inductor

Abstract

An inductor (1) includes a plurality of wirings (2) of a substantially circular shape and a magnetic layer (3), the plurality of wirings (2) are arranged at intervals from each other in a first direction, each of the plurality of wirings (2) includes a conductor (6) and an insulating layer (7), the magnetic layer (3) has a first region (13) in which anisotropic magnetic particles (8) are oriented in a circumferential direction and a second region (14) in which the anisotropic magnetic particles (8) are not oriented in the circumferential direction in a peripheral region, and a center (C2) of an imaginary circular arc (L1) in the second region (14) is not present on a first imaginary line (L2) passing through a center (C1) of the plurality of wirings (2).

Description

TECHNICAL FIELD

[0001] The present application relates to an inductor. BACKGROUND

[0002] An inductor is known to be mounted on an electronic device or the like, and used as a passive element of a voltage conversion member or the like.

[0003] For example, an inductor is proposed which includes a rectangular parallelepiped-shaped substrate main body portion formed of a magnetic material, and an internal conductor of copper or the like embedded in the inside of the substrate main body portion, the cross-sectional shape of the substrate main body portion and the cross-sectional shape of the internal conductor being similar shapes (see Patent Document 1). That is, in the inductor of Patent Document 1, the periphery of a wiring (internal conductor) which is rectangular in cross section (rectangular parallelepiped shape) is covered with a magnetic material.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-144526 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Further, an aspect in which an anisotropic magnetic particle such as a flat magnetic particle is used as a magnetic material, and the anisotropic magnetic particle is oriented around a wiring has been studied, in order to improve the inductance of an inductor.

[0009] However, in the inductor of Patent Document 1, the wiring is rectangular in cross section, and thus, there is a problem in that it is difficult to orient the anisotropic magnetic particle around the wiring due to the presence of corners or the like. Therefore, there is a case in which the improvement of the inductance is not sufficient.

[0010] Therefore, an aspect in which a wiring which is substantially circular in cross section is used, and the anisotropic magnetic particle is oriented around the wiring has been further studied.

[0011] However, in this method, the DC superposition characteristics are not sufficient, and further improvement is sought.

[0012] Further, an inductor including a plurality of wirings is also desired. However, if an inductor includes a plurality of wirings, the magnetic air between adjacent wirings can affect each other, and a problem (crosstalk) in which noise is generated can occur.

[0013] The present application provides an inductor which has good inductance and DC superposition characteristics, and in which crosstalk can be suppressed.

[0014] SOLUTION TO PROBLEM

[0015] The present application [1] provides an inductor, wherein the inductor includes a plurality of wirings each having a substantially circular shape in a cross section, the plurality of wirings being arranged at intervals from each other in a first direction, each of the plurality of wirings including a conductor and an insulating layer covering the conductor, and a magnetic layer covering the plurality of wirings, the magnetic layer containing anisotropic magnetic particles and a binder, the magnetic layer having, in a peripheral region of each of the plurality of wirings, a first region in which the anisotropic magnetic particles are oriented in a circumferential direction of the wiring and a second region in which the anisotropic magnetic particles are not oriented in the circumferential direction of the wiring, the peripheral region being a region in which, in the cross section, a distance from an outer surface of the wiring to an outer side is 1.5 times a value of a distance from a center of gravity of the wiring to the outer surface of the wiring, and a center of an imaginary circular arc connecting one end in the circumferential direction in the second region and the other end in the circumferential direction is not present on a first imaginary line passing through centers of the plurality of wirings adjacent to each other.

[0016] With this inductor, the first region in which the anisotropic magnetic particles are oriented in the circumferential direction is present in the peripheral region of each of the plurality of wirings, and thus the inductance is good.

[0017] Further, the second region in which the anisotropic magnetic particles are not oriented in the circumferential direction of the wiring is present in the peripheral region of each of the plurality of wirings, and thus the DC superposition characteristics are good.

[0018] Further, the center of the second region is not present on the first imaginary line passing through the centers of the plurality of wirings adjacent to each other. Thus, it is possible to lengthen a distance of magnetic flux passing through the second region from one wiring to another wiring. That is, it is possible to substantially lengthen a distance of magnetic flux between the wirings. Thus, it is possible to reduce a magnetic influence from one wiring to another wiring, and it is possible to suppress crosstalk.

[0019] The present application [2] is the inductor according to [1], wherein the center of the imaginary circular arc is located between the first imaginary line and a second imaginary line passing through the centers of the wirings and orthogonal to the first imaginary line.

[0020] With this inductor, by arranging a plurality of wirings in one magnetic layer, and then laminating another magnetic layer on the one magnetic layer in such a manner as to bury the plurality of wirings, it is possible to manufacture the inductor in which the center of the second region is located between the first imaginary line and the second imaginary line. Thus, it is possible to easily manufacture the inductor according to [1].

[0021] Effects of the Invention

[0022] With the inductor of the present application, both the inductance and the DC superposition characteristics are good, and it is possible to suppress crosstalk. BRIEF DESCRIPTION OF DRAWINGS

[0023] [Figure 1 ] Figure 1 A and Figure 1 B indicates one embodiment of the inductor of the present application, Figure 1 A indicates a plan view, Figure 1 B indicates Figure 1 A-A sectional view of A.

