Inductor

Abstract

The inductor (1) includes a plurality of wirings (2) and a magnetic layer (3). The plurality of wirings (2) are arranged at intervals in a first direction. Each of the plurality of wirings (2) includes a conductor wire (6) and an insulating layer (7). A first-direction orientation region (10) is formed between adjacent ones of the plurality of wirings (2) in such a manner as to include a hypothetical line (L2) passing through the centers (C1) of these wirings (2). In the first-direction orientation region (10), anisotropic magnetic particles (8) are oriented along the first direction. The distance (N) of the first-direction orientation region (10) is 60% or less of the interval (S) on the first hypothetical line (L2) between the wirings (2).

Description

Technical Field

[0001] The present invention relates to an inductor. Background Art

[0002] Known inductors are mounted on electronic devices and the like and used as passive components such as voltage conversion components.

[0003] For example, an inductor is proposed which includes: a rectangular parallelepiped-shaped substrate main body formed of a magnetic material; and an internal conductor such as copper buried inside the substrate main body, and the cross-sectional shape of the substrate main body and the cross-sectional shape of the internal conductor are similar shapes (see Patent Document 1). That is, in the inductor of Patent Document 1, a magnetic material covers the periphery of a wiring (internal conductor) which is rectangular (rectangular parallelepiped shape) in cross-section.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 10-144526 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In addition, the following aspect has been studied: using anisotropic magnetic particles such as flat magnetic particles as the magnetic material, and orienting the anisotropic magnetic particles around the wiring to increase the inductance of the inductor.

[0009] However, in the inductor of Patent Document 1, since the wiring is rectangular in cross-section, there is a problem that it is difficult to orient the anisotropic magnetic particles around the wiring due to the presence of corners and the like. Therefore, there are cases where the increase in inductance is not sufficient.

[0010] In addition, an inductor including a plurality of wirings is also desired. However, if the inductor includes a plurality of wirings, due to the anisotropic magnetic particles, there is a problem of noise (crosstalk) generated due to the mutual influence of the magnetism between adjacent wirings.

[0011] The present invention provides an inductor with good inductance and capable of suppressing crosstalk.

[0012] Means for Solving the Problems

[0013] The present invention [1] provides an inductor, wherein the inductor includes a plurality of wirings and a magnetic layer covering the plurality of wirings. The plurality of wirings are arranged at intervals in a first direction. Each of the plurality of wirings includes a wire and an insulating layer covering the wire. The magnetic layer contains anisotropic magnetic particles and a binder. A first-direction orientation region is formed between adjacent ones of the plurality of wirings in such a manner as to include an imaginary line passing through the centers of these wirings. In the first-direction orientation region, the anisotropic magnetic particles are oriented along the first direction, and the distance of the first-direction orientation region is 60% or less of the interval on the imaginary line between the wirings.

[0014] With this inductor, since it includes a plurality of wirings and a magnetic layer covering the plurality of wirings, anisotropic magnetic particles can be easily oriented along the outer peripheral direction around the plurality of wirings. Therefore, the inductance can be increased.

[0015] In addition, a first-direction orientation region is formed in such a manner as to include an imaginary line passing through the centers of the plurality of wirings. In the first-direction orientation region, the anisotropic magnetic particles are oriented along the first direction, and the distance of the first-direction orientation region is 60% or less of the interval on the imaginary line between the wirings. That is, in the space between the wirings, which is a path for magnetic flux flowing along the first direction, the distance of the first-direction orientation region is shorter than the distance of the region other than the first-direction orientation region. Therefore, the magnetic-related influence from one wiring to another wiring can be reduced, and crosstalk can be suppressed.

[0016] The present invention [2] is the inductor according to [1], wherein a first region is respectively provided around the plurality of wirings. In the first region, the anisotropic magnetic particles are oriented along the outer peripheral direction of the wiring. Therefore, the inductance can be increased.

[0017] The present invention [3] is the inductor according to [2], wherein a second region is respectively further provided around the plurality of wirings. In the second region, the anisotropic magnetic particles are not oriented along the outer peripheral direction.

[0018] Therefore, the DC superposition characteristic can be improved.

[0019] Effects of the Invention

[0020] With the inductor of the present invention, the inductance is good, and crosstalk can be suppressed. Description of the Drawings

[0021] Figure 1 Figure 1 A and Figure 1 B show an embodiment of the inductor of the present invention. Figure 1 A shows a top view. Figure 1 ​​B indicates Figure 1 The A - A cross - sectional view of A.

[0022] Figure 2 Figure 2 indicates Figure 1 The partial enlarged view of the dashed - line part of B.

[0023] Figure 3 Figure 3 A and Figure 3 B indicate Figure 1 A and Figure 1 The manufacturing process of the inductor shown by B, Figure 3 A indicates the placement process, Figure 3 B indicates the lamination process.

