Inductor and manufacturing method thereof

Abstract

To provide an inductor and a manufacturing method thereof, which can manufacture the inductor at a low cost while easily and reliably evaluating magnetic properties and testing continuity of wiring.SOLUTION: A manufacturing method of an inductor 1 includes a first step of preparing wiring 2, a second step of forming a magnetic layer 3 made of a magnetic composition containing magnetic particles so as to cover a second outer peripheral surface 13 of a middle part 10 of the wiring 2, and expose a first end 8 and a second end 9 of the wiring 2 from the magnetic layer 3 in a range of 2 mm or more and less than 100 mm, and a third step of removing the first end 8 and the second end 9 of the wiring 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inductor and a method for manufacturing the same. [Background technology]

[0002] 2. Description of the Related Art Conventionally, it is known that inductors are mounted in electronic devices and used as passive elements such as voltage conversion members.

[0003] As such an inductor, for example, an inductor has been proposed that includes an internal conductor such as copper and a chip body made of a magnetic material in which the internal conductor is embedded (see, for example, Patent Document 1 below). In the inductor of Patent Document 1, both end faces of the internal conductor and both end faces of the chip body are formed flush with each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-144526 Summary of the Invention [Problem to be solved by the invention]

[0005] However, before an inductor is installed in an electronic device, it is necessary to contact both end faces of the internal conductor with a probe (test terminal) or the like to evaluate the inductor's magnetic properties, such as its inductance, and / or to test whether the internal conductor is conductive or not.

[0006] However, in the inductor of Patent Document 1, at least one end face of the internal conductor and one end face of the chip body are each formed flush with each other, making it difficult to directly contact the one end face of the internal conductor with a probe, which has the disadvantage that the above-mentioned evaluation and inspection cannot be performed.

[0007] Even if the probe can be brought into contact with one end surface of the inner conductor, the electrical connection between the probe and the inner conductor is likely to be poor, which can cause the above-mentioned evaluation and inspection to become unreliable.

[0008] On the other hand, there is also a demand to manufacture inductors at low cost.

[0009] The present invention provides an inductor and a method for manufacturing the inductor, which allows evaluation of magnetic properties and wiring continuity testing to be easily and reliably performed, while allowing the inductor to be manufactured at low cost. [Means for solving the problem]

[0010] The present invention (1) includes a method for manufacturing an inductor, comprising: a first step of preparing a wiring; a second step of forming a magnetic layer from a magnetic composition containing magnetic particles so as to cover the outer surface of a middle portion of the wiring and such that the ends of the wiring are exposed from the magnetic layer within an area of ​​2 mm or more and less than 100 mm; and a third step of removing the ends of the wiring.

[0011] In this inductor manufacturing method, in the second step, the magnetic layer is formed so that the ends of the wiring are exposed from the magnetic layer by 2 mm or more, so that the terminals can be easily brought into contact with the ends of the wiring and the electrical connection between the terminals and the wiring is reliable. This makes it easy to evaluate the magnetic properties and to perform a continuity test of the wiring.

[0012] In addition, in the second step, the magnetic layer is formed so that the ends of the wiring are exposed from the magnetic layer by less than 100 mm, and in the third step, the ends of the wiring are removed, so that the length of the removed ends can be restricted to a range of less than 100 mm. Therefore, the amount of wiring removed can be restricted, and as a result, the inductor can be manufactured at low cost.

[0013] Therefore, according to this manufacturing method, it is possible to easily and reliably evaluate the magnetic properties and perform a continuity test of the wiring, while manufacturing the inductor at low cost.

[0014] The present invention (2) includes the method for producing an inductor according to (1), in which the length of the wiring in the thickness direction of the inductor is 1000 μm or less.

[0015] Since the length of the wiring inductor in the thickness direction is short, at 1000 μm or less, a thin inductor can be manufactured.

[0016] On the other hand, in a method for manufacturing a thin inductor, if the end face of the wiring and the end face of the magnetic layer are flush with each other as in the inductor of Patent Document 1, it becomes much more difficult to contact the end of the terminal thereafter.

[0017] However, as described above, in the second step, the magnetic layer is formed so that the end of the wiring is exposed from the magnetic layer over a range of 2 mm or more. Therefore, even if the thickness-wise length of the wiring in the inductor is short, such as 1000 μm or less, the terminal can then be easily brought into contact with the end of the wiring.

[0018] Therefore, a thin inductor can be manufactured while the terminals can easily come into contact with the ends of the wiring.

[0019] The present invention (3) includes the method for producing an inductor according to (1) or (2), wherein in the second step, both ends of the wiring are exposed from the magnetic layer.

[0020] In the second step, both ends of the wiring are exposed from the magnetic layer, so that after the second step, each of the two terminals can be easily brought into contact with each of the two ends of the wiring, ensuring reliable electrical connection between the two terminals and the wiring.

[0021] The present invention (4) includes the method for manufacturing an inductor described in any one of (1) to (3), wherein in the first step, the wiring is prepared, the wiring comprising a conductor wire and an insulating layer covering an outer peripheral surface of the conductor wire, and further includes a fourth step, after the second step and before the third step, of exposing the conductor wire from the insulating layer at the end of the wiring.

[0022] In the first step, wiring including a conductor wire and an insulating layer covering the outer peripheral surface of the conductor wire is prepared, so that the insulating layer can suppress short-circuiting between the conductor wire and the magnetic layer.

[0023] In addition, in the fourth step, the conductor wire at the end of the wiring is exposed from the insulating layer, so that the terminal and the conductor wire at the end of the wiring can be easily brought into contact with each other, ensuring a reliable electrical connection between the terminal and the conductor wire.

