inductor

Abstract

An inductor (1) includes: a first wiring (2) and a second wiring (3) adjacent to each other with a space therebetween; a first magnetic layer (4) including a first surface (11) continuous in a planar direction, a second surface (12) continuous in the planar direction and spaced apart from the first surface (11) in a thickness direction, and an inner peripheral surface (10) in contact with an outer peripheral surface (17) of the first wiring and an outer peripheral surface (17) of the second wiring between the first surface (11) and the second surface (12); a second magnetic layer (5) disposed on the first surface (11); and a third magnetic layer (6) disposed on the second surface (12). The second magnetic layer (5) has a third surface (13) disposed opposite the first surface (11) with a space in the thickness direction. The second magnetic layer (5) and the third magnetic layer (6) each have a relative magnetic permeability higher than that of the first magnetic layer (4). The inductor (1) further includes a suppression portion (7) located between the first wiring (2) and the second wiring (3) when projected along the thickness direction, and configured to suppress magnetic coupling between the first wiring (2) and the second wiring (3). The suppression portion (7) includes a slit (21) located between the first surface (11) and the third surface (13).

Description

Technical Field

[0001] This invention relates to inductors. Background Technology

[0002] Inductors are known to be used in electronic devices as passive components such as voltage conversion devices.

[0003] For example, an inductor having a main body made of magnetic material and an internal conductor made of copper embedded inside the main body has been proposed (see, for example, Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

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

[0007] The problem the invention aims to solve

[0008] In recent years, with the miniaturization and high performance of electronic devices, the same characteristics are expected for inductors. In order to improve inductance while miniaturizing, inductors with dense internal conductors are desired. However, when inductors have dense internal conductors, undesirable situations such as magnetic coupling (crosstalk) can occur between adjacent internal conductors due to the magnetic material.

[0009] On the other hand, if the spacing between adjacent internal conductors is widened, although the crosstalk mentioned above can be suppressed, there is an undesirable situation of reduced inductance.

[0010] On the other hand, inductors are also required to have excellent DC superposition characteristics.

[0011] The present invention provides an inductor with excellent DC superposition characteristics, which can suppress the reduction of inductance and suppress crosstalk between adjacent wirings.

[0012] Solution for solving the problem

[0013] The present invention (1) includes an inductor comprising: a first wiring and a second wiring that are spaced apart from each other; a first magnetic layer having a first surface that is continuous in the planar direction, a second surface that is spaced apart in the thickness direction and continuous in the planar direction relative to the first surface, and an inner peripheral surface located between the first surface and the second surface and in contact with the outer peripheral surface of the first wiring and the outer peripheral surface of the second wiring; a second magnetic layer disposed on the first surface; and a third magnetic layer disposed on the second surface, the second magnetic layer having a third surface that is spaced apart from the first surface in the thickness direction and opposite to it, the relative permeability of the second magnetic layer and the third magnetic layer being higher than the relative permeability of the first magnetic layer, the inductor further comprising a suppression portion located between the first wiring and the second wiring when projected along the thickness direction, configured to suppress magnetic coupling between the first wiring and the second wiring, the suppression portion comprising a first suppression portion located between the first surface and the third surface.

[0014] In this inductor, the relative permeability of the second and third magnetic layers is higher than that of the first magnetic layer, and the suppression section includes a first suppression section located between the first and third surfaces. Therefore, it exhibits excellent DC superposition characteristics, suppresses inductance reduction, and suppresses crosstalk between the first and second wirings.

[0015] The present invention (2) includes the inductor described in (1), wherein the aforementioned first suppression portion faces the aforementioned first surface.

[0016] In this inductor, the first suppression part faces the first surface, thus effectively suppressing crosstalk between the first wiring and the second wiring.

[0017] The present invention (3) includes the inductor described in (1) or (2), wherein the aforementioned first suppression portion is exposed from the aforementioned third surface.

[0018] In this inductor, the first suppression part is exposed from the third surface, so the first suppression part can be easily formed.

[0019] The present invention (4) includes the inductor described in any one of (1) to (3), wherein the length of the first suppression portion in the thickness direction is longer than the length of the first suppression portion in the adjacent direction adjacent to the first wiring and the second wiring.

[0020] This inductor can effectively suppress the decrease in inductance and effectively suppress crosstalk between the first and second wirings.

[0021] The present invention (5) includes the inductor described in any one of (1) to (4), wherein the first suppression portion is a slit formed in the second magnetic layer.

[0022] In this inductor, the first suppression part is a slit, which is simple to construct, and since there is air with the lowest relative permeability in the slit, it can reliably suppress crosstalk between the first wiring and the second wiring.

[0023] The present invention (6) includes an inductor as described in any one of (1) to (4), wherein the first suppression portion is a first filling portion filled in the void formed in the second magnetic layer, and the relative permeability of the first filling portion is lower than the relative permeability of the first magnetic layer.

[0024] In this inductor, the first suppression part is a first filling part with a relative permeability lower than that of the first magnetic layer. Therefore, through this first filling part, crosstalk between the first wiring and the second wiring can be reliably suppressed.

[0025] The present invention (7) includes an inductor as described in any one of (1) to (6), and further comprises a processing stabilizing layer disposed on the aforementioned third surface of the aforementioned second magnetic layer.

[0026] The inductor has a processing stabilization layer, so the processing stability of the second magnetic layer is excellent.

[0027] The present invention (8) includes an inductor as described in any one of (1) to (7), wherein the aforementioned third magnetic layer has a fourth surface that is disposed opposite to the aforementioned second surface in the aforementioned thickness direction at a distance, and the aforementioned suppression portion further includes a second suppression portion located between the aforementioned second surface and the aforementioned fourth surface.

[0028] In this inductor, the suppression section also includes a second suppression section located between the second and fourth surfaces, thus suppressing the reduction of inductance and further suppressing crosstalk between the first and second wirings.

[0029] The present invention (9) includes the inductor described in (8), wherein the aforementioned second suppression portion faces the aforementioned second surface.

[0030] In this inductor, the second suppression part faces the second surface, thus effectively suppressing crosstalk between the first wiring and the second wiring.

[0031] The present invention (10) includes the inductor described in (8) or (9), wherein the aforementioned second suppression portion is exposed from the aforementioned fourth surface.

[0032] In this inductor, the second suppression part is exposed from the fourth surface, so the second suppression part can be easily formed.

[0033] The present invention (11) includes the inductor of any one of (8) to (10), wherein the length of the second suppression portion in the thickness direction is longer than the length of the second suppression portion in the adjacent direction adjacent to the first wiring and the second wiring.

[0034] This inductor can effectively suppress the decrease in inductance and effectively suppress crosstalk between the first and second wirings.

[0035] The present invention (12) includes the inductor described in any one of (8) to (11), wherein the aforementioned second suppression portion is a second slit formed in the aforementioned third magnetic layer.

[0036] In this inductor, the second suppression part is the second slit, which is simple to construct. Since there is air with the lowest relative permeability in the second slit, crosstalk between the first wiring and the second wiring can be reliably suppressed.

[0037] The present invention (13) includes the inductor described in any one of (8) to (11), wherein the aforementioned second suppression portion is a second filling portion filled in the void formed in the aforementioned third magnetic layer, and the relative permeability of the aforementioned second filling portion is lower than the relative permeability of the aforementioned first magnetic layer.

[0038] In this inductor, the second suppression part is a second filling part with a relative permeability lower than that of the first magnetic layer. Therefore, through this second filling part, crosstalk between the first wiring and the second wiring can be reliably suppressed.

[0039] The present invention (14) includes the inductor described in any one of (8) to (13), and further comprises a second processing stabilizing layer disposed on the aforementioned fourth surface of the aforementioned third magnetic layer.

[0040] The inductor has a second processing stabilization layer, thus the surface processing of the third magnetic layer is excellent.

[0041] The effects of the invention

[0042] The inductor of the present invention has excellent DC superposition characteristics and can suppress the reduction of inductance, and can suppress crosstalk between the first wiring and the second wiring. Attached Figure Description

[0043] Figure 1 This is a front cross-sectional view of one embodiment of the inductor of the present invention.

[0044] Figure 2 A~ Figure 2 C pair Figure 1 The manufacturing method of the inductor shown will be explained. Figure 2 Figure A illustrates the steps for preparing the first and second wirings and the first and third magnetic sheets. Figure 2 B shows the process of hot pressing them. Figure 2 C shows the process of forming the slit and the second slit.

[0045] Figure 3 for Figure 1 A cross-sectional view of a modified inductor shown (without the second slit).

[0046] Figure 4 for Figure 1 A cross-sectional view of a modified example of the inductor shown (where the slit does not face (or reach) the first surface, and the second slit does not face (or reach) the second surface).

