Inductor

Abstract

An inductor (1) is provided with: a first wiring (21) and a second wiring (22); a first magnetic layer (31) containing magnetic particles having a substantially spherical shape; a second magnetic layer (51) containing magnetic particles having a substantially flat shape; and a third magnetic layer (71) containing magnetic particles having a substantially flat shape. The relative permeability of each of the second magnetic layer (51) and the third magnetic layer (71) is higher than the relative permeability of the first magnetic layer (31). The fourth surface (54) of the first magnetic layer (31) has a second recess (60). The sixth surface (74) of the third magnetic layer (71) has a fourth recess (80).

Description

[0001] This application is a divisional application of application No. 202080056602.2, filed on June 19, 2020, with the title of "Inductor". TECHNICAL FIELD

[0002] The present application relates to an inductor. BACKGROUND

[0003] In the past, an inductor including a plurality of conductors and a magnetic body layer covering the plurality of conductors has been known (for example, refer to Patent Literature 1).

[0004] In Patent Literature 1, a ferrite blank sheet in which the plurality of conductors are arranged is stacked with another ferrite blank sheet, and they are fired, thereby obtaining an inductor.

[0005] PRIOR ART DOCUMENT

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 10-144526 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, for an inductor, a higher inductance, an excellent DC superimposition characteristic, and an excellent Q value are required.

[0010] However, in the inductor described in Patent Literature 1, the above requirements cannot be satisfied.

[0011] The present application provides an inductor having a higher inductance, an excellent DC superimposition characteristic, and an excellent Q value.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] The present invention [1] includes an inductor, wherein the inductor includes: a first wiring and a second wiring which are adjacent to each other at a spaced interval; a first magnetic layer having a first face which is continuous in a planar direction, a second face which is spaced apart from the first face in a thickness direction and is continuous in the planar direction, and an inner peripheral face which is located between the first face and the second face and contacts an outer peripheral face of the first wiring and an outer peripheral face of the second wiring, the first magnetic layer containing magnetic particles of a substantially spherical shape and a resin; a second magnetic layer having a third face which contacts the first face and a fourth face which is spaced apart from the third face in the thickness direction, the second magnetic layer containing magnetic particles of a substantially flat shape and a resin; and a third magnetic layer having a fifth face which contacts the second face and a sixth face which is spaced apart from the fifth face in the thickness direction, the third magnetic layer containing magnetic particles of a substantially flat shape and a resin, a relative magnetic permeability of each of the second magnetic layer and the third magnetic layer being higher than a relative magnetic permeability of the first magnetic layer, the third face having a first recessed portion recessed from a first opposing portion which opposes the first wiring in the thickness direction and a second opposing portion which opposes the second wiring in the thickness direction, between the first opposing portion and the second opposing portion, the fourth face having a second recessed portion recessed from a third opposing portion which opposes the first opposing portion in the thickness direction and a fourth opposing portion which opposes the second opposing portion in the thickness direction, between the third opposing portion and the fourth opposing portion, the fifth face having a third recessed portion recessed from a fifth opposing portion which opposes the first wiring in the thickness direction and a sixth opposing portion which opposes the second wiring in the thickness direction, between the fifth opposing portion and the sixth opposing portion, the sixth face having a fourth recessed portion recessed from a seventh opposing portion which opposes the fifth opposing portion in the thickness direction and an eighth opposing portion which opposes the sixth opposing portion in the thickness direction, between the seventh opposing portion and the eighth opposing portion.

[0014] The inductor 1 includes the first magnetic layer containing magnetic particles of a substantially spherical shape, and the second magnetic layer and the third magnetic layer containing magnetic particles of a substantially flat shape. Also, the relative magnetic permeability of each of the second magnetic layer and the third magnetic layer is higher than the relative magnetic permeability of the first magnetic layer. Therefore, the inductance of the inductor is high, and the DC superposition characteristics are excellent.

[0015] Also, since the second magnetic layer has the first recessed portion and the second recessed portion, in a region of the second magnetic layer surrounded by the first recessed portion and the second recessed portion, the magnetic particles of a substantially flat shape are able to be oriented along the first recessed portion and the second recessed portion. Also, since the third magnetic layer has the third recessed portion and the fourth recessed portion, in a region of the third magnetic layer surrounded by the third recessed portion and the fourth recessed portion, the magnetic particles of a substantially flat shape are able to be oriented along the third recessed portion and the fourth recessed portion. Therefore, an excellent Q value can be obtained.

[0016] Thus, the inductor has a high inductance, excellent DC superimposition characteristics, and excellent Q value.

[0017] The inductor of the present application [2] includes the inductor of the present application [1], wherein a length L1 between the first opposing portion and the first wiring, a length L2 between the second opposing portion and the second wiring, and a depth L3 of the first recess satisfy the following equation (1) and the following equation (2), a length L4 between the fifth opposing portion and the first wiring, a length L5 between the sixth opposing portion and the second wiring, and a depth L6 of the third recess satisfy the following equation (3) and the following equation (4).

[0018] L3 / L1 ≥ 0.2 (1)

[0019] L3 / L2 ≥ 0.2 (2)

[0020] L6 / L4 ≥ 0.2 (3)

[0021] L6 / L5 ≥ 0.2 (4).

[0022] The inductor of the present application [3] includes the inductor of the present application [1] or [2], wherein the depth L3 of the first recess and the depth L7 of the second recess satisfy the following equation (5), and the depth L6 of the third recess and the depth L8 of the fourth recess satisfy the following equation (6).

[0023] L7 / L3 ≥ 0.3 (5)

[0024] L8 / L6 ≥ 0.3 (6)

[0025] The inductor of the present application [4] includes the inductor of any one of the present applications [1] to [3], wherein a length L1 between the first opposing portion and the first wiring and a length L9 in a thickness direction of the first wiring satisfy the following equation (7), a length L2 between the second opposing portion and the second wiring and a length L10 in a thickness direction of the second wiring satisfy the following equation (8), a length L4 between the fifth opposing portion and the first wiring and the length L9 of the first wiring satisfy the following equation (9), and a length L5 between the sixth opposing portion and the second wiring and the length L10 of the second wiring satisfy the following equation (10).

[0026] L1 / L9 ≥ 0.1 (7)

[0027] L2 / L10 ≥ 0.1 (8)

[0028] L4 / L9 ≥ 0.1 (9)

[0029] L5 / L10 ≥ 0.1 (10)

[0030] Effects of the Invention

[0031] The inductor of the present application has a high inductance, excellent DC superposition characteristics, and excellent Q value. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a cross-sectional view of one embodiment of the inductor of the present application.

[0033] Figure 2 is a cross-sectional view of the magnetic particles contained in the first magnetic layer, the second magnetic layer, and the third magnetic layer in the inductor shown in Figure 1

[0034] represents the first step in the manufacturing method of the inductor in which a hot press device is prepared. Figure 3

[0035] represents the second step in the manufacturing method of the inductor in which the magnetic sheet, the first wiring, and the second wiring are placed in the hot press device. Figure 4 Figure 3 represents the third step in the manufacturing method of the inductor in which the outer frame member is made to adhere to the first mold to form a first closed space, and then the first closed space is depressurized to form a depressurized space.

[0036] Figure 5 Figure 4 represents the fourth step in the manufacturing method of the inductor in which the inner frame member is pressed against the first mold to form a second closed space in a depressurized atmosphere.

[0037] Figure 6 represents the fifth step in the manufacturing method of the inductor in which the magnetic sheet, the first wiring, and the second wiring are hot-pressed. Figure 5

[0038] represents the sixth step in the manufacturing method of the inductor in which a through hole is formed in the inductor taken out from the hot press device. Figure 7 Figure 6 represents the seventh step in the manufacturing method of the inductor in which the inductor is taken out from the hot press device.

[0039] Figure 8 Figure 7 represents the eighth step in the manufacturing method of the inductor in which a through hole is formed in the inductor taken out from the hot press device.

[0040] Figure 9 represents a cross-sectional view of a modification of the inductor shown in Figure 1 DETAILED DESCRIPTION

[0041] <One Embodiment>

[0042] Reference Signs List​​​​​Figure 1 and Figure 2 and an embodiment of the inductor of the present application is described.

[0043] The inductor 1 has a substantially sheet shape extending in a direction orthogonal to a thickness direction. The inductor 1 includes a first wiring 21 and a second wiring 22, a first magnetic layer 31, a second magnetic layer 51, and a third magnetic layer 71.

[0044] The first wiring 21 and the second wiring 22 are adjacent to each other at intervals in a first direction orthogonal to an electric transmission direction (second direction) (extending direction) and the thickness direction. Further, the first direction and the second direction are included in a plane direction, and orthogonal to each other in the plane direction. Of the first wiring 21 and the second wiring 22, the first wiring 21 is disposed on one side in the first direction, and the second wiring 22 is disposed on the other side in the first direction. The first wiring 21 and the second wiring 22 each have, for example, a substantially circular shape in a cross section. Further, the first wiring 21 and the second wiring 22 each have an outer peripheral surface 25 facing the first magnetic layer 31 described later. The first wiring 21 and the second wiring 22 each include a conductor wire 23 and an insulating film 24 covering the conductor wire 23.

[0045] The conductor wire 23 has a substantially circular shape in a cross section, sharing a central axis with the first wiring 21 and the second wiring 22, respectively. The material of the conductor wire 23 is a metal conductor such as copper. The lower limit of the radius of the conductor wire 23 is, for example, 25 μm, and the upper limit is, for example, 2000 μm.

