Inductor component

Abstract

To provide an inductor component which can improve an inductance value.SOLUTION: An inductor component comprises: an element assembly which includes a magnetic layer, and which has a first principal surface and a second principal surface facing each other; a coil disposed in the element assembly; and an insulation layer which covers part of an outer surface of the coil. The coil has first inductor wiring wound along a surface perpendicular to a first direction which is perpendicular to the first principal surface and extends from the second principal surface to the first principal surface. At least part of an inner peripheral surface on the innermost periphery of the first inductor wiring is not covered with the insulation layer and comes into contact with the magnetic layer.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an inductor component.

Background Art

[0002] Conventionally, as an inductor component, there is one described in Japanese Patent Application Laid-Open No. 2020-136467 (Patent Document 1). The inductor component includes a body including a magnetic layer, a coil disposed in the body, and an insulating layer covering the entire outer surface of the coil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional inductor component, since the insulating layer covers the entire outer surface of the coil, it is not possible to secure the volume of the magnetic layer, and there are cases where a desired inductance value cannot be obtained.

[0005] Therefore, an object of the present disclosure is to provide an inductor component capable of improving the inductance value.

Means for Solving the Problems

[0006] To solve the above problems, an inductor component according to an aspect of the present disclosure is a body including a magnetic layer and having a first main surface and a second main surface facing each other, a coil disposed in the body, and an insulating layer covering a part of the outer surface of the coil. The coil has a first inductor wiring wound along a plane orthogonal to a first direction which is a direction orthogonal to the first major surface and from the second major surface toward the first major surface. At least a part of the inner peripheral surface of the innermost circumference of the first inductor wiring is in contact with the magnetic layer without being covered by the insulating layer.

[0007] According to the above aspect, since at least a part of the inner peripheral surface of the innermost circumference of the first inductor wiring is in contact with the magnetic layer without being covered by the insulating layer, the volume of the magnetic layer can be increased as compared with the case where the entire outer surface of the first inductor wiring is covered by the insulating layer. As a result, the inductance value of the inductor component can be improved.

Effect of the Invention

[0008] According to the inductor component which is one aspect of the present disclosure, the inductance value can be improved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 4E

Figure 4F

Figure 4G

Figure 4H

Figure 4I

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0010] Hereinafter, an inductor component which is one aspect of the present disclosure will be described in detail with reference to the illustrated embodiments. Note that the drawings include some schematic ones and may not reflect actual dimensions and ratios.

[0011] <First Embodiment> (Configuration) FIG. 1 is a schematic plan view showing a first embodiment of the inductor component. FIG. 2 is a sectional view taken along line II-II of FIG. 1. In FIG. 1, for convenience, hatched lines are drawn at positions where the insulating layer exists.

[0012] The inductor component 1 is mounted on an electronic device such as a personal computer, a DVD player, a digital camera, a TV, a mobile phone, or car electronics, and is, for example, a component having a rectangular parallelepiped shape as a whole. However, the shape of the inductor component 1 is not particularly limited, and it may be a cylindrical shape, a polygonal columnar shape, a frustum of a cone shape, or a frustum of a polygonal pyramid shape.

[0013] As shown in FIGS. 1 and 2, the inductor component 1 includes a base body 10, a coil 15 disposed inside the base body 10, an insulating layer 60 covering a part of the outer surface of the coil 15, a first lead wiring 51 and a second lead wiring 52 provided inside the base body 10 so that the end faces are exposed from the first main surface 10a of the base body 10, a first external electrode 41 and a second external electrode 42 exposed on the first main surface 10a of the base body 10, and a coating layer 50 provided on the first main surface 10a of the base body 10.

[0014] The shape of the base body 10 is not particularly limited, but in this embodiment, it is in the shape of a rectangular parallelepiped. The outer surface of the base body 10 has a first main surface 10a and a second main surface 10b, and a first side surface 10c, a second side surface 10d, a third side surface 10e, and a fourth side surface 10f that are located between the first main surface 10a and the second main surface 10b and connect the first main surface 10a and the second main surface 10b. The first main surface 10a and the second main surface 10b face each other. The first side surface 10c and the second side surface 10d face each other. The third side surface 10e and the fourth side surface 10f face each other.

[0015] In the figure, the thickness direction of the base body 10 (in other words, the direction orthogonal to the first main surface 10a) is defined as the Z direction, the direction from the second main surface 10b toward the first main surface 10a is defined as the forward Z direction, and the direction opposite to the forward Z direction is defined as the reverse Z direction. Also, in this specification, the forward Z direction is the upper side and the reverse Z direction is the lower side. In a plane orthogonal to the Z direction of the base body 10, the length direction of the base body 10, which is the direction in which the first external electrode 41 and the second external electrode 42 are arranged, is defined as the X direction, and the width direction of the base body 10, which is the direction orthogonal to the length direction, is defined as the Y direction. Also, in the X direction, the direction from the first side surface 10c toward the second side surface 10d is defined as the forward X direction, and the direction opposite to the forward X direction is defined as the reverse X direction. In the Y direction, the direction from the third side surface 10e toward the fourth side surface 10f is defined as the forward Y direction, and the direction opposite to the forward Y direction is defined as the reverse Y direction. The forward Z direction corresponds to the "first direction" described in the claims. The reverse Z direction corresponds to the "second direction" described in the claims. In the figure, the first direction is indicated by the reference sign D1, and the second direction is indicated by the reference sign D2.

[0016] The base body 10 has a first magnetic layer 11 and a second magnetic layer 12 that are arranged in order along the first direction D1. This "in order" simply indicates the positional relationship between the first magnetic layer 11 and the second magnetic layer 12, and has nothing to do with the formation order of the first magnetic layer 11 and the second magnetic layer 12.

[0017] The first magnetic layer 11 and the second magnetic layer 12 each contain magnetic powder and a resin containing the magnetic powder. The resin is, for example, an organic insulating material composed of an epoxy-based, phenol-based, liquid crystal polymer-based, polyimide-based, acrylic-based material, or a mixture containing them. The magnetic powder is, for example, an FeSi-based alloy such as FeSiCr, an FeCo-based alloy, an Fe-based alloy such as NiFe, or an amorphous alloy thereof. Therefore, compared with a magnetic layer made of ferrite, the DC superposition characteristics can be improved by the magnetic powder, and since the magnetic powder is insulated by the resin, the loss (iron loss) at high frequencies is reduced. Note that the magnetic layer may not contain an organic resin, such as a sintered body of ferrite or magnetic powder.

