Inductors

Abstract

An inductor (1) comprises a wiring (2) and a magnetic layer (3) covering the wiring (2), wherein the wiring (2) comprises a conductive wire (6) and an insulating layer (7), and the magnetic layer (3) comprises anisotropic magnetic particles (8) and a binder (9). In a peripheral region (11) of the wiring (2), the magnetic layer (3) comprises an orientation region (13) in which the anisotropic magnetic particles (8) are oriented along the periphery of the wiring (2). The peripheral region (11) is a region extending outward from the outer surface of the wiring (2) by 1.5 times the average value of the longest and shortest lengths from the center of gravity of the wiring (2) to the outer surface of the wiring (2) when viewed in cross section. The upper and lower surfaces of the inductor (1) are flat.

Description

Technical Field

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

[0002] It is known that inductors are mounted on electronic devices and used as passive components such as voltage conversion means.

[0003] For example, an inductor has been proposed that includes a rectangular parallelepiped substrate body formed of a magnetic material, and an internal conductor, such as copper, embedded within the substrate body, with the cross-sectional shape of the substrate body and the cross-sectional shape of the internal conductor being similar (see Patent Document 1). Specifically, in the inductor of Patent Document 1, a wiring (internal conductor) having a rectangular (rectangular) shape in cross-section is covered with a magnetic material.

[0004] Prior art literature

[0005] Patent Literature

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

[0007] Problems to be solved by the invention

[0008] Furthermore, studies have been conducted to use anisotropic magnetic particles such as flat magnetic particles as a magnetic material and to orient the anisotropic magnetic particles around 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, the presence of corners and the like sometimes makes it difficult to orient the anisotropic magnetic particles around the wiring, which may result in insufficient improvement in inductance.

[0010] Therefore, a technique has been further studied in which a wiring having a circular shape in cross-sectional view is used and anisotropic magnetic particles are oriented around the wiring.

[0011] However, in the case of orienting the anisotropic magnetic particles around the wiring, referring to Figure 12 , resulting in unevenness on the inductor's top surface caused by the wiring. This results in poor mountability. Specifically, the inductor needs to be transported by a suction conveyor, such as a collet, and placed on the desired wiring substrate. However, the unevenness on the inductor's surface can prevent the collet from adhering to the inductor even when it is attracted. Furthermore, when placing the inductor on the wiring substrate, it is necessary to position it without tilting it.

[0012] The present invention provides an inductor capable of achieving both good inductance and good mountability.

[0013] Solutions for solving problems

[0014] The present invention [1] includes an inductor comprising a wiring and a magnetic layer covering the wiring, wherein the wiring comprises a conductive wire and an insulating layer covering the conductive wire, the magnetic layer comprises anisotropic magnetic particles and a binder, the magnetic layer comprises an orientation region in a peripheral region of the wiring wherein the anisotropic magnetic particles are oriented along the periphery of the wiring, the peripheral region being a region extending outward from the outer surface of the wiring by a value equivalent to 1.5 times the average value of the longest and shortest lengths from the center of gravity of the wiring to the outer surface of the wiring when viewed in cross section, and the inductor having one surface in the thickness direction and the other surface in the thickness direction being flat.

[0015] According to this inductor, since the orientation regions in which the anisotropic magnetic particles are oriented along the periphery of the wiring exist around the wiring, the inductance is excellent.

[0016] Furthermore, since one side of the inductor's thickness is flat, it can be reliably sucked by a conveying device such as a collet, ensuring reliable conveyance of the inductor. Furthermore, since the other side of the inductor is flat, it can be positioned on the mounting object without tilting. This results in excellent mounting performance.

[0017] The present invention [2] includes the inductor according to [1], wherein a plurality of the wirings are arranged at intervals in a direction orthogonal to the thickness direction, and the plurality of wirings are continuous with the magnetic layer interposed therebetween.

[0018] According to this inductor, since the magnetic layer that is continuous in a direction perpendicular to the plurality of wirings is arranged between the plurality of wirings, the inductance is improved.

[0019] The present invention [3] includes the inductor according to [1] or [2], wherein at least one of one surface in the thickness direction and the other surface in the thickness direction of the inductor is formed by the magnetic layer.

[0020] According to this inductor, since at least one of one surface in the thickness direction and the other surface in the thickness direction of the inductor is a magnetic layer, the inductor has good inductance.

[0021] The present invention [4] includes the inductor described in [3], wherein the magnetic layer is continuous from one surface in the thickness direction of the inductor to the other surface in the thickness direction, and both surfaces of the inductor, the one surface in the thickness direction and the other surface in the thickness direction, are formed by the magnetic layer.

[0022] According to this inductor, since both one surface in the thickness direction and the other surface in the thickness direction of the inductor are magnetic layers, the inductor is completely filled with the magnetic layer except for the wiring area, thereby further improving the inductance.

[0023] Effects of the Invention

[0024] According to the inductor of the present invention, both good inductance and mountability can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 in Figure 1 A- Figure 1 B is the first embodiment of the inductor of the present invention, Figure 1 A represents the top view, Figure 1 B means Figure 1 AA section view of A.

[0026] Figure 2 express Figure 1 A partial enlarged view of the dotted line portion of B.

[0027] Figure 3 express Figure 2 A modified example of (a form that makes it easy to understand the flatness of the upper surface of the inductor).

[0028] Figure 4 in Figure 4 A- Figure 4 B is Figure 1 A- Figure 1 The manufacturing process diagram of the inductor shown in B is Figure 4 A represents the configuration process, Figure 4 B represents a lamination step.

[0029] Figure 5 express Figure 1 A- Figure 1 B is a cross-sectional SEM photograph of an actual inductor.