[0024] [ Figure 2 ] Figure 2 indicates Figure 1 B indicates a partial enlarged view of the dotted line portion of B.

[0025] [ Figure 3 ] Figure 3 A and Figure 3 B indicates Figure 1 A and Figure 1 B indicates a manufacturing process of the inductor, Figure 3 A indicates a disposition process, Figure 3 B indicates a lamination process.

[0026] [ Figure 4 ] Figure 4 indicates Figure 1 A and Figure 1 B indicates a cross-sectional view of an actual SEM photograph of the inductor.

[0027] [ Figure 5 ] Figure 5 indicates a sectional view of a modification (a form in which a cross portion is located at a lower end of a wiring) of the inductor of the present application.

[0028] [ Figure 6 ] Figure 6 indicates a plan view of a model of an inductor used in simulation of examples and comparative examples.

[0029] [ Figure 7 ] Figure 7 A ~ Figure 7 C is Figure 6 A-A sectional view of A, Figure 7 A indicates a sectional view of Example 1, Figure 7 B indicates a sectional view of Comparative Example 1, Figure 7 C indicates a sectional view of Comparative Example 2. DETAILED DESCRIPTION

[0030] In Figure 1In A, the paper surface left-right direction is the first direction, the paper surface left side is the first direction one side, and the paper surface right side is the first direction other side. The paper surface up-down direction is the second direction (a direction orthogonal to the first direction), the paper surface upper side is the second direction one side (a direction in the axis direction of the wiring), and the paper surface lower side is the second direction other side (a direction in the axis direction of the wiring). The paper surface thickness direction is the up-down direction (a direction orthogonal to the first direction and the second direction, i.e., the thickness direction), the paper surface front side is the upper side (the third direction one side, i.e., the thickness direction one side), and the paper surface depth side is the lower side (the third direction other side, i.e., the thickness direction other side). Specifically, the direction arrows of the respective drawings are used as reference.

[0031] <One Embodiment>

[0032] 1. Inductor

[0033] Referring to Figure 1 A ~ Figure 2 , one embodiment of the inductor of the present application will be described.

[0034] As shown in Figure 1 A and Figure 1 B, the inductor 1 has a substantially rectangular shape in plan view extending in the surface direction (the first direction and the second direction).

[0035] As shown in Figure 1 A ~ Figure 2 , the inductor 1 includes a plurality of (two) wirings 2 and a magnetic layer 3.

[0036] The plurality of wirings 2 includes a first wiring 4 and a second wiring 5 arranged apart from the first wiring 4 in the width direction (the first direction).

[0037] As shown in Figure 1 A and Figure 1 B, the first wiring 4 extends long in the second direction, for example, has a substantially U-shaped shape in plan view. As shown in Figure 2 , the first wiring 4 has a substantially circular shape in cross section.

[0038] The first wiring 4 includes a conductor wire 6 and an insulating layer 7 covering the conductor wire 6.

[0039] The conductor wire 6 extends long in the second direction, for example, has a substantially U-shaped shape in plan view. In addition, the conductor wire 6 has a substantially circular shape in cross section sharing a central axis with the first wiring 4.

[0040] The material of the conductor wire 6 is, for example, a metal conductor such as copper, silver, gold, aluminum, nickel, and alloys thereof, and copper is preferably selected. The conductor wire 6 can be a single-layer structure, or a multi-layer structure in which plating (e.g., nickel) is performed on the surface of a core conductor (e.g., copper).

[0041] The radius Rl of the wire 6 is, for example, 25 μm or more, preferably 50 μm or more, and, on the other hand, for example, 2000 μm or less, preferably 200 μm or less.

[0042] The insulating layer 7 is a layer for protecting the wire 6 from chemical agents, water, and the like, and preventing short-circuiting of the wire 6. The insulating layer 7 is disposed so as to cover the entire outer circumferential surface of the wire 6.

[0043] The insulating layer 7 has a shape of a substantially circular ring in cross section, sharing the central axis (center Cl) with the first wiring 4.

[0044] As the material of the insulating layer 7, for example, insulating resins such as polyvinyl formal, polyester, polyester imide, polyamide (including nylon), polyimide, polyamide imide, and polyurethane are cited. One of them can be used alone, or two or more of them can be used in combination.

[0045] The insulating layer 7 can be composed of a single layer, or can be composed of a plurality of layers.

[0046] The thickness R2 of the insulating layer 7 is substantially uniform in the radial direction of the wiring 2 at any position in the circumferential direction, and is, for example, 1 μm or more, preferably 3 μm or more, and, on the other hand, for example, 100 μm or less, preferably 50 μm or less.

[0047] The ratio (Rl / R2) of the radius Rl of the wire 6 to the thickness R2 of the insulating layer 7 is, for example, 1 or more, preferably 10 or more, and, for example, 200 or less, preferably 100 or less.

[0048] The radius (Rl+R2) of the first wiring 4 is, for example, 25 μm or more, preferably 50 μm or more, and, on the other hand, for example, 2000 μm or less, preferably 200 μm or less.

[0049] In the case where the first wiring 4 has a substantially U-shaped form, the center-to-center distance D2 of the first wiring 4 is the same distance as the center-to-center distance Dl between the plurality of wirings 2 described later, and is, for example, 20 μm or more, preferably 50 μm or more, and, on the other hand, for example, 3000 μm or less, preferably 2000 μm or less.