[0018] The coil 15 has a first inductor wiring 21 and a second inductor wiring 22. Each of the first inductor wiring 21 and the second inductor wiring 22 is wound along a plane orthogonal to the first direction D1 between the first magnetic layer 11 and the second magnetic layer 12. Specifically, the first magnetic layer 11 exists in the second direction D2 relative to the first inductor wiring 21 and the second inductor wiring 22, and the second magnetic layer 12 exists in the first direction D1 and a direction orthogonal to the first direction D1 relative to the first inductor wiring 21 and the second inductor wiring 22.

[0019] The first inductor wiring 21 is a wiring extending in a spiral shape and wound along a plane orthogonal to the first direction D1. The number of turns of the first inductor wiring 21 is preferably more than one turn. Thereby, the inductance value can be improved. More than one turn means a state in which, in a cross section orthogonal to the axis of the inductor wiring, the inductor wiring has a portion that runs parallel in the winding direction adjacent in the radial direction when viewed from the axial direction, and less than one turn means a state in which, in a cross section orthogonal to the axis, the inductor wiring does not have a portion that runs parallel in the winding direction adjacent in the radial direction when viewed from the axial direction. In this embodiment, the number of turns of the first inductor wiring 21 is two turns. The first inductor wiring 21 is wound in a spiral shape in the clockwise direction from the inner peripheral end 21a to the outer peripheral end 21b when viewed from the Z direction.

[0020] The second inductor wiring 22 is arranged on the second direction D2 side relative to the first inductor wiring 21, and is a wiring extending in a spiral shape, wound along a plane orthogonal to the first direction D1. The second inductor wiring 22 is electrically connected to the first inductor wiring 21. The number of turns of the second inductor wiring 22 is preferably more than one turn. Thereby, the inductance value can be improved. In this embodiment, the number of turns of the second inductor wiring 22 is 2.5 turns. The second inductor wiring 22 is wound in a spiral shape in the clockwise direction from the outer peripheral end 22b toward the inner peripheral end 22a when viewed from the Z direction. The second inductor wiring 22 is arranged between the first inductor wiring 21 and the first magnetic layer 11. Thereby, each of the first inductor wiring 21 and the second inductor wiring 22 is arranged along the first direction D1.

[0021] The outer peripheral end 21b of the first inductor wiring 21 is connected to the second external electrode 42 via the second lead wiring 52 in contact with the top surface of the outer peripheral end 21b. The outer peripheral end 22b of the second inductor wiring 22 is connected to the first external electrode 41 via the first lead wiring 51 in contact with the top surface of the outer peripheral end 22b. The inner peripheral end 22a of the second inductor wiring 22 is connected to the inner peripheral end 21a of the first inductor wiring 21 via the via wiring 25 in contact with the top surface of the inner peripheral end 22a. With the above configuration, the first inductor wiring 21 and the second inductor wiring 22 are connected in series and are electrically connected to the first external electrode 41 and the second external electrode 42.

[0022] Each of the first inductor wiring 21 and the second inductor wiring 22 is made of a conductive material and has a seed layer S and a plating layer P formed so as to be partially in contact with the seed layer S.

[0023] Specifically, as shown in FIG. 2, the seed layer S is disposed substantially at the center in the X-direction line width of the first and second inductor wirings 21 and 22. The seed layer S is provided so as to be exposed from a part of the bottom surfaces 213 and 223 of the first and second inductor wirings 21 and 22. The seed layer S has a shape corresponding to the shapes of the first and second inductor wirings 21 and 22 when viewed in the Z-direction. That is, the seed layer S linearly extends in a spiral shape when viewed in the Z-direction. The line width of the seed layer S is smaller than the line widths of the first and second inductor wirings 21 and 22. The seed layer S is, for example, a laminate of Cu and Ti.

[0024] Note that the line width of the seed layer S may be the same as the line widths of the first and second inductor wirings 21 and 22. When the line width of the seed layer S is made smaller than the line width of the first inductor wiring 21 as in this embodiment, when forming a part of the insulating layer 60 existing between adjacent turns of the first inductor wiring 21 after forming the seed layer S, it is possible to suppress a part of the insulating layer 60 from overriding the seed layer S. If a part of the insulating layer 60 overrides the seed layer S, there is a possibility of a short circuit occurring between adjacent turns.

[0025] The plating layer P covers the seed layer S in the first direction D1 and the direction orthogonal to the first direction D1. As a result, the plating layer P is formed so as to be in partial contact with the seed layer S. The plating layer P is made of a low electrical resistance metal material such as Cu, Ag, Au, or Al, for example.

[0026] Note that in this embodiment, as a method for forming the first and second inductor wirings 21 and 22, a semi-additive method using the seed layer S is used, but known methods such as a subtractive method, a full-additive method, a damascene method, a dual damascene method, or a printing method of a conductive paste may also be used.

[0027] The first lead wiring 51 is made of a conductive material, extends in the first direction D1 from the top surface of the second inductor wiring 22, and penetrates through the insulating layer 60 and the second magnetic layer 12. The first lead wiring 51 is provided on the top surface of the outer peripheral end 22b of the second inductor wiring 22, and includes a via wiring 25 that penetrates through the insulating layer 60, a first columnar wiring 31 that extends in the first direction D1 from the top surface of the via wiring 25 and penetrates through the second magnetic layer 12, a via wiring 25 that is provided on the top surface of the first columnar wiring 31 and penetrates through the insulating layer 60, and a second columnar wiring 32 that extends in the first direction D1 from the top surface of the via wiring 25, penetrates through the second magnetic layer 12, and has an end face exposed on the first main surface 10a of the element body 10. The via wiring is a conductor having a smaller line width (diameter, cross-sectional area) than the columnar wiring.