[0030] Figure 6 in Figure 6 A- Figure 6 B is a process diagram showing the installation of the inductor. Figure 6 A represents the singulation process, Figure 6 B represents the conveying process, Figure 6 C represents the configuration process.

[0031] Figure 7 express Figure 1 A- Figure 1 B shows a modified example of the inductor (a form with a single wiring).

[0032] Figure 8A partially enlarged cross-sectional view showing a second embodiment of an inductor according to the present invention.

[0033] Figure 9 A partially enlarged cross-sectional view showing a third embodiment of an inductor according to the present invention.

[0034] Figure 10 A partially enlarged cross-sectional view showing a fourth embodiment of an inductor according to the present invention.

[0035] Figure 11 A partially enlarged cross-sectional view showing a fifth embodiment of an inductor according to the present invention.

[0036] Figure 12 A partially enlarged cross-sectional view of an inductor (an inductor having an uneven upper surface) serving as a reference for the present invention is shown. DETAILED DESCRIPTION

[0037] exist Figure 1 In A, the left-right direction of the paper is the first direction, the left side of the paper is one side of the first direction, and the right side of the paper is the other side of the first direction. The up-down direction of the paper is the second direction (the direction perpendicular to the first direction), the upper side of the paper is one side of the second direction (one direction in the axial direction of the wiring), and the lower side of the paper is the other side of the second direction (the other direction in the axial direction of the wiring). The paper thickness direction is the up-down direction (the direction perpendicular to the first and second directions, i.e., the thickness direction), the front side of the paper is the upper side (one side of the third direction, i.e., one side in the thickness direction), and the depth side of the paper is the lower side (the other side of the third direction, i.e., the other side in the thickness direction). Specifically, the direction arrows in each figure are used as a reference.

[0038] <First embodiment>

[0039] 1. Inductor

[0040] Reference Figure 1 A- Figure 2 An embodiment of the first embodiment of the inductor according to the present invention will be described.

[0041] like Figure 1 A and Figure 1 As shown in B, the inductor 1 has a generally rectangular shape in plan view extending in the planar directions (the first direction and the second direction).

[0042] The inductor 1 includes a plurality of (two) wirings 2 and a magnetic layer 3 .

[0043] Each of the plurality of wirings 2 includes a first wiring 4 and a second wiring 5 . The second wiring 5 is arranged at a distance from the first wiring 4 in the width direction (a first direction; a direction orthogonal to the thickness direction).

[0044] like Figure 1 A and Figure 1As shown in B, the first wiring 4 extends long in the second direction and has, for example, a substantially U-shaped shape in plan view. Furthermore, the first wiring 4 has a substantially circular shape in cross-sectional view.

[0045] The first wiring 4 includes a conductive wire 6 and an insulating layer 7 covering the conductive wire 6 .

[0046] The conductive wire 6 extends long in the second direction and has, for example, a substantially U-shaped shape in plan view. Furthermore, the conductive wire 6 has a substantially circular shape in cross-section, sharing a central axis with the first wiring 4 .

[0047] The material of the wire 6 is a metal conductor such as copper, silver, gold, aluminum, nickel, or alloys thereof, preferably copper. The wire 6 may be a single-layer structure or a multi-layer structure in which a core conductor (such as copper) is plated (such as nickel).

[0048] The radius R1 of the conductive wire 6 is, for example, not less than 25 μm, or preferably not less than 50 μm, and is, for example, not more than 2000 μm, or preferably not more than 200 μm.

[0049] The insulating layer 7 is a layer for protecting the conductive wire 6 from chemicals and water and preventing a short circuit of the conductive wire 6. The insulating layer 7 is arranged so as to cover the entire outer peripheral surface of the conductive wire 6.

[0050] The insulating layer 7 has a substantially annular shape in cross-sectional view, sharing a central axis (center C1 ) with the first wiring 4 .

[0051] Examples of the material of the insulating layer 7 include insulating resins such as polyvinyl formal, polyester, polyesterimide, polyamide (including nylon), polyimide, polyamideimide, and polyurethane. These may be used alone or in combination of two or more.

[0052] The insulating layer 7 may be composed of a single layer or a plurality of layers.

[0053] 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, for example, 100 μm or less, preferably 50 μm or less.

[0054] The ratio (R1 / R2) of the radius R1 of the conductive 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.

[0055] The radius ( R1 + R2 ) of the first wiring 4 is, for example, 25 μm or more, or preferably 50 μm or more, and, for example, 2000 μm or less, or preferably 200 μm or less.

[0056] When the first wiring 4 is roughly U-shaped, the center-to-center distance D2 of the first wiring 4 is the same as the center-to-center distance D1 between the multiple wirings 2 described later, for example, greater than 20 μm, preferably greater than 50 μm, and for example, less than 3000 μm, preferably less than 2000 μm.

[0057] The second wiring 5 has 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 a conductive wire 6 and an insulating layer 7 covering the conductive wire 6.

[0058] The plurality of wirings 2 (first wirings 4 and second wirings 5) are continuous via a magnetic layer 3. Specifically, the magnetic layer 3 extending in the first direction is disposed between the first wirings 4 and the second wirings 5, and is in contact with both the first wirings 4 and the second wirings 5.

[0059] 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 example, 3000 μm or less, preferably 2000 μm or less.

[0060] The magnetic layer 3 is a layer for increasing inductance.

[0061] Magnetic layer 3 is arranged to cover the entire outer circumference of the plurality of wirings 2. Magnetic layer 3 forms the outer shape of inductor 1. Specifically, magnetic layer 3 has a generally rectangular shape when viewed from above, extending in the planar directions (the first and second directions). Furthermore, magnetic layer 3 exposes the second-direction end edges of the plurality of wirings 2 on its other side in the second direction.