[0050] The second wiring 5 is the same shape as the first wiring 4, and has the same structure, size, and material as the first wiring 4. That is, like the first wiring 4, the second wiring 5 includes the wire 6 and the insulating layer 7 covering the wire 6.

[0051] The center-to-center distance Dl between the first wiring 4 and the second wiring 5 is, for example, 20 μm or more, preferably 50 μm or more, and, on the other hand, for example, 3000 μm or less, preferably 2000 μm or less.

[0052] The magnetic layer 3 is a layer for increasing the inductance.

[0053] The magnetic layer 3 is disposed so as to cover the entire outer circumferential surface of the plurality of wirings 2. The magnetic layer 3 forms the outer shape of the inductor 1. Specifically, the magnetic layer 3 has a substantially rectangular shape in plan view extending in the surface direction (the first direction and the second direction). In addition, the magnetic layer 3 exposes the second direction end edges of the plurality of wirings 2 on the other side surface thereof in the second direction.

[0054] The magnetic layer 3 is formed of a magnetic composition containing anisotropic magnetic particles 8 and a binder 9.

[0055] As the magnetic material constituting the anisotropic magnetic particles (hereinafter, also simply referred to as "particles") 8, a soft magnetic body, a hard magnetic body are cited. From the viewpoint of inductance, it is preferable to cite a soft magnetic body.

[0056] As the soft magnetic body, for example, a single metal body containing one kind of metal element in a pure substance state, an alloy body, for example, as a eutectic body (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.

[0057] As the single metal body, 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, it is appropriately selected from iron (Fe), cobalt (Co), nickel (Ni), and metal elements that can be contained as the first metal element of the soft magnetic body.

[0058] In addition, as the single metal body, for example, a form having a core containing only one kind of metal element and a surface layer containing an inorganic substance and / or an organic substance that modifies part or all of the surface of the core, an organic metal compound containing the first metal element, a form after decomposition (thermal decomposition, etc.) of an inorganic metal compound, and the like 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, and the like are cited. Furthermore, the position of the layer having the inorganic substance and / or the organic substance that 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 body can be obtained, there is no particular limitation, and it can be appropriately selected from known or conventional organic metal compounds and inorganic metal compounds from which the single metal body of the soft magnetic body can be obtained.

[0059] The alloy body is a eutectic body 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 an alloy body of the soft magnetic body.

[0060] The first metal element is an essential element in the alloy body, and examples include iron (Fe), cobalt (Co), nickel (Ni), and the like. In addition, when the first metal element is Fe, the alloy body is an Fe-based alloy, when the first metal element is Co, the alloy body is a Co-based alloy, and when the first metal element is Ni, the alloy body is a Ni-based alloy.

[0061] 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, and examples include 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.

[0062] 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, and examples include 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.

[0063] As an example of the alloy body, Fe-based alloys such as magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), ferrosilicon-aluminum alloy (Fe-Si-Al alloy) (including super ferrosilicon-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 soft magnetic ferrite such as 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), Permalloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, and the like are exemplified.

[0064] As an example of the alloy body, Co-based alloys such as Co-Ta-Zr, cobalt (Co)-based amorphous alloy, and the like are exemplified.

[0065] As an example of the alloy body, Ni-based alloys such as Ni-Cr alloy, and the like are exemplified.

[0066] Among these soft magnetic bodies, from the viewpoint of magnetic characteristics, an alloy body is preferably exemplified, a Fe-based alloy is more preferably exemplified, and a ferrosilicon-aluminum alloy (Fe-Si-Al alloy) is further preferably exemplified. In addition, as the soft magnetic body, a single metal body is preferably exemplified, a single metal body containing an iron element in a pure substance state is more preferably exemplified, and iron single substance or iron powder (carbonyl iron powder) is further preferably exemplified.

[0067] As the shape of the particles 8, from the viewpoint of anisotropy, flat shape (plate shape), needle shape, and the like are exemplified, and from the viewpoint of good relative permeability in the planar direction (two dimensions), flat shape is exemplified. In addition, the magnetic layer 3 can further contain isotropic magnetic particles in addition to the anisotropic magnetic particles 8. The isotropic magnetic particles can have shapes such as spherical shape, granular shape, massive shape, pellet shape, and the like. The average particle diameter of the isotropic magnetic particles is, for example, 0.1 μm or more, preferably 0.5 μm or more, and, for example, 200 μm or less, preferably 150 μm or less.

[0068] Further, the flatness ratio (flatness) of the flat particles 8 is, for example, 8 or more, preferably 15 or more, and further, for example, 500 or less, preferably 450 or less. The flatness ratio is calculated as a ratio of the average particle diameter (average length) (described later) of the particles 8 to the average thickness of the particles 8.

[0069] The average particle diameter (average length) of the particles 8 (anisotropic magnetic particles) is, for example, 3.5 μm or more, preferably 10 μm or more, and further, for example, 200 μm or less, preferably 150 μm or less. If the particles 8 are flat, the average thickness thereof is, for example, 0.1 μm or more, preferably 0.2 μm or more, and further, for example, 3.0 μm or less, preferably 2.5 μm or less.

[0070] As the binder 9, for example, a thermosetting resin, a thermoplastic resin is cited.