[0028] The second lead wiring 52 is made of a conductive material, extends in the first direction D1 from the top surface of the first inductor wiring 21, and penetrates through the second magnetic layer 12. The second lead wiring 52 is provided on the top surface of the outer peripheral end 21b of the first inductor wiring 21, and includes a via wiring 25 that penetrates through the insulating layer 60, and a third columnar wiring 33 that extends in the first direction D1 from the top surface of the via wiring 25, penetrates through the second magnetic layer 12, and has an end face exposed on the first main surface 10a of the element body 10. The first and second lead wirings 51 and 52 are preferably made of the same material as the plating layer P of the first and second inductor wirings 21 and 22.

[0029] The first and second external electrodes 41 and 42 are provided on the first main surface 10a of the element body 10. The first and second external electrodes 41 and 42 are made of a conductive material, and have a three-layer structure in which, for example, Cu with low electrical resistance and excellent stress resistance, Ni with excellent corrosion resistance, and Au with excellent solder wettability and reliability are arranged in this order from the inside to the outside.

[0030] The first external electrode 41 contacts the end face exposed from the first main surface 10a of the element 10 of the first lead wiring 51 and is electrically connected to the first lead wiring 51. Thereby, the first external electrode 41 is electrically connected to the outer peripheral end 22b of the second inductor wiring 22. The second external electrode 42 contacts the end face exposed from the first main surface 10a of the element 10 of the second lead wiring 52 and is electrically connected to the second lead wiring 52. Thereby, the second external electrode 42 is electrically connected to the outer peripheral end 21b of the first inductor wiring 21. In FIG. 1, the first and second external electrodes 41 and 42 are shown by a two-dot chain line for convenience.

[0031] The insulating layer 60 is made of an insulating material that does not contain a magnetic material. The insulating layer 60 is, for example, an organic resin such as an epoxy resin, a phenol resin, a polyimide resin, a liquid crystal polymer, or a combination thereof, a sintered body such as glass or alumina, or a thin film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film.

[0032] At least a part of the innermost peripheral inner peripheral surface 211 of the first inductor wiring 21 is in contact with the second magnetic layer 12 without being covered by the insulating layer 60. The innermost periphery of the inductor wiring refers to the inner periphery on the radially inner side of the inductor wiring when the inductor wiring has one turn or less, and refers to the inner periphery on the radially inner side of the portion constituting one turn including the inner peripheral end of the inductor wiring when the inductor wiring has more than one turn. In this embodiment, the entire innermost peripheral inner peripheral surface 211 of the first inductor wiring 21 is in contact with the second magnetic layer 12 without being covered by the insulating layer 60.

[0033] Of the outer surfaces of the first inductor wiring 21 and the second inductor wiring 22, the portions excluding the innermost peripheral inner peripheral surface 211 of the first inductor wiring 21 are in contact with the insulating layer 60. Thereby, the insulation between the first inductor wiring 21 and the second inductor wiring 22, and the first magnetic layer 11 and the second magnetic layer 12 can be ensured.

[0034] Specifically, the insulating layer 60 is in contact with and covers the entire top surface 212 facing the first direction D1 side of the first inductor wiring 21, the entire bottom surface 213 facing the second direction D2 side of the first inductor wiring 21, the entire outer peripheral surface 214 of the outermost periphery of the first inductor wiring 21, the entire inner peripheral surface 221 of the innermost periphery of the second inductor wiring 22, the entire top surface 222 facing the first direction D1 side of the second inductor wiring 22, the entire bottom surface 223 facing the second direction D2 side of the second inductor wiring 22, and the entire outer peripheral surface 224 of the outermost periphery of the second inductor wiring 22. The outermost periphery of the inductor wiring refers to the outer periphery on the radially outer side of the inductor wiring when the inductor wiring has one turn or less, and refers to the outer periphery on the radially outer side of the portion constituting one turn including the outer peripheral end of the inductor wiring when the inductor wiring has more than one turn.

[0035] Furthermore, the insulating layer 60 is also provided between adjacent turns of the first inductor wiring 21 and between adjacent turns of the second inductor wiring 22. Thereby, in each of the first inductor wiring 21 and the second inductor wiring 22, a short circuit between adjacent turns can be suppressed.

[0036] The coating layer 50 is, for example, a solder resist mainly composed of an epoxy resin. The coating layer 50 is preferably provided in a region of the first main surface 10a of the base body 10 where the first external electrode 41 and the second external electrode 42 are not provided. By providing the coating layer 50, the inductor component 1 can be protected from the external environment.

[0037] According to the inductor component 1, since at least a part of the inner peripheral surface 211 of the innermost periphery of the first inductor wiring 21 is in contact with the second magnetic layer 12 without being covered by the insulating layer 60, compared with the case where the entire outer surface of the first inductor wiring 21 is covered by the insulating layer 60, the volume of the second magnetic layer 12 can be increased. As a result, the inductance value of the inductor component 1 can be improved.

[0038] The inner magnetic path portion of the coil 15 is particularly prone to magnetic flux concentration. In the inductor component 1, since at least a part of the innermost peripheral surface 211 of the innermost periphery of the first inductor wiring 21 is not covered with the insulating layer 60 and is in contact with the second magnetic layer 12, the concentration of the magnetic flux in the inner magnetic path portion of the coil 15 can be alleviated. Thereby, the inductance value can be improved more effectively than the case where a portion other than the innermost peripheral surface 211 of the outermost surface of the first inductor wiring 21 is not covered with the insulating layer 60 and is in contact with the second magnetic layer 12.

[0039] Preferably, the coil 15 further has a second inductor wiring 22 wound along a plane orthogonal to the first direction D1. The second inductor wiring 22 is arranged on the second direction D2 side opposite to the first direction D1 rather than the first inductor wiring 21, is electrically connected to the first inductor wiring 21, the insulating layer 60 exists at least between the first inductor wiring 21 and the second inductor wiring 22, and covers the innermost peripheral surface 221 of the second inductor wiring 22.

[0040] According to the above configuration, since the second inductor wiring 22 is further provided, the inductance value can be further improved. Also, since the insulating layer 60 exists at least between the first inductor wiring 21 and the second inductor wiring 22, the insulation between the first inductor wiring 21 and the second inductor wiring 22 can be ensured. Also, since the insulating layer 60 covers the innermost peripheral surface 221 of the second inductor wiring 22, the insulation between the innermost peripheral surface 211 of the first inductor wiring 21 and the innermost peripheral surface 221 of the second inductor wiring 22 can be ensured.