[0062] The magnetic layer 3 is formed of a magnetic composition containing anisotropic magnetic particles 8 and a binder 9 .

[0063] Examples of materials constituting the anisotropic magnetic particles (hereinafter also referred to simply as "particles") 8 include soft magnetic materials and hard magnetic materials. From the viewpoint of inductance, soft magnetic materials are preferred.

[0064] Examples of soft magnetic materials include single metal bodies containing one metal element in a pure state, and alloy bodies, such as eutectics (mixtures) of one or more metal elements (first metal elements) and one or more metal elements (second metal elements) and / or non-metallic elements (carbon, nitrogen, silicon, phosphorus, etc.). These materials can be used alone or in combination.

[0065] As a single metal body, for example, a metal monomer composed of only one metal element (the first metal element) can be cited. As the first metal element, for example, iron (Fe), cobalt (Co), nickel (Ni), and other metal elements that can be contained as the first metal element of a soft magnetic body can be appropriately selected.

[0066] In addition, as a single metal body, for example, a core containing only one metal element and a surface layer containing part or all of an inorganic and / or organic substance that modifies the surface of the core can be cited, for example, an organometallic compound containing the first metal element, a form after decomposition (thermal decomposition, etc.) of the inorganic metal compound, etc. As the latter form, more specifically, iron powder (sometimes referred to as carbonyl iron powder) after thermal decomposition of an organoiron compound (specifically carbonyl iron) containing iron as the first metal element can be cited. In addition, the position of the layer comprising the inorganic and / or organic substance that modifies the part containing only one metal element is not limited to the surface as described above. In addition, as the organometallic compound or inorganic metal compound that can obtain a single metal body, there is no particular restriction, but it can be appropriately selected from the well-known or commonly used organometallic compound or inorganic metal compound that can obtain a single metal body of a soft magnetic body.

[0067] The alloy body is a fusion body of one or more metal elements (first metal element) and one or more metal elements (second metal element) and / or non-metallic elements (carbon, nitrogen, silicon, phosphorus, etc.). There are no special restrictions as long as it can be used as an alloy body of a soft magnetic body.

[0068] The first metal element is an essential element in the alloy body, and examples thereof include iron (Fe), cobalt (Co), nickel (Ni), etc. Furthermore, 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.

[0069] The second metal element is an element (auxiliary component) auxiliaryly contained in the alloy body and is a metal element compatible (eutectic) with the first metal element. Examples thereof include iron (Fe) (when the first metal element is an element other than Fe), cobalt (Co) (when the first metal element is an element other than Co), nickel (Ni) (when the first metal element is an element 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), and various rare earth elements. These elements can be used alone or in combination of two or more.

[0070] Non-metallic elements are elements (auxiliary components) that are auxiliary elements contained in the alloy body and are compatible (eutectic) with the first metal element. Examples thereof include boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), and sulfur (S). These elements can be used alone or in combination of two or more.

[0071] As an example of an alloy body, an Fe-based alloy can be exemplified by magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), sendust (Fe-Si-Al alloy) (including super sendust), 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 ferrite, and soft magnetic ferrite such as Mn-Mg ferrite, Mn-Zn ferrite, Ni-Zn-Cu ferrite, Cu-Zn ferrite, Cu-Mg-Zn ferrite, etc.), Permind iron cobalt alloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, etc.

[0072] As an example of the alloy body, a Co-based alloy includes, for example, Co-Ta-Zr and a cobalt (Co)-based amorphous alloy.

[0073] As an example of the alloy body, a Ni-based alloy includes, for example, a Ni—Cr alloy.

[0074] Among these soft magnetic materials, alloys are preferred from the perspective of magnetic properties, Fe-based alloys are more preferred, and Sendust (Fe-Si-Al alloy) is even more preferred. Furthermore, as the soft magnetic material, single metals are preferred, single metals containing iron in a pure form are more preferred, and iron alone or iron powder (carbonyl iron powder) is even more preferred.

[0075] As the shape of the particles 8, from the perspective of anisotropy, for example, flat (plate-like) and needle-like shapes are given. From the perspective of good relative magnetic permeability in the plane direction (two-dimensional), flat shapes are given. 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 also have shapes such as spheres, granules, blocks, and pellets. The average particle size 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.

[0076] 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 aspect ratio obtained by dividing the average particle diameter (average length) (described later) of the particles 8 by the average thickness of the particles 8.

[0077] 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.

[0078] Examples of the binder 9 include thermosetting resins and thermoplastic resins.

[0079] Examples of the thermosetting resin include epoxy resins, phenolic resins, melamine resins, thermosetting polyimide resins, unsaturated polyester resins, polyurethane resins, and silicone resins. From the viewpoints of adhesion and heat resistance, epoxy resins and phenolic resins are preferred.

[0080] Examples of the thermoplastic resin include acrylic resins, ethylene-vinyl acetate copolymers, polycarbonate resins, polyamide resins (nylon 6, nylon 66, etc.), thermoplastic polyimide resins, and saturated polyester resins (PET, PBT, etc.). Preferably, acrylic resins are used.

[0081] As the binder 9, a combination of a thermosetting resin and a thermoplastic resin is preferred. A combination of an acrylic resin, an epoxy resin, and a phenolic resin is more preferred. This allows the particles 8 to be more reliably fixed around the wiring 2 in a predetermined orientation and at a high filling rate.

[0082] Furthermore, the magnetic composition may contain additives such as a thermosetting accelerator, inorganic particles, organic particles, and a crosslinking agent as needed.

