JP2020150058A - Inductor - Google Patents

Abstract

To provide an inductor which has a satisfactory inductance and DC superposition characteristic and which can suppress a cross talk.SOLUTION: An inductor 1 comprises: a plurality of wiring lines 2 in a generally circular form; and a magnetic layer 3. The plurality of wiring lines 2 are disposed apart from each other in a first direction and they each have a conducting wire 6 and an insulator layer 7. The magnetic layer 3 has, in a surrounding region, a first region 13 where anisotropic magnetic particles 8 are oriented along a circumferential direction, and a second region 14 where the anisotropic magnetic particles 8 are not oriented along the circumferential direction, and a center C2 of each virtual circular arc L1 in the second region 14 is not present on a first virtual line L2 running through respective centers C1 of the plurality of wiring lines 2.SELECTED DRAWING: Figure 2

Description

The present invention relates to inductors.

It is known that an inductor is mounted on an electronic device or the like and is used as a passive element such as a voltage conversion member.

For example, it is provided with a rectangular parallelepiped chip body made of a magnetic material and an internal conductor such as copper embedded inside the chip body, and the cross-sectional shape of the chip body and the cross-sectional shape of the internal conductor are similar. An inductor has been proposed (see Patent Document 1). That is, in the inductor of Patent Document 1, a magnetic material is coated around a wiring (inner conductor) having a rectangular parallelepiped shape (rectangular parallelepiped shape).

Japanese Unexamined Patent Publication No. 10-144526

By the way, it has been studied to use anisotropic magnetic particles such as flat magnetic particles as a magnetic material and to orient the anisotropic magnetic particles around the wiring to improve the inductance of the inductor. ..

However, in the inductor of Patent Document 1, since the wiring has a rectangular shape in a cross-sectional view, there is a problem that it is difficult to align the anisotropic magnetic particles around the wiring due to the presence of corners and the like. Therefore, the improvement of the inductance may be insufficient.

Therefore, it is further studied to orient the anisotropic magnetic particles around the wiring by using the wiring having a substantially circular shape in cross section.

However, this method has insufficient DC superimposition characteristics, and further improvement is required.

In addition, an inductor having a plurality of wires is also required. However, when the inductor is provided with a plurality of wires, the magnetisms of the adjacent wires affect each other, causing a problem (crosstalk) in which noise is generated.

The present invention provides an inductor having good inductance and DC superimposition characteristics and capable of suppressing crosstalk.

The present invention [1] includes a plurality of wirings having a substantially circular shape in cross-sectional view and a magnetic layer covering the plurality of wirings, and the plurality of wirings are arranged at intervals from each other in the first direction. Each of the plurality of wirings includes a lead wire and an insulating layer covering the lead wire, the magnetic layer contains anisotropic magnetic particles and a binder, and the magnetic layer includes the plurality of wires. In the peripheral region of the wiring, the first region in which the anisotropic magnetic particles are oriented along the circumferential direction of the wiring and the anisotropic magnetic particles are oriented along the circumferential direction of the wiring, respectively. The peripheral region has a second region that is not provided, and the peripheral region advances the value 1.5 times the distance from the center of gravity of the wiring to the outer surface of the wiring to the outside from the outer surface of the wiring. An inductor that is a region and the center of the virtual arc connecting one end in the circumferential direction and the other end in the circumferential direction in the second region does not exist on the first virtual line passing through the centers of the plurality of wirings adjacent to each other. Including.

According to this inductor, the inductance is good because there is a first region in which the anisotropic magnetic particles are oriented along the circumferential direction, respectively, around the plurality of wirings.

Further, since there is a second region around the plurality of wirings in which the anisotropic magnetic particles are not oriented along the circumferential direction of the wiring, the DC superimposition property is good.

Further, the center in the second region does not exist on the first virtual line passing through the centers of the plurality of wirings adjacent to each other. Therefore, the distance that the magnetic flux reaches from one wiring to the other wiring via the second region can be increased. That is, the distance of the magnetic flux between the wirings can be substantially increased. Therefore, the influence of magnetism from one wiring to the other wiring can be reduced, and crosstalk can be suppressed.