[0041] Preferably, it further includes a second lead-out wiring 52 that is connected to an end portion (outer peripheral end 21b) in the extending direction of the first inductor wiring 21 and extends in the first direction D1 and is exposed from the outer surface of the element body 10. According to this configuration, the first inductor wiring 21 and an external circuit or the like can be connected at the shortest distance via the second lead-out wiring 52 without providing unnecessary routing wirings. Similarly, preferably, it further includes a first lead-out wiring 51 that is connected to an end portion (outer peripheral end 22b) in the extending direction of the second inductor wiring 22 and extends in the first direction D1 and is exposed from the outer surface of the element body 10. According to this configuration, the first inductor wiring 21 and an external circuit or the like can be connected at the shortest distance via the first lead-out wiring 51 without providing unnecessary routing wirings.

[0042] (Modification example) FIG. 3 is a schematic cross-sectional view showing an inductor component 1A according to a modification example. FIG. 3 corresponds to the II-II cross section (FIG. 2) of FIG. 1. In FIG. 3, for the sake of convenience, the description of the second side surface side of the element body is omitted.

[0043] As shown in FIG. 3, the thickness t1 in the first direction D1 of the second magnetic layer 12 existing between the first main surface 10a of the element body 10 and the first inductor wiring 21 is smaller than the thickness t2 in the first direction D1 of the first magnetic layer 11 existing between the second main surface 10b of the element body 10 and the second inductor wiring 22.

[0044] According to the above configuration, since the thickness t1 in the first direction D1 of the second magnetic layer 12 existing between the first main surface 10a of the base body 10 and the first inductor wiring 21 is relatively small, the length in the first direction D1 of the second columnar wiring 32 passing through the second magnetic layer 12 can be shortened. As a result, since the length in the first direction D1 of the first lead-out wiring 51 can also be shortened, the first lead-out wiring 51 can be easily formed. When the thickness t1 is relatively large, for example, when forming the second columnar wiring 32 by electrolytic plating, there is a possibility that the plating growth becomes insufficient. Further, according to the above configuration, since the length in the first direction D1 of the first lead-out wiring 51 can be shortened, the electrical resistance of the first lead-out wiring 51 can be reduced. Similarly for a second lead-out wiring (not shown), according to the above configuration, since the length in the first direction D1 of the second lead-out wiring can be shortened, the second lead-out wiring can be easily formed. Also, the electrical resistance of the second lead-out wiring can be reduced.

[0045] When the thickness t1 is relatively small, compared with the case where the thickness t1 is relatively large, magnetic flux is likely to concentrate between the first main surface 10a of the base body 10 and the first inductor wiring 21. In the inductor component 1A, the inner peripheral surface 211 of the innermost circumference of the first inductor wiring 21 is not covered with the insulating layer 60, while the inner peripheral surface 221 of the innermost circumference of the second inductor wiring 22 is covered with the insulating layer 60. Thus, by selectively not covering only the inner peripheral surface 211 of the innermost circumference of the first inductor wiring 21 with the insulating layer 60, even when the thickness t1 is relatively small, it is possible to alleviate the concentration of magnetic flux between the first main surface 10a of the base body 10 and the first inductor wiring 21, and also ensure the insulation between the inner peripheral surface 211 of the innermost circumference of the first inductor wiring 21 and the inner peripheral surface 221 of the innermost circumference of the second inductor wiring 22.

[0046] (Manufacturing method) Next, an example of a manufacturing method of the inductor component 1 will be described. FIGS. 4A to 4I are explanatory diagrams for explaining the manufacturing method of the inductor component 1. FIGS. 4A to 4I correspond to the II-II cross section (FIG. 2) of FIG. 1.

[0047] As shown in FIG. 4A, a support substrate 70 is prepared. The support substrate 70 is made of an inorganic material such as ceramic, epoxy glass, or glass. An insulating resin is applied onto the main surface of the support substrate 70, and is exposed and developed using a photolithography process to pattern the insulating resin. The patterning shape is such that the insulating resin covers at least the bottom surface of the second inductor wiring 22 formed in a later process. Thereafter, by curing the insulating resin, a first insulating resin layer 61 that becomes a part of the insulating layer 60 is formed. As the insulating resin, an epoxy resin, a polyimide resin, or the like may be used.

[0048] As shown in FIG. 4B, a first seed layer S1 is formed so as to cover the first insulating resin layer 61 using a sputtering method or the like. Thereafter, after applying a resist (not shown), the first seed layer S1 is patterned using a photolithography process. The patterning shape is a shape corresponding to the spiral shape of the second inductor wiring 22 formed in a later process. Thereafter, an insulating resin film is laminated so as to cover the first insulating resin layer 61 and the first seed layer S1. Thereafter, the insulating resin film is exposed and developed using a photolithography process to pattern the insulating resin film. The patterning shape is such that the insulating resin film is provided on the inner peripheral surface of the innermost circumference, between adjacent turns, and the outer peripheral surface of the outermost circumference of the second inductor wiring 22 formed in a later process. Thereafter, the insulating resin film is cured to form a second insulating resin layer 62 that becomes a part of the insulating layer 60. As the insulating resin film, an epoxy resin film, a polyimide resin film, or the like may be used.

[0049] As shown in FIG. 4C, while power is supplied to the first seed layer S1, the first plating layer P1 is formed by electrolytic plating. As a result, the first plating layer P1 is formed so as to partially contact the first seed layer S1, and the second inductor wiring 22 is formed. Thereafter, an insulating resin film is laminated so as to cover the first insulating resin layer 61, the second insulating resin layer 62, and the second inductor wiring 22. Thereafter, using a photolithography method, the insulating resin film is exposed and developed to pattern the insulating resin film. The patterning shape is such that the insulating resin film covers the top surface of the second inductor wiring 22. Further, an opening 63a is formed in the insulating resin film at a position where a via wiring 25 connected to the top surface of the second inductor wiring 22 is provided. Thereafter, the insulating resin film is cured to form a third insulating resin layer 63 that becomes part of the insulating layer 60.

