hole 32a of the insulating layer 30. Thus, the end E2 of the coil 12 and the terminal electrode 20B are electrically connected via the lead conductor 19B and the conductor portion 32.

  The insulating layer 30 provided on the main surface 7a of the element body 7 is interposed between the pair of terminal electrodes 20A and 20B on the main surface 7a. In the present embodiment, the insulating layer 30 is provided so as to cover the entire region of the main surface 7a so as to expose the pair of lead conductors 19A and 19B, and in the long side direction (the pair of terminal electrodes 20A). , 20B are adjacent to each other) and extend in a direction crossing the main surface 7a. The insulating layer 30 has through holes 31a and 32a (holes) at positions corresponding to the lead conductors 19A and 19B. Conductor portions 31 and 32 made of a conductive material such as Cu are provided in the through holes 31a and 32a. The insulating layer 30 is made of an insulating material, for example, an insulating resin such as polyimide or epoxy.

  Next, with reference to FIGS. 6-8, the manufacturing method of the coil component 10 is demonstrated. 6-8 is a figure explaining the manufacturing process of the coil component 10. FIG.

  First, as shown in FIG. 6A, the above-described magnetic substrate 11 is prepared, an insulating resin paste pattern is applied on the prepared magnetic substrate 11, and the insulating resin layer 17a of the covering portion 17 is applied. Form. Subsequently, as shown in FIG. 6B, a seed portion 22 for plating the lower coil portion 13 is formed on the insulating resin layer 17a. The seed portion 22 can be formed by plating, sputtering, or the like using a predetermined mask. Subsequently, as shown in FIG. 6C, an insulating resin layer 17b of the covering portion 17 is formed. The insulating resin layer 17 b can be obtained by applying an insulating resin paste to the entire surface of the magnetic substrate 11 and then removing the portion corresponding to the seed portion 22. That is, the insulating resin layer 17b has a function of exposing the seed portion 22. The insulating resin layer 17b is a wall-like portion standing on the magnetic substrate 11, and defines a region where the lower coil portion 13 is formed. Subsequently, as shown in FIG. 6D, a plating layer 24 is formed using the seed portion 22 between the insulating resin layers 17b. At this time, the plating that grows so as to fill the region defined between the insulating resin layers 17 b becomes the lower coil portion 13. As a result, the winding portion of the lower coil portion 13 is positioned between the adjacent insulating resin layers 17b.

  Subsequently, as shown in FIG. 7A, an insulating resin paste pattern is applied on the lower coil portion 13 to form an insulating resin layer 17 c of the covering portion 17. At that time, openings 15 ′ and 16 ′ for forming the connecting portions 15 and 16 are formed in the insulating resin layer 17 c. Subsequently, as shown in FIG. 7B, the connecting portions 15 and 16 are formed by plating in the openings 15 'and 16' of the insulating resin layer 17c.

  Subsequently, as shown in FIG. 7C, the insulating resin layers 17d and 17e of the upper coil portion 14 and the covering portion 17 are formed on the insulating resin layer 17c in the same manner as described above. To do. Specifically, similarly to the procedure shown in FIGS. 6B to 6D, a seed portion for plating the upper coil portion 14 is formed, and a region where the upper coil portion 14 is formed is defined. The insulating resin layer 17d to be formed is formed, and the upper coil portion 14 is plated between the insulating resin layers 17d.

  Then, an insulating resin paste pattern is applied on the upper coil portion 14 to form the insulating resin layer 17e of the covering portion 17. At that time, openings 19A 'and 19B' for forming the lead conductors 19A and 19B are formed in the insulating resin layer 17e. As described above, the covering portion 17 has a laminated structure including a plurality of insulating resin layers 17a to 17e, and the lower coil portion 13 and the upper coil portion 14 are surrounded by the insulating resin layers 17a to 17e. .