[0046] The insulating film 24 covers the entire peripheral surface of the conductor wire 23. The insulating film 24 has a substantially circular ring shape in a cross section, sharing a central axis with the first wiring 21 and the second wiring 22, respectively. As the material of the insulating film 24, for example, an insulating resin such as polyester, polyurethane, polyester imide, polyamide imide, polyimide, or the like is cited. The insulating film 24 is a single layer or a plurality of layers. The lower limit of the thickness of the insulating film 24 is, for example, 1 μm, and the upper limit is, for example, 100 μm.

[0047] The radius of each of the first wiring 21 and the second wiring 22 is the sum of the radius of the conductor wire 23 and the thickness of the insulating film 24, and specifically, the lower limit is, for example, 25 μm, and preferably 50 μm, and the upper limit is, for example, 2000 μm, and preferably 200 μm.

[0048] The lower limit of the distance (interval) L0 between the first wiring 21 and the second wiring 22 can be appropriately set according to the purpose and the object of the inductor 1, and is, for example, 10 μm, and preferably 50 μm, and the upper limit is, for example, 10000 μm, and preferably 5000 μm.

[0049] The first magnetic layer 31 has an inner peripheral surface 32, a first surface 33, and a second surface 34.

[0050] The inner peripheral surface 32 contacts the outer peripheral surface 25 of the first wiring 21 and the outer peripheral surface 25 of the second wiring 22. The inner peripheral surface 32 is located between the first surface 33 and the second surface 34 in the thickness direction, which will be described below.

[0051] The first surface 33 is continuous in the surface direction. The first surface 33 is disposed apart from the inner peripheral surface 32 on the thickness direction side of the inner peripheral surface 32. The first surface 33 is a thickness direction side surface of the first magnetic layer 31. The first surface 33 has a first protruding portion 35, a second protruding portion 36, and a side concave portion 37.

[0052] In a cross section (hereinafter sometimes simply referred to as a "cross section") along the thickness direction and the first direction, the first protruding portion 35 opposes the thickness direction side surface 26 of the outer peripheral surface 25 of the first wiring 21 apart. Further, if the first wiring 21 is in a substantially circular shape in the cross section, an upper limit of a central angle a1 of the side surface 26 of the first wiring 21 is, for example, 90 degrees, and is preferably 60 degrees, and a lower limit is, for example, 15 degrees, and is preferably 30 degrees. The central angle a1 of the side surface 26 of the first wiring 21 is determined with a center axis CA1 of the first wiring 21 as a center. The first protruding portion 35 is a region that overlaps the side surface 26 when projected along a radial direction from the center axis CA1 (or a center of gravity) of the first wiring 21. The first protruding portion 35 is curved along the side surface 26 of the first wiring 21. The curved direction of the first protruding portion 35 is the same as the curved direction of the side surface 26 of the first wiring 21.

[0053] In the cross section, the second protruding portion 36 opposes the thickness direction side surface 26 of the outer peripheral surface 25 of the second wiring 22 apart. Further, if the second wiring 22 is in a substantially circular shape in the cross section, an upper limit of a central angle a2 of the side surface 26 of the second wiring 22 is, for example, 90 degrees, and is preferably 60 degrees, and a lower limit is, for example, 15 degrees, and is preferably 30 degrees. The central angle a2 of the side surface 26 of the second wiring 22 is determined with a center axis CA2 of the second wiring 22 as a center. The second protruding portion 36 is a region that overlaps the side surface 26 when projected along a radial direction from the center axis CA2 (or a center of gravity) of the second wiring 22. The second protruding portion 36 is curved along the side surface 26 of the second wiring 22. The curved direction of the second protruding portion 36 is the same as the curved direction of the side surface 26 of the second wiring 22.

[0054] The one-side recess 37 is provided between the first protrusion 35 and the second protrusion 36. The one-side recess 37 links the first protrusion 35 and the second protrusion 36 in the first direction. The one-side recess 37 does not overlap the first wiring 21 and the second wiring 22 when projected in the thickness direction, but is provided between the first wiring 21 and the second wiring 22. The one-side recess 37 is recessed toward the other side in the thickness direction from the first protrusion 35 and the second protrusion 36.

[0055] The second face 34 is provided opposite the first face 33 with a gap in the other side in the thickness direction. The second face 34 is located on the opposite side of the first face 33 with respect to the first wiring 21 and the second wiring 22. The second face 34 is the other side face in the thickness direction of the first magnetic layer 31. The second face 34 is continuous in the face direction. The second face 34 has a third protrusion 41, a fourth protrusion 42, and an other-side recess 43.

[0056] In a cross section, the third protrusion 41 is opposed to the other side face 27 of the outer peripheral face 25 of the first wiring 21 with a gap. Further, if the first wiring 21 is substantially circular in a cross section, the upper limit of the central angle a3 of the other side face 27 is, for example, 90 degrees, and preferably 60 degrees, and the lower limit is, for example, 15 degrees, and preferably 30 degrees. The central angle a3 of the other side face 27 is determined with the center axis CA1 of the first wiring 21 as the center. The third protrusion 41 is a region that overlaps the other side face 27 when projected in a radial direction from the center axis CA1 (or the center of gravity) of the first wiring 21. The third protrusion 41 is curved along the other side face 27 of the first wiring 21. The direction of the curvature of the third protrusion 41 is the same as the direction of the curvature of the other side face 27 of the first wiring 21.

[0057] In a cross section, the fourth protrusion 42 is opposed to the other side face 27 of the outer peripheral face 25 of the second wiring 22 with a gap. Further, if the second wiring 22 is substantially circular in a cross section, the upper limit of the central angle a4 of the other side face 27 is, for example, 90 degrees, and preferably 60 degrees, and the lower limit is, for example, 15 degrees, and preferably 30 degrees. The central angle a4 of the other side face 27 is determined with the center axis CA2 of the second wiring 22 as the center. The fourth protrusion 42 is a region that overlaps the other side face 27 when projected in a radial direction from the center axis CA2 (or the center of gravity) of the second wiring 22. The fourth protrusion 42 is curved along the other side face 27 of the second wiring 22. The direction of the curvature of the fourth protrusion 42 is the same as the direction of the curvature of the other side face 27 of the second wiring 22.

[0058] The other-side recessed portion 43 is provided between the third protruded portion 41 and the fourth protruded portion 42. The other-side recessed portion 43 links the third protruded portion 41 and the fourth protruded portion 42 in the first direction. The other-side recessed portion 43 does not overlap the first wiring 21 and the second wiring 22 when projected in the thickness direction, but is provided between the first wiring 21 and the second wiring 22. The other-side recessed portion 43 is recessed from the third protruded portion 41 and the fourth protruded portion 42 toward the thickness direction one side.

[0059] The material, physical properties, and dimensions of the first magnetic layer 31 are described later.

[0060] The second magnetic layer 51 is provided on the first face 33 of the first magnetic layer 31. The second magnetic layer 51 has a third face 53 and a fourth face 54.

[0061] The third face 53 is a contact face that contacts the first face 33 of the first magnetic layer 31. The third face 53 is continuous in the face direction. The third face 53 is the thickness direction other-side face of the second magnetic layer 51. The third face 53 has a first opposing portion 55, a second opposing portion 56, and a first recessed portion 57.

[0062] The first opposing portion 55 contacts the first protruded portion 35. Specifically, the first opposing portion 55 has the same shape as the first protruded portion 35 when sectioned. Furthermore, the first opposing portion 55 includes the first top portion 91 at a position located closest to the thickness direction one side.

[0063] The second opposing portion 56 contacts the second protruded portion 36. Specifically, the second opposing portion 56 has the same shape as the second protruded portion 36 when sectioned. Furthermore, the second opposing portion 56 includes the second top portion 92 at a position located closest to the thickness direction one side.

[0064] The first recessed portion 57 contacts the one-side recessed portion 37. The first recessed portion 57 is recessed from the first opposing portion 55 and the second opposing portion 56 toward the thickness direction other side between the first opposing portion 55 and the second opposing portion 56. Specifically, the first recessed portion 57 has the same shape as the one-side recessed portion 37. The first recessed portion 57 has the first bottom portion 38 at a position located closest to the thickness direction other side. In addition, the first recessed portion 57 includes the first circular-arc face 39 at a position located closer to the thickness direction one side than the one-side recessed portion 37. The first circular-arc face 39 includes the first bottom portion 38.

[0065] The fourth face 54 is provided on the thickness direction one side of the third face 53 in a manner spaced apart from the third face 53. The fourth face 54 forms the thickness direction one side face of the second magnetic layer 51 and the inductor 1 respectively. The fourth face 54 is an exposed face that is exposed on the thickness direction one side. The fourth face 54 is continuous in the face direction. The fourth face 54 has a third opposing portion 58, a fourth opposing portion 59, and a second recessed portion 60.

[0066] The third opposing portion 58 opposes the first opposing portion 55 of the third surface 53 in the thickness direction. The third opposing portion 58 is curved along the first opposing portion 55 in a cross section. The third opposing portion 58 has a fifth top portion 86 that opposes the thickness direction one side of the first top portion 91 of the first opposing portion 55. The fifth top portion 86 is located at a position closest to the thickness direction one side of the third opposing portion 58.

[0067] The fourth opposing portion 59 opposes the second opposing portion 56 of the third surface 53 in the thickness direction. The fourth opposing portion 59 is curved along the second opposing portion 56. The fourth opposing portion 59 has a sixth top portion 87 that opposes the thickness direction one side of the second top portion 92. The sixth top portion 87 is located at a position closest to the thickness direction one side in the fourth opposing portion 59.

[0068] The second recessed portion 60 opposes the first recessed portion 57 of the third surface 53 in the thickness direction. The second recessed portion 60 is recessed from the third opposing portion 58 and the fourth opposing portion 59 toward the other side in the thickness direction between the third opposing portion 58 and the fourth opposing portion 59. The second recessed portion 60 is recessed along the first recessed portion 57. The second recessed portion 60 has a third bottom portion 63 located at a position closest to the other side in the thickness direction. The third bottom portion 63 opposes the first bottom portion 38 of the first recessed portion 57 in the thickness direction.