In the present invention [2], the center of the virtual arc is located between the first virtual line and the second virtual line that passes through the center of the wiring and is orthogonal to the first virtual line [1]. ] Is included.

According to this inductor, a plurality of wirings are arranged on one magnetic layer, and then the other magnetic layer is laminated on one magnetic layer so that the plurality of wirings are embedded in the second region. An inductor whose center is located between the first virtual line and the second virtual line can be manufactured. Therefore, the inductor according to [1] can be easily manufactured.

According to the inductor of the present invention, the inductance and DC superimposition are good, and crosstalk can be suppressed.

1A-B is an embodiment of the inductor of the present invention, FIG. 1A is a plan view, and FIG. 1B is a sectional view taken along the line AA of FIG. 1A. FIG. 2 shows a partially enlarged view of the broken line portion of FIG. 1B. 3A-B show the inductor manufacturing process shown in FIGS. 1A-B, FIG. 3A shows an arrangement process, and FIG. 3B shows a lamination process. FIG. 4 shows an actual SEM photographic sectional view of the inductor shown in FIGS. 1A-B. FIG. 5 shows a cross-sectional view of a modified example of the inductor of the present invention (a form in which the intersection is located at the lower end of the wiring). FIG. 6 shows a plan view of an inductor model used in the simulations of Examples and Comparative Examples. 7A-C are cross-sectional views taken along the line AA of FIG. 6, FIG. 7A shows a cross-sectional view of Example 1, FIG. 7B is a cross-sectional view of Comparative Example 1, and FIG. 7C shows Comparative Example 2.

In FIG. 1A, the left-right direction of the paper surface is the first direction, the left side of the paper surface is one side of the first direction, and the right side of the paper surface is the other side of the first direction. The vertical direction of the paper surface is the second direction (direction orthogonal to the first direction), the upper side of the paper surface is one side of the second direction (one direction in the wiring axis direction), and the lower side of the paper surface is the other side of the second direction (the other direction of the wiring axis). ). The paper thickness direction is the vertical direction (third direction orthogonal to the first and second directions, thickness direction), the front side of the paper is the upper side (one side of the third direction, one side of the thickness direction), and the back side of the paper is. The lower side (the other side in the third direction, the other side in the thickness direction). Specifically, it conforms to the direction arrows in each figure.

<One Embodiment>
1. 1. Inductor An embodiment of the inductor of the present invention will be described with reference to FIGS. 1A-2.

As shown in FIGS. 1A-B, the inductor 1 has a substantially rectangular shape in a plan view extending in the plane direction (first direction and second direction).

As shown in FIGS. 1A-2, the inductor 1 includes a plurality of (two) wirings 2 and a magnetic layer 3.

Each of the plurality of wirings 2 includes a first wiring 4 and a second wiring 5 arranged at intervals in the width direction (first direction) from the first wiring 4.

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

The first wiring 4 includes a lead wire 6 and an insulating layer 7 that covers the lead wire 6.

The lead wire 6 extends long in the second direction and has, for example, a substantially U-shape in a plan view. Further, the lead wire 6 has a substantially circular shape in cross section that shares the central axis with the first wiring 4.

The material of the lead wire 6 is, for example, a metal conductor such as copper, silver, gold, aluminum, nickel, or an alloy thereof, and copper is preferable. The conducting wire 6 may have a single-layer structure, or may have a multi-layer structure in which the surface of a core conductor (for example, copper) is plated (for example, nickel).

The radius R1 of the lead wire 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.

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

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

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

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

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, for example, 1 μm or more, preferably 3 μm or more, and for example, 100 μm or less, preferably 100 μm or less. , 50 μm or less.

The ratio (R1 / R2) of the radius R1 of the conducting 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.

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

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

The second wiring 5 has the same shape as the first wiring 4 and has the same configuration, dimensions, and materials. That is, the second wiring 5 includes a lead wire 6 and an insulating layer 7 covering the lead wire 6 as in the first wiring 4.