[0050] As shown in FIG. 4D, using a sputtering method or the like, a second seed layer S2 is formed so as to cover the first to third insulating resin layers 61 to 63 and the opening 63a. Thereafter, after applying a resist (not shown), the second seed layer S2 is patterned using a photolithography method. The patterning shape is a shape corresponding to the spiral shape of the first inductor wiring 21 formed in a later process. At this time, the second seed layer S2 is also formed in the opening 63a. The second seed layer S2 formed in the opening 63a becomes a via wiring 25 connected to the top surface of the second inductor wiring 22. Thereafter, an insulating resin film is laminated so as to cover the first to third insulating resin layers 61 to 63 and the second seed layer S2. Thereafter, using a photolithography method, the insulating resin film is exposed and developed to pattern the insulating resin film. The patterning shape is such that the insulating resin film is provided between adjacent turns of the first inductor wiring 21 formed in a later process and on the outermost peripheral surface. At this time, the insulating resin film is not provided on the innermost peripheral surface of the innermost periphery of the first inductor wiring 21. Thereafter, the insulating resin film is cured to form a fourth insulating resin layer 64 that becomes part of the insulating layer 60.

[0051] As shown in FIG. 4E, while supplying power to the second seed layer S2, a second plating layer P2 is formed by electrolytic plating. As a result, the second plating layer P2 is formed so as to partially contact the second seed layer S2, and the first inductor wiring 21 and the first columnar wiring 31 are formed. Thereafter, an insulating resin film is laminated so as to cover the first to fourth insulating resin layers 61 to 64, the first columnar wiring 31, and the first inductor wiring 21. Thereafter, using a photolithography method, the insulating resin film is exposed and developed to pattern the insulating resin film. The patterning shape is such that the insulating resin film covers the top surfaces of the first columnar wiring 31 and the first inductor wiring 21. Further, an opening 65a is formed in the insulating resin film at a position where a via wiring 25 connected to the top surface of the first inductor wiring 21 and the top surface of the first columnar wiring 31 is provided. Thereafter, the insulating resin film is cured to form a fifth insulating resin layer 65 that becomes part of the insulating layer 60.

[0052] As shown in FIG. 4F, using a sputtering method or the like, a third seed layer S3 is formed so as to cover the first to fifth insulating resin layers 61 to 65 and the opening 65a. The third seed layer S3 formed in the opening 65a becomes a via wiring 25 connected to the top surface of the first inductor wiring 21 and the top surface of the first columnar wiring 31. Thereafter, a resist 75 is applied, exposed and developed using a photolithography method, and an opening 75a is formed at a predetermined position of the resist 75. The predetermined position is the position where the second columnar wiring 32 and the third columnar wiring 33 are provided.

[0053] As shown in FIG. 4G, while supplying power to the third seed layer S3, a third plating layer P3 is formed in the opening 75a of the resist 75 by electrolytic plating. Thereby, the second columnar wiring 32 and the third columnar wiring 33 are formed. Then, the resist 75 is peeled off, and using a photolithography method, the portions of the third seed layer S3 other than the portions provided on the bottom surfaces of the second columnar wiring 32 and the third columnar wiring 33 are etched. Then, a magnetic sheet to be the second magnetic layer 12 is pressure-bonded from above the main surface of the support substrate 70 toward the first inductor wiring 21 and the second inductor wiring 22, and the first inductor wiring 21, the second inductor wiring 22, the first to fifth insulating resin layers 61 to 65, and the first to third columnar wirings 31 to 33 are covered with the second magnetic layer 12. Then, the top surface of the second magnetic layer 12 is ground, and the end faces of the second columnar wiring 32 and the third columnar wiring 33 are exposed from the top surface of the second magnetic layer 12.

[0054] As shown in FIG. 4H, the support substrate 70 is removed, and another magnetic sheet to be the first magnetic layer 11 is pressure-bonded from below the second inductor wiring 22 toward the first inductor wiring 21 and the second inductor wiring 22, and the bottom surface of the first insulating resin layer 61 is covered with the first magnetic layer 11. Then, the first magnetic layer 11 is ground to a predetermined thickness.

[0055] As shown in FIG. 4I, an insulating resin film to be the coating layer 50 is laminated on the top surface of the second magnetic layer 12. Then, using a photolithography method, the insulating resin film is exposed and developed to pattern the insulating resin film. The patterning shape is such that the coating layer 50 covers the region of the top surface of the second magnetic layer 12 excluding the regions where the first and second external electrodes 41 and 42 are formed. Then, the insulating resin film is cured to form the coating layer 50. Then, the first external electrode 41 and the second external electrode 42 are formed, for example, by electroless plating so as to cover the end faces of the second columnar wiring 32 and the third columnar wiring 33 exposed from the top surface of the second magnetic layer 12. The inductor component 1 is manufactured as described above.

[0056] <Second Embodiment> FIG. 5 is a schematic plan view showing a second embodiment of the inductor component. FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 5. In FIG. 5, for convenience, the positions where the insulating layer exists are hatched. In FIG. 6, for convenience, the description of the seed layer is omitted. The second embodiment is different from the first embodiment in the number of turns of the first and second inductor wirings and in that the insulating layer does not cover a part of the top surface of the first inductor wiring. The different configurations will be described below. Other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment are given and the description thereof is omitted.

[0057] As shown in FIGS. 5 and 6, in this embodiment, the number of turns of the first inductor wiring 21B is 4 turns. The number of turns of the second inductor wiring 22B is 4.5 turns. Thereby, the inductance value can be further improved.

[0058] At least a part of the top surface 212 of the first inductor wiring 21B is not covered by the insulating layer 60 and contacts the second magnetic layer 12, and the portion 212p of the top surface 212 of the first inductor wiring 21 that contacts the second magnetic layer 12 is continuous with the innermost peripheral surface 211 of the first inductor wiring 21.