[0069] The material, physical properties, and dimensions of the second magnetic layer 51 are described later.

[0070] The third magnetic layer 71 is disposed on the second surface 34 of the first magnetic layer 31. The third magnetic layer 71 has a fifth surface 73 and a sixth surface 74.

[0071] The fifth surface 73 is a contact surface that contacts the second surface 34 of the first magnetic layer 31. The fifth surface 73 is continuous in the surface direction. The fifth surface 73 is a thickness direction one side surface of the third magnetic layer 71. The fifth surface 73 has a fifth opposing portion 75, a sixth opposing portion 76, and a third recessed portion 77.

[0072] The fifth opposing portion 75 contacts the third protruding portion 41. Specifically, the fifth opposing portion 75 has the same shape as the third protruding portion 41 in a cross section. The fifth opposing portion 75 has a third top portion 93 located at a position closest to the other side in the thickness direction.

[0073] The sixth opposing portion 76 contacts the fourth protruding portion 42. Specifically, the sixth opposing portion 76 has the same shape as the fourth protruding portion 42 in a cross section. The sixth opposing portion 76 has a fourth top portion 94 located at a position closest to the other side in the thickness direction.

[0074] The 3rd recessed portion 77 is in contact with the other-side recessed portion 43. The 3rd recessed portion 77 is recessed from the 5th opposing portion 75 and the 6th opposing portion 76 toward the thickness direction one side between the 5th opposing portion 75 and the 6th opposing portion 76. Specifically, the 3rd recessed portion 77 has the same shape as the other-side recessed portion 43. The 3rd recessed portion 77 has the 2nd bottom portion 44 located at the position closest to the thickness direction one side. In addition, the 3rd recessed portion 77 includes the 2nd circular arc surface 49 located at the position closer to the thickness direction other side than the other-side recessed portion 43. The 2nd circular arc surface 49 includes the 2nd bottom portion 44.

[0075] The 6th surface 74 is disposed on the thickness direction other side of the 5th surface 73 in a manner spaced apart from the 5th surface 73. The 6th surface 74 forms the thickness direction other side surface of each of the 3rd magnetic layer 71 and the inductor 1. The 6th surface 74 is an exposed surface exposed on the thickness direction other side. The 6th surface 74 is continuous in the surface direction. The 6th surface 74 has a 7th opposing portion 78, an 8th opposing portion 79, and a 4th recessed portion 80.

[0076] The 7th opposing portion 78 opposes the 5th opposing portion 75 of the 5th surface 73 in the thickness direction. The 7th opposing portion 78 is curved along the 5th opposing portion 75 in a cross section. The 7th opposing portion 78 has a 7th top portion 88 opposing the 3rd top portion 93 of the 5th opposing portion 75 on the thickness direction other side. The 7th top portion 88 is located at the position closest to the thickness direction other side of the 7th opposing portion 78.

[0077] The 8th opposing portion 79 opposes the 6th opposing portion 76 of the 5th surface 73 in the thickness direction. The 8th opposing portion 79 is curved along the 6th opposing portion 76 in a cross section. The 8th opposing portion 79 has an 8th top portion 89 opposing the 4th top portion 94 of the 6th opposing portion 76 on the thickness direction other side. The 8th top portion 89 is located at the position closest to the thickness direction other side of the 8th opposing portion 79.

[0078] The 4th recessed portion 80 opposes the 3rd recessed portion 77 of the 5th surface 73 in the thickness direction. The 4th recessed portion 80 is recessed from the 7th opposing portion 78 and the 8th opposing portion 79 toward the thickness direction one side between the 7th opposing portion 78 and the 8th opposing portion 79. The 4th recessed portion 80 is recessed along the 3rd recessed portion 77. The 4th recessed portion 80 has a 4th bottom portion 64 located at the position closest to the thickness direction one side. The 4th bottom portion 64 opposes the 2nd bottom portion 44 of the 3rd recessed portion 77 in the thickness direction.

[0079] Next, the materials, physical properties, and dimensions of the 1st magnetic layer 31, the 2nd magnetic layer 51, and the 3rd magnetic layer 71 are described.

[0080] The materials of the 1st magnetic layer 31, the 2nd magnetic layer 51, and the 3rd magnetic layer 71 are magnetic compositions containing magnetic particles and a resin.

[0081] As the magnetic material constituting the magnetic particles, for example, a soft magnetic substance, a hard magnetic substance are cited. From the viewpoint of inductance, a soft magnetic substance is preferably cited.

[0082] As the soft magnetic substance, for example, a single metal substance containing one kind of metal element in a pure substance state, an alloy substance which is a eutectic mixture (mixture) of one or more kinds of metal elements (first metal element) and one or more kinds of metal elements (second metal element) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.) are cited. These can be used alone or in combination.

[0083] As the single metal substance, for example, a metal element consisting of only one kind of metal element (first metal element) is cited. As the first metal element, for example, one is appropriately selected from among iron (Fe), cobalt (Co), nickel (Ni), and other metal elements which can be contained as the first metal element of a soft magnetic substance.

[0084] In addition, as the single metal substance, for example, a form having a core containing only one kind of metal element and a surface layer of an inorganic substance and / or an organic substance which modifies part or all of the surface of the core, for example, a form of an organic metal compound containing the first metal element, a form after decomposition (thermal decomposition, etc.) of an inorganic metal compound, etc. are cited. As the latter form, more specifically, an iron powder (sometimes referred to as a carbonyl iron powder) after thermal decomposition of an organic iron compound (specifically, a carbonyl iron) containing iron as the first metal element, etc. are cited. Furthermore, the position of the layer of the inorganic substance and / or the organic substance which modifies the portion containing only one kind of metal element is not limited to the surface as described above. Furthermore, as the organic metal compound and the inorganic metal compound from which the single metal substance can be obtained, there is no particular limitation, and one can be appropriately selected from among known or conventional organic metal compounds and inorganic metal compounds from which a single metal substance of a soft magnetic substance can be obtained.

[0085] The alloy substance is a eutectic mixture of one or more kinds of metal elements (first metal element) and one or more kinds of metal elements (second metal element) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.), and there is no particular limitation as long as it can be used as a soft magnetic substance.

[0086] The first metal element is an essential element in the alloy substance, and for example, iron (Fe), cobalt (Co), nickel (Ni), etc. are cited. Furthermore, if the first metal element is Fe, the alloy substance is an Fe-based alloy, if the first metal element is Co, the alloy substance is a Co-based alloy, and if the first metal element is Ni, the alloy substance is a Ni-based alloy.

[0087] The second metal element is an element (sub-component) that is contained in the alloy body in a small amount, and is a metal element that is compatible (eutectic) with the first metal element, such as iron (Fe) (in the case where the first metal element is other than Fe), cobalt (Co) (in the case where the first metal element is other than Co), nickel (Ni) (in the case where the first metal element is other than Ni), chromium (Cr), aluminum (Al), silicon (Si), copper (Cu), silver (Ag), manganese (Mn), calcium (Ca), barium (Ba), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), ruthenium (Ru), rhodium (Rh), zinc (Zn), gallium (Ga), indium (In), germanium (Ge), tin (Sn), lead (Pb), scandium (Sc), yttrium (Y), strontium (Sr), various rare earth elements, and the like. These can be used alone or in combination with two or more.

[0088] The non-metal element is an element (sub-component) that is contained in the alloy body in a small amount, and is a non-metal element that is compatible (eutectic) with the first metal element, such as boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), sulfur (S), and the like. These can be used alone or in combination with two or more.

[0089] As an example of the alloy body, Fe-based alloys such as magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), iron-silicon-aluminum alloy (Fe-Si-Al alloy) (including super iron-silicon-aluminum alloy), permalloy (Fe-Ni alloy), Fe-Ni-Mo alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Co alloy, Fe-Cr alloy, Fe-Cr-Al alloy, Fe-Ni-Cr alloy, Fe-Ni-Cr-Si alloy, copper-silicon alloy (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B (-Cu-Nb) alloy, Fe-B-Si-Cr alloy, Fe-Si-Cr-Ni alloy, Fe-Si-Cr alloy, Fe-Si-Al-Ni-Cr alloy, Fe-Ni-Si-Co alloy, Fe-N alloy, Fe-C alloy, Fe-B alloy, Fe-P alloy, ferrite (including stainless steel-based ferrite, and Mn-Mg-based ferrite, Mn-Zn-based ferrite, Ni-Zn-based ferrite, Ni-Zn-Cu-based ferrite, Cu-Zn-based ferrite, Cu-Mg-Zn-based ferrite, and the like, soft magnetic ferrite), Permalloy iron-cobalt-based high magnetic permeability alloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, and the like.

[0090] As an example of the alloy body, Co-based alloys such as Co-Ta-Zr, cobalt (Co)-based amorphous alloy, and the like.

[0091] Examples of Ni-based alloys include, for instance, Ni-Cr alloys.

[0092] like Figure 2 As shown, the magnetic particles contained in the first magnetic layer 31 are approximately spherical in shape. On the other hand, the magnetic particles contained in the second magnetic layer 51 and the third magnetic layer 71 are approximately flat (plate-shaped). Therefore, the approximately spherical magnetic particles in the first magnetic layer 31 can improve the DC superposition characteristics, and the approximately flat magnetic particles in the second magnetic layer 51 and the third magnetic layer 71 can obtain higher inductance, thereby achieving an excellent Q value.

[0093] The lower limit of the average maximum length of the magnetic particles is, for example, 0.1 μm, preferably 0.5 μm, and the upper limit is, for example, 200 μm, preferably 150 μm. The average maximum length of the magnetic particles can be calculated as the median particle size of the magnetic particles.