[0071] As the thermosetting resin, for example, an epoxy resin, a phenol resin, a melamine resin, a thermosetting polyimide resin, an unsaturated polyester resin, a polyurethane resin, a silicone resin, and the like are cited. From the viewpoints of adhesiveness, heat resistance, and the like, an epoxy resin, a phenol resin is preferably cited.

[0072] As the thermoplastic resin, for example, an acrylic resin, an ethylene-vinyl acetate copolymer, a polycarbonate resin, a polyamide resin (nylon 6, nylon 66, and the like), a thermoplastic polyimide resin, a saturated polyester resin (PET, PBT, and the like), and the like are cited. An acrylic resin is preferably cited.

[0073] As the binder 9, a combination of a thermosetting resin and a thermoplastic resin is preferably cited. A combination of an acrylic resin, an epoxy resin, and a phenol resin is more preferably cited. Thereby, the particles 8 can be more reliably fixed in a predetermined orientation state and at a high filling rate around the wiring 2.

[0074] Further, the magnetic composition can contain, as needed, a heat curing catalyst, an inorganic particle, an organic particle, a crosslinking agent, and the like as an additive.

[0075] In the magnetic layer 3, the particles 8 are oriented and uniformly arranged in the binder 9.

[0076] In a cross section, the magnetic layer 3 has a peripheral region 11 and an outer region 12.

[0077] The peripheral region 11 is a peripheral region of the wiring 2, and is located around the plurality of wirings 2 in contact with the plurality of wirings 2. The peripheral region 11 has a shape of a substantially circular ring in cross section sharing a center axis with the wiring 2. More specifically, the peripheral region 11 is a region in the magnetic layer 3 that advances from the outer peripheral surface of the wiring 2 to the radially outer side by a value of 1.5 times (preferably a value of 1.2 times, more preferably a value of 1 time, further preferably a value of 0.8 times, particularly preferably a value of 0.5 times) the radius of the wiring 2 (the distance from the center (barycenter) Cl of the wiring 2 to the outer peripheral surface; R1+R2).

[0078] The peripheral region 11 is disposed around each of the plurality of wirings 2, that is, around the first wiring 4 and around the second wiring 5.

[0079] The peripheral region 11 includes a plurality of (two) first regions 13 and a plurality of (two) second regions 14.

[0080] The plurality of first regions 13 are circumferential direction orientation regions. That is, in the first region 13, the particles 8 are oriented in the circumferential direction of the wiring 2 (the first wiring 4 or the second wiring 5).

[0081] The plurality of first regions 13 are disposed on the upper side (one side in the third direction) and the lower side (the other side in the third direction) of the wiring 2 opposite each other across the center Cl of the wiring 2. That is, the plurality of first regions 13 include an upper side first region 15 disposed on the upper side of the wiring 2 and a lower side first region 16 disposed on the lower side of the wiring 2. In addition, the center Cl of the wiring 2 is located at a central position in the vertical direction between the upper side first region 15 and the lower side first region 16.

[0082] In each first region 13, the direction in which the relative magnetic permeability of the particle 8 is high (for example, the face direction of the particle in the case of a flat anisotropic magnetic particle) is substantially in line with the tangent of the circle centered on the center Cl of the wiring 2.

[0083] More specifically, the case where the angle formed by the face direction of the particle 8 and the tangent of the circle in which the particle 8 is located is 15 degrees or less is defined as the particle 8 being oriented in the circumferential direction.

[0084] The proportion of the number of particles 8 oriented in the circumferential direction with respect to the total number of particles 8 included in the first region 13 is, for example, more than 50%, preferably 70% or more, and more preferably 80% or more. That is, in the first region 13, it can be, for example, that less than 50% of the particles 8 are not oriented in the circumferential direction, preferably that 30% or less of the particles 8 are not oriented in the circumferential direction, and more preferably that 20% or less of the particles 8 are not oriented in the circumferential direction.

[0085] The proportion of the total area of the plurality of first regions 13 with respect to the area of the entire peripheral region 11 is, for example, 40% or more, preferably 50% or more, more preferably 60% or more, and also, for example, 90% or less, preferably 80% or less.

[0086] The relative permeability in the circumferential direction of the first region 13 is, for example, 5 or more, preferably 10 or more, more preferably 30 or more, and also, for example, 500 or less. The relative permeability in the radial direction is, for example, 1 or more, preferably 5 or more, and also, for example, 100 or less, preferably 50 or less, more preferably 25 or less. Also, the ratio of the relative permeability in the circumferential direction with respect to the relative permeability in the radial direction (circumferential direction / radial direction) is, for example, 2 or more, preferably 5 or more, and also, for example, 50 or less. If the relative permeability is within the above range, the inductance is excellent.

[0087] The relative permeability can be measured, for example, by using an impedance analyzer (manufactured by Agilent, "4291B") with a magnetic material test jig.

[0088] The plurality of second regions 14 are circumferential direction non-oriented regions. That is, in the second regions 14, the particles 8 are not oriented in the circumferential direction of the wiring 2. In other words, in the second regions 14, the particles 8 are oriented or not oriented in a direction other than the circumferential direction of the wiring 2 (for example, the first direction, the radial direction).