[0024] The present invention (5) includes an inductor comprising a plurality of wirings and a magnetic layer covering the intermediate portion of each of the plurality of wirings, the magnetic layer containing magnetic particles, and each end of the plurality of wirings being exposed from the magnetic layer within a range of 2 mm or more and less than 100 mm.

[0025] In this inductor, the ends of each of the multiple wirings are exposed from the magnetic layer by 2 mm or more. This allows the terminals to be easily brought into contact with the ends of the wirings, ensuring reliable electrical connections between the terminals and the wirings. This allows for easy and reliable evaluation of the magnetic properties of the inductor and continuity testing of the wirings.

[0026] Furthermore, since the ends of each of the multiple wirings are exposed from the magnetic layer within a range of less than 100 mm, the inductors can be manufactured by cutting the inductors into individual pieces corresponding to each of the multiple wirings in order to remove the ends, thereby reducing the amount of wiring that is removed, and as a result, multiple inductors can be manufactured at low cost. Effect of the Invention

[0027] According to the inductor and the manufacturing method thereof of the present invention, the inductor can be manufactured at low cost while easily and reliably evaluating the magnetic properties and inspecting the continuity of the wiring. [Brief description of the drawings]

[0028] [Figure 1]Figures 1A to 1D show manufacturing process diagrams of a first embodiment of a manufacturing method for an inductor of the present invention. Figures 1A to 1B show a first process, with Figure 1A being a plan view and Figure 1B being a front view as viewed in the direction of an arrow in Figure 1A. Figures 1C to 1D show a second process, with Figure 1C being a plan view and Figure 1D being a front view. [Diagram 2] Fig. 2 shows a manufacturing process diagram of the first embodiment, following Fig. 1D. Fig. 2E to Fig. 2F show a fourth process and an evaluation inspection process, with Fig. 2E showing a plan view and Fig. 2F showing a front view. Fig. 2G to Fig. 2H show a third process, with Fig. 2G showing a plan view of the inductor and Fig. 2H showing a front view of the inductor. [Diagram 3] FIG. 3 shows a flowchart of the manufacturing method of the first embodiment shown in FIGS. 1A to 2H. [Figure 4] Figures 4A to 4C are examples of detailed perspective views of the second process shown in Figures 1C to 1D, where Figure 4A shows the process of preparing the wiring and a first magnetic sheet, Figure 4B shows the process of pressing the first magnetic sheet onto the wiring, and the process of preparing the second magnetic sheet and the third magnetic sheet, and Figure 4C shows the process of pressing the second magnetic sheet and the third magnetic sheet onto the first magnetic sheet and the wiring to form a magnetic sheet. [Diagram 5] FIG. 5 is a perspective view illustrating the evaluation and inspection process shown in FIGS. 2E to 2F. [Figure 6] FIG. 6 is a perspective view illustrating a modified example of the evaluation and inspection process of the first embodiment shown in FIG. [Figure 7] FIG. 7 shows a perspective view of a modified example of the inductor of the first embodiment shown in FIGS. 1C and 1D. [Figure 8] FIG. 8 shows an inductor in a modification of the third step of the first embodiment shown in FIG. 2G and a plan view of the inductor. [Figure 9] FIG. 9 shows an inductor in a modification of the third step of the first embodiment shown in FIG. 2G and a plan view of the inductor. [Figure 10] FIG. 10 shows an inductor in a modification of the third step of the first embodiment shown in FIG. 2G and a plan view of the inductor. [Figure 11]11A and 11B are plan views of a modified example of the third step of the first embodiment shown in FIG. 2G, where FIG. 11A shows a modified example in which the magnetic layer is not cut but the wiring is cut, and FIG. 11B shows a modified example in which the magnetic layer and the wiring are cut. [Figure 12] FIG. 12 is a plan view illustrating a third step of the second embodiment of the method for producing an inductor of the present invention. [Figure 13] FIG. 13 is a plan view illustrating a third step of the third embodiment of the inductor manufacturing method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] A first embodiment of a method for producing an inductor according to the present invention and an inductor obtained thereby will be described with reference to FIGS. 1A to 5. FIG.

[0030] First Embodiment As shown in FIGS. 1A to 2H, in the method for manufacturing an inductor 1, an inductor 30 including a plurality of wirings 2 and a magnetic layer 3 covering them is manufactured, and then a plurality of inductors 1 are manufactured from the inductor 30.

[0031] Specifically, the manufacturing method of the inductor 1 includes a first step of preparing the wiring 2, a second step of forming the magnetic layer 3 so as to cover the middle portion 10 of the wiring 2 and to expose the first end 8 and the second end 9 of the wiring 2 from the magnetic layer 3, and a third step of removing the first end 8 and the second end 9 of the wiring 2. In this manufacturing method, the first step, the second step, and the third step are carried out in this order, as shown in Fig. 3.

[0032] This manufacturing method further includes a fourth step, which occurs after the second step and before the third step, of exposing the conductor 6 from the insulating layer 7 at the first end 8 and the second end 9 of the wiring 2, and an evaluation and inspection step, which occurs after the fourth step and before the third step, of evaluating the inductance of the multiple inductors 1 and inspecting the continuity of the multiple wirings 2. That is, in this manufacturing method, the first step, second step, fourth step, evaluation and inspection step, and third step are performed in this order, as shown in Fig. 3.

[0033] 1A and 1B, in a first step, a plurality of wirings 2 are prepared. The plurality of wirings 2 includes, for example, a first wiring 4 and a second wiring 5.