[0047] Figure 5 for Figure 1 A cross-sectional view of a modified example of the inductor shown (where the slit is not exposed from the third surface and the second slit is not exposed from the fourth surface).

[0048] Figure 6 for Figure 1 A cross-sectional view of a modified inductor shown (where the slit does not face the first surface and is not exposed from the third surface, and the second slit does not face the second surface and is not exposed from the fourth surface).

[0049] Figure 7 for Figure 1 A cross-sectional view of a modified example of the inductor shown (in the manner in which the slit and the second slit connect to each other).

[0050] Figure 8 for Figure 1 A cross-sectional view of a modified example of the inductor shown (where the slit leads to the middle slit and the second slit leads to the second middle slit).

[0051] Figure 9 for Figure 1 A cross-sectional view of a modified example of the inductor shown (where the length of the slit in the thickness direction L2 is shorter than the length of the slit in the adjacent direction L3, and the length of the second slit in the thickness direction L4 is shorter than the length of the second slit in the adjacent direction L5).

[0052] Figure 10 for Figure 1 A cross-sectional view of a modified example of the inductor shown (in which the recess and the second recess coincide with the first wiring and the second wiring when projected along adjacent directions).

[0053] Figure 11 for Figure 1 A cross-sectional view of a modified example of the inductor shown (with the slits offset from the second slit).

[0054] Figure 12 for Figure 1 A cross-sectional view of a modified example of the inductor shown (where the first suppression part is the first filling part and the second suppression part is the second filling part).

[0055] Figure 13 for Figure 12A cross-sectional view of a modified example of the inductor shown (where the first filling part is embedded in the second magnetic layer and the second filling part is embedded in the third magnetic layer).

[0056] Figure 14 for Figure 13 A cross-sectional view of a modified example of the inductor shown (the first and second filling portions are arranged in a manner that the cross-sections are approximately circular).

[0057] Figure 15 for Figure 1 A cross-sectional view of a modified example of the inductor shown (with the inner side and the second inner side being tapered).

[0058] Figure 16 A~ Figure 16 Section B describes the manufacturing method (including processing method) of the inductor in the modified example. Figure 16 B illustrates the process of configuring the processing stability layer and the second processing stability layer. Figure 16 B shows the process of forming the slit and the second slit. Detailed Implementation

[0059] Reference Figures 1-2 C will describe one embodiment of the inductor of the present invention. It should be noted that, in Figure 2 A~ Figure 2 In C, in order to clearly show the relative arrangement of the first wiring 2 to the second wiring 3 with the first magnetic sheet 25 to the third magnetic sheet 27 and the first magnetic layer 4 to the third magnetic layer 6 (all described later), the wire 8 and the insulating film 9 (described later) are omitted, and only the first wiring 2 and the second wiring 3 (described later) are drawn.

[0060] like Figure 1 As shown, the inductor 1 has a sheet shape extending in the planar direction. The inductor 1 includes: a first wiring 2, a second wiring 3, a first magnetic layer 4, a second magnetic layer 5, a third magnetic layer 6, and a suppression portion 7.

[0061] Wiring 1 (2) and wiring 2 (3) are adjacent to each other with a gap between them. Wiring 1 (2) and wiring 2 (3) are parallel. They are perpendicular to the direction of current transmission. Figure 1 When the paper is cut in the thickness direction (length direction) (normal section), the first wiring 2 and the second wiring 3 each have a roughly circular shape. The first wiring 2 and the second wiring 3 each have a conductor 8 and an insulating film 9 covering them.

[0062] The conductor 8 is a conductor wire. The conductor 8 has a cross-section that is approximately circular, sharing a central axis with both the first wiring 2 and the second wiring 3. Examples of materials for the conductor 8 include metallic conductors such as copper, silver, gold, aluminum, nickel, and their alloys, with copper being a preferred example. The conductor 8 can be a single-layer structure or a multi-layer structure in which the surface of the core conductor (e.g., copper) is plated (e.g., with nickel). The diameter of the conductor 8 is, for example, 50 μm or more and 5000 μm or less.

[0063] The insulating film 9 protects the conductor 8 from damage by chemicals and water, and also prevents short circuits between the conductor 8 and the first magnetic layer 4. The insulating film 9 covers the entire outer peripheral surface (circumferential surface) of the conductor 8. The insulating film 9 has a cross-section that is approximately annular, sharing a central axis (center) with both the first wiring 2 and the second wiring 3. The insulating film 9 forms the outer peripheral surface 17 of both the first wiring 2 and the second wiring 3. Examples of materials for the insulating film 9 include polyvinyl alcohol formaldehyde, polyester, polyesterimide, polyamide (including nylon), polyimide, polyamide-imide, polyurethane, and other insulating resins. One of these can be used alone, or two or more can be used in combination. The insulating film 9 can be a single layer or multiple layers. The thickness of the insulating film 9 is, for example, 1 μm or more and 100 μm or less. The ratio of the radius of the conductor 8 to the thickness of the insulating film 9 is, for example, 2 or more and 500 or less.

[0064] The diameter L1 (average of the maximum length) of each of the first wiring 2 and the second wiring 3 is, for example, greater than 25 μm and less than 2000 μm.

[0065] The lower limit of the spacing L between adjacent first wirings 2 and second wirings 3 is, for example, 10, preferably 50, and the upper limit is, for example, 5000, preferably 3000. The upper limit of the ratio (L1 / L) of the diameter L1 of each first wiring 2 and second wiring 3 to the spacing L of adjacent first wirings 2 and second wirings 3 is, for example, 200, preferably 50, more preferably 30, and even more preferably 20, and the lower limit is, for example, 0.01. If the ratio (L1 / L) is below the above-mentioned upper limit, the reduction of inductance can be suppressed.

[0066] The first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6 work together to improve the inductance of the inductor 1 and enhance the DC superposition characteristics of the inductor 1.

[0067] The first magnetic layer 4 has a sheet shape extending in both the longitudinal direction of the first wiring 2 and the second wiring 3, and in the adjacent direction of the first wiring 2 and the second wiring 3 (surface direction). The first magnetic layer 4 has a first surface 11, a second surface 12, and an inner peripheral surface 10.

[0068] The first surface 11 is continuous in the surface direction of the first magnetic layer 4. The first surface 11 has a shape (e.g., a wavy shape) corresponding to the first wiring 2 and the second wiring 3. The first surface 11 is located on the side further in the thickness direction than the first wiring 2 and the second wiring 3.

[0069] In detail, when the first surface 11 has the aforementioned wave shape, it has a protrusion 31 and a recess 32. The protrusion 31 follows the outer peripheral surface 17 of the first wiring 2 and the second wiring 3 respectively.

[0070] The recess 32 is located between the two protrusions 31 and is recessed towards the other side in the thickness direction. When projected along the adjacent direction, the recess 32 does not coincide with the first wiring 2 and the second wiring 3, but is located on the side further in the thickness direction than them.

[0071] The second surface 12 is spaced apart from the first surface 11 on the opposite side in the thickness direction. The second surface is continuous in the surface direction of the first magnetic layer 4. The second surface 12 has a shape (e.g., a wavy shape) corresponding to the first wiring 2 and the second wiring 3. The second surface 12 is located on the opposite side in the thickness direction than the first wiring 2 and the second wiring 3.

[0072] In detail, when the second surface 12 has the aforementioned wave shape, it has a second protrusion 33 and a second recess 34. The second protrusion 33 follows the outer peripheral surface 17 of the first wiring 2 and the second wiring 3 respectively.

[0073] The second recess 34 is located between the two second protrusions 33 and is recessed towards the thickness direction. When projected along the adjacent direction, the second recess 34 does not coincide with the first wiring 2 and the second wiring 3, but is located on the other side of the thickness direction, which is closer to them.

[0074] The inner peripheral surface 10 is located between the first surface 11 and the second surface 12. The inner peripheral surface 10 is formed midway along the thickness direction of the first magnetic layer 4. The inner peripheral surface 10 contacts and covers the outer peripheral surfaces 17 of the first wiring 2 and the second wiring 3, respectively.

[0075] The relative permeability and material of the first magnetic layer 4 will be described in detail later.

[0076] The second magnetic layer 5 is disposed on the first surface 11 of the first magnetic layer 4. The second magnetic layer 5 has a sheet shape extending in the surface direction. The second magnetic layer 5 has a third surface 13 and a fifth surface 15.

[0077] The third surface 13 is disposed opposite to the first surface 11 on one side in the thickness direction, spaced apart. The third surface 13 forms one side of the inductor 1 in the thickness direction. The third surface 13 is flat, or, although not shown, may have a wavy shape following the first surface 11.