[0059] Specifically, when viewed from the Z direction, an insulating layer 60 is provided in a part of the top surface 212 of the first inductor wiring 21B that exists within a predetermined region R1 around the first lead wiring 51 and in a part that exists within a predetermined region R2 around the second lead wiring 52. On the other hand, when viewed from the Z direction, an insulating layer 60 is not provided in parts of the top surface 212 of the first inductor wiring 21B other than the predetermined region R1 around the first lead wiring 51 and other than the predetermined region R2 around the second lead wiring 52, and they are in contact with the second magnetic layer 12. The shape of the predetermined region R1 is not particularly limited, but in this embodiment, when viewed from the Z direction, it is in a substantially fan shape centered on the first lead wiring 51. Similarly, the shape of the predetermined region R2 is not particularly limited, but in this embodiment, when viewed from the Z direction, it is in a substantially fan shape centered on the second lead wiring 52.

[0060] According to the above configuration, since the volume of the second magnetic layer 12 can be further increased, the inductance value can be further improved. Also, as described above, when the thickness in the first direction D1 of the second magnetic layer 12 existing between the first main surface 10a of the base body 10 and the first inductor wiring 21B is relatively small, compared with the case where the thickness is relatively large, magnetic flux is likely to concentrate between the first main surface 10a of the base body 10 and the first inductor wiring 21B. According to the inductor component 1B, since at least a part of the top surface 212 of the first inductor wiring 21B is in contact with the second magnetic layer 12 without being covered by the insulating layer 60, even when the above thickness is relatively small, the concentration of magnetic flux between the first main surface 10a of the base body 10 and the first inductor wiring 21B can be alleviated.

[0061] Preferably, it further includes a second lead-out wiring 52 that is connected to an end portion (outer peripheral end 21b) in the extending direction of the first inductor wiring 21, extends in the first direction D1, and is exposed from the outer surface of the base body 10. The distance d1 between the portion 212p in contact with the second magnetic layer 12 of the top surface 212 of the first inductor wiring 21B and the second lead-out wiring 52 is 80 μm or more. The distance d1 between the portion 212p in contact with the second magnetic layer 12 and the second lead-out wiring 52 refers to the shortest distance between the portion 212p in contact with the second magnetic layer 12 and the outer periphery of the second lead-out wiring 52 as viewed from the Z direction.

[0062] According to the above configuration, the occurrence of a short circuit between the portion 212p in contact with the second magnetic layer 12 and the second lead wiring 52 can be suppressed. Specifically, when a potential difference occurs in the conductor portion of the inductor component 1B due to ESD (Electro Static Discharge) or the like, a short circuit may occur through the magnetic powder of the first and second magnetic layers 11 and 12. In particular, since the distance between the first and second lead wirings 51 and 52 and the first and second inductor wirings 21B and 22B existing around the first and second lead wirings 51 and 52 is relatively short, they are likely to short circuit. The inventors have found that even if a part of the top surface 212 of the first inductor wiring 21B is not covered with the insulating layer 60 and is brought into contact with the second magnetic layer 12, if the distance d1 is 80 μm or more, the short circuit risk can be reduced to the same extent as when the entire top surface 212 of the first inductor wiring 21B is covered with the insulating layer 60.

[0063] Preferably, it further includes a first lead wiring 51 that is connected to an end portion (outer peripheral end 22b) in the extending direction of the second inductor wiring 22, extends in the first direction D1, and is exposed from the outer surface of the element body 10. The distance d2 between the portion 212p in contact with the second magnetic layer 12 of the top surface 212 of the first inductor wiring 21 and the first lead wiring 51 is 80 μm or more. The distance d2 between the portion 212p in contact with the second magnetic layer 12 and the first lead wiring 51 refers to the shortest distance between the portion 212p in contact with the second magnetic layer 12 and the outer periphery of the first lead wiring 51 as viewed in the Z direction. According to this configuration, the occurrence of a short circuit between the portion 212p in contact with the second magnetic layer 12 and the first lead wiring 51 can be suppressed.

[0064] As a manufacturing method of the inductor component 1B, for example, in the manufacturing method described with reference to FIGS. 4A to 4I, when patterning the first seed layer S1 and the second seed layer S2, they are made into 4 turns and 4.5 turns respectively so as to correspond to the number of turns of the first and second inductor wirings. When patterning the insulating resin film of the fifth insulating resin layer 65, the fifth insulating resin layer 65 may be formed only within the predetermined region R1 and the predetermined region R2.

[0065] <Third Embodiment> FIG. 7 is a schematic cross-sectional view showing a third embodiment of the inductor component. FIG. 7 corresponds to the II-II cross section (FIG. 2) of FIG. 1. The third embodiment is different from the first embodiment in the shape of the first inductor wiring, the position where the seed layer is provided in the first inductor wiring, and the point that the insulating layer does not cover a part of the top surface of the first inductor wiring. The different configurations will be described below. Other configurations are the same as those of the first embodiment, and the same reference numerals as those of the first embodiment are given and the description thereof is omitted.

[0066] As shown in FIG. 7, a part of the top surface 212 of the first inductor wiring 21C is in contact with the second magnetic layer 12 without being covered by the insulating layer 60. Specifically, the top surface 212 of the portion including the innermost circumference of the first inductor wiring 21C is in contact with the second magnetic layer 12 without being covered by the insulating layer 60. Thereby, the volume of the second magnetic layer 12 can be further increased and the inductance value can be further improved as compared with the case where the entire top surface 212 of the first inductor wiring 21C is covered by the insulating layer 60.

[0067] In a cross section orthogonal to the extending direction of the first inductor wiring 21 and intersecting the portion of the inner peripheral surface 211 of the innermost circumference of the first inductor wiring 21 that contacts the second magnetic layer 12, the seed layer IS existing in the portion including the innermost circumference of the first inductor wiring 21C is biased to the side opposite to the inner peripheral surface 211 side of the innermost circumference of the first inductor wiring 21 with respect to the center of the first inductor wiring 21 in the direction (X direction) orthogonal to the first direction D1. The portion including the innermost circumference of the first inductor wiring 21C refers to the portion of the first inductor wiring 21C that constitutes one turn including the inner peripheral end 21a of the first inductor wiring 21C. When the number of turns of the first inductor wiring 21C exceeds one turn as in this embodiment, the above cross section may be a cross section orthogonal to the extending direction of the portion including the innermost circumference of the first inductor wiring 21C and intersecting the portion of the inner peripheral surface 211 of the innermost circumference of the first inductor wiring 21 that contacts the second magnetic layer 12.