[0034] The first wiring 4 includes a conductive wire 6 and an insulating layer 7 that covers the conductive wire 6.

[0035] The conductor 6 extends long in the direction of electrical current flow and has, for example, a generally U-shape in plan view. Specifically, in the first step, the first wiring 4 is placed on a horizontal table (not shown) so that the conductor 6 has a generally U-shape in plan view, so that the conductor 6 has the above-described shape in plan view. The conductor 6 has a generally circular shape in cross section that shares a central axis with the first wiring 4.

[0036] The material of the conductor 6 is a metal conductor such as copper, silver, gold, aluminum, nickel, or an alloy thereof, preferably copper. The conductor 6 may have a single-layer structure or a multi-layer structure in which the surface of a core conductor (e.g., copper) is plated (e.g., nickel) or the like.

[0037] The radius R1 of the conductor 6 is the distance from the center of the conductor 6 to the first outer peripheral surface 12 and is, for example, 25 μm or more, preferably 50 μm or more, and for example, 2000 μm or less, preferably 250 μm or less.

[0038] The insulating layer 7 is a layer for protecting the conductor 6 from chemicals and water, and for preventing a short circuit of the conductor 6. The insulating layer 7 is disposed so as to cover the entire surface of a first outer peripheral surface 12, which is an example of the outer peripheral surface of the conductor 6.

[0039] The insulating layer 7 has a generally circular ring shape in cross section, sharing a central axis (center) with the first wiring 4.

[0040] Examples of materials for the insulating layer 7 include insulating resins such as polyvinyl formal, polyester, polyesterimide, polyamide (including nylon), polyimide, polyamideimide, and polyurethane. These may be used alone or in combination of two or more. The insulating layer 7 may be composed of a single layer or multiple layers.

[0041] The thickness T1 of the insulating layer 7 is the distance from the first outer surface 12 of the conductor 6 to the second outer surface 13, which is an example of the outer surface of the first wiring 4 (wiring 2), and is approximately uniform in the radial direction of the wiring 2 at any position in the circumferential direction, and is, for example, 1 μm or more, preferably 3 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

[0042] The radius R2 of the first wiring 4 is the sum (R1+T1) of the radius R1 of the conductive wire 6 and the thickness T1 of the insulating layer 7, and specifically, is the length R2 from the center of the first wiring 4 to the second outer peripheral surface 13. The radius 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 250 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less.

[0043] The diameter D of the first wiring 4 (corresponding to the thickness of the first wiring 4 in the inductor 1) is twice the radius R2 of the first wiring 4 described above (2 × R2), and specifically, for example, is 50 μm or more, preferably 100 μm or more, and for example, is 4000 μm or less, preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 400 μm or less, and particularly preferably 300 μm or less.

[0044] When the radius R2 and / or diameter D of the first wiring 4 is equal to or greater than the above-mentioned lower limit, excellent inductance can be obtained. When the radius and / or diameter of the first wiring 4 is equal to or less than the above-mentioned upper limit, a thin inductor 1 can be obtained.

[0045] As shown in FIG. 1A, the first wiring 4 integrally has a first end portion 8 and a second end portion 9 disposed on both sides in the direction of current flow, and a middle portion 10 located midway in the direction of current flow (between them).

[0046] The first end 8 and the second end 9 are used, for example, as electrical contacts (terminal portions) in an evaluation and inspection process described below.

[0047] The intermediate portion 10 connects the first end portion 8 and the second end portion 9 in the current flow direction. The intermediate portion 10 has, in the center in the current flow direction, a curved portion 11 having, for example, a generally semicircular arc shape in a plan view. Further, the intermediate portion 10 has a first connecting portion 19 connected (continuous) to the first end portion 8, and a second connecting portion 29 connected (continuous) to the second end portion 9.

[0048] The first connecting portion 19 is disposed and formed in a straight line with the first end portion 8 in a plan view. Although not depicted in FIGS. 1A and 1B, the first connecting portion 19 is disposed and formed in a straight line with the first end portion 8 in a cross section along the direction of electrical flow. One end of the first connecting portion 19 is connected to the first end portion 8, and the other end of the first connecting portion 19 is connected to one end of the curved portion 11.

[0049] The second connecting portion 29 is disposed and formed in a straight line with the second end portion 9 in a plan view. Although not depicted in FIGS. 1A and 1B, the second connecting portion 29 is disposed and formed in a straight line with the second end portion 9 in a cross section along the direction of electrical flow. One end of the second connecting portion 29 is connected to the second end portion 9, and the other end of the second connecting portion 29 is connected to the other end of the curved portion 11.

[0050] The intermediate portion 10 is the entire portion of the wiring 2 excluding the first end portion 8 and the second end portion 9. In each of the multiple wirings 2, the intermediate portion 10 has a planar area of, for example, 60% or more, 80% or more, and for example, 99% or less, preferably 95% or less.

[0051] The center distance L2 between the first end 8 and the second end 9 in a cross-sectional view (or a front view) is, for example, 20 μm or more, preferably 50 μm or more, and for example, 3000 μm or less, preferably 2000 μm or less.

[0052] The second wiring 5 has the same shape, structure and material as the first wiring 4 .

[0053] The center-to-center distance L1 between the second end 9 of the first wiring 4 and the first end 8 of 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.

[0054] As shown in Figures 1C and 1D, in the second step, the magnetic layer 3 is formed so as to cover the second outer surface 13 of the middle portion 10 of the wiring 2 and to expose the first end 8 and the second end 9 of the wiring 2.