[0078] The fifth surface 15 is positioned opposite the third surface 13 on the opposite side of the thickness direction. The fifth surface 15 is in contact with the first surface 11.

[0079] The relative permeability and material of the second magnetic layer 5 will be described in detail later.

[0080] The third magnetic layer 6 is disposed on the second surface 12 of the first magnetic layer 4. The third magnetic layer 6 has a sheet shape extending in the surface direction. The third magnetic layer 6 has a fourth surface 14 and a sixth surface 16.

[0081] The fourth surface 14 and the second surface 12 are arranged opposite each other at a distance in the thickness direction. The fourth surface 14 forms the other side of the inductor 1 in the thickness direction. The fourth surface 14 is flat, or, although not shown, it may have a wavy shape that follows the second surface 12.

[0082] The relative permeability of the second magnetic layer 5 and the third magnetic layer 6 is higher than that of the first magnetic layer 4. Because the relative permeability of the second magnetic layer 5 and the third magnetic layer 6 is higher than that of the first magnetic layer 4, the inductor 1 has excellent DC superposition characteristics and can maintain a high inductance value.

[0083] The relative permeabilities of the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6 were all measured at a frequency of 10 MHz. Alternatively, the relative permeabilities of the first magnetic sheet 25, the second magnetic sheet 26, and the third magnetic sheet 27, which are precursors to the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6, can be measured in advance and considered to be substantially the same as the relative permeabilities of the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6.

[0084] Specifically, the lower limit of R1, the ratio of the relative permeability of the second magnetic layer 5 to the relative permeability of the first magnetic layer 4, is, for example, 1.1, preferably 1.5, more preferably 2, further preferably 5, particularly preferably 10, and most preferably 15. The upper limit is, for example, 10000. The ratio R2, the ratio of the relative permeability of the third magnetic layer 6 to the relative permeability of the first magnetic layer 4, is the same as R1. If the ratios R1 and / or R2 are above the aforementioned lower limits, the DC superposition characteristics are even better.

[0085] The first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6 all contain magnetic particles. Specifically, the materials used for the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6 include, for example, magnetic compositions containing magnetic particles and binders.

[0086] Magnetic materials that constitute magnetic particles include, for example, soft magnetic materials and hard magnetic materials. From the viewpoint of inductance and DC superposition characteristics, soft magnetic materials are preferred.

[0087] Examples of soft magnetic materials include: for example, a single metallic body containing one metallic element in its pure state; and an alloy body, such as a eutectic (mixture) of one or more metallic elements (first metallic element) and one or more metallic elements (second metallic element) and / or non-metallic elements (carbon, nitrogen, silicon, phosphorus, etc.). They can be used alone or in combination.

[0088] As a single metallic substance, examples include metallic elements containing only one metallic element (the first metallic element). As the first metallic element, it can be appropriately selected from iron (Fe), cobalt (Co), nickel (Ni), and other metallic elements that can serve as the first metallic element of a soft magnetic material.

[0089] Furthermore, examples of single metallic bodies include: for example, a core containing only one metallic element, and a surface layer containing inorganic and / or organic matter that modifies part or all of the surface of the core; for example, forms obtained by decomposing (thermally decomposing, etc.) an organometallic compound containing the first metallic element, or an inorganic metal compound. More specifically, examples of the latter include iron powder (sometimes called carbonyl iron powder) obtained by the thermal decomposition of an organoiron compound containing iron as the first metallic element (specifically, carbonyl iron). It should be noted that the location of the layer containing inorganic and / or organic matter that modifies the portion containing only one metallic element is not limited to the surface described above. It should also be noted that there are no particular limitations on the organometallic compounds or inorganic metal compounds that can produce single metallic bodies; appropriate selections can be made from known and conventional organometallic compounds or inorganic metal compounds that can produce single metallic bodies that produce soft magnetic materials.

[0090] An alloy body is a eutectic of one or more metallic elements (first metallic element) and one or more metallic elements (second metallic element) and / or non-metallic elements (carbon, nitrogen, silicon, phosphorus, etc.). There are no particular restrictions as long as the alloy body can be used as a soft magnetic material.

[0091] The first metallic element is an essential element in the alloy; examples include iron (Fe), cobalt (Co), and nickel (Ni). It should be noted that if the first metallic element is Fe, the alloy is an Fe-based alloy; if the first metallic element is Co, the alloy is a Co-based alloy; and if the first metallic element is Ni, the alloy is a Ni-based alloy.

[0092] The second metallic element is a minor element (secondary component) present in the alloy, and is a metallic element compatible (eutectic) with the first metallic element. Examples include iron (Fe) (when the first metallic element is not Fe), cobalt (Co) (when the first metallic element is not Co), nickel (Ni) (when the first metallic element is not 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), rubidium (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. Two or more of these can be used alone or in combination.

[0093] Nonmetallic elements are minor components (secondary elements) in an alloy. They are nonmetallic elements that are compatible with the primary metallic element (eutectic). Examples include boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), and sulfur (S). These can be used alone or in combination of two or more.

[0094] Examples of Fe-based alloys as alloy bodies include magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), iron-silicon-aluminum soft magnetic alloy (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, 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, and F... Fe-Si-Al-Ni-Cr alloys, Fe-Ni-Si-Co alloys, Fe-N alloys, Fe-C alloys, Fe-B alloys, Fe-P alloys, ferrites (including stainless steel ferrites, as well as soft magnetic ferrites such as Mn-Mg ferrites, Mn-Zn ferrites, Ni-Zn ferrites, Ni-Zn-Cu ferrites, Cu-Zn ferrites, and Cu-Mg-Zn ferrites), iron-cobalt magnetic alloys (Permendur, Fe-Co alloys), Fe-Co-V alloys, Fe-based amorphous alloys, etc.

[0095] Examples of Co-based alloys that are examples of alloy bodies include Co-Ta-Zr and cobalt (Co)-based amorphous alloys.

[0096] Examples of Ni-based alloys that are examples of alloy bodies include Ni-Cr alloys.

[0097] The shape of magnetic particles is not particularly limited. Examples of anisotropic shapes include roughly flat (plate-shaped) and roughly needle-shaped (including roughly spindle (rugby ball)-shaped); and roughly spherical, roughly particle-shaped, roughly block-shaped, etc., which are roughly isotropic.

[0098] The lower limit of the average maximum length of the magnetic particles is, for example, 0.1 μm, preferably 0.5 μm, and the upper limit is, for example, 200 μm, preferably 150 μm. The average maximum length of the magnetic particles can be calculated in the form of the median particle size of the magnetic particles.

[0099] The lower limit of the volume ratio (fill rate) of magnetic particles in the magnetic composition is, for example, 10% by volume, preferably 20% by volume, and the upper limit is, for example, 90% by volume, preferably 80% by volume.

[0100] Examples of adhesives include thermoplastic components such as acrylic resins and thermosetting components such as epoxy resin compositions. Acrylic resins include, for example, carboxyl-containing acrylate copolymers. Epoxy resin compositions include, for example, an epoxy resin (such as a cresol-phenolic varnish-type epoxy resin) as a main agent, an epoxy resin curing agent (such as a phenolic resin), and an epoxy resin curing accelerator (such as an imidazole compound).

[0101] As a binder, thermoplastic and thermosetting components can be used separately or in combination, with the combination of thermoplastic and thermosetting components being preferred.

[0102] It should be noted that a more detailed formulation of the above-mentioned magnetic composition is described in Japanese Patent Application Publication No. 2014-165363, etc.

[0103] The type, shape, size, volume ratio, etc. of the magnetic particles in the magnetic composition can be appropriately changed so that the relative permeability of the second magnetic layer 5 and the third magnetic layer 6 is higher than that of the first magnetic layer 4.

[0104] If the shape of the magnetic particles is illustrated, the material of the first magnetic layer 4 comprises magnetic particles of approximately spherical shape, and the materials of the second magnetic layer 5 and the third magnetic layer 6 both comprise magnetic particles of approximately flat shape (e.g., Examples 1 to 4 described later). Alternatively, the material of any one of the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6 comprises magnetic particles of approximately spherical shape (e.g., Examples 5 to 8 described later).

[0105] The suppression part 7 is configured to suppress the magnetic coupling between the first wiring 2 and the second wiring 3. When projected along the thickness direction, the suppression part 7 is located between the first wiring 2 and the second wiring 3.

[0106] In detail, when projected along the thickness direction, the suppression part 7 does not coincide with either the first wiring 2 or the second wiring 3. When projected along the thickness direction, the suppression part 7 is located between the first point 51, which is closest to the second wiring 3 on the outer peripheral surface 17 of the first wiring 2, and the second point 52, which is closest to the first wiring 2 on the outer peripheral surface 17 of the second wiring 3.