[0068] According to the above configuration, even when at least a part of the innermost peripheral surface of the first inductor wiring 21C is not covered by the insulating layer 60, the height of the plating layer P in the first direction D1 in the portion including the innermost periphery of the first inductor wiring 21C can be ensured, and the spread of the plating layer P in the direction orthogonal to the first direction D1 can be suppressed.

[0069] Preferably, the first inductor wiring 21C has a bottom surface 213 facing the second direction D2 opposite to the first direction D1, and the seed layer IS existing in the portion including the innermost periphery of the first inductor wiring 21C is provided at a corner between the outer peripheral surface 215 opposite to the innermost peripheral surface 211 of the first inductor wiring 21C and the bottom surface 213 of the first inductor wiring 21C. According to this configuration, the height of the plating layer P in the first direction D1 in the portion including the innermost periphery of the first inductor wiring 21C can be more reliably ensured, and the spread of the plating layer P in the direction orthogonal to the first direction D1 can be further suppressed.

[0070] Preferably, the first inductor wiring 21C has a top surface 212 facing the first direction D1 side, and the portion including the innermost periphery of the first inductor wiring 21C has a curved surface C at a corner between the innermost peripheral surface 211 of the first inductor wiring 21C and the top surface 212 of the first inductor wiring 21C. The shape of the curved surface C is not particularly limited, but in this embodiment, it is a convex curved surface convex to the outside of the first inductor wiring 21C.

[0071] According to the above configuration, the distance in the facing direction between the wiring or the like facing the innermost peripheral surface 211 of the first inductor wiring 21C and the portion including the innermost periphery of the first inductor wiring 21C can be increased compared to the case where the above corner has a shape where a plane intersects a plane. Therefore, the occurrence of a short circuit between the wiring or the like and the first inductor wiring 21C can be suppressed. Further, since the above corner has the curved surface C, the hindrance of the magnetic flux by the above corner can be suppressed.

[0072] As a method for manufacturing the inductor component 1C, for example, in the manufacturing method described with reference to FIGS. 4A to 4I, when patterning the second seed layer S2, in a cross section orthogonal to the extending direction of the first inductor wiring and intersecting a portion of the inner peripheral surface of the innermost periphery of the first inductor wiring that contacts the second magnetic layer, the seed layer existing in the portion of the first inductor wiring including the innermost periphery may be arranged to be biased to the side opposite to the inner peripheral surface side of the innermost periphery of the first inductor wiring with respect to the center of the first inductor wiring in a direction orthogonal to the first direction D1.

[0073] Note that the present disclosure is not limited to the above-described embodiments, and design changes can be made without departing from the gist of the present disclosure. For example, the respective characteristic points of the first to third embodiments may be combined in various ways.

[0074] In the first to third embodiments, the first and second lead wirings, the first and second external electrodes, and the coating layer were provided, but these members are not essential and may not be provided, or may be replaced with other members.

[0075] In the first to third embodiments, the inductor wiring was two layers, but it may be one layer or three or more layers.

[0076] In the first to third embodiments, the entire inner peripheral surface of the innermost periphery of the first inductor wiring was in contact with the second magnetic layer without being covered by the insulating layer, but a part of the inner peripheral surface of the innermost periphery of the first inductor wiring may be in contact with the second magnetic layer without being covered by the insulating layer, and the other part of the inner peripheral surface may be covered by the insulating layer. In the first to third embodiments, the entire inner peripheral surface of the innermost periphery of the second inductor wiring was covered by the insulating layer, but at least a part of the inner peripheral surface of the innermost periphery of the second inductor wiring may be in contact with the second magnetic layer without being covered by the insulating layer. Thereby, the volume of the magnetic layer can be further increased, and the inductance value can be further improved.

[0077] In the first to third embodiments, the entire outer peripheral surface of the outermost periphery of the first and second inductor wirings was covered with the insulating layer, but at least a part of the outer peripheral surface of the outermost periphery of the first and second inductor wirings may be in contact with the second magnetic layer without being covered with the insulating layer. Thereby, the volume of the magnetic layer can be further increased, and the inductance value can be further improved.

[0078] In the first to third embodiments, the entire bottom surface of the second inductor wiring was covered with the insulating layer, but at least a part of the bottom surface of the second inductor wiring may be in contact with the first magnetic layer without being covered with the insulating layer. Thereby, the volume of the magnetic layer can be further increased, and the inductance value can be further improved.

[0079] In the second and third embodiments, a part of the top surface of the first inductor wiring was covered with the insulating layer, and the other part of the top surface was in contact with the second magnetic layer without being covered with the insulating layer, but the entire top surface of the first inductor wiring may be in contact with the second magnetic layer without being covered with the insulating layer. Thereby, the volume of the magnetic layer can be further increased, and the inductance value can be further improved.