[0083] In magnetic layer 3, particles 8 are uniformly oriented within binder 9. Magnetic layer 3 extends continuously from the top surface (one surface in the thickness direction) to the bottom surface (the other surface in the thickness direction) of inductor 1. When projected along the plane, magnetic layer 3 encompasses wiring 2. Specifically, the top surface of magnetic layer 3 is located above the top end of wiring 2, and the bottom surface of magnetic layer 3 is located below the bottom end of wiring 2.

[0084] The magnetic layer 3 has a peripheral region 11 and an outer region 12 in a cross-sectional view.

[0085] The peripheral region 11 is located in the peripheral region of the wiring 2 and is positioned around the plurality of wirings 2 in contact with the wirings 2. The peripheral region 11 has a substantially annular shape when viewed in cross-section, sharing a central axis with the wirings 2. More specifically, the peripheral region 11 is a region of the magnetic layer 3 that extends radially outward from the outer peripheral surface of the wiring 2 by a value equivalent to 1.5 times (preferably 1.2 times, more preferably 1 times, even more preferably 0.8 times, and particularly preferably 0.5 times) the radius R 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).

[0086] The peripheral region 11 is arranged around each of the plurality of wirings 2 , that is, around the first wiring 4 and around the second wiring 5 .

[0087] Each peripheral region 11 has a plurality of (two) oriented regions 13 and a plurality of (two) non-oriented regions 14 .

[0088] The plurality of orientation regions 13 are circumferential orientation regions. That is, in the orientation regions 13, the particles 8 are oriented along the circumferential direction (around) the wiring 2 (the first wiring 4 or the second wiring 5).

[0089] The plurality of alignment regions 13 are arranged opposite each other above the wiring 2 (on one side in the third direction) and below the wiring 2 (on the other side in the third direction) with the center C1 of the wiring 2 interposed therebetween. Specifically, the plurality of alignment regions 13 include an upper alignment region 15 arranged above the wiring 2 and a lower alignment region 16 arranged below the wiring 2. Furthermore, the center C1 of the wiring 2 is located at the center in the vertical direction between the upper alignment region 15 and the lower alignment region 16.

[0090] In each orientation region 13 , the direction of high relative magnetic permeability of the particle 8 (for example, the particle surface direction in the case of flat anisotropic magnetic particles) substantially coincides with the direction of the tangent to the circle centered at the center C1 of the wiring 2 .

[0091] More specifically, when the angle formed between the plane direction of the particle 8 and the tangent line of the circle on which the particle 8 is located is 15 degrees or less, it is defined that the particle 8 is oriented in the circumferential direction.

[0092] The ratio of the number of particles 8 oriented in the circumferential direction to the total number of particles 8 contained in the oriented region 13 is, for example, greater than 50%, preferably greater than 70%, and more preferably greater than 80%. That is, the oriented region 13 may contain, for example, less than 50% of particles 8 that are not oriented in the circumferential direction, preferably less than 30% of particles 8 that are not oriented in the circumferential direction, and more preferably less than 20% of particles 8 that are not oriented in the circumferential direction.

[0093] The ratio of the total area of ​​the plurality of alignment regions 13 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 for example, 90% or less, preferably 80% or less.

[0094] The relative magnetic permeability in the circumferential direction of the orientation region 13 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 radial 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 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 for example, 50 or less. When the relative magnetic permeability is within the above range, the inductance is excellent.

[0095] The relative magnetic permeability can be measured, for example, by using an impedance analyzer (manufactured by Agilent, “4291B”) equipped with a magnetic material testing device.

[0096] The plurality of non-oriented regions 14 are circumferentially non-oriented regions. That is, in the non-oriented regions 14, the particles 8 are not oriented along the circumference of the wiring 2. In other words, in the non-oriented regions 14, the particles 8 are oriented in a direction other than the circumference of the wiring 2 (e.g., radially) or are not oriented.

[0097] The plurality of non-oriented regions 14 are arranged opposite to each other on one side in the first direction and on the other side in the first direction of the wiring 2, with the wiring 2 interposed therebetween. Specifically, the plurality of non-oriented regions 14 include a first non-oriented 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 non-oriented region 18 arranged on the other side in the first direction of the wiring 2. The first non-oriented region 17 and the second non-oriented region 18 are substantially line-symmetrical about a straight line passing through the center C1 in the vertical direction.

[0098] In each non-oriented region 14, the direction of the relatively high magnetic permeability of the particle 8 (for example, the particle face direction in the case of flat anisotropic magnetic particles) does not coincide with the direction of the tangent to a circle centered at the center C1 of the wiring 2. More specifically, when the angle between the face direction of the particle 8 and the tangent to the circle in which the particle 8 lies exceeds 15°, it is defined that the particle 8 is not circumferentially oriented.

[0099] The ratio of the number of particles 8 not oriented in the circumferential direction to the total number of particles 8 included in the non-oriented region 14 exceeds 50%, preferably 70% or more, and is, for example, 95% or less, preferably 90% or less.

[0100] The non-oriented region 14 may also contain particles 8 oriented in the circumferential direction, for example. The ratio of the number of particles 8 oriented in the circumferential direction to the total number of particles 8 contained in the non-oriented region 14 is less than 50%, preferably 30% or less, and is, for example, 5% or more, preferably 10% or more.

[0101] Furthermore, when the particles 8 oriented in the circumferential direction are included, it is preferable that the particles 8 oriented in the circumferential direction are arranged on the innermost side of the non-oriented region 14 , that is, on the surface of the wiring 2 .

[0102] The ratio of the total area of ​​the plurality of non-oriented regions 14 to 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, and more preferably 40% or less.