[0089] The plurality of second regions 14 are disposed on the first direction one side and the first direction other side of the wiring 2 opposite each other with the wiring 2 interposed therebetween. That is, the plurality of second regions 14 have a one side second region 17 disposed on the first direction one side of the wiring 2 (the first wiring 4 or the second wiring 5) and an other side second region 18 disposed on the first direction other side of the wiring 2. The one side second region 17 and the other side second region 18 are substantially linearly symmetrical with the second imaginary line L3 as a reference.

[0090] Further, the second imaginary line L3 is a straight line passing through the center C1 of the first wiring 4 or the second wiring 5 and extending in the up-down direction.

[0091] In each of the second regions 14, the direction in which the relative permeability of the particle 8 is high (for example, the face direction of the particle in the case of a flat anisotropic magnetic particle) is not coincident with the tangent of the circle with the center C1 of the wiring 2 as the center.

[0092] More specifically, the case where the angle formed by the face direction of the particle 8 and the tangent of the circle in which the particle 8 is present exceeds 15 degrees is defined as the particle 8 not being oriented in the circumferential direction.

[0093] The proportion of the number of the particles 8 not oriented in the circumferential direction with respect to the total number of the particles 8 contained in the second region 14 exceeds 50%, preferably 70% or more, and, for example, 95% or less, preferably 90% or less.

[0094] In the second region 14, for example, the particles 8 oriented in the circumferential direction can also be contained. The proportion of the number of the particles 8 oriented in the circumferential direction with respect to the total number of the particles 8 contained in the second region 14 is less than 50%, preferably 30% or less, and, for example, 5% or more, preferably 10% or more.

[0095] Further, in the case where the particles 8 oriented in the circumferential direction are contained, it is preferable that the particles 8 oriented in the circumferential direction be disposed at the innermost side of the second region 14, that is, the surface of the wiring 2.

[0096] The proportion of the total area of the plurality of second regions 14 with respect to the area of the entire peripheral region 11 is, for example, 10% or more, preferably 20% or more, and, for example, 60% or less, preferably 50% or less, more preferably 40% or less.

[0097] The center C2 of the second region 14 is not present on the first imaginary line L2. That is, the center C2 is located on the lower side with respect to the first imaginary line L2, and the center C2 is preferably located at a position that is a distance of 0.1 times the radius R downward from the first imaginary line L2, and the center C2 is more preferably located at a position that is a distance of 0.3 times the radius R downward from the first imaginary line L2. More specifically, the center C2 is preferably located at 10 μm below the first imaginary line L2, and more preferably at 30 μm below the first imaginary line L2.

[0098] Further, the center C2 of the second region 14 is located between the first imaginary line L2 and the second imaginary line L3. That is, the center C2 of the second region 14 is also not present on either of the first imaginary line L2 and the second imaginary line L3.

[0099] Further, the center C2 of the second region 14 is the center of the imaginary circular arc L1 that links the one end in the circumferential direction and the other end in the circumferential direction in the second region 14. More specifically, the center C2 of the second region 14 is the center of the imaginary circular arc L1 that links the radial center of the one end edge in the circumferential direction and the radial center of the other end edge in the circumferential direction in the second region 14.

[0100] The first imaginary line L2 is a straight line that passes through the centers C1 of a plurality of wirings 2 adjacent to each other and extends in the first direction.

[0101] In the 2nd region 14, a crossing portion (top portion) 19 is formed by at least two kinds of particles 8 having different orientation directions. That is, the particles 8 (1st particles) which are relatively located on the upper side within the 2nd region 14 and which change from the circumferential direction orientation to the 1st direction orientation as going toward the lower end side of the 2nd region 14 in the circumferential direction of the wiring 2 and the particles 8 (2nd particles) which are relatively located on the lower side (lower than the 1st particles) within the 2nd region 14 and which change from the circumferential direction orientation to the 1st direction orientation as going toward the upper end side of the 2nd region 14 in the circumferential direction constitute at least two sides of a substantially triangular shape, and thus the crossing portion 19 is formed. Specifically, the 1st particles and the 2nd particles form a substantially triangular shape (preferably, an acute triangle shape) together with the particles 8 (3rd particles) which are oriented in the circumferential direction on the inner side of the 2nd region 14.

[0102] The crossing portion 19 is not present on a 1st imaginary line L2 passing through the centers of the 1st wiring 4 and the 2nd wiring 5. That is, the crossing portion 19 is disposed on the lower side of the 1st imaginary line L2 at a position spaced apart from the 1st imaginary line L2. More specifically, the angle θ formed by a straight line connecting the center of the crossing portion 19 and the center C1 of the wiring 2 and the 1st imaginary line L2 is, for example, 15° or more, preferably 45° or more, and, for example, 75° or less, preferably 60° or less.

[0103] In the peripheral region 11 (particularly, in each of the 1st region 13 and the 2nd region 14), the filling rate of the particles 8 is, for example, 40 vol% or more, preferably 45 vol% or more, and, for example, 90 vol% or less, preferably 70 vol% or less. If the filling rate is the above lower limit or more, the inductance is excellent.

[0104] The filling rate can be calculated by measurement of the actual specific gravity, binarization of a cross-sectional view of a SEM photograph, or the like.

[0105] In the peripheral region 11, a plurality of 1st regions 13 and a plurality of 2nd regions 14 are disposed in such a manner as to be adjacent to each other in the circumferential direction. Specifically, the upper 1st region 15, the one 2nd region 17, the lower 1st region 16, and the other 2nd region 18 are sequentially continuous in the circumferential direction.