[0107] The suppression section 7 includes a slit 21 as an example of a first suppression section and a second slit 22 as an example of a second suppression section. In this embodiment, it is preferable that the suppression section 7 only includes the slit 21 and the second slit 22.

[0108] The slit 21 is located between the first surface 11 and the third surface 13. Specifically, the suppression portion 7 is formed throughout the entire thickness direction of the second magnetic layer 5. Specifically, the slit 21 penetrates the second magnetic layer 5 in the thickness direction. However, although the slit 21 penetrates the second magnetic layer 5, it neither penetrates nor cuts into the first magnetic layer 4. The slit 21 faces the first surface 11. That is, the slit 21 exposes the corresponding recess 32 of the first surface 11. Additionally, the slit 21 is exposed from the third surface 13. In other words, the slit 21 opens towards the thickness direction. This slit 21 is divided by the recess 32 of the first surface 11 of the first magnetic layer 4 and the two inner surfaces 23 of the second magnetic layer 5 that expose it. The spacing between the two inner surfaces 23 is the same throughout the thickness direction; specifically, they are parallel.

[0109] The length L2 of the slit 21 in the thickness direction is longer than the length L3 of the slit 21 in the adjacent direction. The ratio (L2 / L3) of the length L2 of the slit 21 in the thickness direction to the length L3 of the slit 21 in the adjacent direction is greater than 1. Specifically, the lower limit of the ratio (L2 / L3) is, for example, 1.5, preferably 3, more preferably 5, and even more preferably 10. In addition, the upper limit is, for example, 1000. If the ratio (L2 / L3) is greater than or equal to the above-mentioned lower limit, crosstalk between the first wiring 2 and the second wiring 3 can be effectively suppressed.

[0110] The upper limit of the ratio (L3 / L) of the length L3 of the slit 21 in the adjacent direction to the interval L of the adjacent first wiring 2 and second wiring 3 is, for example, 0.95, preferably 0.9, and the lower limit is, for example, 0.0001.

[0111] Specifically, the upper limit of the length L3 of the slit 21 in the adjacent direction is, for example, 1000 μm, preferably 700 μm, preferably 500 μm, more preferably 300 μm, and the lower limit is, for example, 5 μm.

[0112] The second slit 22 is located between the second surface 12 and the fourth surface 14. Specifically, the suppression portion 7 is formed along the entire thickness of the third magnetic layer 6. The second slit 22 is formed in the third magnetic layer 6. Specifically, the second slit 22 penetrates the third magnetic layer 6 in the thickness direction. However, although the second slit 22 penetrates the third magnetic layer 6, it neither penetrates nor cuts into the first magnetic layer 4. The second slit 22 faces the second surface 12. That is, the second slit 22 exposes the corresponding third surface 13 (the second recess 34). Additionally, the second slit 22 is exposed from the fourth surface 14. In other words, the second slit 22 opens towards the other side in the thickness direction. This second slit 22 is divided by the second recess 34 of the second surface 12 and the two second inner surfaces 24 of the third magnetic layer 6 that expose it. The spacing between the two second inner surfaces 24 is the same throughout the thickness direction; specifically, they are parallel.

[0113] The length L4 of the second slit 22 in the thickness direction is longer than the length L5 of the second slit 22 in the adjacent direction. The lower limit of the ratio (L4 / L5) of the length L4 of the second slit 22 in the thickness direction to the length L5 of the second slit 22 in the adjacent direction is greater than 1. Specifically, the ratio (L4 / L5) is, for example, 1.5, preferably 3, more preferably 5, and even more preferably 10. In addition, the upper limit is, for example, 1000. If the ratio (L4 / L5) is greater than or equal to the above-mentioned lower limit, crosstalk between the first wiring 2 and the second wiring 3 can be effectively suppressed.

[0114] The lower limit of the ratio (L5 / L) of the length L5 of the second slit 22 in the adjacent direction to the interval L of the adjacent first wiring 2 and second wiring 3 is, for example, 0.95, preferably 0.9, and the upper limit is, for example, 0.0001.

[0115] Specifically, the length L5 of the second slit 22 in the adjacent direction is the same as the length L3 of the slit 21 in the adjacent direction.

[0116] The thickness of inductor 1 is the length between the third surface 13 and the fourth surface 14. Specifically, the lower limit of the thickness of inductor 1 is, for example, 30 μm, preferably 50 μm, and the upper limit is, for example, 10000 μm, preferably 2000 μm.

[0117] To obtain inductor 1, such as Figure 2 As shown in A, firstly, prepare the first wiring 2 and the second wiring 3, two first magnetic pieces 25, one second magnetic piece 26, and one third magnetic piece 27.

[0118] Two first magnetic sheets 25 are precursor sheets for forming the first magnetic layer 4. A second magnetic sheet 26 is a precursor sheet for forming the second magnetic layer 5. A third magnetic sheet 27 is a precursor sheet for forming the third magnetic layer 6. These precursor sheets are, for example, of order B.

[0119] The second magnetic sheet 26, a first magnetic sheet 25, the first wiring 2 and the second wiring 3, another first magnetic sheet 25, and the third magnetic sheet 27 are arranged sequentially toward the other side in the thickness direction.

[0120] Next, they are hot-pressed along the thickness direction. The two first magnetic sheets 25 are deformed to form the first magnetic layer 4 by embedding the first wiring 2 and the second wiring 3. The second magnetic sheet 26 is deformed to follow the first surface 11 to form the second magnetic layer 5. The third magnetic sheet 27 is deformed to follow the second surface 12 to form the third magnetic layer 6. It should be noted that through the above hot pressing, the precursor sheets (first magnetic sheets 25 to third magnetic sheets 27) become C-order. Thus, an inductor 1 is obtained that does not have the suppression part 7 but has the first magnetic layers 4 to the third magnetic layers 6.

[0121] like Figure 2 As shown in C, slits 21 and 22 are then formed on the second magnetic layer 5 and the third magnetic layer 6 of the inductor 1, respectively. To form slits 21 and 22, a cutting device is used, for example.

[0122] Examples of cutting devices include: contact cutting devices that make physical contact with the second magnetic layer 5 and / or the third magnetic layer 6, such as cutting devices; and non-contact cutting devices that do not make physical contact with the second magnetic layer 5 and / or the third magnetic layer 6, such as laser devices.

[0123] As an example of a contact cutting device, the cutting device includes a support table (not shown), a cutting saw 28 disposed opposite to it at a distance, and a moving device (not shown) for moving it. The cutting saw 28 may include, for example, a cutting blade with a disc shape.

[0124] Therefore, an inductor 1 having a suppression portion 7 having a slit 21 and a second slit 22 can be manufactured.

[0125] <Effects of one implementation method>

[0126] In this inductor 1, the relative permeability of the second magnetic layer 5 and the third magnetic layer 6 is higher than that of the first magnetic layer 4, and the suppression part 7 includes a slit 21 located between the first surface 11 and the third surface 13. Therefore, it has excellent DC superposition characteristics and can suppress the reduction of inductance, and can suppress crosstalk between the first wiring 2 and the second wiring 3.

[0127] In this inductor 1, the slit 21 faces the first surface 11, thus effectively suppressing crosstalk between the first wiring 2 and the second wiring 3.

[0128] In this inductor 1, the slit 21 is exposed from the third surface 13, so the slit 21 can be easily formed.

[0129] In this inductor 1, the length L2 of the slit 21 in the thickness direction is longer than the length L3 of the slit 21 in the adjacent direction. Therefore, it can suppress the reduction of inductance as much as possible and effectively suppress crosstalk between the first wiring 2 and the second wiring 3.

[0130] In this inductor 1, the first suppression part is a slit 21, which is simple to construct. Since there is air in the slit 21 with a relative permeability of 1, the crosstalk between the first wiring 2 and the second wiring 3 can be reliably suppressed through the slit 21.

[0131] In the inductor 1, the suppression part 7 also includes a second slit 22 located between the second surface 12 and the fourth surface 14, so that it can suppress the decrease of inductance and suppress crosstalk between the first wiring 2 and the second wiring 3.

[0132] In this inductor 1, the second slit 22 faces the second surface 12, thus effectively suppressing crosstalk between the first wiring 2 and the second wiring 3.

[0133] In this inductor 1, the second slit 22 is exposed from the fourth surface 14, thus the second slit 22 can be easily formed.

[0134] In this inductor 1, the length L4 of the second slit 22 in the thickness direction is longer than the length L5 of the second slit 22 in the adjacent direction. Therefore, it can suppress the reduction of inductance as much as possible and effectively suppress crosstalk between the first wiring 2 and the second wiring 3.