  Subsequently, as shown in FIG. 7D, portions of the plating layer 24 that do not constitute the lower coil portion 13 and the upper coil portion 14 (inner diameter portions of the lower coil portion 13 and the upper coil portion 14 and The portion corresponding to the outer peripheral portion) is removed by etching. In other words, the plating layer 24 not covered with the covering portion 17 in FIG. Subsequently, as shown in FIG. 8A, the lead conductor 19A is formed at a position corresponding to the opening 19A ′ of the insulating resin layer 17e, and the lead conductor 19B is formed at a position corresponding to the opening 19B ′. Form. Specifically, seed portions for the lead conductors 19A and 19B are formed on the openings 19A ′ and 19B ′ by plating or sputtering using a predetermined mask, and the lead conductors 19A and 19A are formed using the seed portions. 19B is formed by plating.

  Subsequently, as shown in FIG. 8B, a magnetic resin is applied to the entire surface of the magnetic substrate 11 and a predetermined curing process is performed to form a magnetic resin layer 18. Thereby, the periphery of the covering portion 17 and the lead conductors 19 </ b> A and 19 </ b> B is covered with the magnetic resin layer 18. At this time, the magnetic resin layer 18 is filled in the inner diameter portion of the coil 12. Subsequently, as shown in FIG. 8C, polishing is performed so that the lead conductors 19 </ b> A and 19 </ b> B are exposed from the magnetic resin layer 18.

  Through the above process, the element body 7 in which the lead conductors 19A and 19B are exposed from the main surface 7a of the element body 7 is obtained, and the step of preparing the element body 7 is completed.

  Subsequently, as shown in FIG. 8D, before the terminal electrodes 20A and 20B are formed by plating, an insulating material such as an insulating resin paste is applied onto the main surface 7a, whereby the insulating layer 30 is formed. Form. When the insulating layer 30 is formed, the entire main surface 7a is covered, and the through holes 31a and 32a are formed at positions corresponding to the pair of lead conductors 19A and 19B, and the pair of lead conductors 19A and 19B are formed from the insulating layer 30. Expose. Specifically, an insulating material is once applied to the entire region of the main surface 7a, and thereafter, the insulating layer 30 at portions corresponding to the lead conductors 19A and 19B is removed.

  Then, a seed portion (not shown) is formed on the insulating layer 30 in a region corresponding to the terminal electrodes 20A and 20B by plating, sputtering, or the like using a predetermined mask. The seed portion is also formed on the lead conductors 19A and 19B exposed from the through holes 31a and 32a of the insulating layer 30. Subsequently, the terminal electrodes 20A and 20B are formed by electroless plating using the seed portion. At this time, the plating grows so as to fill the through holes 31a and 32a of the insulating layer 30 to form the conductor portions 31 and 32, and the terminal electrodes 20A and 20B on the insulating layer 30 are formed. As described above, the coil component 10 is formed.

  As a result of repeated studies on various characteristics of a magnetic substrate using a Ni-Zn ferrite material, the inventors have designed a NiO content within a predetermined range to obtain a high effective saturation magnetic flux density. I got the knowledge. Therefore, the inventors conducted the following experiment and confirmed the relationship between the NiO content and the effective saturation magnetic flux density.

  In the experiment, a plurality of magnetic substrates having different NiO contents of the Ni—Zn-based ferrite material were prepared, and effective saturation magnetic flux density (Bms), residual magnetic flux density (Br), coercive force (Hc), and magnetic permeability for each of them. μ ′ and complex permeability μ ″ were determined. The experimental results were as shown in FIG.