[0106] Further, the boundary (one end edge or the other end edge) in the circumferential direction between the 1st region 13 and the 2nd region 14 is an imaginary straight line extending from the center of the wiring 2 to the radially outer side.

[0107] The outer region 12 is a region in the magnetic layer 3 other than the peripheral region 11. The outer region 12 is disposed on the outer side of the peripheral region 11 in such a manner as to be continuous with the peripheral region 11.

[0108] In the outer region 12, the particles 8 are oriented along the planar direction (particularly, the 1st direction).

[0109] In the outer region 12, the direction in which the relative magnetic permeability of the particles 8 is high (for example, the face direction of the particles in the case of flat anisotropic magnetic particles) is substantially coincident with the first direction. More specifically, the case where the angle formed by the face direction of the particles 8 and the first direction is 15° or less is defined as the particles 8 being oriented in the first direction.

[0110] In the outer region 12, the proportion of the number of particles 8 oriented in the first direction with respect to the total number of particles 8 contained in the outer region 12 exceeds 50%, preferably 70% or more, and more preferably 90% or more. That is, in the outer region 12, it can be that less than 50% of the particles 8 are not oriented in the first direction, preferably 30% or less of the particles 8 are not oriented in the first direction, and more preferably 10% or less of the particles 8 are not oriented in the first direction.

[0111] In the outer region 12, the relative magnetic permeability in the first direction is, for example, 5 or more, preferably 10 or more, and more preferably 30 or more, and is, for example, 500 or less. The relative magnetic permeability in the up-down direction is, for example, 1 or more, preferably 5 or more, and is, for example, 100 or less, preferably 50 or less, and more preferably 25 or less. Furthermore, the ratio of the relative magnetic permeability in the first direction with respect to the relative magnetic permeability in the up-down direction (first direction / up-down direction) is, for example, 2 or more, preferably 5 or more, and is, for example, 50 or less. If the relative magnetic permeability is within the above range, the inductance is excellent.

[0112] In the outer region 12, the filling rate of the particles 8 is, for example, 40% by volume or more, preferably 45% by volume or more, and is, for example, 90% by volume or less, preferably 70% by volume or less. If the filling rate is the above lower limit or more, the inductance is excellent.

[0113] The first direction length Tl of the magnetic layer 3 is, for example, 5 mm or more, preferably 10 mm or more, and is, for example, 5000 mm or less, preferably 2000 mm or less.

[0114] The second direction length T2 of the magnetic layer 3 is, for example, 5 mm or more, preferably 10 mm or more, and is, for example, 5000 mm or less, preferably 2000 mm or less.

[0115] The up-down direction length (thickness) T3 of the magnetic layer 3 is, for example, 100 μm or more, preferably 200 μm or more, and is, for example, 2000 μm or less, preferably 1000 μm or less.

[0116] 2. Method for manufacturing an inductor

[0117] Reference Figure 3 A and Figure 3One embodiment of a method of manufacturing the inductor 1 will be described with reference to FIGS. 1A to 1C. The method of manufacturing the inductor 1, for example, sequentially includes a preparation step, a disposition step, and a lamination step.

[0118] In the preparation step, a plurality of wirings 2 and two anisotropic magnetic sheets 20 are prepared.

[0119] The two anisotropic magnetic sheets 20 each have a sheet shape extending in a planar direction and are formed of a magnetic composition. In the anisotropic magnetic sheet 20, the particles 8 are oriented in the planar direction. It is preferable to use two anisotropic magnetic sheets 20 in a semi-cured state (B-stage).

[0120] As such anisotropic magnetic sheets 20, a soft magnetic thermosetting adhesive film, a soft magnetic film, and the like described in Japanese Patent Application Publication No. 2014-165363, Japanese Patent Application Publication No. 2015-92544, and the like are cited.

[0121] In the disposition step, as shown in FIG. 1A, the plurality of wirings 2 are disposed on the upper surface of one anisotropic magnetic sheet 20, and the other anisotropic magnetic sheet 20 is disposed in opposition to the plurality of wirings 2. Figure 3

[0122] Specifically, the lower anisotropic magnetic sheet 21 is placed on a water platform, and then the plurality of wirings 2 are disposed on the upper surface of the lower anisotropic magnetic sheet 21 at desired intervals in the first direction.

[0123] Next, the upper anisotropic magnetic sheet 22 is disposed in opposition to the upper side of the lower anisotropic magnetic sheet 21 and the upper side of the plurality of wirings 2 at intervals.

[0124] In the lamination step, as shown in FIG. 1C, the two anisotropic magnetic sheets 20 are laminated in a manner to bury the plurality of wirings 2. Figure 3

[0125] Specifically, the upper anisotropic magnetic sheet 22 is pressed toward the lower side.

[0126] At this time, in a case where the two anisotropic magnetic sheets 20 are in a semi-cured state, by the pressing, the plurality of wirings 2 are slightly sunk into the lower anisotropic magnetic sheet 21, and in the sunk portion, the particles 8 are oriented along the plurality of wirings 2. That is, the lower first region 16 is formed.