The distance D1 between the centers of 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.

The magnetic layer 3 is a layer for improving the inductance.

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 a plan view extending in the plane direction (first direction and second direction). Further, the magnetic layer 3 exposes the second-direction end edges of the plurality of wirings 2 on the other surface in the second direction.

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

Examples of the magnetic material constituting the anisotropic magnetic particle (hereinafter, also abbreviated as “particle”) 8 include a soft magnetic material and a hard magnetic material. A soft magnetic material is preferably used from the viewpoint of inductance.

Examples of the soft magnetic material include a single metal body containing one kind of metal element in a pure substance state, for example, one or more kinds of metal elements (first metal element) and one or more kinds of metal elements (second metal element). Examples include alloys that are eutectic (mixtures) with (metal elements) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.). These can be used alone or in combination.

Examples of the single metal body include a simple metal composed of only one kind of metal element (first metal element). The first metal element is appropriately selected from, for example, iron (Fe), cobalt (Co), nickel (Ni), and other metal elements that can be contained as the first metal element of the soft magnetic material. ..

The single metal body includes, for example, a core containing only one kind of metal element and a surface layer containing an inorganic substance and / or an organic substance that modifies a part or all of the surface of the core, for example. Examples thereof include an organic metal compound containing a first metal element and a form in which an inorganic metal compound is decomposed (thermal decomposition, etc.). In the latter form, more specifically, iron powder obtained by thermally decomposing an organic iron compound (specifically, carbonyl iron) containing iron as the first metal element (sometimes referred to as carbonyl iron powder). And so on. The position of the layer containing the inorganic substance and / or the organic substance that modifies the portion containing only one kind of metal element is not limited to the above-mentioned surface. The organometallic compound or inorganic metal compound capable of obtaining a single metal body is not particularly limited, and a known or commonly used organometallic compound or inorganic metal compound capable of obtaining a soft magnetic single metal body is not particularly limited. Can be appropriately selected from.

The alloy body is a eutectic of one or more kinds of metal elements (first metal element) and one or more kinds of metal elements (second metal element) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.). It is not particularly limited as long as it is a body and can be used as an alloy body of a soft magnetic material.

The first metal element is an essential element in the alloy body, and examples thereof include iron (Fe), cobalt (Co), and nickel (Ni). If the first metal element is Fe, the alloy body is an Fe-based alloy, and if the first metal element is Co, the alloy body is a Co-based alloy, and the first metal element is Ni. For example, the alloy body is a Ni-based alloy.

The second metal element is an element (sub-component) secondarily contained in the alloy body, and is a metal element that is compatible (co-fused) with the first metal element. For example, iron (Fe) (the first). 1 When the 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 Examples thereof include (Ge), tin (Sn), lead (Pb), scandium (Sc), yttrium (Y), strontium (Sr), and various rare earth elements. These can be used alone or in combination of two or more.

The non-metal element is an element (sub-component) secondarily contained in the alloy body, and is a non-metal element that is compatible (combined) with the first metal element. For example, boron (B) and carbon. Examples thereof include (C), nitrogen (N), silicon (Si), phosphorus (P) and sulfur (S). These can be used alone or in combination of two or more.

Examples of Fe-based alloys that are examples of alloys include magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), sentust (Fe-Si-Al alloy) (including super sentust), and permalloy (including supersendust). 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, silicon copper (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 , Ferrites (stainless ferrites, Mn-Mg-based ferrites, Mn-Zn-based ferrites, Ni-Zn-based ferrites, Ni-Zn-Cu-based ferrites, Cu-Zn-based ferrites, Cu-Mg-Zn-based ferrites, etc. (Including soft ferrite), permenzur (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy and the like.

Examples of Co-based alloys that are examples of alloys include Co-Ta-Zr and cobalt (Co) -based amorphous alloys.

Examples of Ni-based alloys, which are examples of alloys, include Ni—Cr alloys.