[0024] Figure 4 Figure 4 indicates Figure 1 A and Figure 1 The actual SEM photo cross - sectional view of the inductor shown by B.

[0025] Figure 5 Figure 5 Indicates the cross - sectional view of the modified example of the inductor of the present invention (the form in which the center part of the second region is located on the first imaginary line). Detailed implementation mode

[0026] In Figure 1 A, the left - right direction of the paper surface is the first direction, the left side of the paper surface is the side of the first direction, and the right side of the paper surface is the other side of the first direction. The up - down direction of the paper surface is the second direction (the direction orthogonal to the first direction), the upper side of the paper surface is the side of the second direction (one direction on the axis direction of the wiring), and the lower side of the paper surface is the other side of the second direction (the other direction on the axis direction of the wiring). The thickness direction of the paper surface is the up - down direction (the direction orthogonal to the first direction and the second direction, that is, the thickness direction), the front side of the paper surface is the upper side (the side of the third direction, that is, one side of the thickness direction), and the back side of the paper surface is the lower side (the other side of the third direction, that is, the other side of the thickness direction). Specifically, it is based on the direction arrows in each figure.

[0027] <One implementation mode>

[0028] 1. Inductor

[0029] Refer to Figure 1 A~ Figure 2 To describe one implementation mode of the inductor of the present invention.

[0030] As Figure 1 A and Figure 1 B show, the inductor 1 has a substantially rectangular shape in plan view extending in the plane direction (the first direction and the second direction).

[0031] As​​​​​​​​Figure 1 A to Figure 2 As shown in Figure 2 , the inductor 1 includes a plurality of (two) wirings 2 and a magnetic layer 3.

[0032] (Wiring)

[0033] The plurality of wirings 2 include a first wiring 4 and a second wiring 5 disposed at an interval from the first wiring 4 in the width direction (first direction).

[0034] As Figure 1 A and Figure 1 As shown in B, the first wiring 4 extends longitudinally in the second direction and has, for example, a substantially U-shaped shape in plan view. As Figure 2 As shown, the first wiring 4 has a substantially circular shape in cross section.

[0035] The first wiring 4 includes a conductor 6 and an insulating layer 7 covering the conductor 6.

[0036] The conductor 6 extends longitudinally in the second direction and has, for example, a substantially U-shaped shape in plan view. In addition, the conductor 6 has a substantially circular shape in cross section that shares a central axis with the first wiring 4.

[0037] The material of the conductor 6 is, for example, a metal conductor such as copper, silver, gold, aluminum, nickel, and their alloys, and copper is preferably selected. The conductor 6 may have a single-layer structure or a multi-layer structure formed by plating (e.g., nickel) on the surface of a core conductor (e.g., copper).

[0038] The radius R1 of the conductor 6 is, for example, 25 μm or more, preferably 50 μm or more, and, for example, 2000 μm or less, preferably 200 μm or less.

[0039] The insulating layer 7 is a layer for protecting the conductor 6 from the influence of chemicals and water and preventing short circuits of the conductor 6. The insulating layer 7 is disposed so as to cover the entire outer peripheral surface of the conductor 6.

[0040] The insulating layer 7 has a substantially annular shape in cross section that shares a central axis (central C1) with the first wiring 4.

[0041] As materials for the insulating layer 7, for example, insulating resins such as polyvinyl formal, polyester, polyesterimide, polyamide (including nylon), polyimide, polyamideimide, and polyurethane are cited. They may be used alone or in combination of two or more.

[0042] The insulating layer 7 may be composed of a single layer or multiple layers.

[0043] Regarding the thickness R2 of the insulating layer 7, at any position in the circumferential direction, the thickness R2 is substantially uniform in the radial direction of the wiring 2, for example, 1 μm or more, preferably 3 μm or more, and for another example, 100 μm or less, preferably 50 μm or less.

[0044] The ratio (R1 / R2) of the radius R1 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 another example, 200 or less, preferably 100 or less.

[0045] The radius (R1 + R2) of the first wiring 4 is, for example, 25 μm or more, preferably 50 μm or more, and for another example, 2000 μm or less, preferably 200 μm or less.

[0046] When the first wiring 4 is substantially U-shaped, the center-to-center distance D2 between the first wirings 4 is the same distance as the center-to-center distance D1 between a plurality of wirings 2 described later, for example, 20 μm or more, preferably 50 μm or more, and for another example, 3000 μm or less, preferably 2000 μm or less.

[0047] The second wiring 5 has the same shape as the first wiring 4 and has the same structure, dimensions, and material as the first wiring 4. That is, similarly to the first wiring 4, the second wiring 5 includes a wire 6 and an insulating layer 7 that covers the wire 6.