[0094] The volume percentage (filling rate) of magnetic particles in the magnetic composition is, for example, 10% or more, or, for example, 90% or less.

[0095] Examples of resins include thermosetting resins. Examples of thermosetting resins include epoxy resins, melamine resins, thermosetting polyimide resins, unsaturated polyester resins, polyurethane resins, and silicone resins. From the viewpoint of adhesion, heat resistance, etc., epoxy resins are preferred.

[0096] When the thermosetting resin contains epoxy resin, the thermosetting resin can also be formulated as an epoxy resin composition containing epoxy resin (such as cresol phenolic varnish-type epoxy resin), curing agent (such as phenolic resin), and curing accelerator (such as imidazole compound) in appropriate proportions. The amount of thermosetting resin relative to 100 volume parts of magnetic particles is, for example, 10 volume parts or more, and also, for example, 90 volume parts or less.

[0097] Furthermore, the resin can contain thermoplastic resins such as acrylic resin in appropriate proportions. In addition, detailed formulations of the above-mentioned magnetic composition are described in Japanese Patent Application Publication No. 2014-165363, etc.

[0098] The relative permeabilities of the first magnetic layer 31, the second magnetic layer 51, and the third magnetic layer 71 were all measured at a frequency of 10 MHz. The relative permeabilities of the second magnetic layer 51 and the third magnetic layer 71 are each higher than the relative permeability of the first magnetic layer 31. Specifically, the lower limit of the ratio of the relative permeability of the second magnetic layer 51 and the third magnetic layer 71 to the relative permeability of the first magnetic layer 31 is, for example, greater than 1, preferably 1.1, more preferably 1.5, and the upper limit is, for example, 20, preferably 10.

[0099] Since the relative permeability of each of the second magnetic layer 51 and the third magnetic layer 71 is higher than the relative permeability of the first magnetic layer 31, the direct current superposition characteristics of the inductor 1 are excellent.

[0100] Further, the relative permeability of each of the first magnetic layer 31, the second magnetic layer 51, and the third magnetic layer 71 can be found by measuring the relative permeability of the first sheet 65, the second sheet 66, and the third sheet 67 (refer to FIG. 6) used to form them. Figure 4 to Figure 6 In addition, the relative permeability of each of the first magnetic layer 31, the second magnetic layer 51, and the third magnetic layer 71 can also be directly measured.

[0101] Next, the dimensions of the first magnetic layer 31, the second magnetic layer 51, and the third magnetic layer 71 are described.

[0102] The length LI between the first opposing portion 55 and the first wiring 21, the length L2 between the second opposing portion 56 and the second wiring 22, and the depth L3 of the first recessed portion, for example, satisfy the following equation (1) and the following equation (2), preferably satisfy the following equation (1A) and the following equation (2A), more preferably satisfy the following equation (IB) and the following equation (2B), and further, for example, satisfy the following equation (IC) and the following equation (2C).

[0103] L3 / L1 ≥ 0.2 (1)

[0104] L3 / L2 ≥ 0.2 (2)

[0105] L3 / L1 ≥ 0.3 (1A)

[0106] L3 / L2 ≥ 0.3 (2A)

[0107] L3 / L1 ≥ 0.4 (IB)

[0108] L3 / L2 ≥ 0.4 (2B)

[0109] L3 / L1 < 1.5 (IC)

[0110] L3 / L2 < 1.5 (2C)

[0111] If LI, L2, and L3 satisfy the above equations, the depth L3 of the first recessed portion 57 can be made sufficiently deep with respect to the length LI between the first opposing portion 55 and the first wiring 21 and the length L2 between the second opposing portion 56 and the second wiring 22. Therefore, as described above, the magnetic flux density of the first magnetic layer 31 can be made sufficiently high. Figure 2As shown, the substantially flat-shaped magnetic particles in the second magnetic layer 51 located in the vicinity of the first recessed portion 57 can be sufficiently oriented with respect to the first recessed portion 57. As a result, the Q value of the inductor 1 can be improved.

[0112] The lower limit of the ratio (L2 / L1) of the length L2 between the second opposing portion 56 and the second wiring 22 to the length LI between the first opposing portion 55 and the first wiring 21 is, for example, 0.7, preferably 0.9, and the upper limit is, for example, 1.3, preferably 1.1.

[0113] Further, the length L4 between the fifth opposing portion 75 and the first wiring 21, the length L5 between the sixth opposing portion 76 and the second wiring 22, and the depth L6 of the third recessed portion 77 satisfy, for example, the following equation (3) and the following equation (4), preferably satisfy the following equation (3A) and the following equation (4A), more preferably satisfy the following equation (3B) and the following equation (4B), and further satisfy, for example, the following equation (3C) and the following equation (4C).

[0114] L6 / L4≥0.2 (3)

[0115] L6 / L5≥0.2 (4)

[0116] L6 / L4≥0.3 (3A)

[0117] L6 / L5≥0.3 (4A)

[0118] L6 / L4≥0.4 (3B)

[0119] L6 / L5≥0.4 (4B)

[0120] L6 / L4<1.5 (3C)

[0121] L6 / L5<1.5 (4C)

[0122] If L4, L5, and L6 satisfy the above equations, the depth L6 of the third recessed portion 77 can be sufficiently deep with respect to the length L4 between the fifth opposing portion 75 and the first wiring 21 and the length L5 between the sixth opposing portion 76 and the second wiring 22. Therefore, the substantially flat-shaped magnetic particles in the third magnetic layer 71 located in the vicinity of the third recessed portion 77 can be sufficiently oriented with respect to the third recessed portion 77. As a result, the Q value of the inductor 1 can be improved.

[0123] Further, with respect to L1 to L6, for example, the formula (1), the formula (2), the formula (3), and the formula (4) are satisfied simultaneously, preferably the formula (1A), the formula (2A), the formula (3A), and the formula (4A) are satisfied simultaneously, more preferably the formula (1B), the formula (2B), the formula (3B), and the formula (4B) are satisfied simultaneously, further preferably the formula (1C), the formula (2C), the formula (3C), and the formula (4C) are satisfied simultaneously. Thereby, the Q value of the inductor 1 can be efficiently improved.

[0124] Further, the lower limit of the ratio (L5 / L4) of the length L5 between the 6th relative portion 76 and the 2nd wiring 22 with respect to the length L4 between the 5th relative portion 75 and the 1st wiring 21 is, for example, 0.7, preferably 0.9, and the upper limit is, for example, 1.3, preferably 1.1.

[0125] Further, for example, the depth L3 of the 1st recessed portion 57 and the depth L7 of the 2nd recessed portion 60 satisfy the following formula (5), preferably the following formula (5A), more preferably the following formula (5B), and further, for example, the following formula (5C).

[0126] L7 / L3 ≥ 0.3 (5)

[0127] L7 / L3 ≥ 0.5 (5A)

[0128] L7 / L3 ≥ 0.7 (5B)

[0129] L7 / L3 < 1.0 (5C)

[0130] If L3 and L7 satisfy the above formula, the depth L7 of the 2nd recessed portion 60 can be made sufficiently deep with respect to the depth L3 of the 1st recessed portion 57. Therefore, as shown in FIG. 6, the substantially flat-shaped magnetic particles located between the 1st recessed portion 57 and the 2nd recessed portion 60 can be sufficiently oriented along the 1st recessed portion 57 and the 2nd recessed portion 60 which is deeply recessed. As a result, the Q value of the inductor 1 can be improved. Figure 2

[0131] The depth L6 of the 3rd recessed portion 77 and the depth L8 of the 4th recessed portion 80 satisfy the following formula (6), preferably the following formula (6A), more preferably the following formula (6B), and further, for example, the following formula (6C).

[0132] L8 / L6 ≥ 0.3 (6)

[0133] L8 / L6 ≥ 0.5 (6A)

[0134] L8 / L6 ≥ 0.7 (6B)

[0135] ​L8 / L6 < 1.0 (6C)

[0136] If L6 and L8 satisfy the above formula, the depth L8 of the fourth recess 80 can be made sufficiently deep relative to the depth L6 of the third recess 77. Therefore, as shown in FIG. 8, the magnetic particles in the substantially flat shape located between the third recess 77 and the fourth recess 80 can be sufficiently oriented along the third recess 77 and the fourth recess 80 which is deeply recessed. As a result, the Q value of the inductor 1 can be improved. Figure 2

[0137] In addition, with respect to the depths L3, L6 to L8, for example, the formula (5) and the formula (6) are satisfied at the same time, the formula (5A) and the formula (6A) are preferably satisfied at the same time, the formula (5B) and the formula (6B) are more preferably satisfied at the same time, and the formula (5C) and the formula (6C) are further preferably satisfied at the same time. Thereby, the Q value of the inductor 1 can be efficiently improved.

[0138] Further, for example, the length LI between the first opposing portion 55 and the first wiring 21 and the thickness direction length L9 of the first wiring 21 satisfy the following formula (7), preferably the following formula (7A), more preferably the following formula (7B), and further, for example, the following formula (7C).

[0139] LI / L9 > 0.1 (7)

[0140] LI / L9 > 0.2 (7A)

[0141] LI / L9 > 0.25 (7B)

[0142] LI / L9 < 1.0 (7C)

[0143] If LI and L9 satisfy the above formula, the length LI between the first opposing portion 55 and the first wiring 21 can be made sufficiently long relative to the thickness direction length L9 of the first wiring 21. Therefore, the inductance of the inductor 1 can be maintained high, and the Q value of the inductor 1 can be improved.

[0144] The length L2 between the second opposing portion 56 and the second wiring 22 and the thickness direction length LIO of the second wiring 22 satisfy the following formula (8), preferably the following formula (8A), more preferably the following formula (8B), and further, for example, the following formula (8C).