Among these soft magnetic materials, an alloy body is preferable, a Fe-based alloy is more preferable, and sendust (Fe—Si—Al alloy) is more preferable, from the viewpoint of magnetic properties. Further, as the soft magnetic material, preferably a single metal body, more preferably a single metal body containing an iron element in a pure substance state, still more preferably iron alone or iron powder (carbonyl iron powder). Can be mentioned.

Examples of the shape of the particles 8 include a flat shape (plate shape) and a needle shape from the viewpoint of anisotropy, and preferably from the viewpoint of good relative magnetic permeability in the plane direction (two-dimensional). Flat shape is mentioned. The magnetic layer 3 may further contain non-anisotropic magnetic particles in addition to the anisotropic magnetic particles 8. The non-anisotropic magnetic particles may have a shape such as a spherical shape, a granular shape, a lump shape, or a pellet shape. The average particle size of the non-anisotropic 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.

The flatness (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 flatness is calculated as, for example, an 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.

The average particle diameter (average length) of the particles 8 (anisotropic magnetic particles) is, for example, 3.5 μm or more, preferably 10 μm or more, and for example, 200 μm or less, preferably 150 μm or less. If the particles 8 are flat, their 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.

Examples of the binder 9 include a thermosetting resin and a thermoplastic resin.

Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin, thermosetting polyimide resin, unsaturated polyester resin, polyurethane resin, silicone resin and the like. From the viewpoint of adhesiveness, heat resistance and the like, epoxy resin and phenol resin are preferable.

Examples of the thermoplastic resin include acrylic resin, ethylene-vinyl acetate copolymer, polycarbonate resin, polyamide resin (6-nylon, 6,6-nylon, etc.), thermoplastic polyimide resin, saturated polyester resin (PET, PBT, etc.). ) And so on. Acrylic resin is preferable.

Preferably, the binder 9 is a combination of a thermosetting resin and a thermoplastic resin. More preferably, a combination of an acrylic resin, an epoxy resin and a phenol resin can be mentioned. As a result, the particles 8 can be more reliably fixed around the wiring 2 in a predetermined orientation state and with a high filling.

In addition, the magnetic composition can also contain additives such as a thermosetting catalyst, inorganic particles, organic particles, and a cross-linking agent, if necessary.

In the magnetic layer 3, the particles 8 are uniformly arranged while being oriented in the binder 9.

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

The peripheral region 11 is a peripheral region of the wiring 2, and is located around the plurality of wirings 2 so as to come into contact with the plurality of wirings 2. The peripheral region 11 has a substantially annular shape in cross section that shares the central axis with the wiring 2. More specifically, the peripheral region 11 is 1.5 times the radius of the wiring 2 (distance from the center (centroid) C1 of the wiring 2 to the outer peripheral surface; R1 + R2) of the magnetic layer 3 (preferably 1). .2 times value, more preferably 1 time value, further preferably 0.8 times value, particularly preferably 0.5 times value), a region extending radially outward from the outer peripheral surface of the wiring 2.

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

The peripheral region 11 includes a plurality (two) first regions 13 and a plurality (two) second regions 14, respectively.

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

The plurality of first regions 13 are arranged on the upper side (one side in the third direction) and the lower side (the other side in the third direction) of the wiring 2 so as to face each other with the center C1 of the wiring 2 interposed therebetween. That is, the plurality of first regions 13 include an upper first region 15 arranged on the upper side of the wiring 2 and a lower first region 16 arranged on the lower side of the wiring 2. Further, the center C1 of the wiring 2 is located at the center in the vertical direction of the upper first region 15 and the lower first region 16.

In each of the first regions 13, the direction in which the relative magnetic permeability of the particles 8 is high (for example, in the case of flat anisotropy magnetic particles, the plane direction of the particles) is abbreviated as the tangent of a circle centered on the center C1 of the wiring 2. Match. More specifically, when the angle formed by the plane direction of the particle 8 and the tangent line of the circle in which the particle 8 is located is 15 ° or less, it is defined that the particle 8 is oriented in the circumferential direction. ..