[0135] In this inductor 1, the second suppression part is the second slit 22, which is simple to construct. Since there is air in the slit 21 with a relative permeability of 1, which is the lowest, crosstalk between the first wiring 2 and the second wiring 3 can be reliably suppressed.

[0136] <Variation Example>

[0137] In the variations, components and processes identical to those in the first embodiment are marked with the same reference numerals, and their detailed descriptions are omitted. Furthermore, unless otherwise specified, the variations can achieve the same effects as the first embodiment. Moreover, a first embodiment and its variations can be appropriately combined.

[0138] like Figure 3 As shown, in this inductor 1, the suppression section 7 does not have the second slit 22 (see reference). Figure 1 The suppression part 7 has only slit 21. From the viewpoint of efficiently suppressing crosstalk between the first wiring 2 and the second wiring 3, it is preferable that the suppression part 7 has slit 21 and second slit 22.

[0139] like Figure 4 As shown, slit 21 does not face the first surface 11 and is spaced apart from the first surface 11 in the thickness direction. Second slit 22 does not face the second surface 12 and is spaced apart from the second surface 12 in the thickness direction. Preferably, as in one embodiment, slit 21 faces the first surface 11, and second slit 22 faces the second surface 12.

[0140] like Figure 5 As shown, slit 21 is not exposed from the third surface 13, and one end edge of slit 21 in the thickness direction is closed by the second magnetic layer 5. Second slit 22 is not exposed from the fourth surface 14, and the other end edge of second slit 22 in the thickness direction is closed by the third magnetic layer 6. Preferably, as in one embodiment, slit 21 is exposed from the third surface 13, and second slit 22 is exposed from the fourth surface 14.

[0141] like Figure 6 As shown, slit 21 does not face the first surface 11 and does not protrude from the third surface 13. Slit 21 is located at the midpoint of the thickness direction between the first surface 11 and the third surface 13. Second slit 22 does not face the second surface 12 and does not protrude from the fourth surface 14. Second slit 22 is located at the midpoint of the thickness direction between the second surface 12 and the fourth surface 14.

[0142] like Figure 7 As shown, slit 21 and slit 22 are connected to each other via an intermediate slit 29. The intermediate slit 29 is located between the first surface 11 and the second surface 12. The intermediate slit 29 penetrates the first magnetic layer 4 in the thickness direction. Preferably, as in one embodiment, the intermediate slit 29 is not formed in the inductor 1.

[0143] like Figure 8 As shown, slit 21 leads to intermediate slit 29. Intermediate slit 29 cuts into the first surface 11 of the first magnetic layer 4 towards the middle portion in the thickness direction. Second slit 22 leads to second intermediate slit 30. Second intermediate slit 30 cuts into the second surface 12 of the first magnetic layer 4 towards the middle portion in the thickness direction. Second intermediate slit 30 and intermediate slit 29 are arranged opposite each other at a distance in the thickness direction.

[0144] like Figure 9As shown, the length L2 of the slit 21 in the thickness direction is shorter than the length L3 of the slit 21 in the adjacent direction. Furthermore, although not shown, the lengths L2 and L3 in the slit 21 can be the same. The upper limit of the ratio (L2 / L3) of the length L2 of the slit 21 in the thickness direction to the length L3 of the slit 21 in the adjacent direction is, for example, 1 or less, preferably less than 1; the lower limit of the ratio (L2 / L3) is 0.01, preferably 0.05, more preferably 0.1, and even more preferably 0.2.

[0145] The length L4 of the second slit 22 in the thickness direction is shorter than the length L5 of the second slit 22 in the adjacent direction. Furthermore, although not shown, the lengths L4 and L5 in the second slit 22 can be the same. The upper limit of the ratio (L4 / L5) of the length L4 of the second slit 22 in the thickness direction to the length L5 of the second slit 22 in the adjacent direction is, for example, 1 or less, preferably less than 1. The lower limit of the ratio (L2 / L3) is 0.01, preferably 0.05, more preferably 0.1, and even more preferably 0.2.

[0146] like Figure 10 As shown, when projected along adjacent directions, the recess 32 in the first surface 11 coincides with the first wiring 2 and the second wiring 3. When projected along adjacent directions, the second recess 34 in the second surface 12 coincides with the first wiring 2 and the second wiring 3.

[0147] like Figure 11 As shown, when projected along the thickness direction, slit 21 and the second slit 22 are offset (deviation) in adjacent directions.

[0148] like Figure 12 As shown, the gap 35, which serves as slit 21, is filled with a first filling portion 37. The gap 35, which serves as slit 22, is filled with a second filling portion 38.

[0149] like Figure 13 As shown, the first filling portion 37 is not exposed from the third surface 13 and is embedded in the second magnetic layer 5. The second filling portion 38 is not exposed from the fourth surface 14 and is embedded in the third magnetic layer 6. The first filling portion 37 and the second filling portion 38 each have a roughly rectangular cross-sectional shape. The relative permeability of the first filling portion 37 and the second filling portion 38 is lower than the relative permeability of the first magnetic layer 4.

[0150] Regarding the materials for the first filling portion 37 and the second filling portion 38, examples include non-magnetic compositions that do not contain magnetic particles and contain a binder. Examples of binders are given in the aforementioned magnetic compositions.

[0151] To obtain inductor 1, refer to... Figure 2As in A, firstly, two first magnetic sheets 25, a first wiring 2, and a second wiring 3 are prepared and hot-pressed together. When the first magnetic sheet 25 contains thermosetting components, it is C-shaped by hot pressing. This forms the first magnetic layer 4. Next, a first filling portion 37 and a second filling portion 38 in a solid state at room temperature are respectively disposed in the recess 32 of the first surface 11 and the second recess 34 of the second surface 12. Then, they are clamped with a second magnetic sheet 26 and a third magnetic sheet 27 and hot-pressed together. This forms the second magnetic layer 5 with the first filling portion 37 embedded and the third magnetic layer 6 with the second filling portion 38 embedded.

[0152] like Figure 14 As shown, the first filling portion 37 and the second filling portion 38 each have a roughly circular shape in cross-section.

[0153] like Figure 15 As shown, the two inner surfaces 23 of the dividing slit 21 have conical shapes with opposing lengths that gradually decrease from the third surface 13 toward the first surface 11. The two second inner surfaces 24 of the dividing slit 22 have conical shapes with opposing lengths that gradually decrease from the fourth surface 14 toward the second surface 12.

[0154] Depending on the thickness of the first magnetic layer 4, the first magnetic sheet 25 can be composed of multiple sheets. Depending on the thickness of the second magnetic layer 5, the second magnetic sheet 26 can be composed of multiple sheets. Depending on the thickness of the third magnetic layer 6, the third magnetic sheet 27 can be composed of multiple sheets.

[0155] Although not illustrated, the shapes of the first wiring 2 and the third wiring 3 are not particularly limited; for example, they can also be rectangular in cross-section.

[0156] Although not illustrated, the second magnetic layer 5, with the pre-formed slit 21, can be adhered to the first surface 11 of the first magnetic layer 4. Alternatively, the third magnetic layer 6, with the pre-formed second slit 22, can be adhered to the second surface 12 of the first magnetic layer 4.

[0157] like Figure 16 As shown in B, the inductor 1 may also include a processing stabilization layer 71 and a processing stabilization layer 72.

[0158] The processing stabilizing layer 71 and the processing stabilizing layer 72 improve the surface machinability of the third surface 13 of the second magnetic layer 5 and the surface machinability of the fourth surface 14 of the third magnetic layer 6, respectively.

[0159] A processing stabilizing layer 71 is disposed on the third surface 13 of the second magnetic layer 5. The processing stabilizing layer 71 also has slits 21 formed thereon. The processing stabilizing layer 71 contacts the entire third surface 13.

[0160] The processing stabilized layer 71 comprises a cured thermosetting resin composition. That is, the material of the processing stabilized layer 71 comprises a thermosetting resin composition.

[0161] The thermosetting resin composition contains a thermosetting resin as an essential component and particles as an optional component.

[0162] As a thermosetting resin, it includes a main agent, a curing agent, and a curing accelerator.

[0163] Examples of main agents include epoxy resins and silicone resins, with epoxy resins being the preferred choice. Examples of epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, modified bisphenol A type epoxy resin, modified bisphenol F type epoxy resin, modified bisphenol S type epoxy resin, biphenyl type epoxy resin, and other difunctional epoxy resins; and polyfunctional epoxy resins with three or more functions, such as phenolic varnish epoxy resin, cresol varnish epoxy resin, trihydroxyphenylmethane type epoxy resin, tetraphenolic ethane type epoxy resin, and dicyclopentadiene type epoxy resin. These epoxy resins can be used alone or in combination of two or more. Difunctional epoxy resins are preferred, and bisphenol A type epoxy resins are more preferred.