[0145] L2 / L10 > 0.1 (8)

[0146] L2 / L10 > 0.2 (8A)

[0147] ​L2 / L10 ≥ 0.25 (8B)

[0148] L2 / L10 < 1.0 (8C)

[0149] If L2 and L10 satisfy the above formula, the length L2 between the second opposing portion 56 and the second wiring 22 can be made sufficiently long relative to the thickness direction length L10 of the second wiring 22. Therefore, a higher inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0150] The length L4 between the fifth opposing portion 75 and the first wiring 21 and the length L9 of the first wiring 21 satisfy, for example, the following formula (9), preferably the following formula (9A), more preferably the following formula (9B), and further satisfy, for example, the following formula (9C).

[0151] L4 / L9 ≥ 0.1 (9)

[0152] L4 / L9 ≥ 0.2 (9A)

[0153] L4 / L9 ≥ 0.25 (9B)

[0154] L4 / L9 < 1.0 (9C)

[0155] If L4 and L9 satisfy the above formula, the length L4 between the fifth opposing portion 75 and the first wiring 21 can be made sufficiently long relative to the length L9 of the first wiring 21. Therefore, a higher inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0156] The length L5 between the sixth opposing portion 76 and the second wiring 22 and the length L10 of the second wiring 22 satisfy, for example, the following formula (10), preferably the following formula (10A), more preferably the following formula (10B), and further satisfy, for example, the following formula (10C).

[0157] L5 / L10 ≥ 0.1 (10)

[0158] L5 / L10 ≥ 0.2 (10A)

[0159] L5 / L10 ≥ 0.25 (10B)

[0160] L5 / L10 < 1.0 (10C)

[0161] If L5 and L10 satisfy the above formula, the length L5 between the 6th opposing portion 76 and the 2nd wiring 22 can be made sufficiently long relative to the length L10 of the 2nd wiring 22. Thus, a high inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0162] Further, with respect to L1, L2, L4, L5, L9, L10 described above, for example, formula (7), formula (8), formula (9), and formula (10) are satisfied simultaneously, preferably formula (7A), formula (8A), formula (9A), and formula (10A) are satisfied simultaneously, more preferably formula (7B), formula (8B), formula (9B), and formula (10B) are satisfied simultaneously, further preferably formula (7C), formula (8C), formula (9C), and formula (10C) are satisfied simultaneously. Thereby, the Q value of the inductor 1 can be efficiently improved.

[0163] The lengths of L1 to L10 described above are defined as follows.

[0164] The length L1 between the 1st opposing portion 55 and the 1st wiring 21 is the shortest distance L1 between the 1st top portion 91 and the 1st wiring 21.

[0165] The length L2 between the 2nd opposing portion 56 and the 2nd wiring 22 is the shortest distance between the 2nd top portion 92 and the 2nd wiring 22.

[0166] The depth L3 of the 1st recessed portion 57 is the longest thickness direction length L3 from a line segment connecting the 1st top portion 91 and the 2nd top portion 92 to the 1st bottom portion 38 of the 1st recessed portion 57.

[0167] The length L4 between the 5th opposing portion 75 and the 1st wiring 21 is the shortest distance L4 between the 3rd top portion 93 and the 1st wiring 21.

[0168] The length L5 between the 6th opposing portion 76 and the 2nd wiring 22 is the shortest distance L5 between the 4th top portion 94 and the 2nd wiring 22.

[0169] The depth L6 of the 3rd recessed portion 77 is the longest thickness direction length L6 from a line segment connecting the 3rd top portion 93 and the 4th top portion 94 to the 2nd bottom portion 44 of the 3rd recessed portion 77.

[0170] The depth L7 of the 2nd recessed portion 60 is the longest thickness direction length L7 from a line segment connecting the 5th top portion 86 and the 6th top portion 87 to the 3rd bottom portion 63 of the 2nd recessed portion 60.

[0171] The depth L8 of the 4th recessed portion 80 is the longest thickness direction length L8 from a line segment connecting the 7th top portion 88 and the 8th top portion 89 to the 4th bottom portion 64 of the 4th recessed portion 80.

[0172] The lower limit of the Q value of the inductor 1 is, for example, 30, preferably 35, and more preferably 40. If the Q value is equal to or higher than the above lower limit, the resistance component of the loss becomes small, and thus the inductance becomes high. On the other hand, the upper limit of the Q value of the inductor 1 is not particularly limited, and the Q value is preferably high.

[0173] Next, one example of a manufacturing method of the inductor 1 will be described.

[0174] The manufacturing method of the inductor 1 includes a first step (see Figure 3 ) of preparing the hot press device 2 and a second step (see Figure 7 ) of hot pressing the magnetic sheet 8 (to be described later) and the first and second wirings 21 and 22 using the hot press device 2.

[0175] [First Step]

[0176] As shown in Figure 3 , in the first step, the hot press device 2 is prepared.

[0177] The hot press device 2 is an isostatic press device capable of isostatic pressing of the magnetic sheet 8 and the first and second wirings 21 and 22 (see Figure 4 ) isotropically. The hot press device 2 includes the first die 3, the second die 4, the inner frame member 5, the outer frame member 81, and the flowable soft sheet 6.

[0178] Further, in this one embodiment, the hot press device 2 is configured so that the second die 4, the inner frame member 5, and the outer frame member 81 can be brought close to the first die 3 to be pressed (caulked). Further, the first die 3 is stationary in the pressing direction of the hot press device 2.

[0179] The first die 3 has a substantially plate shape. The first die 3 has a first pressing surface 61 facing the second die 4 to be described next. The first pressing surface 61 extends in a direction (a surface direction) orthogonal to the pressing direction. The first pressing surface 61 is flat. Further, the first die 3 includes a heater not shown.

[0180] The second die 4 is spaced apart from the first die 3 in the pressing direction in the first step. The second die 4 is movable relative to the first die 3 in the pressing direction. The second die 4 has a substantially plate shape smaller than the first die 3. Specifically, the second die 4 is included in the first die 3 when projected in the pressing direction. In detail, the second die 4 overlaps with a central portion in the surface direction of the first die 3 when projected in the pressing direction. The second die 4 has a second pressing surface 62 that presses a central portion in the surface direction of the first pressing surface 61 facing the first die 3. The second pressing surface 62 extends in the surface direction. The second pressing surface 62 is parallel to the first pressing surface 61. Further, the second die 4 includes a heater not shown.

[0181] The inner frame member 5 surrounds the periphery of the second mold 4. In detail, the inner frame member 5 surrounds the entire periphery of the second mold 4, which is not illustrated. Further, the inner frame member 5 is spaced apart from the peripheral end portion of the first mold 3 in the pressing direction in the first process. That is, the inner frame member 5 is arranged in opposition to the peripheral end portion of the first mold 3 in the first process, spaced apart in the pressing direction. The inner frame member 5 integrally has a third pressing surface 98 facing the peripheral end portion of the first pressing surface 61 and an inner side surface 99 facing the inner side. The inner frame member 5 is movable in the pressing direction with respect to both the first mold 3 and the second mold 4.

[0182] Further, a sealing member, which is not illustrated, is provided between the inner frame member 5 and the second mold 4. The sealing member, which is not illustrated, prevents the flowable soft sheet 6, which will be described later, from penetrating between the inner frame member 5 and the second mold 4 during the relative movement of the inner frame member 5 and the second mold 4.

[0183] The outer frame member 81 surrounds the periphery of the inner frame member 5. In detail, the outer frame member 81 surrounds the entire periphery of the inner frame member 5, which is not illustrated. Further, the outer frame member 81 is spaced apart from the peripheral end portion of the first mold 3 in the pressing direction in the first process. That is, the outer frame member 81 is arranged in opposition to the peripheral end portion of the first mold 3 in the first process, spaced apart in the pressing direction. The outer frame member 81 integrally has a contact surface 82 facing the peripheral end portion of the first pressing surface 61 and a chamber inner side surface 83 facing the inner side. The outer frame member 81 is movable in the pressing direction with respect to both the first mold 3 and the inner frame member 5.

[0184] Further, the outer frame member 81 has an exhaust port 15. An exhaust direction upstream side end portion of the exhaust port 15 faces an inner end portion of the chamber inner side surface 83. The exhaust port 15 is connected to the vacuum pump 16 via an exhaust line 46. Further, the exhaust line 46 is closed in the first process.

[0185] Further, a sealing member, which is not illustrated, is provided between the outer frame member 81 and the inner frame member 5. The sealing member, which is not illustrated, prevents the second closed space (to be described later) 45 from communicating with the outside during the relative movement of the outer frame member 81 and the inner frame member 5.

[0186] The flowable soft sheet 6 has a substantially plate shape extending in a surface direction orthogonal to the pressing direction. The flowable soft sheet 6 is arranged on the second pressing surface 62 of the second mold 4. Further, the flowable soft sheet 6 is also arranged on the inner side surface 99 of the inner frame member 5. More specifically, the flowable soft sheet 6 contacts the entire surface of the second pressing surface 62 and the pressing direction downstream side portion of the inner side surface 99. Further, a sealing member, which is not illustrated, is provided between the flowable soft sheet 6 and the inner side surface 99 of the inner frame member 5. The inner frame member 5 is movable in the pressing direction with respect to the flowable soft sheet 6.

[0187] As the material of the flowable soft sheet 6, there is no particular limitation as long as it can exhibit flowability and softness at the time of heat pressing, for example, gel or soft elastomer is cited. The material of the flowable soft sheet 6 can be a commercially available product, for example, aGEL series (manufactured by Taica Corporation), Riken Elastomers series (manufactured by Riken technos Corporation), and the like are cited. The thickness of the flowable soft sheet 6 is not particularly limited, and specifically, the lower limit of the thickness is, for example, 1 mm, and preferably 2 mm, and the upper limit of the thickness is, for example, 1000 mm, and preferably 100 mm.