[0055] In the second step, the magnetic layer 3 is formed from a magnetic composition containing magnetic particles. Specifically, the magnetic composition contains magnetic particles and a binder.

[0056] Examples of the magnetic material constituting the magnetic particles include soft magnetic materials and hard magnetic materials. From the viewpoint of inductance, the soft magnetic materials are preferable.

[0057] Examples of soft magnetic bodies include single metal bodies that contain one type of metal element in a pure substance state, and alloy bodies that are eutectic bodies (mixtures) of one or more types of metal elements (first metal elements) and one or more types of metal elements (second metal elements) and / or nonmetal elements (carbon, nitrogen, silicon, phosphorus, etc.). These can be used alone or in combination.

[0058] The single metal body may be, for example, a metal element consisting of only one type of metal element (first metal element). The first metal element may be, for example, iron (Fe), cobalt (Co), nickel (Ni), or any other metal element that can be contained as the first metal element in a soft magnetic body.

[0059] In addition, the single metal body may be, for example, a form including a core containing only one type of metal element and a surface layer containing an inorganic and / or organic substance that modifies a part or the whole of the surface of the core, such as a form in which an organometallic compound or an inorganic metal compound containing a first metal element is decomposed (e.g., thermally decomposed). More specifically, the latter form may be iron powder (sometimes called carbonyl iron powder) obtained by thermally decomposing an organoiron compound (specifically, carbonyl iron) containing iron as the first metal element. The position of the layer containing an inorganic and / or organic substance that modifies the part containing only one type of metal element is not limited to the surface as described above. The organometallic compound or inorganic metal compound that can obtain the single metal body is not particularly limited, and can be appropriately selected from known or commonly used organometallic compounds or inorganic metal compounds that can obtain a single metal body of a soft magnetic material.

[0060] The alloy body is a eutectic of one or more metal elements (first metal elements) and one or more metal elements (second metal elements) and / or non-metallic elements (carbon, nitrogen, silicon, phosphorus, etc.), and is not particularly limited as long as it can be used as an alloy body of a soft magnetic material.

[0061] The first metallic element is an essential element in the alloy body, and examples of the first metallic element include iron (Fe), cobalt (Co), nickel (Ni), etc. If the first metallic element is Fe, the alloy body is an Fe-based alloy, if the first metallic element is Co, the alloy body is a Co-based alloy, and if the first metallic element is Ni, the alloy body is a Ni-based alloy.

[0062] The second metallic element is an element (secondary component) secondarily contained in the alloy body, and is a metallic element that is compatible (eutectic) with the first metallic element, and examples of the second metallic element include iron (Fe) (when the first metallic element is other than Fe), cobalt (Co) (when the first metallic element is other than Co), nickel (Ni) (when the first metallic element is other than Ni), chromium (Cr), aluminum (Al), silicon (Si), copper (Cu), silver (Ag), manganese (Mn), calcium (Ca), barium (Barium), and the like. Ba, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), ruthenium (Ru), rhodium (Rh), zinc (Zn), gallium (Ga), indium (In), germanium (Ge), tin (Sn), lead (Pb), scandium (Sc), yttrium (Y), strontium (Sr), various rare earth elements, etc. These can be used alone or in combination of two or more.

[0063] The nonmetallic element is an element (secondary component) secondarily contained in the alloy body, and is a nonmetallic element that is compatible (eutectic) with the first metallic element, such as boron (B), carbon (C), nitrogen (N), silicon (Si), phosphorus (P), sulfur (S), etc. These may be used alone or in combination of two or more kinds.

[0064] Examples of the alloy body include Fe-based alloys, such as magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), Sendust (Fe-Si-Al alloy) (including super Sendust), Permalloy (Fe-Ni alloy), Fe-Ni-Mo alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Co alloy, Fe-Cr alloy, Fe-Cr-Al alloy, Fe-Ni-Cr alloy, Fe-Ni-Cr-Si alloy, silicon copper (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B(-Cu-Nb) alloy, Fe-B-Si-Cr alloy, Fe-S Examples of such alloys include i-Cr-Ni alloys, Fe-Si-Cr alloys, 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, and soft ferrites such as Mn-Mg ferrites, Mn-Zn ferrites, Ni-Zn ferrites, Ni-Zn-Cu ferrites, Cu-Zn ferrites, and Cu-Mg-Zn ferrites), permendur (Fe-Co alloys), Fe-Co-V alloys, and Fe-based amorphous alloys.

[0065] Examples of the alloy body, which is a Co-based alloy, include Co-Ta-Zr and cobalt (Co)-based amorphous alloys.

[0066] An example of the alloy body is a Ni-based alloy, such as a Ni-Cr alloy.

[0067] Among these soft magnetic materials, from the viewpoint of magnetic properties, an alloy body is preferable, an Fe-based alloy is more preferable, and sendust (Fe-Si-Al alloy) is even more preferable. As the soft magnetic material, a single metal body is preferable, a single metal body containing iron element in a pure substance state is more preferable, and iron alone or iron powder (carbonyl iron powder) is even more preferable.

[0068] The volume proportion of the magnetic particles in the magnetic composition is, for example, 40 volume% or more, preferably 50 volume% or more, more preferably 60 volume% or more, and for example, 95 volume% or less, preferably 90 volume% or less.

[0069] The shape of the magnetic particles is not particularly limited, and examples thereof include anisotropic shapes such as flat (plate-like) and needle-like, and non-anisotropic shapes such as spherical. From the viewpoint of orientation, anisotropic shapes are preferred, and more preferably, flat shapes are preferred from the viewpoint of good relative magnetic permeability in the planar direction (two-dimensional).