[0048] The interval S between the first wiring 4 and the second wiring 5 is the shortest distance between the outer peripheral edges of the first wiring 4 and the second wiring 5, that is, the distance on the first imaginary line L2 of the portion of the magnetic layer 3 located between the first wiring 4 and the second wiring 5. Specifically, the interval S between the wirings 2 (4, 5) is, for example, 20 μm or more, preferably 70 μm or more, and for another example, 2000 μm or less, preferably 1000 μm or less.

[0049] The center-to-center distance D1 between the first wiring 4 and the second wiring 5 is, for example, 20 μm or more, preferably 50 μm or more, and for another example, 3000 μm or less, preferably 2000 μm or less.

[0050] (Magnetic layer)

[0051] The magnetic layer 3 is a layer for increasing the inductance.

[0052] The magnetic layer 3 is arranged so as to cover the entire outer peripheral 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 plane direction (the first direction and the second direction). In addition, the magnetic layer 3 exposes the end edges of the plurality of wirings 2 in the second direction on the other side surface in the second direction.

[0053] The magnetic layer 3 is formed of a magnetic composition containing anisotropic magnetic particles 8 and a binder 9.

[0054] As the magnetic material constituting the anisotropic magnetic particles (hereinafter, also simply referred to as "particles".) 8, a soft magnetic material and a hard magnetic material are cited. From the viewpoint of inductance, a soft magnetic material is preferably selected.

[0055] As the soft magnetic material, for example, a single metal body containing one metal element in a pure substance state, and an alloy body which is a eutectic melt (mixture) of one or more metal elements (the first metal element) and one or more metal elements (the second metal element) and / or non-metal elements (such as carbon, nitrogen, silicon, phosphorus, etc.) are cited. They can be used alone or in combination.

[0056] As the single metal body, for example, a metal simple substance composed of only one metal element (the 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 material.

[0057] In addition, as the single metal body, for example, a form having a core containing only one metal element and a surface layer containing inorganic substances and / or organic substances that partially or entirely modify the surface of the core is cited, such as a form after decomposition (thermal decomposition, etc.) of an organometallic compound or an inorganic metal compound containing the first metal element. As the latter form, more specifically, iron powder (sometimes referred to as carbonyl iron powder) obtained by thermal decomposition of an organoiron compound (specifically, carbonyl iron) containing iron as the first metal element is cited. In addition, the position of the layer containing inorganic substances and / or organic substances that modify the part containing only one metal element is not limited to the surface as described above. In addition, there is no particular limitation on the organometallic compound and inorganic metal compound that can obtain the single metal body, and they can be appropriately selected from known or conventional organometallic compounds and inorganic metal compounds that can obtain the single metal body of the soft magnetic material.

[0058] The alloy body is a eutectic melt of one or more metal elements (the first metal element) and one or more metal elements (the second metal element) and / or non-metal elements (such as 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 material.

[0059] The first metal element is an essential element in the alloy body, and for example, iron (Fe), cobalt (Co), nickel (Ni), etc. are cited. In addition, if the first metal element is Fe, the alloy body is an Fe-based alloy, if the first metal element is Co, the alloy body is a Co-based alloy, and if the first metal element is Ni, the alloy body is a Ni-based alloy.

[0060] The second metal element is a minor element (secondary component) contained in the alloy body and is a metal element compatible (eutectic) with the first metal element. For example, iron (Fe) (when the first metal element is other than Fe), cobalt (Co) (when the first metal element is other than Co), nickel (Ni) (when 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, etc. They can be used alone or in combination of two or more.

[0061] The non-metal element is a minor element (secondary component) contained in the alloy body and is a non-metal element compatible (eutectic) with the first metal element. For example, boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), sulfur (S), etc. They can be used alone or in combination of two or more.

[0062] As an example of the alloy body, the Fe-based alloy, for example, magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), Fe-Si-Al alloy (including super Fe-Si-Al 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, 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 ferrites 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, etc.), Permendur Fe-Co-based high magnetic permeability alloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, etc.

[0063] As an example of the alloy body, the Co-based alloy, for example, Co-Ta-Zr, cobalt (Co)-based amorphous alloy, etc.

[0064] As an example of the alloy body, a Ni-based alloy includes, for example, a Ni—Cr alloy.

[0065] Among these soft magnetic bodies, from the point of view of magnetic properties, alloy bodies are preferably cited, Fe-based alloys are more preferably cited, and Fe-Si-Al alloys are further preferably cited. In addition, as the soft magnetic body, single metal bodies are preferably cited, single metal bodies containing iron elements in a pure state are more preferably cited, and iron alone or iron powder (carbonyl iron powder) are further preferably cited.

[0066] As the shape of the particles 8, from the viewpoint of anisotropy, for example, flat (plate-like) and needle-like shapes are given, and from the viewpoint of good relative magnetic permeability in the plane direction (two-dimensional), flat shapes are given. In addition, in addition to the anisotropic magnetic particles 8, the magnetic layer 3 can further contain isotropic magnetic particles. The isotropic magnetic particles can also have shapes such as spheres, particles, blocks, and pellets. The average particle size of the isotropic magnetic particles is, for example, greater than 0.1 μm, preferably greater than 0.5 μm, and is, for example, less than 200 μm, preferably less than 150 μm.