[0164] The lower limit of epoxy equivalent of epoxy resin is, for example, 10 g / eq., and the upper limit is, for example, 1000 g / eq.

[0165] As a curing agent, if the main agent is an epoxy resin, examples include phenolic resins and isocyanate resins. Examples of phenolic resins include phenolic varnish resins, cresol phenolic varnish resins, phenol aralkyl resins, phenol biphenyl resins, dicyclopentadiene-type phenolic resins, and methyl-type phenolic resins, among other multifunctional phenolic resins. These can be used alone or in combination of two or more. Phenolic varnish resins and phenol biphenyl resins are preferred examples of phenolic resins. If the main agent is an epoxy resin and the curing agent is a phenolic resin, the lower limit of the total number of hydroxyl groups in the phenolic resin relative to 1 equivalent of epoxy groups in the epoxy resin is, for example, 0.7 equivalents, preferably 0.9 equivalents, and the upper limit is, for example, 1.5 equivalents, preferably 1.2 equivalents. Specifically, the lower limit of the mass parts of the curing agent relative to 100 parts by mass of the main agent is, for example, 1 part by mass, and for example, 50 parts by mass.

[0166] As a curing accelerator, it is a catalyst (thermosetting catalyst) that promotes the curing of the main agent (preferably an epoxy resin curing accelerator), and examples include: organophosphorus compounds; imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazolium (2P4MHZ). The lower limit of the mass fraction of the curing accelerator relative to 100 parts by mass of the main agent is, for example, 0.05 parts by mass, and the upper limit is, for example, 5 parts by mass.

[0167] The particles are an optional component in the thermosetting resin composition. The particles are dispersed in the thermosetting resin. The particles are at least one type selected from the group consisting of the first particle and the second particle.

[0168] The first particle has a generally spherical shape. The lower limit of the median particle size of the first particle is, for example, 1 μm, preferably 5 μm, and the upper limit is, for example, 250 μm, preferably 200 μm. The median particle size of the first particle is determined using a laser diffraction particle size distribution measuring device. Alternatively, the median particle size of the first particle can also be determined, for example, by binarization processing based on cross-sectional observation of the laminate 1.

[0169] The material of the first particle is not particularly limited. Examples of materials for the first particle include metals, inorganic compounds, and organic compounds. To improve the coefficient of thermal expansion, metals and inorganic compounds are preferred.

[0170] The metal is included in the thermosetting resin composition when the processing stabilizing layer 71 functions as an inductance-enhancing layer. Examples of metals include magnets exemplified in the magnetic layer 5, and more preferably, organoferric compounds containing iron as the first metal element, and more preferably, iron carbonyl.

[0171] The inorganic compound is included in the thermosetting resin composition to enable the processing stabilizing layer 71 to function as a thermal expansion coefficient suppression layer. Examples of inorganic compounds include inorganic fillers, specifically silica, alumina, etc., with silica being a preferred example.

[0172] Specifically, spherical silicon dioxide is preferably listed as the first particle, and spherical carbonyl iron is also preferably listed.

[0173] The second particle has a generally flat shape. A generally flat shape includes a generally plate-like shape.

[0174] The lower limit of the flatness (flatness) of the second particle is, for example, 8, preferably 15, and the upper limit is, for example, 500, preferably 450. The flatness of the second particle is calculated using the same method as that used for the flatness of the magnetic particles in the magnetic layer 5 described above.

[0175] The lower limit of the median particle size of the second particle is, for example, 1 μm, preferably 5 μm, and the upper limit of the median particle size of the second particle is, for example, 250 μm, preferably 200 μm.

[0176] The median particle size of the second particle was determined using the same method as that used for the median particle size of the first particle.

[0177] The lower limit of the average thickness of the second particle is, for example, 0.1 μm, preferably 0.2 μm, and the upper limit is, for example, 3.0 μm, preferably 2.5 μm.

[0178] The material of the second particle is an inorganic compound. Examples of inorganic compounds include thermally conductive compounds such as boron nitride. Therefore, it is preferable that the inorganic compound is included in the thermosetting resin composition so that the processing stabilizing layer 71 functions as a thermal conductivity improving layer.

[0179] Specifically, as the second particle, a flat-shaped boron nitride is preferably listed.

[0180] The first particle and the second particle may be contained in the thermosetting resin composition by means of only one of them, or both of them.

[0181] The minimum mass fraction of particles (first particle and / or second particle) relative to 100 parts by mass of thermosetting resin is, for example, 10 parts by mass, preferably 50 parts by mass, and the maximum mass fraction is, for example, 2000 parts by mass, preferably 1500 parts by mass. Furthermore, the minimum mass fraction of particles in the cured product is, for example, 10% by mass, and the maximum mass fraction is, for example, 90% by mass. When the thermosetting resin composition contains both first and second particles, the minimum mass fraction of the second particle relative to 100 parts by mass of the first particle is, for example, 30 parts by mass, and the maximum mass fraction is, for example, 300 parts by mass.

[0182] Particles are an optional component in thermosetting resin compositions, therefore thermosetting resin compositions may also be free of particles.

[0183] The lower limit of the thickness of the processing stabilizing layer 71 is, for example, 1 μm, preferably 10 μm, and the upper limit is, for example, 1000 μm, preferably 100 μm. The lower limit of the ratio of the thickness of the processing stabilizing layer 71 to the thickness of the laminate 1 is, for example, 0.001, preferably 0.005, more preferably 0.01, and the upper limit is, for example, 0.5, preferably 0.3, more preferably 0.1.

[0184] The material and dimensions of the second processing stabilizing layer 72 are the same as those of the processing stabilizing layer 71.

[0185] In order to manufacture an inductor 1 having a processing stabilization layer 71 and a second processing stabilization layer 72, such as Figure 2 As shown in B, an inductor 1 without the suppression part 7 is fabricated. Then, as... Figure 16 As shown in A, two processing stabilizers 73 are respectively arranged (stacked) on the third surface 13 and the fourth surface 14.

[0186] The processing stabilizer 73 is formed into a sheet shape from the materials of the processing stabilizer layer 71 and the second processing stabilizer layer 72. The processing stabilizer 73 preferably contains a B-stage thermosetting resin composition.

[0187] It should be noted that a solvent can also be further mixed into the above-mentioned thermosetting resin composition, and the material can be prepared in the form of a varnish. Furthermore, a thermoplastic resin can also be further mixed into the material.

[0188] Examples of solvents include alcohols such as methanol, ethers such as dimethyl ether, and ketones such as methyl ethyl ketone and cyclohexanone. The mixing ratio of the solvent is adjusted such that the lower limit of the mass percentage of the solids in the varnish is, for example, 10% by mass, and the upper limit is, for example, 95% by mass.

[0189] In this method, varnish is applied to the surface of a release sheet (not shown) and allowed to dry to form two processing stabilized sheets 73.

[0190] Next, pressure is applied to the two processing stabilizers 73 from both sides in the thickness direction. The two processing stabilizers 73 are then attached to the third surface 13 and the fourth surface 14, respectively.

[0191] Then, they are heated to C-order the processing stabilized sheet 73. This forms a slit 21 in the processing stabilized layer 71 and the second magnetic layer 5. Additionally, a second slit 22 is formed in the second processing stabilized layer 72 and the third magnetic layer 6. Thus, a laminate 1 is obtained in which slits 21 and 22 are formed in each of the processing stabilized layer 71 and the second magnetic layer 5, and in each of the second processing stabilized layer 72 and the third magnetic layer 6.

[0192] The modified inductor 1 has a processing stabilization layer 71, so the processing stability of the second magnetic layer 5 is excellent.

[0193] In a detailed description, although not illustrated, when the inductor 1 is composed only of the first wiring 2, the second wiring 3, the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6 without the processing stabilizing layer 71, the inner end of the third surface 13 of the second magnetic layer 5 facing the slit 21 will warp (bulge) towards the thickness direction when the slit 21 is formed on the second magnetic layer 5. In this case, when the slit 21 is formed on the second magnetic layer 5, the magnetic particles are difficult to break because they are made of metal, and because their shape is generally flat, the adhesive around the magnetic particles will be entrained, and the second magnetic layer 5 will move towards the thickness direction.

[0194] However, the inductor 1 in this embodiment is as follows: Figure 16 As shown in B, it has a processing stabilizing layer 71, which contains at least one type of particle selected from the group consisting of the first particle and the second particle as an optional component.