[0188] The heat pressing device 2 is described in detail in, for example, Japanese Patent Application Publication No. 2004-296746, and the like. In addition, for the heat pressing device 2, a commercially available product can be used, for example, a dry laminator series (manufactured by Nippon Densho Co., Ltd.), and the like can be used.

[0189] [2nd Process]

[0190] In the 2nd process, as shown in FIG. 2, the magnetic sheet 8 and the 1st and 2nd wirings 21 and 22 are heat pressed by the heat pressing device 2. Specifically, the 2nd process includes a 3rd process, a 4th process, a 5th process, and a 6th process. In the 2nd process, the 3rd process, the 4th process, the 5th process, and the 6th process are sequentially performed. Figure 7

[0191] [3rd Process]

[0192] As shown in FIG. 3, in the 3rd process, first, the 1st release sheet 14 is disposed on the 1st pressing surface 61 of the 1st mold 3. Figure 4 The 1st release sheet 14 is smaller than the inner frame member 5 when projected in the thickness direction.

[0193]

[0194] ​​The first release sheet 14 includes, for example, in order toward the downstream side in the pressing direction, the first peeling film 11, the cushion film 12, and the second peeling film 13. The materials of the first peeling film 11 and the second peeling film 13 can be appropriately selected according to the use and purpose, for example, a polyester such as polyethylene terephthalate (PET), a polyolefin such as polymethylpentene (TPX), polypropylene, or the like. The thickness of the first peeling film 11 and the thickness of the second peeling film 13 are, for example, each 1 μm or more and, for example, 1000 μm or less. The cushion film 12 includes a soft layer. The soft layer flows in the planar direction and the thickness direction at the time of heat pressing in the second process. As the material of the soft layer, a heat flow material that flows in the planar direction and the pressing direction by heat pressing in the second process described later is exemplified. The heat flow material includes, for example, an olefin-(meth)acrylate copolymer (ethylene-methyl (meth)acrylate copolymer or the like), an olefin-vinyl acetate copolymer, or the like as a main component. The thickness of the cushion film 12 is, for example, 50 μm or more and, for example, 500 μm or less. The cushion film 12 can use a commercially available product, for example, a release film OT series (manufactured by Sekisui Chemical Co., Ltd.) or the like.

[0195] Further, the first release sheet 14 can include either one of the first peeling film 11 and the second peeling film 13 and the cushion film 12, or can be only the cushion film 12.

[0196] After the first release sheet 14 is disposed to the first mold 3, the magnetic sheet 8 and the first wiring 21 and the second wiring 22 are placed between the first release sheet 14 and the second release sheet 7 in a manner that overlaps the flowable soft sheet 6 when projected in the pressing direction.

[0197] The magnetic sheet 8 includes three kinds of magnetic sheets for forming the first magnetic layer 31, the second magnetic layer 51, and the third magnetic layer 71. Specifically, the magnetic sheet 8 includes a first sheet 65, a second sheet 66, and a third sheet 67. The first sheet 65 is a magnetic sheet for making the first magnetic layer 31. The second sheet 66 is a magnetic sheet for making the second magnetic layer 51. The third sheet 67 is a magnetic sheet for making the third magnetic layer 71. The first sheet 65, the second sheet 66, and the third sheet 67 are each one or a plurality. The magnetic sheet 8 is formed of the magnetic composition described above. Further, in the magnetic composition that forms the magnetic sheet 8, the thermosetting resin is B-stage.

[0198] Specifically, in the case where the first sheet 65 is a plurality, the third sheet 67, one first sheet 65, the first wiring 21 and the second wiring 22, another first sheet 65, and the second sheet 66 are sequentially stacked in the pressing direction. At this time, the magnetic sheet 8 can be temporarily fixed with respect to the first wiring 21 and the second wiring 22 using a platen press including two parallel platens to make a laminate 48.

[0199] Subsequently, the second release sheet 7 is arranged on the laminate 48 (the second sheet 66).

[0200] The second release sheet 7 has the same layer structure as the first release sheet 14. For example, the first release sheet 14 is smaller than the inner frame member 5 when projected in the thickness direction.

[0201] [4th process]

[0202] In the 4th process, as shown by an arrow and Figure 4 the outer frame member 81 is brought into contact with the first mold 3 to form the reduced-pressure space 85. Figure 5 Specifically, the peripheral end portion of the outer frame member 81 is pressed against the first pressure surface 61 of the first mold 3. Thus, the contact surface 82 of the outer frame member 81 and the peripheral end portion of the first pressure surface 61 of the first mold 3 are brought into close contact (preferably, pressure) with each other.

[0203] The reduced-pressure space 85 is demarcated by the chamber inner side surface 83 of the outer frame member 81, the third pressure surface 98 and the inner side surface 99 of the inner frame member 5, the second pressure surface 62, and the first pressure surface 61 of the first mold 3. Further, the chamber inner side surface 83 that demarcates the reduced-pressure space 85 constitutes the chamber device together with the first mold 3.

[0204] The pressure of the outer frame member 81 against the first mold 3 is set to a degree that enables the air tightness (communication with the outside is not allowed) of the reduced-pressure space 85 described later to be ensured by the close contact between the contact surface 82 and the first pressure surface 61, specifically, 0.1 MPa or higher and 20 MPa or lower.

[0205] Thus, the first closed space 84 is formed among the first mold 3, the outer frame member 81, and the flowable soft sheet 6. The first closed space 84 is shielded from the outside. However, the exhaust line 46 is in communication with the first closed space 84.

[0206] On the other hand, the second release sheet 7 and the flowable soft sheet 6 are also spaced apart in the pressure direction.

[0207] Subsequently, in the 4th process, the first closed space 84 is depressurized to form the reduced-pressure space 85.

[0208] Specifically, the vacuum pump 16 is driven, and then the exhaust line 46 is opened. Thus, the first closed space 84 that is in communication with the exhaust port 15 is depressurized. Thus, the first closed space 84 becomes the reduced-pressure space 85.

[0209] The upper limit of the pressure of the reduced-pressure space 85 (or the exhaust line 46) is, for example, 100000 Pa, and preferably 10000 Pa, and the lower limit is 1 Pa.

[0210] Thus, the first closed space 84 is depressurized to form the reduced-pressure space 85.

[0211] [Step 5]

[0212] In the fifth process, such as Figure 5 arrows and Figure 6 As shown, the inner frame component 5 is pressed against the first mold 3 to form the second sealed space 45.

[0213] Specifically, the inner frame member 5 is pressed against the periphery of the first pressing surface 61 of the first mold 3. As a result, the third pressing surface 98 of the inner frame member 5 and the periphery of the first pressing surface 61 of the first mold 3 are in close contact with each other.

[0214] The pressure of the inner frame member 5 relative to the first mold 3 is set to a degree that prevents the fluid soft sheet 6 in the sixth process described later from leaking to the outside through the tight seal between the third pressure surface 98 and the first pressure surface 61. Specifically, it is 0.1 MPa or more and 50 MPa or less.

[0215] Thus, a second sealed space 45 is formed on the inner side of the inner frame member 5, which is surrounded by the first mold 3 and the fluid flexible sheet 6 in the pressure direction. The communication between the second sealed space 45 and the exhaust pipe 46 is blocked by the inner frame member 5.

[0216] The second enclosed space 45 has the same decompression degree (air pressure) as the aforementioned decompression space 85.

[0217] In addition, the second release sheet 7 and the flowable soft sheet 6 are spaced apart in the direction of pressure application.

[0218] [Step 6]

[0219] like Figure 6 arrows and Figure 7 As shown, in the sixth step, the second mold 4 is brought close to the first mold 3, and the magnetic sheet 8, the first wire 21 and the second wire 22 are hot-pressed through the fluid flexible sheet 6, the second release sheet 7 and the first release sheet 14.

[0220] First, the heaters contained in the first mold 3 and the second mold 4 are heated. Then, the second mold 4 is moved in the direction of pressure application. As a result, the fluid flexible sheet 6 moves closer to the second release sheet 7.

[0221] Therefore, the fluid flexible sheet 6 softly contacts the entire surface of the upstream side of the second release sheet 7 in the pressure direction, except for the peripheral end. At this time, due to the fluidity and flexibility of the fluid flexible sheet 6, the fluid flexible sheet 6 deforms together with the second release sheet 7 along the shape of the first wiring 21 and the second wiring 22. The fluid flexible sheet 6 and the second release sheet 7 are tightly fitted together.

[0222] The second mold 4 is then hot-pressed toward the first mold 3.

[0223] The lower limit of the pressure of the hot pressing is, for example, 0.1 MPa, preferably 1 MPa, more preferably 2 MPa, and the upper limit is, for example, 30 MPa, preferably 20 MPa, more preferably 10 MPa. The lower limit of the heating temperature is, for example, 100°C, preferably 110°C, more preferably 130°C, and the upper limit is, for example, 200°C, preferably 185°C, more preferably 175°C. The lower limit of the heating time is, for example, 1 minute, preferably 5 minutes, more preferably 10 minutes, and the upper limit is, for example, 1 hour, preferably 30 minutes.

[0224] Thus, the magnetic sheet 8 and the first and second wires 21 and 22 are pressed from both sides in the thickness direction and the planar direction of the magnetic sheet 8 with equal pressure. In other words, the magnetic sheet 8 and the first and second wires 21 and 22 are isostatically pressed.

[0225] Thus, the magnetic sheet 8 flows to bury the first and second wires 21 and 22. In addition, the magnetic sheet 8 spans between adjacent first and second wires 21 and 22.