[0067] The flattening ratio (flatness) of the flat particles 8 is, for example, 8 or more, preferably 15 or more, and for example, 500 or less, preferably 450 or less. The flattening ratio is calculated as, for example, the diameter-to-thickness ratio obtained by dividing the average particle diameter (average length) (described later) of the particles 8 by the average thickness of the particles 8.

[0068] The average particle size (average length) of the particles 8 (anisotropic magnetic particles) is, for example, 3.5 μm or more, preferably 10 μm or more, and for example, 200 μm or less, preferably 150 μm or less. If the particles 8 are flat, the average thickness is, for example, 0.1 μm or more, preferably 0.2 μm or more, and for example, 3.0 μm or less, preferably 2.5 μm or less.

[0069] Examples of the binder 9 include thermosetting resins and thermoplastic resins.

[0070] Examples of the thermosetting resin include epoxy resins, phenolic resins, melamine resins, thermosetting polyimide resins, unsaturated polyester resins, polyurethane resins, silicone resins, etc. From the viewpoint of adhesiveness, heat resistance, etc., epoxy resins and phenolic resins are preferred.

[0071] Examples of the thermoplastic resin include acrylic resins, ethylene-vinyl acetate copolymers, polycarbonate resins, polyamide resins (nylon 6, nylon 66, etc.), thermoplastic polyimide resins, saturated polyester resins (PET, PBT, etc.), etc. Preferably, acrylic resins are used.

[0072] As the binder 9, a thermosetting resin and a thermoplastic resin are preferably selected. More preferably, an acrylic resin, an epoxy resin, and a phenolic resin are selected. Thereby, the particles 8 can be more reliably fixed around the wiring 2 in a predetermined orientation state and at a high filling rate.

[0073] In addition, if necessary, the magnetic composition can also contain additives such as a thermosetting catalyst, inorganic particles, organic particles, and a crosslinking agent.

[0074] In the magnetic layer 3, within the binder 9, the particles 8 are oriented and uniformly arranged.

[0075] In a cross-sectional view, the magnetic layer 3 has a peripheral region 11 and an outer region 12.

[0076] The peripheral region 11 is the 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 substantially circular ring shape in a cross-sectional view that shares a central axis with the wiring 2. More specifically, the peripheral region 11 is a region in the magnetic layer 3 that advances radially outward from the outer peripheral surface of the wiring 2 by a value that is 1.5 times (preferably 1.2 times, more preferably 1 time, further preferably 0.8 times, and particularly preferably 0.5 times) the radius of the wiring 2 (the average value of the distance from the center (center of gravity) C1 of the wiring 2 to the outer peripheral surface; R1 + R2).

[0077] The peripheral region 11 is disposed around each of the plurality of wirings 2, that is, around the first wiring 4 and the second wiring 5.

[0078] The peripheral region 11 includes a plurality (two) of first regions 13 and a plurality (two) of second regions 14.

[0079] The plurality of first regions 13 are circumferential direction orientation regions. That is, in the first region 13, the particles 8 are oriented along the circumferential direction (outer peripheral direction) of the wiring 2 (the first wiring 4 or the second wiring 5).

[0080] The plurality of first regions 13 are disposed opposite to each other across the center C1 of the wiring 2 on the upper side (the first direction side) and the lower side (the other side of the first direction) of the wiring 2. That is, the plurality of first regions 13 include an upper first region 15 disposed on the upper side of the wiring 2 and a lower first region 16 disposed on the lower side of the wiring 2. In addition, the center C1 of the wiring 2 is located at the central position in the vertical direction between the upper first region 15 and the lower first region 16.

[0081] In each of the first regions 13, the direction in which the relative magnetic permeability of the particles 8 is higher (for example, in the case of flat anisotropic magnetic particles, the plane direction of the particles) is substantially coincident with the tangent to the circle centered on the center C1 of the wiring 2.

[0082] More specifically, a case where the angle formed by the plane direction of the particle 8 and the tangent to 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.

[0083] The ratio of the number of particles 8 oriented in the circumferential direction 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 may be, for example, that less than 50% of the particles 8 not oriented in the circumferential direction are contained, preferably 30% or less of the particles 8 not oriented in the circumferential direction are contained, and more preferably 20% or less of the particles 8 not oriented in the circumferential direction are contained. The ratio of the total area of the plurality of first regions 13 to the area of the entire peripheral region 11 is, for example, 40% or more, preferably 50% or more, and more preferably 60% or more, and is, for example, 90% or less, preferably 80% or less.