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

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

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

The specific magnetic permeability can be measured, for example, by an impedance analyzer (manufactured by Agilent, “4291B”) using a magnetic material test fixture.

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

The plurality of second regions 14 are arranged on one side and the other side of the wiring 2 in the first direction so as to face each other with the wiring 2 interposed therebetween. That is, the plurality of second regions 14 are located on one side of the second region 17 of the wiring 2 (first wiring 4 or the second wiring 5) arranged on one side in the first direction and on the other side of the wiring 2 in the first direction. It has a second region 18 on the other side to be arranged. The second region 17 on one side and the second region 18 on the other side are substantially line-symmetrical with respect to the second virtual line L3.

The second virtual line L3 is a straight line that passes through the center C1 of the first wiring 4 or the second wiring and extends in the vertical direction.

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 anisotropy magnetic particles, the plane direction of the particles) coincides with the tangent line of the circle centered on the center C1 of the wiring 2. do not do. More specifically, when the angle formed by the plane direction of the particle 8 and the tangent of the circle in which the particle 8 is located exceeds 15 °, it is defined that the particle 8 is not oriented in the circumferential direction. ..

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. , 95% or less, preferably 90% or less.

The second region 14 may include, for example, particles 8 oriented in the circumferential direction. 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, 5 % Or more, preferably 10% or more.

When the particles 8 oriented in the circumferential direction are included, the particles 8 oriented in the circumferential direction are preferably arranged on the innermost side of the second region 14, that is, on the surface of the wiring 2.

The total area ratio of the plurality of second regions 14 is, for example, 10% or more, preferably 20% or more, and for example, 60% or less, preferably 50% or less, based on the entire peripheral region 11. More preferably, it is 40% or less.

The center C2 of the second region 14 does not exist on the first virtual line L2. That is, the center C2 is located below the first virtual line L2, preferably below the first virtual line L2 by a distance of 0.1 times the radius R, and more preferably. , Is located below the first virtual line L2 by a distance of 0.3 times the radius R. More specifically, the center C2 is preferably located 10 μm below, more preferably 30 μm below the first virtual line L2.

Further, the center C2 of the second region 14 is located between the first virtual line L2 and the second virtual line L3. That is, the center C2 of the second region 14 does not exist on either the first virtual line L2 or the second virtual line L3.

The center C2 of the second region 14 is the center of the virtual arc L1 connecting one end in the circumferential direction and the other end in the circumferential direction in the second region 14. More specifically, the center C2 of the second region 14 is the center of the virtual arc L1 connecting the radial center of one end edge in the circumferential direction and the radial center of the other end edge in the circumferential direction in the second region 14. Is.

The first virtual line L2 is a straight line extending in the first direction through the centers C1 of a plurality of wirings 2 adjacent to each other.

In the second region 14, the intersection (top) 19 is formed by at least two types of particles 8 having different orientation directions. That is, on the upper side of the second region 14, the particles 8 (first particles) oriented in the first direction from the circumferential direction toward the outside of the wiring 2, and on the lower side of the second region 14, on the outside of the wiring 2. Particles 8 (second particles) that are oriented in the first direction from the circumferential direction toward each other form at least two sides having a substantially triangular shape, thereby forming an intersection 19. Specifically, the first particle and the second particle have a substantially triangular shape (preferably an acute-angled triangular shape) together with the particle 8 (third particle) oriented in the circumferential direction inside the second region 14. Form.

The intersection 19 does not exist between the first wiring 4 and the second wiring 5 on the first virtual line L2 passing through the center thereof. That is, the intersection 19 is arranged below the first virtual line L2 at a position separated from the virtual 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 virtual line L2 is, for example, 15 ° or more, preferably 45 ° or more, and also. For example, it is 75 ° or less, preferably 60 ° or less.

In the peripheral region 11 (particularly, each of the first region 13 and the second 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 volumes. % Or less, preferably 70% by volume or less. If the filling rate is at least the above lower limit, the inductance is excellent.