[0080] <1> A base body including a magnetic layer and having a first main surface and a second main surface facing each other, A coil disposed in the base body, And an insulating layer covering a part of the outer surface of the coil, The coil has a first inductor wiring wound along a plane orthogonal to a first direction that is a direction orthogonal to the first main surface and from the second main surface toward the first main surface, At least a part of the inner peripheral surface of the innermost periphery of the first inductor wiring is in contact with the magnetic layer without being covered with the insulating layer, an inductor component. <2> The coil further has a second inductor wiring wound along a plane orthogonal to the first direction, The second inductor wiring is disposed on the second direction side opposite to the first direction with respect to the first inductor wiring, and is electrically connected to the first inductor wiring. The insulating layer is present at least between the first inductor wiring and the second inductor wiring, and covers the inner peripheral surface of the innermost circumference of the second inductor wiring. The inductor component according to <1>. <3> The inductor component according to <2>, further comprising a lead wiring connected to an end portion of the first inductor wiring in the extending direction thereof, and extending in the first direction and exposed from the outer surface of the element body. <4> The thickness of the magnetic layer in the first direction existing between the first main surface of the element body and the first inductor wiring is smaller than the thickness of the magnetic layer in the first direction existing between the second main surface of the element body and the second inductor wiring. The inductor component according to <3>. <5> The first inductor wiring has a top surface facing the first direction side. At least a part of the top surface of the first inductor wiring is not covered by the insulating layer and contacts the magnetic layer. The portion of the top surface of the first inductor wiring that contacts the magnetic layer is continuous with the inner peripheral surface of the innermost circumference of the first inductor wiring. The inductor component according to any one of <1> to <4>. <6> The inductor component further comprises a lead wiring connected to an end portion of the first inductor wiring in the extending direction thereof, and extending in the first direction and exposed from the outer surface of the element body. The distance between the portion of the top surface of the first inductor wiring that contacts the magnetic layer and the lead wiring is 80 μm or more. The inductor component according to <5>. <7> The first inductor wiring has a seed layer and a plating layer formed to partially contact the seed layer. In a cross-section that is orthogonal to the extending direction of the first inductor wiring and intersects a portion of the inner peripheral surface of the innermost periphery of the first inductor wiring that contacts the magnetic layer, the seed layer present in the portion of the first inductor wiring that includes the innermost periphery is biased and disposed on the side opposite to the inner peripheral surface side of the innermost periphery of the first inductor wiring with respect to the center of the first inductor wiring in a direction orthogonal to the first direction. The inductor component according to any one of <1> to <6>. <8> The first inductor wiring has a bottom surface facing the second direction side opposite to the first direction. The seed layer present in the portion of the first inductor wiring that includes the innermost periphery is provided at a corner between the outer peripheral surface on the side opposite to the inner peripheral surface of the innermost periphery of the first inductor wiring and the bottom surface of the first inductor wiring. The inductor component according to <7>. <9> The first inductor wiring has a top surface facing the first direction side. The portion of the first inductor wiring that includes the innermost periphery has a curved surface at a corner between the inner peripheral surface of the innermost periphery of the first inductor wiring and the top surface of the first inductor wiring. The inductor component according to <7> or <8>.

Explanation of Reference Numerals

[0081] 1, 1A, 1B, 1C Inductor components 10 Element body 10a First main surface 10b Second main surface 10c~10f First to fourth side surfaces 11 First magnetic layer 12 Second magnetic layer 15, 15B, 15C Coils 21, 21B, 21C First inductor wirings 211 Inner peripheral surface of the innermost periphery of the first inductor wiring 212 Top surface of the first inductor wiring 213 Bottom surface of the first inductor wiring 214 Outer peripheral surface of the outermost periphery of the first inductor wiring 22, 22B Second Inductor Wiring 221 Inner Peripheral Surface of the Innermost Periphery of the Second Inductor Wiring 222 Top Surface of the Second Inductor Wiring 223 Bottom Surface of the Second Inductor Wiring 224 Outer Peripheral Surface of the Outermost Periphery of the Second Inductor Wiring 25 Via Wiring 31, 32, 33 First, Second, and Third Columnar Wirings 41, 42 First and Second External Electrodes 50 Coating Layer 51, 52 First and Second Lead-Out Wirings 60 Insulation Layer C Curved Surface d1, d2 Distances D1 First Direction D2 Second Direction P Plating Layer S, IS Seed Layer t1, t2 Thicknesses

Claims

1. A body including a magnetic layer and having a first main surface and a second main surface facing each other, a coil disposed within the body, and an insulating layer covering a part of the outer surface of the coil, wherein the coil has a first inductor wiring wound along a plane orthogonal to a first direction which is a direction orthogonal to the first main surface and from the second main surface toward the first main surface, the first inductor wiring has a seed layer, a plating layer formed to be partially in contact with the seed layer, and a top surface facing the first direction side, at least a part of the inner peripheral surface of the innermost circumference of the first inductor wiring is in contact with the magnetic layer, in a cross section orthogonal to the extending direction of the first inductor wiring and intersecting a portion of the inner peripheral surface of the innermost circumference of the first inductor wiring that is in contact with the magnetic layer, the seed layer existing in the portion of the first inductor wiring including the innermost circumference is disposed offset to a side opposite to the inner peripheral surface side of the innermost circumference of the first inductor wiring with respect to the center of the first inductor wiring in a direction orthogonal to the first direction, an inductor component, wherein a boundary between the inner peripheral surface of the innermost circumference of the first inductor wiring and the top surface of the first inductor wiring in a portion of the first inductor wiring including the innermost circumference is a convex curved surface convex outward.

2. The coil further has a second inductor wiring wound along a plane orthogonal to the first direction, the second inductor wiring is disposed on a second direction side opposite to the first direction with respect to the first inductor wiring and is electrically connected to the first inductor wiring, the inductor component according to claim 1, wherein the insulating layer exists at least between the first inductor wiring and the second inductor wiring and covers the inner peripheral surface of the innermost circumference of the second inductor wiring.

3. The inductor component according to claim 2, further comprising a lead wiring connected to an end portion in the extending direction of the first inductor wiring and extending in the first direction to be exposed from the outer surface of the body.

4. The inductor component according to claim 3, wherein a thickness of the magnetic layer in the first direction existing between the first main surface of the body and the first inductor wiring is smaller than a thickness of the magnetic layer in the first direction existing between the second main surface of the body and the second inductor wiring.

5. The first inductor wiring has a top surface facing the first direction side, At least a part of the top surface of the first inductor wiring contacts the magnetic layer. The portion of the top surface of the first inductor wiring that contacts the magnetic layer is continuous with the innermost peripheral inner surface of the first inductor wiring. The inductor component according to any one of claims 1 to 4. **Claim 6** Further comprising a lead-out wiring connected to an end portion in the extending direction of the first inductor wiring and extending in the first direction to be exposed from the outer surface of the element body. The distance between the portion of the top surface of the first inductor wiring that contacts the magnetic layer and the lead-out wiring is 80 μm or more. The inductor component according to claim 5. **Claim 7** The first inductor wiring has a bottom surface facing the second direction side opposite to the first direction. The seed layer present in the portion including the innermost periphery of the first inductor wiring is provided at a corner between the outer peripheral surface on the opposite side of the innermost peripheral inner surface of the first inductor wiring and the bottom surface of the first inductor wiring. The inductor component according to any one of claims 1 to 4.

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