[0084] The relative magnetic permeability in the circumferential direction of the first region 13 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 radial 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. In addition, the ratio of the relative magnetic permeability in the circumferential direction to the relative magnetic permeability in the radial direction (circumferential direction / radial 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.

[0085] The relative magnetic permeability can be measured, for example, by using an impedance analyzer (manufactured by Agilent Technologies, "4291B") with a magnetic material test jig.

[0086] The plurality of second regions 14 are circumferentially non-oriented regions. That is, in the second region 14, the particles 8 are not oriented along the circumferential direction (outer peripheral direction) of the wiring 2. In other words, in the second region 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).

[0087] The plurality of second regions 14 are arranged opposite to each other across the wiring 2 on one side and the other side in the first direction of the wiring 2. That is, the plurality of second regions 14 have a first-side second region 17 arranged on one side in the first direction of the wiring 2 (the first wiring 4 or the second wiring 5) and a second-side second region 18 arranged on the other side in the first direction of the wiring 2. The first-side second region 17 and the second-side second region 18 are substantially line-symmetric with respect to the second imaginary line L3.

[0088] In addition, the second imaginary line L3 is a straight line passing through the center C1 of the first wiring 4 or the second wiring and extending in the vertical direction.

[0089] In each of the second regions 14, the direction in which the relative magnetic permeability of the particles 8 is high (for example, in the case of flat anisotropic magnetic particles, the plane direction of the particles) does not coincide with the tangent to the circle centered on the center C1 of the wiring 2.

[0090] More specifically, a case where the angle formed by the plane direction of the particle 8 and the tangent to the circle in which the particle 8 is located exceeds 15 degrees is defined as the particle 8 not being oriented in the circumferential direction.

[0091] The ratio of the number of particles 8 not oriented in the circumferential direction to the total number of particles 8 included in the second region 14 exceeds 50%, preferably 70% or more, and for example, is 95% or less, preferably 90% or less.

[0092] In the second region 14, for example, particles 8 oriented in the circumferential direction may also be included. The ratio of the number of particles 8 oriented in the circumferential direction to the total number of particles 8 included in the second region 14 is less than 50%, preferably 30% or less, and for example, is 5% or more, preferably 10% or more.

[0093] In addition, in the case of including particles 8 oriented in the circumferential direction, preferably, the particles 8 oriented in the circumferential direction are arranged on the innermost side of the second region 14, that is, on the surface of the wiring 2.

[0094] The ratio of the total area of the plurality of second regions 14 to the area of the entire peripheral region 11 is, for example, 10% or more, preferably 20% or more, and for example, is 60% or less, preferably 50% or less, more preferably 40% or less.

[0095] The center C2 of the second region 14 does not exist on the first imaginary line L2. That is, the center C2 is located below the first imaginary line L2, and the center C2 is preferably located at a position 0.1 times the radius R below the first imaginary line L2, and more preferably located at a position 0.3 times the radius R below the first imaginary line L2. More specifically, the center C2 is preferably located 10 μm below the first imaginary line L2, and more preferably located 30 μm below the first imaginary line L2.

[0096] In addition, 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 does not exist on any of the first imaginary line L2 and the second imaginary line L3.

[0097] In addition, the center C2 of the second region 14 is the center of an imaginary circular arc L1 that connects one circumferential end and the other circumferential end in the second region 14. More specifically, the center C2 of the second region 14 is the center of an imaginary circular arc L1 that connects the radial center of one circumferential end edge and the radial center of the other circumferential end edge in the second region 14.

[0098] The first imaginary line L2 is a straight line that passes through the centers C1 of a plurality of adjacent wirings 2 and extends in the first direction.

[0099] In the second region 14, an intersection (top) 19 is formed by at least two types of particles 8 having different orientation directions. That is, in the second region 14, particles 8 (first particles) that are relatively located on the upper side and change from circumferential orientation to first-direction orientation as they go toward the lower end side of the second region 14 in the circumferential direction and particles 8 (second particles) that are relatively located on the lower side (lower than the first particles) in the second region 14 and change from circumferential orientation to first-direction orientation as they go toward the upper end side of the second region 14 in the circumferential direction form at least two sides of a substantially triangular shape, thereby forming the intersection 19. Specifically, the first particles and the second particles, together with particles 8 (third particles) that are oriented in the circumferential direction inside the second region 14, form a substantially triangular shape (preferably an acute triangular shape).

[0100] The intersection 19 does not exist on the first imaginary line L2 passing through their centers between the first wiring 4 and the second wiring 5. That is, the intersection 19 is disposed on the lower side of the first imaginary line L2 at a position spaced apart from the imaginary circular arc L1. More specifically, the angle θ formed by the straight line connecting the center of the intersection 19 and the center C1 of the wiring 2 and the first imaginary line L2 is, for example, 15° or more, preferably 45° or more, and for example, 75° or less, preferably 60° or less.