[0070] The flattening ratio (flatness) of the flat magnetic particles is, for example, 8 or more, preferably 15 or more, and for example, 500 or less, preferably 450 or less. The flattening ratio is calculated, for example, as an aspect ratio obtained by dividing the average particle diameter (average length) (described later) of the flat magnetic particles by the average thickness of the flat magnetic particles.

[0071] The flat magnetic particles have an average particle diameter (average length) of, 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 flat magnetic particles are flat, they have an average thickness of, 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.

[0072] 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.

[0073] The binder may be, for example, a resin, and examples of such a resin include thermosetting resins such as epoxy resins and phenolic resins, and thermoplastic resins such as acrylic resins. These may be used alone or in combination.

[0074] Preferably, a thermosetting resin and a thermoplastic resin are used in combination, and more preferably, an acrylic resin, an epoxy resin, and a phenol resin are used in combination.

[0075] If necessary, additives such as a thermosetting catalyst, inorganic particles (excluding magnetic particles), organic particles, and a crosslinking agent can also be added to the magnetic composition.

[0076] The proportions of the binder and additives in the magnetic composition are the remainder of that of the magnetic particles described above.

[0077] Details of the magnetic composition are described in, for example, JP 2014-165363 A.

[0078] In the second step, the magnetic sheet 20 is first prepared from the magnetic composition, for example, in the shape of a substantially rectangular sheet. The magnetic sheet 20 has one side and the other side that are opposed in the thickness direction, parallel to each other, and flat. The magnetic sheet 20 is preferably prepared by first preparing a varnish of the magnetic composition, applying it to a release sheet (not shown) to prepare an A-stage sheet, and then heating it to prepare a B-stage sheet.

[0079] Next, the second outer peripheral surface 13 of each of the intermediate portions 10 (the intermediate portions 10 including the curved portions 11) of the multiple wirings 2 is covered with the magnetic sheet 20. Preferably, the intermediate portions 10 of each of the multiple wirings 2 are embedded in the magnetic sheet 20 of the B-stage sheet. Alternatively, the intermediate portions 10 of each of the multiple wirings 2 are embedded in the magnetic sheet 20 of the B-stage sheet. The magnetic sheet 20 in which the intermediate portions 10 are embedded forms the magnetic layer 3.

[0080] More specifically, in the second step, as shown in Figures 4A to 4B, magnetic sheet 20 is prepared (manufactured) including first magnetic sheet 21, second magnetic sheet 22, and third magnetic sheet 23, each of which is independent of the other. The planar shapes of first magnetic sheet 21, second magnetic sheet 22, and third magnetic sheet 23 are the same as the above-mentioned magnetic sheet 20. Furthermore, the planar dimensions of first magnetic sheet 21, second magnetic sheet 22, and third magnetic sheet 23 are the same as one another.

[0081] 4A, a plurality of wirings 2 are separately placed on a horizontal stand (not shown) in the above-mentioned arrangement. Specifically, the plurality of wirings 2 are arranged so that the first end 8 and the second end 9 of each of the plurality of wirings 2 overlap when projected in the adjoining direction.

[0082] As shown in FIG. 4B, the middle portion 10 of each of the multiple wirings 2 is then covered with a first magnetic sheet 21 (preferably a first magnetic sheet 21 in the B stage). More specifically, the first magnetic sheet 21 is pressed from one side in the thickness direction toward the middle portion 10. As a result, the entire second outer peripheral surface 13 of the middle portion 10 (except for the other edge in the thickness direction) is covered with the first magnetic sheet 21. Note that, in the case where the magnetic composition contains a thermosetting resin, the first magnetic sheet 21 after pressing is still in the B stage, for example.

[0083] In first magnetic sheet 21, one surface in the thickness direction has a curved surface corresponding to wiring 2 when viewed from the front (or in a cross-sectional view).

[0084] 4C, second magnetic sheet 22 and third magnetic sheet 23 (preferably second magnetic sheet 22 and third magnetic sheet 23 in B stage when the magnetic composition contains a thermosetting resin) are then arranged on one side and the other side in the thickness direction of midway portion 10 and first magnetic sheet 21, respectively, and second magnetic sheet 22 and third magnetic sheet 23 are pressed against midway portion 10 and first magnetic sheet 21. Note that, when the magnetic composition contains a thermosetting resin, second magnetic sheet 22 and third magnetic sheet 23 after pressing are both still in B stage, for example.

[0085] In this way, the magnetic sheet 20, which includes the second magnetic sheet 22, the first magnetic sheet 21, and the third magnetic sheet 23 in this order from one side to the other in the thickness direction, is formed so as to cover the second outer peripheral surface 13 of the multiple wirings 2. Note that, as shown in Fig. 4C, the boundaries between the second magnetic sheet 22, the first magnetic sheet 21, and the third magnetic sheet 23 are clearly depicted, but for example, in the magnetic sheet 20 which is a laminated sheet of the second magnetic sheet 22, the first magnetic sheet 21, and the third magnetic sheet 23, the boundaries may not be clear, and more specifically, the boundaries may not be confirmed as shown in Fig. 1D.

[0086] One surface in the thickness direction of the magnetic sheet 20 is flat.

[0087] On the other hand, the first end 8 and the second end 9 of each of the multiple wirings 2 are exposed from the magnetic sheet 20. Specifically, the first end 8 and the second end 9 protrude from one end face (tip face) 16 of the four peripheral end faces of the magnetic sheet 20.