[0195] Specifically, when the processing stabilizing layer 71 does not contain particles, there is no deformation of the processing stabilizing layer 71 caused by the movement of the aforementioned particles. Therefore, the deformation of the second magnetic layer 5 can be suppressed by the cured material in the processing stabilizing layer 71.

[0196] When the processing stabilizing layer 71 contains the first particles that are approximately spherical in shape, the movement of the first particles in the processing stabilizing layer 71, simultaneously with the adhesive around the tape, is suppressed. Therefore, deformation of the second magnetic layer 5 can be suppressed by the cured material in the processing stabilizing layer 71.

[0197] When the stabilizing layer 71 contains second particles made of an inorganic compound, even if they are generally flat, the second particles are prone to breakage when the slit 21 is formed in the second magnetic layer 5 because the material of the second particles is a brittle inorganic compound. Therefore, movement of the second particles in the stabilizing layer 71 is suppressed. As a result, deformation of the second magnetic layer 5 can be suppressed by processing the cured material in the stabilizing layer 71.

[0198] Therefore, since the modified inductor 1 has the above-mentioned processing stabilization layer 71, the deformation of the second magnetic layer 5 can be suppressed when the slit 21 is formed in the inductor 1.

[0199] Furthermore, since the inductor 1 of this modified example has the second processing stabilization layer 72 described above, for the reasons mentioned above, deformation of the third magnetic layer 6 can be suppressed when the slit 22 is formed on the third magnetic layer 6.

[0200] It should be noted that, although not shown in the figure, the inductor 1 may also have only the processing stabilization layer 71 instead of the second processing stabilization layer 72.

[0201] In addition, the inductor 1 of the above-described modified example (preferably an inductor 1 having a processing stabilization layer 71 and a second processing stabilization layer 72) satisfies at least one of the tests (a) to (e).

[0202] Experiment (a): A sample of inductor 1 was fabricated by machining its shape into a 3cm square, and its relative permeability μ1 at a frequency of 10MHz was determined. Then, the sample was immersed in 200mL of a copper sulfate plating solution containing 66g / L copper sulfate pentahydrate, 180g / L sulfuric acid, 50ppm chlorine, and TOP LUCINA at 25°C for 120 minutes, and the relative permeability μ2 of the sample at a frequency of 10MHz was determined. The rate of change of permeability before and after immersion was calculated using the following formula.

[0203] As a result, the rate of change of the magnetic permeability of the sample was less than 5%.

[0204] Rate of change of permeability (%) = |μ1-μ2| / μ1×100

[0205] Experiment (b): A sample was fabricated by machining the inductor 1 into a 3cm square shape, and its relative permeability μ3 at a frequency of 10MHz was determined. Then, the sample was immersed in 200mL of an acid-active aqueous solution containing 55g / L sulfuric acid at 25°C for 1 minute, and the relative permeability μ4 at a frequency of 10MHz was determined. The rate of change of permeability before and after immersion was calculated using the following formula. The result showed that the rate of change of the sample's permeability was less than 5%.

[0206] Rate of change of permeability (%) = |μ3-μ4| / μ3×100

[0207] Experiment (c): A sample was fabricated by machining inductor 1 into a 3cm square shape, and its relative permeability μ5 at a frequency of 10MHz was determined. Then, the sample was immersed in 200mL of Reduction Solution Securiganth P manufactured by Atotech Japan at 45°C for 5 minutes, and the relative permeability μ6 at a frequency of 10MHz was determined. The rate of change of permeability before and after immersion was calculated using the following formula. The result showed that the rate of change of permeability of the sample was less than 5%.

[0208] Rate of change of permeability (%) = |μ₅ - μ₆| / μ₅ × 100

[0209] Experiment (d): A sample was fabricated by machining inductor 1 into a 3cm square shape, and its relative permeability μ7 at a frequency of 10MHz was determined. Then, the sample was immersed in 200mL of Concentrate Compact CP (manufactured by Atotech Japan) at 80°C for 15 minutes, and the relative permeability μ8 at a frequency of 10MHz was determined. The rate of change of permeability before and after immersion was calculated using the following formula. The results showed that the rate of change of permeability of the sample was less than 5%.

[0210] Rate of change of permeability (%) = |μ7 - μ8| / μ7 × 100

[0211] Experiment (e): A sample was fabricated by machining inductor 1 into a 3cm square shape, and its relative permeability μ9 at a frequency of 10MHz was determined. Then, the sample was immersed in 200mL of Swelling Dip Securiganth P (manufactured by Atotech Japan) at 60°C for 5 minutes, and the relative permeability μ10 at a frequency of 10MHz was determined. The rate of change of permeability before and after immersion was calculated using the following formula. The result showed that the rate of change of permeability of the sample was less than 5%.

[0212] Rate of change of permeability (%) = |μ9 - μ10| / μ9 × 100

[0213] Under the condition that test (a) is satisfied, the upper limit of the rate of change of magnetic permeability of the sample in test (a) is preferably 4%, more preferably 3%.

[0214] If test (a) is met, the inductor 1 exhibits excellent stability when immersed in the copper sulfate solution used for electrolytic copper plating.

[0215] Under the condition that test (b) is satisfied, the upper limit of the rate of change of magnetic permeability of the sample in test (b) is preferably 4%, more preferably 3%.

[0216] If test (b) is met, the inductor 1 exhibits excellent stability when immersed in acidic solutions.

[0217] Under the condition that test (c) is satisfied, the upper limit of the rate of change of magnetic permeability of the sample in test (c) is preferably 4%, more preferably 3%.

[0218] In Test (c), the Reduction Solution Securiganth P manufactured by Atotech Japan contains an aqueous sulfuric acid solution and is used as a neutralizing solution (neutralizing agent, or aqueous solution for neutralization). Therefore, if Test (c) is met, inductor 1 exhibits excellent stability when immersed in the neutralizing solution.

[0219] Under the condition of satisfying test (d), the upper limit of the rate of change of magnetic permeability of the sample in test (d) is preferably 4%, more preferably 3%.

[0220] The Concentrate Compact CP manufactured by Atotech Japan in test (d) contained a potassium permanganate solution. Therefore, if test (d) is met, inductor 1 exhibits excellent stability when immersed in a descaling (cleaning) potassium permanganate solution.

[0221] Under the condition of satisfying test (e), the upper limit of the rate of change of magnetic permeability of the sample in test (e) is preferably 4%, more preferably 3%.

[0222] In test (e), the Swelling Dip Securiganth P manufactured by Atotech Japan is an aqueous solution containing glycol ethers and sodium hydroxide, used as a swelling solution. Therefore, if test (e) is met, inductor 1 exhibits excellent stability when immersed in the swelling solution.

[0223] Ideally, all of tests (a) to (e) are satisfied. As a result, inductor 1 exhibits excellent stability when immersed in copper sulfate solution for electrolytic copper plating, acid-active solution, neutralizing solution, potassium permanganate solution for descaling (cleaning), and swelling solution, and also exhibits excellent stability to various processes using these liquids.

[0224] [Example]

[0225] The following preparation examples, embodiments, and comparative examples further illustrate the present invention. It should be noted that the present invention is not limited to any of the preparation examples, embodiments, and comparative examples. Furthermore, the specific values ​​of mixing ratios (including ratios), physical property values, parameters, etc., used in the following description can be replaced with the upper limit (defined by "below" or "less than") or lower limit (defined by "above" or "greater than") of the corresponding mixing ratios (including ratios), physical property values, parameters, etc., described in the above "Specific Embodiments".

[0226] Preparation Example 1

[0227] (Preparation of adhesive)

[0228] An adhesive is prepared by mixing 24.5 parts by weight of epoxy resin (main agent), 24.5 parts by weight of phenolic resin (curing agent), 1 part by weight of imidazole compound (curing accelerator), and 50 parts by weight of acrylic resin (thermoplastic resin).

[0229] Comparative Example 1

[0230] First, prepare the first wiring 2 and the second wiring 3. The diameter L1 of each of the first wiring 2 and the second wiring 3 is 260 μm. Then, fabricate the first magnetic sheet 25, the second magnetic sheet 26 and the third magnetic sheet 27 in a manner that is the type and filling rate of the magnetic particles described in Table 1.

[0231] like Figure 2 As shown in Figure A, a second magnetic sheet 26, a first magnetic sheet 25, a first wiring 2 and a second wiring 3, another first magnetic sheet 25, and a third magnetic sheet 27 are then arranged sequentially on the other side of the thickness direction. It should be noted that the spacing L between the first wiring 2 and the second wiring 3 is 240 μm.

[0232] like Figure 2 As shown in B, they are then hot-pressed to form the first magnetic layer 4, the second magnetic layer 5, and the third magnetic layer 6. This produces an inductor 1 without the suppression section 7.