[0103] In the peripheral region 11 (particularly in each of the oriented region 13 and the non-oriented region 14), 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. When the filling rate is at least the lower limit, the inductance is excellent.

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

[0105] In the peripheral region 11, multiple oriented regions 13 and multiple non-oriented regions 14 are arranged adjacent to each other in the circumferential direction. Specifically, the upper oriented region 15, the non-oriented region 17 on one side, the lower oriented region 16, and the non-oriented region 18 on the other side are continuous in this order in the circumferential direction. Furthermore, the circumferential boundary (one end edge or the other end edge) between the oriented regions 13 and the non-oriented regions 14 is an imaginary straight line extending radially outward from the center of the wiring 2.

[0106] The outer region 12 is a region of the magnetic layer 3 excluding the peripheral region 11. The outer region 12 is arranged outside the peripheral region 11 so as to be continuous with the peripheral region 11.

[0107] In the outer region 12 , the particles 8 are oriented along the planar direction (particularly the first direction).

[0108] In the outer region 12, the direction of the higher relative magnetic permeability of the particle 8 (for example, the particle face direction in the case of flat anisotropic magnetic particles) is substantially aligned with the first direction. More specifically, the case where the angle formed between the particle face direction and the first direction is 15° or less is defined as the particle 8 being oriented in the first direction.

[0109] In the outer region 12, the ratio of the number of particles 8 oriented in the first direction to the total number of particles 8 contained in the outer region 12 is greater than 50%, preferably greater than 70%, and more preferably greater than 90%. In other words, the outer region 12 may contain less than 50% of particles 8 not oriented in the first direction, preferably less than 30% of particles 8 not oriented in the first direction, and more preferably less than 10% of particles 8 not oriented in the first direction.

[0110] 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. When the relative magnetic permeability is within the above range, the inductance is excellent.

[0111] 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. When the filling rate is greater than the lower limit, the inductance is excellent.

[0112] The upper surface of the magnetic layer 3 forms the upper surface of the inductor 1 . In other words, the upper surface of the inductor 1 is formed by the magnetic layer 3 .

[0113] The upper surface of magnetic layer 3, i.e., the upper surface of inductor 1, is flat. Specifically, on the upper surface of magnetic layer 3, a vertical distance H1 between uppermost end A1 in wiring region A and midpoint M1 between wirings 2 is 30 μm or less, preferably 20 μm or less, and more preferably less than 5 μm.

[0114] The lower surface of the magnetic layer 3 forms the lower surface of the inductor 1 . In other words, the lower surface of the inductor 1 is formed by the magnetic layer 3 .

[0115] The lower surface of magnetic layer 3, i.e., the lower surface of inductor 1, is flat. Specifically, on the lower surface of magnetic layer 3, a vertical distance H2 between the lowest end A2 in wiring region A and the midpoint M2 between wirings 2 is 30 μm or less, preferably 20 μm or less, and more preferably less than 5 μm.

[0116] The wiring area A is the area overlapping the wiring 2 (first wiring 4 or second wiring 5) when projected in the thickness direction. The midpoints M1 and M2 are located at the center in the first direction on a straight line connecting the centers (centers of gravity) C1 of two adjacent wirings 2.

[0117] In addition, Figure 2 The case where the vertical distances H1 and H2 are both 0 μm (completely flat) is shown in FIG. 1 . For ease of understanding of the vertical distances, as a reference, Figure 3 ] shows a case where both the vertical distances H1 and H2 are 1 μm or more and 30 μm or less.

[0118] The first direction length T1 of the magnetic layer 3 is, for example, greater than or equal to 5 mm, or preferably greater than or equal to 10 mm, and is, for example, less than or equal to 5000 mm, or preferably less than or equal to 2000 mm.

[0119] The second direction length T2 of the magnetic layer 3 is, for example, greater than or equal to 5 mm, or preferably greater than or equal to 10 mm, and is, for example, less than or equal to 5000 mm, or preferably less than or equal to 2000 mm.

[0120] The vertical length T3 of the magnetic layer 3 (particularly the thickness at the midpoint M1 ) is, for example, 100 μm or more, preferably 200 μm or more, and, for example, 2000 μm or less, preferably 1000 μm or less.

[0121] 2. Inductor Manufacturing Method

[0122] Reference Figure 4 A- Figure 4 B. One embodiment of a method for manufacturing the inductor 1 will be described. The method for manufacturing the inductor 1 includes, for example, a preparation step, a placement step, and a lamination step in this order.

[0123] In the preparation step, a plurality of wirings 2 and two anisotropic magnetic sheets 20 are prepared.

[0124] The two anisotropic magnetic sheets 20 are each formed of a magnetic composition and have a sheet shape extending in the plane direction. In the anisotropic magnetic sheets 20, the particles 8 are oriented in the plane direction. It is preferable to use two anisotropic magnetic sheets 20 in a semi-cured state (B stage).

[0125] Examples of such anisotropic magnetic sheets 20 include soft magnetic thermosetting adhesive films and soft magnetic films described in Japanese Patent Application Laid-Open Nos. 2014-165363 and 2015-92544.

[0126] In the configuration process, Figure 4 As 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 above the plurality of wirings 2 so as to face the one anisotropic magnetic sheet 20 .

[0127] Specifically, the lower anisotropic magnetic sheet 21 is placed on a horizontal table 23 having a flat upper surface, and then the plurality of wires 2 are arranged on the upper surface of the lower anisotropic magnetic sheet 21 at desired intervals in the first direction.

[0128] Next, the upper anisotropic magnetic sheet 22 is disposed on the upper side of the lower anisotropic magnetic sheet 21 and on the upper sides of the plurality of wirings 2 so as to face each other at intervals.