  As shown in the table of FIG. 9, the prepared magnetic substrate has a NiO content of 24.5 mol% in the magnetic substrate of Example 1, and in the magnetic substrates of Example 2, Example 2 ′, and Example 2 ″. The NiO content is 26.5 mol%, and in the magnetic substrates of Example 3 and Example 3 ′, the NiO content is 29.5 mol%. The magnetic substrate used in Example 2 has a diameter of 60 mm, and the magnetic substrate used in Examples 2 ′ and 2 ″ has a diameter of 6 inches. In Example 2 ′, measurement was performed at the peripheral edge of the magnetic substrate, and in Example 2 ″, measurement was performed at the center of the magnetic substrate. Further, the magnetic substrate used in Example 3 has a diameter of 60 mm, and the magnetic substrate used in Example 3 'has a diameter of 6 inches. The magnetic substrate of Comparative Example 1 has a NiO content of 23.5 mol%, the magnetic substrates of Comparative Examples 2 and 3 have a NiO content of 30.5 mol%, and the magnetic substrate of Comparative Example 4 has a NiO content. Is 19.5 mol%.

  As is apparent from the experimental results shown in FIG. 9, in the magnetic substrate of each example in which the NiO content is in the range of 24 to 30 mol%, an effective saturation magnetic flux density having a sufficiently high value (that is, 495). ~ 536mT) was obtained. On the other hand, in the magnetic substrate of each comparative example in which the NiO content is outside the range of 24 to 30 mol%, the value is significantly lower than the value of the effective saturation magnetic flux density of the magnetic substrate according to the above example (that is, 427 to 476 mT).

  That is, as in the magnetic substrate 11 described above, a high effective saturation magnetic flux density is obtained in a magnetic substrate in which the NiO content in the Ni—Zn ferrite material is 24 to 30 mol%. In other words, the magnetic substrate 11 employing the above ferrite material is unlikely to be in a magnetic saturation state. Therefore, even when the magnetic substrate 11 is thinned in order to reduce the size of the coil component 10, it is possible to effectively suppress the situation where the DC superimposition characteristics of the coil component 10 are deteriorated.

  Particularly, in the configuration in which the thickness t2 of the magnetic substrate 11 is thicker than the thickness t1 of the coating layer portion 18e of the magnetic resin layer 18 (t2> t1) as in the above-described embodiment, the magnetic substrate is more than the magnetic resin layer 18. 11 is more likely to be in a magnetic saturation state. Therefore, by configuring the magnetic substrate 11 with the ferrite material, a magnetic saturation state in the magnetic substrate 11 is less likely to occur, and a decrease in DC superposition characteristics can be suppressed.

  As is clear from the experimental results shown in FIG. 9, when the magnetic permeability of the magnetic substrate 11 at 10 MHz or less (μ ″) is less than 35, a high effective saturation magnetic flux density can be obtained.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, You may change in the range which does not change the summary described in each claim, or may apply to others.

  For example, the number of coil conductor layers and the like are not limited to the above embodiment. For example, the number of coil conductor layers constituting the coil 12 is not limited to two, and may be one or three or more.

  DESCRIPTION OF SYMBOLS 1 ... Power supply circuit unit, 7 ... Element body, 7a ... Main surface, 10 ... Coil component, 11 ... Magnetic substrate, 11a ... Main surface, 12 ... Coil, 18 ... Magnetic resin layer, 18e ... Covering layer part.

Claims (4)

A magnetic substrate having a main surface and made of a Ni-Zn-based ferrite material and having a NiO content of 24 to 30 mol% in the ferrite material;
A coil disposed on the main surface of the magnetic substrate and having a coil axis along the normal direction of the main surface;
A coil component comprising: a magnetic resin layer provided on a main surface of the magnetic substrate and covering the coil from the main surface side.   The coil component according to claim 1, wherein the magnetic substrate has a complex permeability of less than 35 at 10 MHz or less. The magnetic resin layer has a layered covering layer portion facing the magnetic substrate across the coil;
The coil component according to claim 1 or 2, wherein a thickness of the magnetic substrate is thicker than a thickness of the covering layer portion of the magnetic resin layer. A step of preparing a magnetic substrate composed of a Ni-Zn ferrite material and having a NiO content of 24 to 30 mol% in the ferrite material;
Disposing a coil having a coil axis along the normal direction of the main surface on the main surface of the magnetic substrate;
Forming a magnetic resin layer covering the coil from the main surface side on the main surface of the magnetic substrate.

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