[0101] In the peripheral region 11 (particularly, in the regions of the first region 13 and the second region 14 respectively), the filling rate of the particles 8 is, for example, 40% by volume or more, preferably 45% by volume or more, and for example, 90% by volume or less, preferably 70% by volume or less. If the filling rate is above the above lower limit, the inductance is excellent.

[0102] The filling rate can be calculated by measuring the actual specific gravity, binarizing the SEM photo cross-sectional view, etc.

[0103] In the peripheral region 11, a plurality of first regions 13 and a plurality of second regions 14 are arranged adjacent to each other in the circumferential direction. Specifically, the upper first region 15, one second region 17, the lower first region 16, and the other second region 18 are sequentially continuous in the circumferential direction.

[0104] In addition, the circumferential boundary (one end edge or the other end edge) between the first region 13 and the second region 14 is an imaginary straight line extending radially outward from the center of the wiring 2.

[0105] The outer region 12 is the region in the magnetic layer 3 other than the peripheral region 11. The outer region 12 is disposed outside the peripheral region 11 in a continuous manner with the peripheral region 11.

[0106] In the outer region 12, the particles 8 are oriented along the plane direction (particularly the first direction).

[0107] In the outer region 12, the direction in which the relative magnetic permeability of the particles 8 is higher (for example, in the case of flat anisotropic magnetic particles, the plane direction of the particles) is substantially the same as the first direction. More specifically, the case where the angle formed by the plane direction of the particles 8 and the first direction is 15° or less is defined as the particles 8 being oriented along the first direction.

[0108] In the outer region 12, the proportion of the number of particles 8 oriented along the first direction with respect to the total number of particles 8 included 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 may be that there are less than 50% of the particles 8 not oriented along the first direction, preferably 30% or less of the particles 8 not oriented along the first direction, and more preferably 10% or less of the particles 8 not oriented along the first direction.

[0109] In the outer region 12, the relative magnetic permeability in the first direction is, for example, 5 or more, preferably 10 or more, more preferably 30 or more, and for example, 500 or less. The relative magnetic permeability in the vertical direction is, for example, 1 or more, preferably 5 or more, and for example, 100 or less, preferably 50 or less, and more preferably 25 or less. In addition, the ratio of the relative magnetic permeability in the first direction to the relative magnetic permeability in the vertical direction (first direction / vertical direction) is, for example, 2 or more, preferably 5 or more, and for example, 50 or less. If the relative magnetic permeability is within the above range, the inductance is excellent.

[0110] 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 for example, 90% by volume or less, preferably 70% by volume or less. If the filling rate is above the above lower limit, the inductance is excellent.

[0111] In addition, a first direction alignment region 10 including a first imaginary line L2 is formed in a region between a plurality of wirings 2 including a peripheral region 11 and an outer region 12. That is, in a cross-section of the inductor 1 cut along the first direction and the up-and-down direction, the first direction alignment region 10 is located between the plurality of wirings 2 and includes the first imaginary line L2. Specifically, the first direction alignment region 10 is a region centered on the first imaginary line L2 at an up-and-down position and having a length in the up-and-down direction of 40% of the radius R1 of the wire 6 (preferably 50 μm), and is a region where the particles 8 are aligned in the first direction.

[0112] The proportion of the number of particles 8 aligned in the first direction with respect to the total number of particles 8 included in the first direction alignment region 10 is, for example, 85% or more, preferably 90% or more, and more preferably 95% or more. That is, in the first direction alignment region 10, for example, the particles 8 not aligned in the first direction may be contained in 15% or less, preferably 10% or less, and more preferably 5% or less.

[0113] In addition, in regions adjacent to the first direction side and the other side in the first direction of the first direction alignment region 10, the particles 8 are not aligned in the first direction.

[0114] The first direction distance N of the first direction alignment region 10 is, for example, 500 μm or less, preferably 400 μm or less, more preferably 300 μm or less, and for example, 10 μm or more, preferably 40 μm or more.

[0115] The first direction distance N of the first direction alignment region 10 is 60% or less, preferably 50% or less, and further preferably 30% or less with respect to the interval S between the wirings, and for example, 5% or more. If the above ratio (N / S×100%) is below the above upper limit, crosstalk between the wirings 2 can be suppressed.

[0116] The first direction length T1 of the magnetic layer 3 is, for example, 5 mm or more, preferably 10 mm or more, and for example, 5000 mm or less, preferably 2000 mm or less.

[0117] The second direction length T2 of the magnetic layer 3 is, for example, 5 mm or more, preferably 10 mm or more, and for example, 5000 mm or less, preferably 2000 mm or less.

[0118] The up-and-down direction length (thickness) T3 of the magnetic layer 3 is, for example, 100 μm or more, preferably 200 μm or more, and for example, 2000 μm or less, preferably 1000 μm or less.