[0129] In the lamination process, Figure 4 As shown in B, two anisotropic magnetic sheets 20 are stacked so that the plurality of wirings 2 are buried.

[0130] Specifically, a rigid or flexible pressing member 24 with a flat lower surface is used to press the upper anisotropic magnetic sheet 22 downward. That is, the lower surface of the pressing member 24 is brought into contact with the upper surface of the upper anisotropic magnetic sheet 22, and the pressing member 24 is pressed toward the lower anisotropic magnetic sheet 21.

[0131] By being sandwiched between two flat members (the horizontal surface 23 and the pressing member 24 ), the upper and lower surfaces of the obtained inductor 1 are formed to be flat.

[0132] At this time, when the two anisotropic magnetic sheets 20 are in a semi-cured state, the plurality of wires 2 are slightly sunken into the lower anisotropic magnetic sheet 21 by pressing, and in the sunken portion, the particles 8 are oriented along the plurality of wires 2. That is, the lower oriented region 16 is formed.

[0133] Furthermore, the upper anisotropic magnetic sheet 22 covers the plurality of wirings 2 along the plurality of wirings 2, and the particles 8 of the upper anisotropic magnetic sheet 22 are oriented along the plurality of wirings 2. Furthermore, the upper anisotropic magnetic sheet 22 is stacked on the upper surface of the lower anisotropic magnetic sheet 21. Specifically, an upper oriented region 15 is formed by the upper anisotropic magnetic sheet 22 above the wirings 2. Furthermore, on both sides (lateral sides) of the wirings 2 in the first direction, near where the lower anisotropic magnetic sheet 21 and the upper anisotropic magnetic sheet 22 contact, the particles 8 oriented along the lower anisotropic magnetic sheet 21 and the upper anisotropic magnetic sheet 22 collide, resulting in the formation of a non-oriented region 14.

[0134] Furthermore, when the anisotropic magnetic sheets 20 are in a semi-cured state, heating is performed. This causes the anisotropic magnetic sheets 20 to enter a cured state (stage C). Furthermore, the contact interface 29 between the two anisotropic magnetic sheets 20 disappears, and the two anisotropic magnetic sheets 20 form a single magnetic layer 3.

[0135] Therefore, if Figure 2 As shown in FIG. 1 , an inductor 1 is obtained which includes a wiring 2 having a substantially circular shape in cross-section and a magnetic layer 3 covering the wiring 2. That is, the inductor 1 is formed by stacking a plurality (two) of anisotropic magnetic sheets 20 with the wiring 2 interposed therebetween. Figure 5 2 shows a cross-sectional view (SEM photograph) of an example of an actual inductor 1 .

[0136] 3. Purpose

[0137] The inductor 1 is a component of an electronic device, that is, a component used to manufacture the electronic device. It does not include electronic components (chips, capacitors, etc.) or a wiring board for mounting the electronic components, but is distributed as a single component and is industrially usable.

[0138] The inductor 1 is mounted (installed) on, for example, electronic equipment. Specifically, the inductor 1 is installed, for example Figure 6 A- Figure 6 As shown in C, the process includes a singulation step, a conveying step, an arranging step, and a connecting step in sequence.

[0139] In the singulation process, Figure 6 As shown by the dotted line A, the inductor 1 is cut into individual pieces.

[0140] That is, in the inductor 1 , the magnetic layer 3 of the inductor 1 is completely cut in the thickness direction so as to have one wiring 2 (the first wiring 4 or the second wiring 5 ).

[0141] Examples of a method for cutting the inductor 1 include a method using a disc-shaped dicing saw, a method using a cutter, and a method using a laser.

[0142] In the conveying step, the individualized inductors 1 are conveyed. Specifically, a suction conveying device such as a collet 25 is used to move the inductors 1 above the wiring board 28 .

[0143] Specifically, if Figure 6 As shown by the imaginary line A, multiple (two) collets 25 are moved upwards to the inductor 1. At this time, each collet 25 is moved (see Figure 6 A), so that the front end surface 26 of each collet 25 is located above the wiring 2.

[0144] Then, if Figure 6 As shown in B, the collet 25 is moved downward so that the front end surface 26 of the collet 25 contacts the upper surface of the inductor 1. Then, the front end surface 26 of the collet 25 is sucked so that the front end surface 26 of the collet 25 and the upper surface of the inductor 1 are in close contact.

[0145] At this time, since the upper surface of the inductor 1 is flat, a gap is unlikely to be generated between the front end surface 26 of the collet 25 and the inductor 1. Therefore, the collet 25 is firmly fixed to the inductor 1.

[0146] Next, the collet 25 is moved upward while the inductor 1 is in close contact with the collet 25. That is, the inductor 1 is lifted. Then, the collet 25 is moved upward to the desired wiring board 28.

[0147] In the placement step, the inductor 1 is placed on the upper surface of the wiring substrate 28 .

[0148] Specifically, the collet 25 is moved downward so that the lower surface of the inductor 1 contacts the upper surface of the wiring substrate 28. Next, the suction of the collet 25 is released and the collet 25 is separated from the inductor 1 (see Figure 6 C).

[0149] Therefore, if Figure 6 As shown in C, the inductor 1 is arranged on the upper surface of the wiring substrate 28 .

[0150] In the connection step, the inductor 1 is electrically connected to the wiring board 28. That is, the inductor 1 and the wiring board 28 are electrically connected directly or through other electronic components (semiconductor chips, capacitors, etc.).

[0151] Specifically, for example, a passage 27 leading to the conductive wire 6 is formed in the inductor 1 (see Figure 6 C). Next, the wire 6 is electrically connected to the wiring substrate 28 or the electronic component through the via 27 by wire bonding, flip chip mounting, soldering, or the like.