[0226] In addition, the peripheral side surface 52 of the magnetic sheet 8 is pressed from the side (the outer side) toward the inner side by the flowable soft sheet 6 and the second release sheet 7. Thus, the peripheral side surface 52 of the magnetic sheet 8 can be inhibited from flowing out to the outer side.

[0227] Further, the flow of the magnetic sheet 8 described above is caused by the flow of the B-stage thermosetting resin and the flow of the thermoplastic resin, which are adjusted as needed, due to heating by the heater of the first mold 3 and the heater of the second mold 4.

[0228] By further heating by the heaters, the thermosetting resin becomes the C-stage. That is, the first magnetic layer 31, the second magnetic layer 51, and the third magnetic layer 71, which are cured bodies (C-stage bodies) containing the magnetic particles and the thermosetting resin, are formed.

[0229] Thus, the inductor 1 including the first and second wires 21 and 22, the first magnetic layer 31 covering the first and second wires 21 and 22 in a manner spanning between adjacent first and second wires 21 and 22, the second magnetic layer 51 disposed on the first face 33 of the first magnetic layer 31, and the third magnetic layer 71 disposed on the second face 34 of the first magnetic layer 31 is manufactured.

[0230] As Figure 8As shown, the inductor 1 is then taken out of the self-heating press device 2. Next, the inductor 1 is subjected to outer shape processing. For example, a via hole 47 is formed in portions of the second magnetic layer 51 and the first magnetic layer 31 corresponding to the end portions in the length direction of the first wiring 21 and the end portions in the length direction of the second wiring 22. Specifically, the via hole 47 is formed by removing the corresponding portions of the second magnetic layer 51 and the first magnetic layer 31 and the insulating film 24 using a laser, a puncher, or the like. The via hole 47 exposes a portion of the one side surface 26 of the lead wire 23.

[0231] Next, an unillustrated conductive member or the like is disposed in the via hole 47, and an external device and the lead wire 23 are electrically connected by means of the conductive member or the like and a conductive connecting material such as solder, solder paste, or silver paste. The conductive member includes a plating layer.

[0232] Next, as necessary, the conductive member and the conductive connecting material are subjected to reflow soldering in a reflow soldering process.

[0233] [Effects of One Embodiment]

[0234] The inductor 1 includes a first magnetic layer 31 containing substantially spherical magnetic particles, and a second magnetic layer 51 and a third magnetic layer 71 containing substantially flat magnetic particles. Further, the relative magnetic permeability of each of the second magnetic layer 51 and the third magnetic layer 71 is higher than the relative magnetic permeability of the first magnetic layer 31. Therefore, the inductor 1 has a high inductance and excellent DC superposition characteristics.

[0235] Further, since the second magnetic layer 51 has the first recess 57 and the second recess 60, the substantially flat magnetic particles can be efficiently oriented along the first recess 57 and the second recess 60 in the region of the second magnetic layer 51 surrounded by the first recess 57 and the second recess 60. In addition, since the third magnetic layer 71 has the third recess 77 and the fourth recess 80, the substantially flat magnetic particles can be efficiently oriented along the third recess 77 and the fourth recess 80 in the region of the third magnetic layer 71 surrounded by the third recess 77 and the fourth recess 80. Therefore, an excellent Q value can be obtained.

[0236] Thus, the inductor has a high inductance, excellent DC superposition characteristics, and an excellent Q value.

[0237] Further, if L1, L2, and L3 satisfy Expression (1) and Expression (2), the depth L3 of the first recess 57 can be made sufficiently deep relative to the length L1 between the first opposing portion 55 and the first wiring 21 and the length L2 between the second opposing portion 56 and the second wiring 22. Therefore, as shown in FIG. 6, the substantially flat magnetic particles can be efficiently oriented along the first recess 57 and the second recess 60 in the region of the second magnetic layer 51 surrounded by the first recess 57 and the second recess 60. Figure 2As shown, the generally flat magnetic particles in the second magnetic layer 51 located near the first recess 57 can be sufficiently oriented relative to the first recess 57. As a result, the Q value of the inductor 1 can be improved.

[0238] L3 / L1≥0.2 (1)

[0239] L3 / L2≥0.2 (2)

[0240] Furthermore, if L4, L5, and L6 satisfy equations (3) and (4), the depth L6 of the third recess 77 can be made sufficiently deep relative to the length L4 between the fifth opposing portion 75 and the first wiring 21, and the length L5 between the sixth opposing portion 76 and the second wiring 22. Therefore, the generally flat magnetic particles in the third magnetic layer 71 located near the third recess 77 can be sufficiently oriented relative to the third recess 77. As a result, the Q value of the inductor 1 can be improved.

[0241] L6 / L4≥0.2 (3)

[0242] L6 / L5≥0.2 (4)

[0243] If L3 and L7 satisfy equation (5), then the depth L7 of the second recess 60 can be made sufficiently deep relative to the depth L3 of the first recess 57. Therefore, as Figure 2 As shown, the generally flat magnetic particles located between the first recess 57 and the second recess 60 can be sufficiently oriented along the first recess 57 and the deeper second recess 60. As a result, the Q value of the inductor 1 can be improved.

[0244] L7 / L3≥0.3 (5)

[0245] If L6 and L8 satisfy equation (6), then the depth L8 of the fourth recess 80 can be made sufficiently deep relative to the depth L6 of the third recess 77. Therefore, as Figure 2 As shown, the generally flat magnetic particles located between the third recess 77 and the fourth recess 80 can be sufficiently oriented along the third recess 77 and the deeper fourth recess 80. As a result, the Q value of the inductor 1 can be improved.

[0246] L8 / L6≥0.3 (6)

[0247] If L1 and L9 satisfy equation (7), then the length L1 between the first relative portion 55 and the first wiring 21 can be made sufficiently long relative to the thickness direction length L9 of the first wiring 21. Therefore, a high inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0248] L1 / L9≥0.1 (7)

[0249] If L2 and L10 satisfy equation (8), then the length L2 between the second opposing portion 56 and the second wiring 22 can be made sufficiently long relative to the thickness direction length L10 of the second wiring 22. Therefore, a high inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0250] L2 / L10≥0.1 (8)

[0251] If L4 and L9 satisfy equation (9), then the length L4 between the third relative portion 58 and the first wiring 21 can be made sufficiently long relative to the length L9 of the first wiring 21. Therefore, a high inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0252] L4 / L9≥0.1 (9)

[0253] If L5 and L10 satisfy the above formula, then the length L5 between the fourth relative portion 59 and the second wiring 22 can be made sufficiently long relative to the length L10 of the second wiring 22. Therefore, a high inductance of the inductor 1 can be maintained, and the Q value of the inductor 1 can be improved.

[0254] L5 / L10≥0.1 (10)

[0255]

[0256] In the following variations, the same reference numerals are used for components and processes identical to those in the first embodiment described above, and detailed descriptions are omitted. Furthermore, unless otherwise specified, the variations can achieve the same effects as the first embodiment. Moreover, a first embodiment and its variations can be appropriately combined.

[0257] In one embodiment, multiple magnetic sheets 8 are hot-pressed together, but it is also possible, for example, to hot-press the first sheet 65, the second sheet 66, and the third sheet 67 sequentially, as not shown in the figure.

[0258] In addition, using Figure 3 The hot pressing device 2 shown manufactures the inductor 1, but the manufacturing device is not particularly limited if the second recess 60 can be formed in the second magnetic layer 51 and the fourth recess 80 can be formed in the third magnetic layer 71.

[0259] However, the flatbed press cannot form the second recess 60 and the fourth recess 80 as described above, but instead makes the fourth surface 54 and the sixth surface 74 flat. Therefore, the flatbed press is not suitable in this embodiment.

[0260] like Figure 9As shown, the inductor 1 may also include a functional layer 95 that does not contain magnetic particles. The functional layer 95 includes a first functional layer 96 disposed on the fourth surface 54 of the second magnetic layer 51 and a second functional layer 97 disposed on the sixth surface 74 of the third magnetic layer 71. The first functional layer 96 and the second functional layer 97 are, for example, resin layers made only of resin.

[0261] One side of the first functional layer 96 in the thickness direction and the other side of the second functional layer 97 in the thickness direction are both flat surfaces. One side of the first functional layer 96 in the thickness direction and / or the other side of the second functional layer 97 in the thickness direction can be provided, for example, as a pickup surface for an adsorption (suction) type pickup device.

[0262] Alternatively, the functional layer 95 can also be a barrier layer that inhibits the permeation of water and / or oxygen. Thus, the barrier layer can be used to inhibit corrosion of the second magnetic layer 51 and the third magnetic layer 71.

[0263] The first wiring 21 and the second wiring 22 may also have, for example, a shape that is approximately rectangular in cross-section or a shape that is approximately polygonal in cross-section, as not shown in the figure.

[0264] Example

[0265] The following examples of modulation, embodiments, and comparative examples further illustrate the present invention. However, the present invention is not limited to any particular modulation example, embodiment, or comparative example. Furthermore, the specific numerical values ​​of mixing ratios (including ratios), physical property values, parameters, etc., used in the following description can replace the corresponding upper limit values ​​(values ​​defined as "less than" or "less than") or lower limit values ​​(values ​​defined as "above" or "greater than") of the mixing ratios (including ratios), physical property values, parameters, etc., described in the "Specific Embodiments" above.

[0266] Modulation Example 1

[0267] (Preparation of adhesive)

[0268] Mix 24.5 parts by weight of epoxy resin (main agent), 24.5 parts by weight of phenolic resin (curing agent), 1 part by weight of imidazole compound (curing accelerator), and 50 parts by weight of acrylic resin (thermoplastic resin) to prepare an adhesive.

[0269] Example 1

[0270] like Figure 3 As shown, firstly, a dry laminator (manufactured by Nikko Corporation) is prepared as the aforementioned hot pressing device 2 (the first step is carried out).