[0119] 2. Manufacturing method of inductor

[0120] Refer to Figure 3 A and Figure 3 B to describe an embodiment of the manufacturing method of the inductor 1. The manufacturing method of the inductor 1 successively includes, for example, a preparation process, an arrangement process, and a lamination process.

[0121] In the preparation process, a plurality of wirings 2 and two anisotropic magnetic sheets 20 are prepared.

[0122] The two anisotropic magnetic sheets 20 each have a sheet shape extending in the plane direction and are formed of a magnetic composition. In the anisotropic magnetic sheet 20, the particles 8 are oriented in the plane direction. Preferably, two anisotropic magnetic sheets 20 in a semi-cured state (B stage) are used.

[0123] Examples of such anisotropic magnetic sheets 20 include soft magnetic thermosetting adhesive films, soft magnetic films, etc. described in JP-A-2014-165363, JP-A-2015-92544, etc.

[0124] In the arrangement process, as Figure 3 shown in A, a plurality of wirings 2 are arranged on the upper surface of one anisotropic magnetic sheet 20, and another anisotropic magnetic sheet 20 is arranged opposite above the plurality of wirings 2.

[0125] Specifically, the lower anisotropic magnetic sheet 21 is placed on a horizontal table, and then a plurality of wirings 2 are arranged on the upper surface of the lower anisotropic magnetic sheet 21 at a desired interval in the first direction.

[0126] Next, the upper anisotropic magnetic sheet 22 is arranged opposite at an interval above the lower anisotropic magnetic sheet 21 and above the plurality of wirings 2.

[0127] In the lamination process, as Figure 3 shown in B, the two anisotropic magnetic sheets 20 are laminated so as to bury the plurality of wirings 2.

[0128] Specifically, the upper anisotropic magnetic sheet 22 is pressed downward.

[0129] At this time, when the two anisotropic magnetic sheets 20 are in a semi-cured state, by pressing, the plurality of wirings 2 slightly sink into the lower anisotropic magnetic sheet 21, and in the sunken portion, the particles 8 are oriented along the plurality of wirings 2. That is, the lower first region 16 is formed.

[0130] 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 on the upper surface of the lower anisotropic magnetic sheet 21.

[0131] 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 (sides) in the first direction of the wiring 2, near the portions where the lower anisotropic magnetic sheet 21 contacts the upper anisotropic magnetic sheet 22, the particles 8 oriented in the lower anisotropic magnetic sheet 21 and the upper anisotropic magnetic sheet 22 collide. As a result, the second region 14 and the crossing portion 19 are formed.

[0132] In addition, when the anisotropic magnetic sheet 20 is in a semi-cured state, heating is performed. Thereby, the anisotropic magnetic sheet 20 becomes a cured state (C stage). Further, the contact interface 25 between the two anisotropic magnetic sheets 20 disappears, and the two anisotropic magnetic sheets 20 form a single magnetic layer 3.

[0133] Thus, as Figure 2 shown, the inductor 1 including the wiring 2 having a substantially circular shape in 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 with the wiring 2 sandwiched therebetween. In addition, a cross-sectional view (SEM photograph) of an example of the actual inductor 1 is shown in Figure 4 .

[0134] 3. Use

[0135] The inductor 1 is a component of an electronic device, that is, it is a component used for manufacturing an electronic device. It does not contain electronic components (chips, capacitors, etc.) or a mounting substrate for mounting electronic components, but circulates as a single component and is a device that can be industrially utilized.

[0136] The inductor 1 is mounted (assembled) on an electronic device or the like, for example. The electronic device includes a mounting substrate and electronic components (chips, capacitors, etc.) mounted on the mounting substrate, but this is not shown in the figure. And the inductor 1 is mounted on the mounting substrate by a connecting member such as solder and is electrically connected to other electronic devices, functioning as a passive component such as a coil.

[0137] Then, by using the inductor 1, since it includes a plurality of wirings 2 and the magnetic layer 3 covering the plurality of wirings 2, the particles 8 can easily be oriented in the circumferential direction around the plurality of wirings 2. Therefore, the easy magnetization axis of the particles 8 is the same as the direction of the magnetic field lines generated around the wiring, and thereby the inductance can be increased.

[0138] In addition, a first direction orientation region 10 is formed so as to overlap with the first imaginary line L2. In the first direction orientation region 10, the particles 8 are oriented in the first direction, and the distance N in the first direction of the first direction orientation region 10 is 50% or less of the interval S on the first imaginary line L2 between the wirings 2. That is, in the space between the wirings 2, which is a path for the magnetic flux flowing in the first direction, the distance N of the first direction orientation region 10 is shorter than the distance of the region other than the first direction orientation region 10 (that is, the regions on both sides of the first direction orientation region 10 where the particles 8 are not oriented in the first direction). Therefore, the magnetic-related influence from one wiring 2 (the first wiring 4 or the second wiring 5) to the other wiring (the second wiring 5 or the first wiring 4) can be reduced, and crosstalk can be suppressed.