[0088] As shown in FIG. 1C, the length L of each of the first end 8 and the second end 9 exposed from the magnetic sheet 20 is in the range of not less than 2 mm and less than 100 mm.

[0089] 2E and 5, if the length L is less than 2 mm, in the evaluation and inspection step (described later), terminal 25 (described later) cannot be easily brought into contact with first end 8 and second end 9 of wiring 2, making the electrical connection between terminal 25 and wiring 2 uncertain. Therefore, evaluation of the magnetic properties of inductor 1 and continuity inspection of wiring 2 cannot be easily and reliably performed.

[0090] On the other hand, if the length L is 100 mm or more, as shown in Fig. 2G, in consideration of removing the first end 8 and the second end 9 of the wiring 2 in the third step (described later), the length L of the first end 8 and the second end 9 to be removed cannot be suppressed to a range of less than 100 mm. Therefore, the amount of wiring to be removed cannot be suppressed, which reduces the yield of the wiring 2, and as a result, the inductor 1 cannot be manufactured at low cost.

[0091] Specifically, the range of the length L is preferably 3 mm or more, more preferably 4 mm or more, even more preferably 5 mm or more, and even more preferably 10 mm or more, and is preferably 99 mm or less, more preferably 95 mm or less, even more preferably 75 mm or less, particularly preferably 50 mm or less, most preferably 40 mm or less, and even more preferably 25 mm or less.

[0092] Thereafter, if the magnetic sheet 20 is still in the B stage, it is changed to the C stage.

[0093] As shown in Figures 1C and 1D, this forms a magnetic layer 3 consisting of a magnetic sheet 20 so as to expose the first end 8 and the second end 9 of each of the multiple wirings 2 and to cover the middle portion 10 of each of the multiple wirings 2.

[0094] This second step provides an inductor 30 including a plurality of wirings 2 and a magnetic layer 3 covering the intermediate portions 10 of each of the plurality of wirings 2. In this inductor 30, the magnetic layer 2 contains magnetic particles, and the first end 8 and the second end 9 of each of the plurality of wirings 2 are exposed from the magnetic layer 3 in a direction perpendicular to the thickness direction of the magnetic layer 3 within a range of 2 mm or more and less than 100 mm.

[0095] 2G and 2H, this inductor 30 is an assembly sheet for obtaining an inductor 1 described later, and is not the inductor 1 itself, but includes a first end 8 and a second end 9 in addition to a plurality of inductors 1. Inductor 30 is a device that can be distributed independently and is industrially applicable.

[0096] The thickness of the inductor 30 is the same as the thickness of the magnetic layer 3, and specifically, for example, 5000 μm or less, preferably 1000 μm or less, and for example, 100 μm or more.

[0097] As shown in FIG. 2F, in the fourth step, the conductive wires 6 are exposed from the insulating layer 7 at the first end 8 and the second end 9 of each of the multiple wirings 2.

[0098] For example, by laser processing in which laser light is irradiated from one side in the thickness direction, the insulating layer 7 facing one thickness direction end of the first outer peripheral surface 12 of the conductor 6 at the first end 8 and the second end 9 is removed, exposing one thickness direction end of the first outer peripheral surface 12 of the conductor 6 from the insulating layer 7.

[0099] Alternatively, one end in the thickness direction of the first outer circumferential surface 12 of the conductive wire 6 can be exposed from the insulating layer 7 by polishing.

[0100] In the evaluation and inspection step, for example, the inductance of the multiple inductors 1 is evaluated, and a continuity test of the multiple wirings 2 is performed.

[0101] Specifically, a pair of terminals 25 are arranged on one thickness-wise side of the first end 8 and the second end 9, and the other thickness-wise side of the pair of terminals 25 is brought into contact with the first outer surface 12 of the conductor 6 exposed from the insulating layer 7 at the first end 8 and the second end 9.

[0102] The shape of terminal 25 is not particularly limited, and examples thereof include an approximately cylindrical shape having a relatively wide flat surface on the other end face in the thickness direction, or a needle shape extending long in the thickness direction of inductor 30, and from the viewpoints of convenience and ensuring a wide contact area with conductor 6, an approximately cylindrical shape is preferred.

[0103] The terminal 25 is connected to a testing device (specifically, an LCR meter, a vector network analyzer, an impedance analyzer, etc.) via a connection wire (not shown).

[0104] In evaluating inductance, the impedance is measured while applying a weak current to a pair of terminals 25, and the measured value is substituted into a theoretical formula to calculate the inductance determined by one wiring 2 and the magnetic layer 3 around it.

[0105] In the continuity test of the wiring 2, the resistance between a pair of terminals 25 is measured to check whether the wiring 2 is conductive or not.

[0106] As shown in FIGS. 2G to 2H, in a third step, the first end 8 and the second end 9 of the wiring 2 are removed.

[0107] Specifically, the inductor 30 is cut so as to correspond to each of the multiple wirings 2 and to be separated from the first end 8 and the second end 9, thereby obtaining the inductor 1.

[0108] At this time, rather than removing only the exposed first end portion 8 and second end portion 9, the inside of the magnetic layer 3 is removed in a manner that cuts away the inner side.

[0109] For example, the wiring 2 and the magnetic layer 3 are cut so as to form a first cutting line 26 that is on the inside of the peripheral end face of the magnetic layer 3 in a plan view, and the magnetic layer 3 is cut so as to form a second cutting line 27 that passes between the adjacent first wiring 4 and second wiring 5. For example, dicing, laser processing, punching, etc. are used for the above cutting.