[0271] In addition, the magnetic particles and the binder of Modification Example 1 were formulated and mixed in the manner that the volume ratios were as described in Table 1, and the first sheet 65, the second sheet 66 and the third sheet 67 (magnetic sheet 8) were made in the manner that the types and volume ratios of the magnetic particles were as described in Table 1.

[0272] A laminate 48 was fabricated using a flatbed press, with the first wiring 21 (L9 = 260 μm) and the second wiring 22 (L10 = 260 μm) held by the magnetic sheet 8. The distance L0 between the first wiring 21 and the second wiring 22 was 240 μm. The flatbed press conditions were: temperature 110℃, 1 minute, and pressure 0.9 MPa (gauge pressure 2 kN).

[0273] After that, as Figure 5 As shown, the outer frame component 81 is sealed to the first mold 3, forming the first sealed space 84. Next, the vacuum pump 16 is driven to depressurize the first sealed space 84, forming a depressurized space 85 (step 4). The air pressure in the depressurized space 85 is 2666 Pa (20 torr).

[0274] After that, as Figure 6 As shown, the inner frame component 5 is pressed against the first mold 3, forming a second sealed space 45 (the fifth step) that is 2666 Pa smaller than the decompression space 85.

[0275] After that, as Figure 7 As shown, the second mold 4 is brought close to the first mold 3, and the magnetic sheet 8, the first wiring 21, and the second wiring 22 are hot-pressed (step 6) through the flowable flexible sheet 6, the second release sheet 7, and the first release sheet 14. The hot-pressing temperature is 170°C, and the time is 15 minutes. The hot-pressing pressure is as described in Table 1.

[0276] Thus, an inductor 1 is manufactured, comprising a first wiring 21 and a second wiring 22, a first magnetic layer 31, a second magnetic layer 51 and a third magnetic layer 71.

[0277] Example 2

[0278] The thicknesses of the first piece 65, the second piece 66, and the third piece 67 are changed as shown in Table 2. Otherwise, the same process as in Example 1 is performed to produce the inductor 1.

[0279] Comparative Example 1

[0280] As shown in Table 3, alternatives Figure 3 to Figure 7 The hot pressing device 2 is used to hot press the first piece 65, the second piece 66 and the third piece 67. Otherwise, the process is the same as in Example 1 to produce the inductor 1.

[0281] evaluate

[0282] (Cross-sectional observation and dimensions)

[0283] The dimensions of each member of the inductor 1 of each example at the time of cross section were found by cross-sectional observation by SEM. The results thereof are described in Table 4.

[0284] Also, the shapes of the second magnetic layer 51 and the third magnetic layer 71 were observed. In Example 1 and Example 2, the second magnetic layer 51 had the second recess 60. The third magnetic layer 71 had the fourth recess 80.

[0285] The shape of the inductor 1 of Comparative Example 1 was observed. In the inductor 1 of Comparative Example 1, the second magnetic layer 51 did not include the second recess 60, and the fourth face 54 was flat. In the inductor 1 of Comparative Example 1, the third magnetic layer 71 did not include the fourth recess 80, and the sixth face 74 was flat.

[0286] <Inductance>

[0287] The inductances of the first wiring 21 and the second wiring 22 of the inductor 1 in each example and comparative example were measured. The inductance at a frequency of 10 MHz was evaluated in accordance with the following criteria. Furthermore, in the measurement, an impedance analyzer (manufactured by Agilent, "4291B") was used.

[0288] [Criteria]

[0289] O: The inductance was 250 nH or more.

[0290] <DC superimposition characteristics>

[0291] The inductance reduction rate of the inductor 1 in each example and comparative example at a frequency of 10 MHz was measured, and the DC superimposition characteristics were evaluated. Furthermore, in the measurement of the inductance reduction rate, an impedance analyzer (manufactured by SOKKIA, "65120B") was used. The inductance reduction rate was evaluated in accordance with the following criteria.

[0292] [Inductance in a state where no DC bias current was applied / Inductance in a state where a DC bias current of 10 A was applied] / [Inductance in a state where a DC bias current of 10 A was applied] x 100 (%)

[0293] [Criteria]

[0294] O: The inductance reduction rate was 30% or less with respect to Comparative Example 1.

[0295] <Q value>

[0296] The Q value of the inductor 1 in each example and comparative example was measured. The Q value was evaluated in accordance with the following criteria. Furthermore, in the measurement, an impedance analyzer (manufactured by Agilent, "4291B") was used.

[0297] [Reference]

[0298] O: Q value is 30 or more.

[0299] X: Q value is less than 30.

[0300] [Table 1]

[0301]

[0302] [Table 2]

[0303]

[0304] [Table 3]

[0305]

[0306] [Table 4]

[0307]

[0308] [Table 5]

[0309]

[0310] Furthermore, the above-described application is provided as an example of the present application, but this is merely an example and is not to be interpreted limitatively. Variations of the present application that will be apparent to those skilled in the art are included in the foregoing claims.

[0311] Industrial Applicability

[0312] Inductors are used for a variety of purposes.

[0313] Explanation of Reference Signs

[0314] 1, inductor; 21, 1st wiring; 22, 2nd wiring; 25, outer peripheral surface; 31, 1st magnetic layer; 32, inner peripheral surface; 33, 1st surface; 34, 2nd surface; 51, 2nd magnetic layer; 53, 3rd surface; 54, 4th surface; 55, 1st opposing portion; 56, 2nd opposing portion; 57, 1st recessed portion; 58, 3rd opposing portion; 59, 4th opposing portion; 60, 2nd recessed portion; 71, 3rd magnetic layer; 73, 5th surface; 74, 6th surface; 75, 5th opposing portion; 76, 6th opposing portion; 77, 3rd recessed portion; 78, 7th opposing portion; 79, 8th opposing portion; 80, 4th recessed portion; L1, length between 1st opposing portion and 1st wiring; L2, length between 2nd opposing portion and 2nd wiring; L3, depth of 1st recessed portion; L4, length between 5th opposing portion and 1st wiring; L5, length between 6th opposing portion and 2nd wiring; L6, depth of 3rd recessed portion; L7, depth of 2nd recessed portion; L8, depth of 4th recessed portion; L9, length of 1st wiring; L10, length of 2nd wiring.

Claims

1. An inductor, characterized in that, The inductor includes: The first wiring and the second wiring are adjacent to each other with a gap between them; The first magnetic layer has a first surface that is continuous in the surface direction, a second surface that is spaced apart in the thickness direction from the first surface and is continuous in the surface direction, and an inner peripheral surface located between the first surface and the second surface and in contact with the outer peripheral surface of the first wiring and the outer peripheral surface of the second wiring. The first magnetic layer contains generally spherical magnetic particles and resin. A second magnetic layer having a third surface in contact with the first surface and a fourth surface spaced apart from the third surface in the thickness direction, the second magnetic layer containing generally flat magnetic particles and resin; and The third magnetic layer has a fifth surface in contact with the second surface and a sixth surface spaced apart from the fifth surface in the thickness direction. This third magnetic layer contains generally flat magnetic particles and resin. The relative permeability of the second and third magnetic layers is higher than that of the first magnetic layer. The third surface has a first recess that is recessed from the first and second opposing portions between a first opposing portion opposite to the first wiring in the thickness direction and a second opposing portion opposite to the second wiring in the thickness direction. The fifth surface has a third recess that is recessed from the fifth and sixth opposing portions between a fifth opposing portion opposite to the first wiring in the thickness direction and a sixth opposing portion opposite to the second wiring in the thickness direction. The length L1 between the first opposing portion and the first wiring, the length L2 between the second opposing portion and the second wiring, and the depth L3 of the first recess satisfy the following equations (1) and (2). The length L4 between the fifth opposing portion and the first wiring, the length L5 between the sixth opposing portion and the second wiring, and the depth L6 of the third recess satisfy the following equations (3) and (4). In the second magnetic layer, the generally flat magnetic particles are oriented relative to the first recess. In the third magnetic layer, the generally flat magnetic particles are oriented relative to the third recess. L3 / L1≥0.2 (1) L3 / L2≥0.2 (2) L6 / L4≥0.2 (3) L6 / L5≥0.2 (4).

2. The inductor according to claim 1, characterized in that, The inductor also includes: A first functional layer, disposed on the fourth surface of the second magnetic layer; and The second functional layer is disposed on the sixth surface of the third magnetic layer.

3. The inductor according to claim 1, characterized in that, The length L1 between the first opposing portion and the first wiring and the thickness direction length L9 of the first wiring satisfy the following equation (7). The length L2 between the second opposing portion and the second wiring and the thickness direction length L10 of the second wiring satisfy the following equation (8). The length L4 between the fifth opposing portion and the first wiring and the length L9 of the first wiring satisfy the following equation (9). The length L5 between the sixth opposite portion and the second wiring and the length L10 of the second wiring satisfy the following formula (10). L1 / L9≥0.1 (7) L2 / L10≥0.1 (8) L4 / L9≥0.1 (9) L5 / L10≥0.1 (10).

4. The inductor according to claim 2, characterized in that, The length L1 between the first opposing portion and the first wiring and the thickness direction length L9 of the first wiring satisfy the following equation (7). The length L2 between the second opposing portion and the second wiring and the thickness direction length L10 of the second wiring satisfy the following equation (8). The length L4 between the fifth opposing portion and the first wiring and the length L9 of the first wiring satisfy the following equation (9). The length L5 between the sixth opposite portion and the second wiring and the length L10 of the second wiring satisfy the following formula (10). L1 / L9≥0.1 (7) L2 / L10≥0.1 (8) L4 / L9≥0.1 (9) L5 / L10≥0.1 (10).

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