[0139] In addition, in the inductor 1, in the peripheral region 11 of the plurality of wirings 2, first regions 13 serving as circumferential direction orientation regions are respectively provided. Therefore, the inductance can be increased.

[0140] In addition, in the inductor 1, in the peripheral region 11 of the plurality of wirings 2, second regions 14 serving as circumferential direction non-orientation regions are respectively provided. Therefore, the hard magnetization axis of the particles 8 is the same as the direction of the magnetic field lines generated around the wiring, and thus the DC superposition characteristic is good.

[0141] In addition, the center C2 in the second region 14 does not exist on the first imaginary line L2. Thus, the distance through which the magnetic flux reaches the second wiring 5 from the first wiring 4 via the second region 14 can be extended. That is, the distance through which the magnetic flux passes between the wirings 2 can be substantially extended.

[0142] Therefore, the magnetic-related influence from the first wiring 4 to the second wiring 5 can be reduced, and crosstalk can be further suppressed.

[0143] <Variation Example>

[0144] Next, Figure 1 A to Figure 2 a variation example of one embodiment shown will be described. In addition, in the variation example, the same reference numerals are given to the components that are the same as those in the above-described one embodiment, and the description thereof is omitted.

[0145] For these variation examples, the same effects as those of the above-described one embodiment and the like are also achieved.

[0146] In Figure 2 the embodiment shown, the center C2 in the second region 14 does not exist on the first imaginary line L2, but it may also be, for example, as Figure 5 shown, the center C2 in the second region 14 exists on the first imaginary line L2.

[0147] That is,Figure 5 The illustrated embodiment is substantially line-symmetric with respect to the first imaginary line L2.

[0148] From the viewpoint of further reducing crosstalk, the embodiment shown in Figure 1 A to Figure 2 is preferably selected.

[0149] In Figure 2 the illustrated embodiment, the wiring 2 has a substantially circular shape in cross-section, but its cross-sectional shape is not particularly limited. For example, it may be a substantially elliptical shape, a substantially rectangular shape (including a square and a rectangle), or a substantially irregular shape, although this is not illustrated in this case. In addition, as a form in which the wiring 2 includes a substantially rectangular shape, at least one side may be bent, or alternatively, at least one corner may be bent.

[0150] For any of the above embodiments, the peripheral region 11 is a region that advances outward from the outer peripheral surface of the wiring 2 by a value that is 1.5 times the average value of the longest length and the shortest length from the center of gravity C1 of the wiring 2 to the outer peripheral surface of the wiring 2 ([longest length + shortest length] / 2) in cross-section.

[0151] In Figure 1 A and Figure 1 the illustrated embodiment, two wirings 2 are included, but the number is not limited, and three or more wirings 2 can also be provided.

[0152] In Figure 1 A and Figure 1 the illustrated embodiment, each wiring 2 has a substantially U-shaped shape in plan view, but its shape is not limited and can be appropriately set.

[0153] In Figure 1 A and Figure 1 the illustrated embodiment, the magnetic layer 3 can also have alignment marks.

[0154] In Figure 1 A and Figure 1 the illustrated embodiment, the ratio of the anisotropic magnetic particles 8 in the magnetic layer 3 can be uniform in the magnetic layer 3, or can become higher or lower as it is farther from each wiring 2.

[0155] Industrial Applicability

[0156] The inductor of the present invention can be used as a passive component such as a voltage conversion member, for example.

[0157] Description of Reference Numerals

[0158] 1. Inductor; 2. Wiring; 3. Magnetic layer; 6. Lead wire; 7. Insulating layer; 8. Anisotropic magnetic particles; 10. First direction orientation region; 13. First region; 14. Second region; C1. Center of the wiring; C2. Center of the imaginary arc; L2. First imaginary line.

Claims

1. An inductor, characterized in that, the inductor includes a plurality of wirings and a magnetic layer covering the plurality of wirings, the plurality of wirings are arranged at intervals in a first direction, each of the plurality of wirings includes a wire and an insulating layer covering the wire, the magnetic layer contains anisotropic magnetic particles and a binder, a first-direction orientation region is formed between the plurality of adjacent wirings in a manner including a hypothetical line passing through the centers of these wirings, and in this first-direction orientation region, the anisotropic magnetic particles are oriented along the first direction, the distance of the first-direction orientation region is 60% or less of the interval on the hypothetical line between the wirings.

2. The inductor according to claim 1, characterized in that, a first region is respectively provided around the plurality of wirings, and in this first region, the anisotropic magnetic particles are oriented along the outer peripheral direction of the wiring.

3. The inductor according to claim 2, characterized in that, a second region is respectively further provided around the plurality of wirings, and in this second region, the anisotropic magnetic particles are not oriented along the outer peripheral direction.

Images