[0152] Such an inductor 1 is used as a passive element such as a coil, for example.

[0153] Furthermore, in inductor 1, an orientation region 13 (circumferential orientation region) exists around wiring 2, where particles 8 are oriented along the periphery of wiring 2. Consequently, the easy magnetization axis of particles 8 aligns with the direction of the magnetic field lines generated around the wiring, resulting in excellent inductance.

[0154] Furthermore, inductor 1 has a non-oriented region 14 (circumferential non-oriented region) around wiring 2, which is not oriented along the circumference of wiring 2. Consequently, the hard axis of magnetization of particles 8 aligns with the direction of the magnetic field lines generated around the wiring. Consequently, DC superposition characteristics are excellent.

[0155] Furthermore, since the top surface of the inductor 1 is flat, it can be sucked by a conveying device such as the collet 25, reliably securing the inductor 1 to the collet 25. This prevents the inductor 1 from falling out of the collet 25 during conveyance, allowing for reliable conveyance of the inductor 1. Furthermore, since the bottom surface of the inductor 1 is flat, it can be placed on the top surface of the wiring substrate 28 without tilting. This results in excellent mountability.

[0156] Furthermore, a plurality of wirings 2 are arranged at intervals in the first direction, and the plurality of wirings 2 are continuous with the magnetic layer 3 interposed therebetween. Therefore, the magnetic layer 3 is arranged between the plurality of wirings 2. As a result, the amount of the magnetic layer 3 is increased, and the inductance is further improved.

[0157] Furthermore, magnetic layer 3 extends continuously from the top to the bottom of inductor 1, with both the top and bottom surfaces of inductor 1 being formed by magnetic layer 3. With this inductor 1, inductor 1 is completely filled with magnetic layer 3, excluding the area containing wiring 2. Consequently, inductor 1 has extremely excellent inductance.

[0158] 4. Modifications

[0159] Reference Figure 7 ,illustrate Figure 1 A- Figure 2 In the modification example, the same components as those in the above-described embodiment are denoted by the same reference numerals, and their description is omitted.

[0160] exist Figure 1In the embodiment shown in B, the wiring 2 has a substantially U-shaped shape in a plan view, but the shape is not limited and can be set appropriately.

[0161] In addition, Figure 1 A- Figure 1 In the embodiment shown in B, there are two wirings 2, but the number is not limited, and for example, it can be one or three or more.

[0162] For example, in Figure 7 , an inductor 1 having one wiring 2 is shown. Figure 7 The top surface of the inductor 1 shown is flat. Specifically, the vertical distance between the uppermost end A1 in the wiring area A and a point M'1 50 μm away from the uppermost end A1 in the plane direction is 30 μm or less (preferably 20 μm or less, and more preferably less than 5 μm). In other words, the point M'1 50 μm away from the uppermost end A1 in the plane direction is used as the reference for flatness, instead of the midpoint M1.

[0163] The lower surface of the magnetic layer 3 is also flat, and the reference for this flatness is the same as the reference for the flatness of the upper surface of the magnetic layer 3. That is, instead of the midpoint M2, a point M'2 50 μm away in the plane direction is used as the reference.

[0164] In addition, Figure 1 A- Figure 1 In the embodiment shown in B, the cross-sectional shape of the wiring 2 is generally circular, but its shape is not limited thereto. For example, it may be generally elliptical, generally rectangular (including square and rectangular), or generally irregular. Furthermore, in the embodiment where the wiring 2 has a generally rectangular shape, at least one side may be curved, or at least one corner may be curved.

[0165] In any of the above-mentioned embodiments, the peripheral area 11 is an area that advances outward from the outer peripheral surface of the wiring 2 by a value equivalent to 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) when viewed in section.

[0166] In addition, Figure 1 A and Figure 1 In the embodiment shown in B, the ratio of the anisotropic magnetic particles 8 in the magnetic layer 3 may be uniform in the magnetic layer 3 , or may be higher or lower as the distance from each wiring 2 increases.

[0167] <Second to fifth embodiments>

[0168] Reference Figures 8 to 11, the second to fifth embodiments of the inductor of the present invention are described. In these embodiments, components identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. These embodiments also exhibit the same functions and effects as the first embodiment. Furthermore, modifications of the first embodiment are also applicable to these embodiments.

[0169] (1) Second embodiment

[0170] In the first embodiment, both the upper and lower surfaces of the inductor 1 are formed by the magnetic layer 3. However, in the second embodiment, for example, at least one of the upper and lower surfaces of the inductor 1 may be formed by the magnetic layer 3. For example, in one embodiment of the second embodiment, Figure 8 As shown, only the lower surface of the inductor 1 is formed by the magnetic layer 3 .

[0171] exist Figure 8 In the illustrated embodiment, the upper surface of the inductor 1 is formed of a non-magnetic resin layer 30 that does not contain particles 8. Specifically, the inductor 1 includes a plurality of (two) wirings 2, a magnetic layer 3, and a non-magnetic resin layer 30.

[0172] The non-magnetic resin layer 30 is disposed on the upper surface of the magnetic layer 3 so as to be in contact with the entire upper surface of the magnetic layer 3. The upper surface of the non-magnetic resin layer 30 is flat, and the lower surface of the non-magnetic resin layer 30 is uneven.

[0173] The non-magnetic resin layer 30 is formed from a resin composition containing a binder. Examples of the binder include the binder 9 exemplified in the magnetic composition. Furthermore, the resin composition may contain additives such as a thermosetting catalyst, inorganic particles, organic particles, and a crosslinking agent as needed.