[0127] In addition, the upper anisotropic magnetic sheet 22 covers the plurality of wirings 2 along the plurality of wirings 2, the particles 8 of the upper anisotropic magnetic sheet 22 are oriented along the plurality of wirings 2, and the upper anisotropic magnetic sheet 22 is laminated to the upper surface of the lower anisotropic magnetic sheet 21.

[0128] ​​That is, on the upper side of the wiring 2, the upper first region 15 is formed by the upper anisotropic magnetic sheet 22, and on both sides (lateral sides) of the wiring 2 in the first direction, in the vicinity of the portions where the lower anisotropic magnetic sheet 21 and the upper anisotropic magnetic sheet 22 are in contact, the particles 8 oriented in the lower anisotropic magnetic sheet 21 and the upper anisotropic magnetic sheet 22 collide with each other, as a result of which the second region 14 and the cross portion 19 are formed.

[0129] Further, in the case where the anisotropic magnetic sheet 20 is in a semi-cured state, heating is performed. As a result of this, the anisotropic magnetic sheet 20 becomes a cured state (C-stage). In addition, the contact interface 25 of the two anisotropic magnetic sheets 20 disappears, and the two anisotropic magnetic sheets 20 form one magnetic layer 3.

[0130] As a result of this, as shown in FIG. 8, the inductor 1 including the wiring 2 in a substantially circular shape in a cross section and the magnetic layer 3 covering the wiring 2 is obtained. That is, the inductor 1 is formed by laminating a plurality of (two) anisotropic magnetic sheets 20 in a manner of sandwiching the wiring 2. Further, a cross-sectional view (SEM photograph) of one example of the actual inductor 1 is shown in FIG. 9. Figure 2 Figure 4

[0131] 3. Use

[0132] The inductor 1 is a component of an electronic device, that is, is a component for manufacturing an electronic device, does not contain an electronic element (chip, capacitor, etc.), a mounting substrate on which the electronic element is mounted, and is circulated as a single component, and is a device that can be utilized in industry.

[0133] The inductor 1 is mounted (assembled) on an electronic device or the like, for example. The electronic device includes a mounting substrate and an electronic element (chip, capacitor, etc.) mounted on the mounting substrate, but this case is not shown. Further, the inductor 1 is mounted on the mounting substrate by a connection member such as solder, and is electrically connected to other electronic devices, and functions as a passive element such as a coil.

[0134] Further, in the inductor 1, in the peripheral regions 11 of the plurality of wirings 2, the first regions 13 in which the particles 8 are oriented in the circumferential direction exist respectively, and thus the inductance is good.

[0135] In addition, in the peripheral regions 11 of the plurality of wirings 2, the second regions 14 in which the particles 8 are not oriented in the circumferential direction exist respectively, and thus the DC superimposition characteristics are good.

[0136] Further, the center C2 in the second region 14 does not exist on the first imaginary line L2. Thus, it is possible to extend the distance of the magnetic flux passing through the second region 14 from the first wiring 4 to the second wiring 5. That is, it is possible to substantially extend the distance of the magnetic flux passing between the wirings 2.

[0137] ​​Therefore, the influence on the magnetic gas from the first wiring 4 to the second wiring 5 can be reduced, and crosstalk can be suppressed.

[0138] In addition, the center C2 of the second region 14 is located between the first imaginary line L2 and the second imaginary line L3 in the circumferential direction. Therefore, as Figure 3 A and Figure 3 B show, by arranging a plurality of wirings 2 on the upper surface of the lower anisotropic magnetic sheet 21, and then laminating the upper anisotropic magnetic sheet 22 on the lower anisotropic magnetic sheet 21 in such a manner that the plurality of wirings 2 are buried, the second region 14 can be easily arranged at the above position. Therefore, an inductor 1 having good inductance and DC superimposition characteristics and in which crosstalk can be suppressed can be easily obtained.

[0139] <Modification example>

[0140] Reference Figure 5 will be made Figure 1 A ~ Figure 2 to one modification example of the embodiment shown in . In addition, in the modification example, the same reference numerals are assigned to the same members as those of the above embodiment, and the description thereof will be omitted. The modification examples also have the same effects as those of the above embodiment.

[0141] In Figure 2 the embodiment shown in , the up-down direction position of the intersection portion 19 is located between the center C1 of the wiring 2 and the lowermost end of the wiring 2, but for example, as shown in Figure 5 , the up-down direction position of the intersection portion 19 can be located at the same position as the lowermost end of the wiring 2.

[0142] In Figure 5 the embodiment shown in , for example, as the two anisotropic magnetic sheets 20, a lower anisotropic magnetic sheet 21 in a cured state and an upper anisotropic magnetic sheet 22 in a semi-cured state are used. Thereby, the plurality of wirings 2 do not sink into the lower anisotropic magnetic sheet 21, and thus the inductor 1 shown in Figure 5 can be easily manufactured.

[0143] In Figure 1 the embodiment shown in A and Figure 1 B, two wirings 2 are included, but the number thereof is not limited, and three or more wirings 2 can also be provided.

[0144] In Figure 1 the embodiment shown in A and Figure 1 B, each wiring 2 has a substantially U-shaped shape in plan view, but the shape thereof is not limited, and can be appropriately set.

[0145] In Figure 1 the embodiment shown in A and Figure 1In the embodiment shown in B, the magnetic layer 3 can also have alignment marks.