The filling rate can be calculated by measuring the actual specific gravity, binarizing the cross-sectional view of the SEM photograph, and the like.

In the peripheral region 11, the plurality of first regions 13 and the plurality of second regions 14 are arranged so as to be adjacent to each other in the circumferential direction. Specifically, the upper first region 15, the one-sided second region 17, the lower first region 16, and the other-side second region 18 are continuous in this order in the circumferential direction. The boundary (one end edge or the other end edge) in the circumferential direction between the first region 13 and the second region 14 is a virtual straight line extending radially outward from the center of the wiring 2.

The outer region 12 is a region other than the peripheral region 11 in the magnetic layer 3. The outer region 12 is arranged outside the peripheral region 11 so as to be continuous with the peripheral region 11.

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

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

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 exceeds 50%, preferably 70% or more, and more. Preferably, it is 90% or more. That is, the outer region 12 may contain less than 50%, preferably 30% or less, more preferably 10% or less of the particles 8 that are not oriented in the first direction.

In the outer region 12, the specific 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, more preferably 25 or less. The ratio of the relative magnetic permeability in the first direction to 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 in the above range, the inductance is excellent.

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 at least the above lower limit, the inductance is excellent.

The length T ₁ of the magnetic layer 3 in the first direction is, for example, 5 mm or more, preferably 10 mm or more, and for example, 5000 mm or less, preferably 2000 mm or less.

The length T ₂ in the second direction 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.

The vertical length (thickness) T ₃ 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.

2. 2. Inductor Manufacturing Method An embodiment of the inductor 1 manufacturing method will be described with reference to FIGS. 3A-B. The method for manufacturing the inductor 1 includes, for example, a preparation step, a placement step, and a lamination step in order.

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

Each of the two anisotropic magnetic sheets 20 has a sheet shape extending in the plane direction and is formed of a magnetic composition. In the anisotropic magnetic sheet 20, the particles 8 are oriented in the plane direction. Preferably, two semi-cured (B stage) anisotropic magnetic sheets 20 are used.

Examples of such an anisotropic magnetic sheet 20 include soft magnetic thermosetting adhesive films and soft magnetic films described in JP-A-2014-165363 and JP-A-2015-92544.

In the arrangement step, as shown in FIG. 3A, a plurality of wirings 2 are arranged on the upper surface of one anisotropic magnetic sheet 20, and the other anisotropic magnetic sheet 20 is arranged so as to face each other above the plurality of wirings 2. To do.

Specifically, the lower anisotropic magnetic sheet 21 is placed on a horizontal table, and subsequently, a plurality of wirings 2 are placed on the upper surface of the lower anisotropic magnetic sheet 21 in the first direction at desired intervals. Deploy.

Next, the upper anisotropic magnetic sheet 22 is arranged on the lower anisotropic magnetic sheet 21 and the upper side of the plurality of wirings 2 at intervals.

In the laminating step, as shown in FIG. 3B, the two anisotropic magnetic sheets 20 are laminated so as to embed the plurality of wirings 2.

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

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

Further, the upper anisotropic magnetic sheet 22 is covered along a plurality of wirings 2, and the particles 8 are oriented along the plurality of wirings 2 and laminated on the upper surface of the lower anisotropic magnetic sheet 21. .. 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) of the first direction of the wiring 2, the lower anisotropic magnetic sheet 21 is formed. In the vicinity of the contact with the upper anisotropic magnetic sheet 22, the particles 8 oriented thereto collide with each other, and as a result, the second region 14 and the intersection 19 are formed.

When the anisotropic magnetic sheet 20 is in a semi-cured state, it is heated. As a result, the anisotropic magnetic sheet 20 is in a cured state (C stage). Further, the contact interface 25 of the two anisotropic magnetic sheets 20 disappears, and the two anisotropic magnetic sheets 20 form one magnetic layer 3.