[0110] This provides a plurality of inductors 1 each including one wiring 2, covering the entire second outer peripheral surface 13 in the flow direction, and including one magnetic layer 3. That is, the inductor 1 is separated (cut out) from the inductor 30 so that the first end 8 and the second end 9 remain in the inductor 30. That is, the inductor 1 is obtained such that the first end 8 and the second end 9 are removed. Note that this inductor 1 preferably includes only one wiring 2 and one magnetic layer 3.

[0111] The inductor 1 has, for example, a rectangular flat plate shape, and specifically has a plurality (four) of flat peripheral end faces. The inductor 1 does not include a first end portion 8 and a second end portion 9. The inductor 1 is a device that can be distributed independently and is industrially applicable.

[0112] At one end surface 18 of the four peripheral end surfaces of this inductor 1, the end surface of the wiring 2 and the end surface of the magnetic layer 3 are formed flush with each other.

[0113] The thickness of the inductor 1 is similar to the thickness of the magnetic layer 3 described above.

[0114] In the manufacturing method of this inductor 1, as shown in Fig. 1C and Fig. 1D, in the second step, the magnetic layer 3 is formed so that the first end 8 and the second end 9 of the wiring 2 are exposed from the magnetic layer 3 by 2 mm or more. Therefore, as shown in Fig. 2E and Fig. 2F, in the evaluation and inspection step after the second step, the terminal 25 can be easily brought into contact with the first end 8 and the second end 9 of the wiring 2, and the electrical connection between the terminal 25 and the wiring 2 is reliable. Therefore, the evaluation of the inductance of the inductors 1 and 30 and the continuity inspection of the wiring 2 can be easily and reliably performed.

[0115] Specifically, since the first end 8 and the second end 9 of the wiring 2 are exposed from the magnetic layer 3 by 2 mm or more, terminals 25 having various shapes can be brought into contact with the conductor 6, and as shown in Fig. 2F and Fig. 5, for example, not only a needle-shaped terminal 25 (solid line) whose other end (tip) in the thickness direction is sharp, but also a terminal 25 (virtual line) having a substantially cylindrical shape can be brought into contact with the conductor 6. Therefore, regardless of the shape and / or size of the terminal 25, the contact between the terminal 25 and the wiring 2 can be easily and reliably achieved. In other words, there is a high degree of freedom in the terminals 25 that can be used, and therefore inspection and evaluation using the terminals 25 are easy.

[0116] Conversely, if the first end 8 and the second end 9 of the wiring 2 are exposed from the magnetic layer 3 by less than 2 mm, it may be possible to contact the needle-shaped terminal 25 (solid line) with the conductor 6, but it is difficult to contact the approximately cylindrical terminal 25 (virtual line) with the conductor 6.

[0117] 1C and 1D, in the second step, the magnetic layer 3 is formed so that the first end 8 and the second end 9 of the wiring 2 are exposed from the magnetic layer 3 by less than 100 mm, and in the third step, the first end 8 and the second end 9 of the wiring 2 are removed by the third step as shown in Figs. 2G and 2H, so that the length L of the first end 8 and the second end 9 to be removed can be suppressed to a range of less than 100 mm. This makes it possible to suppress the amount (or length) of the wiring 2 to be removed, which results in an excellent yield of the wiring 2 and, as a result, allows the inductor 1 to be manufactured at low cost.

[0118] Therefore, according to this manufacturing method, the inductor 1 can be manufactured at low cost while the inductance of the inductor 1 and the continuity test of the wiring 2 can be easily and reliably performed.

[0119] Furthermore, with this manufacturing method, when the diameter D of the wiring 2 is small, ie, 1000 μm or less, a thin inductor 1 can be manufactured.

[0120] On the other hand, in a method of manufacturing a thin inductor 1, if the end face of the wiring 2 and one end face 16 of the magnetic layer 3 are flush with each other, as in the inductor of Patent Document 1, it becomes even more difficult to subsequently contact the end face of the wiring 2 with the terminal 25.

[0121] However, in this first embodiment, as described above, in the second step, the magnetic layer 3 is formed so that the first end 8 and the second end 9 of the wiring 2 are exposed from the magnetic layer 3 over a range of 2 mm or more. Therefore, even if the diameter D of the wiring 2 is small, such as 500 μm or less, the terminal 25 can then be easily brought into contact with the first end 8 and the second end 9.

[0122] Therefore, the terminal 25 can easily come into contact with the first end 8 and the second end 9 of the wiring 2, and a thin inductor 1 can be manufactured.

[0123] Furthermore, as shown in FIG. 1C, in the second step of this first embodiment, the first end 8 and the second end 9 of the wiring 2 are exposed from the magnetic layer 3. Therefore, after the second step, in the evaluation inspection step shown in FIG. 2E, each of the two terminals 25 can be easily brought into contact with each of the first end 8 and the second end 9 of the wiring 2, and the electrical connection between the two terminals 25 and the wiring 2 is reliable.

[0124] As shown in Figure 1B, in the first step of this first embodiment, a wiring 2 is prepared having a conductor 6 and an insulating layer 7 covering a first outer surface 12 of the conductor 6. However, in the fourth step, as shown in Figures 2F and 5, the conductor 6 is exposed from the insulating layer 7 at the first end 8 and the second end 9 of the wiring 2, so that the terminal 25 can easily come into contact with the conductor 6 at the first end 8 and the second end 9 of the wiring 2, and the electrical connection between the terminal 25 and the conductor 6 is reliable.