[0174] The thickness T4 of the non-magnetic resin layer 30 at the midpoint M1 is, for example, 0.01 times or more, preferably 0.05 times or more, and for example, 10 times or less, preferably 5 times or less, relative to the thickness T5 of the magnetic layer 3 at the midpoint M1. Specifically, the thickness T4 of the non-magnetic resin layer 30 at the midpoint M1 is, for example, 5 μm or more, preferably 10 μm or more, and for example, 500 μm or less, preferably 200 μm or less.

[0175] From the viewpoint that the magnetic layer 3 occupies a wider area in the inductor 1 and the inductance is more excellent, the first embodiment is preferably used.

[0176] (2) Third embodiment

[0177] In the first embodiment, both the upper and lower surfaces of the inductor 1 are formed of the magnetic layer 3 , but, for example, in the third embodiment, Figure 9 As shown, the upper and lower surfaces of the inductor 1 are formed of non-magnetic resin layers 30 .

[0178] exist Figure 9 In the illustrated embodiment, the upper and lower surfaces of inductor 1 are formed of nonmagnetic resin layers 30 that do not contain particles 8. Specifically, inductor 1 includes a plurality of (two) wirings 2, a magnetic layer 3, a first nonmagnetic resin layer 31, and a second nonmagnetic resin layer 32.

[0179] The first non-magnetic resin layer 31 is disposed on the upper surface of the magnetic layer 3 so as to be in contact with the entire upper surface of the magnetic layer 3. The upper surface of the first non-magnetic resin layer 31 is flat, and the lower surface of the first non-magnetic resin layer 31 is uneven.

[0180] The second non-magnetic resin layer 32 is disposed on the lower surface of the magnetic layer 3 so as to be in contact with the entire lower surface of the magnetic layer 3. The lower surface of the second non-magnetic resin layer 32 is flat, and the upper surface of the second non-magnetic resin layer 32 is uneven.

[0181] From the viewpoint that the magnetic layer 3 occupies a wider area in the inductor 1 and the inductance is more excellent, the first embodiment is preferably used.

[0182] (3) Fourth to fifth embodiments

[0183] In the first embodiment, the plurality of wirings 2 are continuous with the magnetic layer 3 interposed therebetween. However, for example, in the fourth to fifth embodiments, the plurality of wirings 2 may be continuous with the magnetic layer 3 interposed therebetween. Figures 10 and 11 As shown, the plurality of wirings 2 are not continuous via the magnetic layer 3. That is, in the fourth to fifth embodiments, the plurality of magnetic layers 3 are arranged at intervals in the first direction, and each of the plurality of magnetic layers 3 is formed so as to surround the wirings 2.

[0184] Specifically, in the fourth embodiment, as Figure 10 As shown, magnetic layer 3 is formed to surround wiring 2 and be exposed from the bottom surface of inductor 1. Magnetic layer 3 forms a portion of the bottom surface of inductor 1. In other words, a portion of the bottom surface of inductor 1 is formed by magnetic layer 3. Specifically, the top surface of inductor 1 is formed by non-magnetic resin layer 30, while the bottom surface of inductor 1 is formed by magnetic layer 3 and the non-magnetic resin layer.

[0185] In addition, in the fifth embodiment, as Figure 11 As shown, the magnetic layer 3 is formed so as to surround the wiring 2. The periphery of the magnetic layer 3 is covered with the non-magnetic resin layer 30. That is, the upper and lower surfaces of the inductor 1 are formed by the non-magnetic resin layer 30.

[0186] Of the fourth and fifth embodiments, the fourth embodiment is preferably used. Regarding the magnetic layer 3, since part of the lower surface of the inductor 1 is formed by the magnetic layer 3, the inductor 1 contains a large proportion of the magnetic layer 3. Therefore, the inductor 1 has excellent inductance.

[0187] Among the first to fifth embodiments, the first to third embodiments are preferably mentioned. In these embodiments, since the wiring 2 is continuous with the magnetic layer 3 interposed therebetween, many magnetic layers 3 are present between the wirings 2. Therefore, the inductance is excellent.

[0188] Industrial applicability

[0189] The inductor of the present invention can be used as a passive element such as a voltage conversion means, for example.

[0190] Description of Reference Numerals

[0191] 1. Inductor; 2. Wiring; 3. Magnetic layer; 6. Conductor; 7. Insulation layer; 8. Anisotropic magnetic particles; 13. Orientation region.

Claims

1. An inductor, characterized in that: The inductor includes a wiring and a magnetic layer covering the wiring. The wiring includes a conductive wire and an insulating layer covering the conductive wire. The magnetic layer contains anisotropic magnetic particles and a binder, In a peripheral region of the wiring, the magnetic layer has an orientation region in which the anisotropic magnetic particles are oriented along the periphery of the wiring. The peripheral region is a region extending outward from the outer surface of the wiring by a value equivalent to 1.5 times the average value of the longest length and the shortest length from the center of gravity of the wiring to the outer surface of the wiring when viewed in cross section. The inductor has one side in the thickness direction and the other side in the thickness direction that are flat. A plurality of the wirings are arranged at intervals in a direction perpendicular to the thickness direction, and all of the plurality of wirings are continuous with the magnetic layer interposed therebetween.

2. The inductor according to claim 1, wherein At least one of one surface in the thickness direction and the other surface in the thickness direction of the inductor is formed by the magnetic layer.

3. The inductor according to claim 2, wherein: The magnetic layer is continuous from one side in the thickness direction of the inductor to the other side in the thickness direction. Both one surface in the thickness direction and the other surface in the thickness direction of the inductor are formed by the magnetic layer.

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