As a result, as shown in FIG. 2, an inductor 1 including a wiring 2 having a substantially circular cross-sectional view and a magnetic layer 3 covering the wiring 2 can be obtained. That is, the inductor 1 is formed by laminating a plurality of (two) anisotropic magnetic sheets 20 so as to sandwich the wiring 2. A cross-sectional view (SEM photograph) of an example of the actual inductor 1 is shown in FIG.

3. 3. Application The inductor 1 is a component of an electronic device, that is, a component for manufacturing an electronic device, and is distributed as a single component without including an electronic element (chip, capacitor, etc.) or a mounting substrate on which the electronic element is mounted. , An industrially usable device.

The inductor 1 is mounted (embedded) in, for example, an electronic device. Although not shown, the electronic device includes a mounting board and electronic elements (chips, capacitors, etc.) mounted on the mounting board. Then, the inductor 1 is mounted on a mounting substrate via a connecting member such as solder, is electrically connected to other electronic devices, and acts as a passive element such as a coil.

According to the inductor 1, each of the peripheral regions 11 of the plurality of wirings 2 has a first region 13 in which the particles 8 are oriented along the circumferential direction, so that the inductance is good.

Further, since the peripheral region 11 of the plurality of wirings 2 has a second region 14 in which the particles 8 are not oriented along the circumferential direction, the DC superimposition property is good.

Further, the center C2 in the second region 14 does not exist on the first virtual line L2. Therefore, the distance that the magnetic flux reaches from the first wiring 4 to the second wiring 5 via the second region 14 can be increased. That is, the distance through which the magnetic flux between the wirings 2 passes can be substantially increased. Therefore, the influence of magnetism on the first wiring 4 to the second wiring 5 can be reduced, and crosstalk can be suppressed.

Further, the center C2 of the second region 14 is located between the first virtual line L2 and the second virtual line L3 in the circumferential direction. Therefore, as shown in FIGS. 3A-B, a plurality of wirings 2 are arranged on the upper surface of the lower anisotropic magnetic sheet 21, and then the plurality of wirings 2 are embedded in the upper anisotropic magnetic sheet 21. By laminating the anisotropic magnetic sheet 22 on the lower anisotropic magnetic sheet 21, the second region 14 can be easily arranged at the above position. Therefore, an inductor 1 having good inductance and DC superimposition characteristics and capable of suppressing crosstalk can be easily obtained.

<Modification example>
A modified example of the embodiment shown in FIGS. 1A and 2 will be described with reference to FIG. In the modified example, the same members as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. These modifications also have the same effects as those of the above-described embodiment.

In the embodiment shown in FIG. 2, the vertical position of the intersection 19 is between the center C1 of the wiring 2 and the lowermost end of the wiring 2. For example, as shown in FIG. 5, the vertical position of the intersection 19 The position can be the same as the lowermost end of the wiring 2.

In the embodiment shown in FIG. 5, for example, as the two anisotropic magnetic sheets 20, a cured lower anisotropic magnetic sheet 21 and a semi-cured upper anisotropic magnetic sheet 22 are used. As a result, the plurality of wirings 2 do not sink into the lower anisotropic magnetic sheet 21, so that the inductor 1 shown in FIG. 5 can be easily manufactured.

In the embodiment shown in FIGS. 1A-B, two wirings 2 are provided, but the number thereof is not limited and may be three or more.

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

In the embodiment shown in FIGS. 1A-B, the magnetic layer 3 may also have an alignment mark.

In the embodiment shown in FIGS. 1A-B, the proportion of the anisotropic magnetic particles 8 in the magnetic layer 3 may be uniform in the magnetic layer 3 and may increase as the distance from each wiring 2 increases, or It may be lower.

<Simulation result>
Example 1
As a model similar to the embodiment of FIG. 5, the models shown in FIGS. 6 and 7A were used. In this model, the self-inductance, mutual inductance, inductance density, DC superimposition characteristics and coupling coefficient of the inductor were calculated by simulation under the conditions shown below.