[0233] Example 1

[0234] like Figure 2 C and Figure 3As shown, a slit 21 with a length (width) L3 of 60 μm was formed in the second magnetic layer 5 of the inductor 1 of Comparative Example 1 using a cutting saw 28.

[0235] Thus, an inductor 1 having a suppression section 7 with a slit 21 is manufactured.

[0236] Example 2

[0237] like Figure 1 and Figure 2 As shown in Figure C, a second slit 22 with a length (width) L5 of 60 μm is further formed on the third magnetic layer 6. Otherwise, the inductor 1 is manufactured in the same manner as in Example 1. It should be noted that the suppression part 7 has slit 21 and second slit 22.

[0238] Example 3

[0239] like Figure 13 As shown, the first filling portion 37 and the second filling portion 38 are respectively embedded in the second magnetic layer 5 and the third magnetic layer 6, respectively replacing the slit 21 and the second slit 22. Otherwise, the inductor 1 having the suppression portion 7 having the first filling portion 37 and the second filling portion 38 is manufactured in the same manner as in Embodiment 1.

[0240] The first filling portion 37 and the second filling portion 38 are each formed of room-temperature solid polyimide resin with a relative magnetic permeability of 1. The first filling portion 37 and the second filling portion 38 each have a rectangular cross-sectional shape before being embedded in the second magnetic layer 5 and the third magnetic layer 6, respectively.

[0241] Example 4

[0242] like Figure 7 As shown, an intermediate slit 29 leading to the slit 21 and the second slit 22 is formed in the suppression part 7, and the inductor 1 is manufactured in the same manner as in Embodiment 2.

[0243] Comparative Example 2 and Examples 5-8

[0244] Inductors 1 of Comparative Examples 2 and 5 to 8 were manufactured in the same manner as those of Comparative Examples 1 and Examples 1 to 4, except that spherical magnetic particles were used instead of the flat magnetic particles contained in the second magnetic sheet 26 and the third magnetic sheet 27.

[0245] <Evaluation>

[0246] Evaluate the following items and record the results in Tables 3 and 4.

[0247] Crosstalk

[0248] The coupling coefficients of the first wiring 2 and the second wiring 3 of the inductor 1 in each embodiment were measured. Additionally, as a reference, the coupling coefficients of the first wiring 2 and the second wiring 3 of the inductor 1 in Comparative Example 1 were also measured. Next, crosstalk was evaluated according to the following criteria. It should be noted that an impedance analyzer (Agilent Technologies, "4291B") was used in the measurements.

[0249] [Benchmark]

[0250] ◎: Compared with Comparative Example 1 or Comparative Example 2, the coupling coefficient was reduced by more than 40%.

[0251] ○: Compared with Comparative Example 1 or Comparative Example 2, the coupling coefficient was reduced by more than 20% but less than 40%.

[0252] <Inductor>

[0253] The mutual inductance between the first wiring 2 and the second wiring 3 of inductor 1 in each embodiment was measured. The inductance was evaluated according to the following criteria. It should be noted that an impedance analyzer (Agilent Technologies, "4291B") was used in the measurement.

[0254] [Benchmark]

[0255] ○: Compared with Comparative Example 1 or Comparative Example 2, the self-perception was maintained at over 70%.

[0256] △: Compared with Comparative Example 1 or Comparative Example 2, the self-perception was maintained at more than 50% but less than 70%.

[0257] <DC superposition characteristics>

[0258] The inductance reduction rate of inductor 1 in each embodiment was measured to evaluate the DC superposition characteristics. It should be noted that an impedance analyzer (manufactured by Kuwagi Electronics Co., Ltd., "65120B") was used to measure the inductance reduction rate. The inductance reduction rate was evaluated according to the following criteria.

[0259] [Inductance without DC bias current - Inductance with DC bias current of 10A] / [Inductance with DC bias current of 10A] × 100 (%)

[0260] [Benchmark]

[0261] ○: The inductance reduction rate is less than 50% compared to Comparative Example 1 or Comparative Example 2.

[0262] ×: The inductance reduction rate is greater than 50% compared to Comparative Example 1 or Comparative Example 2.

[0263] [Table 1]

[0264]

[0265] [Table 2]

[0266]

[0267] [Table 3]

[0268]

[0269] [Table 4]

[0270]

[0271] It should be noted that the above-described invention is provided as an illustrative embodiment of the present invention, but it is merely an example and not intended to be limiting. Modifications of the present invention that will be apparent to those skilled in the art are included within the scope of the claims.

[0272] Industrial availability

[0273] Inductors are used in electronic devices, etc.

[0274] Explanation of reference numerals in the attached figures

[0275] 1. Inductor

[0276] 2. First wiring

[0277] 3. Second wiring

[0278] 4. First magnetic layer

[0279] 5. Second magnetic layer

[0280] 6. Third magnetic layer

[0281] 7. Inhibition section

[0282] 10 Inner circumferential surface

[0283] 11 Page 1

[0284] 12 Page 2

[0285] 13 Page 3

[0286] 14 Page 4

[0287] 17. Outer Peripheral Surface

[0288] 21 Slits

[0289] 22 Second Slit

[0290] 35 gap

[0291] 37 First Filling Section

[0292] 38 Second filling section

[0293] 71 Processing stabilizing layer

[0294] 72 Second Processing Stabilization Layer

[0295] The length of the slit in the thickness direction of L2

[0296] L3 Length of slits in adjacent directions

[0297] The length of the second slit in the thickness direction of L4

[0298] L5 Length of the second slit in the adjacent direction

Claims

1. An inductor, characterized in that, have: The first and second wirings are adjacent to each other and spaced apart; The first magnetic layer comprises: a first surface that is continuous in the planar direction; a second surface that is spaced apart from the first surface in the thickness direction and continuous in the planar direction; and an inner peripheral surface located between the first surface and the second surface and in contact with the outer peripheral surface of the first wiring and the outer peripheral surface of the second wiring. A second magnetic layer, disposed on the first surface; and A third magnetic layer is disposed on the second surface. The second magnetic layer has a third surface that is spaced apart from the first surface in the thickness direction and is opposite to it. The first surface and the second surface have wave shapes corresponding to the first wiring and the second wiring, The first surface has two protrusions that follow the outer peripheral surfaces of the first wiring and the second wiring, and a recess located between the two protrusions and recessed towards the other side in the thickness direction. The second surface has two second protrusions that follow the outer peripheral surfaces of the first wiring and the second wiring, and a second recess located between the two second protrusions and recessed towards the thickness direction. The relative permeability of the second and third magnetic layers is higher than that of the first magnetic layer. The inductor further includes a suppression portion located in the recess between the first wiring and the second wiring when projected along the thickness direction, in order to suppress magnetic coupling between the first wiring and the second wiring. The suppression portion includes a first suppression portion located between the first surface and the third surface.

2. The inductor according to claim 1, characterized in that, The first inhibition part faces the first surface.

3. The inductor according to claim 1, characterized in that, The first inhibition part is exposed from the third surface.

4. The inductor according to claim 1, characterized in that, The length of the first suppression portion in the thickness direction is longer than the length of the first suppression portion in the adjacent direction of the first wiring and the second wiring.

5. The inductor according to claim 1, characterized in that, The first suppression part is a slit formed in the second magnetic layer.

6. The inductor according to claim 1, characterized in that, The first suppression portion is a first filling portion that fills the voids formed in the second magnetic layer. The relative permeability of the first filling portion is lower than that of the first magnetic layer.

7. The inductor according to claim 1, characterized in that, It also has a processing stabilizing layer disposed on the third surface of the second magnetic layer.

8. The inductor according to claim 1, characterized in that, The third magnetic layer has a fourth surface that is spaced apart from the second surface in the thickness direction and is opposite to it. The suppression portion further includes a second suppression portion located between the second surface and the fourth surface.

9. The inductor according to claim 8, characterized in that, The second inhibition part faces the second surface.

10. The inductor according to claim 8, characterized in that, The second inhibition part is exposed from the fourth surface.

11. The inductor according to claim 8, characterized in that, The length of the second suppression portion in the thickness direction is longer than the length of the second suppression portion in the adjacent direction of the first wiring and the second wiring.

12. The inductor according to claim 8, characterized in that, The second suppression portion is a second slit formed in the third magnetic layer.

13. The inductor according to claim 8, characterized in that, The second suppression portion is a second filling portion that fills the voids formed in the third magnetic layer. The relative permeability of the second filling portion is lower than that of the first magnetic layer.

14. The inductor according to claim 8, characterized in that, It also has a second processing stabilizing layer disposed on the fourth surface of the third magnetic layer.

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