[0146] exist Figure 1 A and Figure 1 In the embodiment shown in B, the proportion of anisotropic magnetic particles 8 in the magnetic layer 3 can also be uniform in the magnetic layer 3, and can also be increased or decreased as it moves away from each wiring 2.

[0147] <Simulation Results>

[0148] Example 1

[0149] As with Figure 5 A model with a similar implementation method, using Figure 6 and Figure 7 Model A is shown. In this model, under the conditions shown below, the self-inductance, mutual inductance, inductance density, DC superposition characteristics, and coupling coefficient of the inductor are calculated by simulation.

[0150] Software: Maxwell 3D, manufactured by ANSYS.

[0151] The radius R1 of conductor 6 is 110 μm.

[0152] The thickness R2 of insulating layer 7 is 5 μm.

[0153] The length T1 in the first direction of magnetic layer 3 is 14.5 mm.

[0154] The length T2 in the second direction of magnetic layer 3 is 12 mm.

[0155] Wiring 2, second direction length: 10mm

[0156] The thickness T3 of magnetic layer 3 is 430 μm.

[0157] Radial length of surrounding region 11: 60 μm.

[0158] The relative permeability μ in the circumferential direction of the circumferential orientation region 30 is 140.

[0159] The radial relative permeability μ of the circumferential orientation region 30 is 10.

[0160] The relative permeability μ in the first direction of the first-direction orientation region 31 is 140.

[0161] The relative permeability μ in the vertical direction of the first orientation region 31 is 10.

[0162] The vertical distance of the first orientation region 31 is 60 μm.

[0163] Frequency: 10MHz

[0164] The center-to-center distance D1 between wiring 2 is 0.5mm, 1.0mm, or 1.5m.

[0165] • For the DC superposition characteristic, the variation of the magnetic property B relative to the external magnetic field strength H was set. In addition, for the surface direction, a nonlinear mode (the mode in which B gradually saturates as the external magnetic field strength H increases) was set, and for the thickness direction, a linear mode (the mode in which B remains constant and unsaturated relative to the external magnetic field strength H) was set.

[0166] With a DC current applied to the wiring, the inductance value relative to the DC magnetic field was calculated.

[0167] A scan was performed with current values ​​ranging from 0.1A to 100A. At this time, the inductance value when the DC current is 0.1A was used as a reference (100%), and the DC current value when it is reduced to 70% was used as the DC superimposed current value and calculated.

[0168] These results are presented in Table 1.

[0169] Comparative Example 1

[0170] like Figure 6 and Figure 7 As shown in Figure B, the center C2 of the first direction orientation region 31 is changed to be located on the first imaginary line L2, and the vertical length of the first direction orientation region 31 is changed to 50 μm. Otherwise, the values ​​are calculated in the same manner as in Example 1. The results are shown in Table 1.

[0171] Comparative Example 2

[0172] like Figure 6 and Figure 7 As shown in Figure C, the first direction orientation region 31 is not configured, so the peripheral region 11 is only a circumferential direction orientation region. Otherwise, the values ​​are calculated in the same manner as in Example 1. The results are shown in Table 1.

[0173] Table 1

[0174] [Table 1]

[0175]

[0176] Research

[0177] As shown in Table 1, compared to the inductor of Comparative Example 1, the coupling coefficient in the inductor of Example 1 is lower for any center-to-center distance D1 of the wiring. Therefore, there is less influence between wirings, reducing crosstalk. Furthermore, the inductance density is higher, resulting in good inductance. Additionally, the decrease in inductance when DC currents overlap is less, indicating good DC superposition characteristics.

[0178] In addition, in the inductor of Example 1, the decrease in inductance at the time of DC current superposition is less than that of the inductor of Comparative Example 2, and the DC superposition characteristics are good.

[0179] Industrial Applicability

[0180] The inductor of the present application can be used, for example, as a passive element such as a voltage conversion member.

[0181] Explanation of Reference Numerals

[0182] 1, inductor; 2, wiring; 3, magnetic layer; 6, wire; 7, insulating layer; 8, anisotropic magnetic particle; 13, 1st region; 14, 2nd region; C1, center of wiring; C2, center of imaginary circular arc; L1, imaginary circular arc; L2, 1st imaginary line; L3, 2nd imaginary line.

Claims

1. An inductor characterized by comprising a plurality of wirings in a circular shape in a cross section, and a magnetic layer covering the plurality of wirings, the plurality of wirings are arranged at intervals from each other in a first direction, each of the plurality of wirings comprises a conductor and an insulating layer covering the conductor, the magnetic layer contains anisotropic magnetic particles and a binder, the magnetic layer has, in a peripheral region of each of the plurality of wirings, a first region in which the anisotropic magnetic particles are oriented in a circumferential direction of the wiring, and a second region in which the anisotropic magnetic particles are not oriented in the circumferential direction of the wiring, the peripheral region is a region in which, in the cross section, a distance from an outer surface of the wiring to an outer side is 1.5 times a value of a distance from a center of gravity of the wiring to the outer surface of the wiring, a center of an imaginary circular arc connecting a circumferential direction one end and a circumferential direction other end in the second region is not present on a first imaginary line passing through centers of the plurality of wirings adjacent to each other.

2. The inductor according to claim 1, characterized in that the center of the imaginary circular arc is present between the first imaginary line and a second imaginary line passing through the center of the wiring and orthogonal to the first imaginary line. ​

Images