Soft: "Maxwell 3D" manufactured by ANSYS, radius R1: 110 μm of lead wire 6, thickness R2: 5 μm of insulating layer 7, first direction length T1: 14.5 mm of magnetic layer 3, second direction of magnetic layer 3 Length T2: 12 mm, length of wiring 2 in the second direction: 10 mm, thickness of magnetic layer 3 T3: 430 μm, radial length of peripheral region 11: 60 μm, specific magnetic permeability in the circumferential direction of the circumferential orientation region 30 μ: 140, radial specific magnetic permeability μ: 10 of the circumferential orientation region 30, first-direction specific magnetic permeability μ: 140 of the first-direction alignment region 31, vertical ratio of the first-direction orientation region 31 Magnetic permeability μ: 10, vertical distance of first orientation region 31: 60 μm, frequency: 10 MHz, center-to-center distance between wiring 2 D1: 0.5 mm, 1.0 mm, or 1.5 mm
-For the DC superimposition characteristic, the change in the magnetic characteristic B with respect to the external magnetic field strength H was set. In addition, it is set to be non-linear in the plane direction (a mode in which B gradually saturates when the external magnetic field strength H becomes stronger), and linear in the thickness direction (B is always with respect to the external magnetic field strength H). It was set in a constant and non-saturating mode).

The inductance value with respect to the DC magnetic field was calculated with the DC current applied to the wiring.

The current value was swept from 0.1A to 100A. At this time, the inductance value when the DC current was 0.1 A was used as a reference (100%), and the value of the DC current when the DC current was reduced to 70% was calculated as the DC superimposed current value.

These results are shown in Table 1.

Comparative Example 1
As shown in FIGS. 6 and 7B, the first embodiment is changed except that the center C2 of the first orientation region 31 is located on the first virtual line L2 and its vertical length is changed to 50 μm. Each value was calculated in the same manner as above. The results are shown in Table 1.

Comparative Example 2
As shown in FIGS. 6 and 7C, each value was calculated in the same manner as in Example 1 except that the first orientation region 31 was not arranged and the peripheral region 11 was only the circumferential orientation region. The results are shown in Table 1.

Consideration As is clear from Table 1, the inductor of Example 1 has a lower coupling coefficient at any inter-wiring distance D1 than the inductor of Comparative Example 1, so that the influence between wirings is small and crosstalk Was reduced. Moreover, since the inductance density was high, the inductance was good. In addition, the decrease in inductance during DC current superimposition was small, and the DC superimposition characteristics were good.

Further, the inductor of Example 1 had less decrease in inductance at the time of DC current superposition and had good DC superimposition characteristics as compared with the inductor of Comparative Example 2.

1 Inductor 2 Wiring 3 Magnetic layer 6 Conductive wire 7 Insulating layer 8 Anisotropic magnetic particles 13 1st region 14 2nd region C1 Wiring center C2 Virtual arc center L1 Virtual arc L2 1st virtual line L3 2nd virtual line

Claims (2)

A plurality of wirings having a substantially circular shape in cross section and a magnetic layer covering the plurality of wirings are provided.
The plurality of wires are arranged so as to be spaced apart from each other in the first direction.
Each of the plurality of wires includes a conducting wire and an insulating layer covering the conducting wire.
The magnetic layer contains anisotropic magnetic particles and a binder, and contains
The magnetic layer is formed in the peripheral region of the plurality of wirings, respectively.
A first region in which the anisotropic magnetic particles are oriented along the circumferential direction of the wiring, and
The anisotropic magnetic particles have a second region that is not oriented along the circumferential direction of the wiring.
The peripheral region is a region in which a value 1.5 times the distance from the center of gravity of the wiring to the outer surface of the wiring is advanced outward from the outer surface of the wiring in a cross-sectional view.
An inductor characterized in that the center of a virtual arc connecting one end in the circumferential direction and the other end in the circumferential direction in the second region does not exist on the first virtual line passing through the centers of the plurality of wirings adjacent to each other. .. The first aspect of the present invention is characterized in that the center of the virtual arc is located between the first virtual line and the second virtual line that passes through the center of the wiring and is orthogonal to the first virtual line. The inductor described.