[0125] In the inductor 30 of the first embodiment shown in Figures 1C and 1D, the first end 8 and the second end 9 of each of the multiple wirings 2 are exposed from the magnetic layer 3 by 2 mm or more. Therefore, as shown in Figures 2E and 2F, the terminal 25 can be easily brought into contact with the first end 8 and the second end 9 of the wiring 2, and the electrical connection between the terminal 25 and the wiring 2 is reliable. Therefore, the inductance of the inductor 1 can be evaluated and the continuity test of the wiring 2 can be easily and reliably performed.

[0126] Furthermore, since the first end 8 and second end 9 of each of the multiple wirings 2 are exposed from the magnetic layer 3 within a range of less than 100 mm, even if the inductor 30 is divided into individual pieces corresponding to each of the multiple wirings 2 so as to remove the first end 8 and second end 9, and the inductor 1 is manufactured, the amount of wiring removed can be reduced, and as a result, the multiple inductors 1 can be manufactured at low cost.

[0127] Variations In the following modifications, the same components and steps as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. In addition, each modification can achieve the same effects as those in the first embodiment, unless otherwise specified. Furthermore, the first embodiment and the modifications can be appropriately combined.

[0128] As shown in Figures 2E and 5, in the fourth step of the first embodiment, at the first end 8 and the second end 9, the insulating layer 7 facing one thickness-wise end of the first outer peripheral surface 12 of the conductor 6 is removed to expose one thickness-wise end of the first outer peripheral surface 12 of the conductor 6 from the insulating layer 7.

[0129] As shown in Figure 6, in this modified example, the insulating layer 7 facing the entire first outer surface 12 of the conductor 6 can be removed to expose the entire first outer surface 12 of the conductor 6 from the insulating layer 7. That is, in the fourth step, the insulating layer 7 at the first end 8 and the second end 9 can be entirely removed.

[0130] 1C, in the first embodiment, in the second step (inductor 30), both the first end 8 and the second end 9 are exposed from the magnetic layer 3. However, although not shown, only one of the first end 8 and the second end 9 can be exposed from the magnetic layer 3.

[0131] As shown in Fig. 5, the cross-sectional shape of the wiring 2 (or the front view shapes of the first end 8 and the second end 9) is substantially circular, but in a modified example, it is substantially rectangular as shown in Fig. 7. Specifically, in the inductor 30, each of the first end 8 and the second end 9 has a substantially box shape.

[0132] The thickness T2 of the wire 2 in this modification is similar to the diameter D of the wire 2 in the first embodiment.

[0133] Furthermore, in this modified example, the corners of the wiring 2 in cross-sectional view (for example, corners formed by one side in the thickness direction and both outer sides in the adjacent direction (the direction in which the first wiring 4 and the second wiring 5 are adjacent)) may also have, for example, a curved shape.

[0134] Furthermore, as shown in Figures 4A to 4C, in the first embodiment, the magnetic layer 3 is formed as a laminated sheet of three magnetic sheets (first magnetic sheet 21, second magnetic sheet 22 and third magnetic sheet 23), but the number is not limited and may be 1, 2, or 4 or more.

[0135] In addition, in the second step of the first embodiment, the wiring 2 is covered with a magnetic sheet 20 (magnetic layer 3) formed into a sheet shape, but it is also possible to form the magnetic layer 3, for example, by applying a varnish of a magnetic composition to the wiring 2 and then forming the magnetic composition into a sheet shape.

[0136] 2G, in a third step of the embodiment, the intermediate portion 10 of the wiring 2 embedded in the magnetic layer 3 is cut. That is, the inductor 30 is cut so that the first cutting line 26 is formed.

[0137] 8, the portion of the wiring 2 that is not embedded in the magnetic layer 3 (specifically, the boundary portion between the wiring 2 and the intermediate portion 10) can also be cut. The wiring 2 is cut so that a third cutting line 28 that runs along the end face of the inductor 30 is formed.

[0138] As shown in FIG. 2G, in a third step of the embodiment, the magnetic layer 3 is cut so as to separate the wirings 2, that is, so as to form second cutting lines 27.

[0139] 9, in the modified example, the magnetic layer 3 is cut without dividing the multiple wirings 2 into individual pieces, that is, without forming the second cutting lines 27. The inductor 1 obtained in the third step includes the multiple wirings 2.

[0140] In the modification of FIG. 9, the magnetic layer 3 and the wiring 2 are cut.

[0141] 10, in a modified example, it is also possible to cut only the wiring 2 without cutting the magnetic layer 3. The wiring 2 is cut so that the third cutting line 28 is formed.

[0142] In one embodiment, an inductor 30 is fabricated that includes multiple wires 2, as shown in FIG. 1C.

[0143] However, in a modified example, an inductor preparation sheet 15 having one wiring 2 can be prepared as shown in FIGS. 11A and 11B.

[0144] As shown in FIG. 11A, in the third step, the wiring 2 and the magnetic layer 3 are cut so that a first cutting line 26 is formed.

[0145] Alternatively, as shown in FIG. 11B, in the third step, the wiring 2 is cut so that a third cutting line 28 is formed.

[0146] In one embodiment, the evaluation and inspection step includes evaluating the inductance of the inductor 1 and inspecting the continuity of the wiring 2, but it may be possible to perform only one of them.

[0147] The proportion of magnetic particles in the magnetic layer 3 may be uniform throughout the magnetic layer 3, or may increase or decrease with increasing distance from each wiring 2. To manufacture an inductor 1 in which the proportion of magnetic particles in the magnetic layer 3 increases with increasing distance from the wiring 2, for example, as shown in Fig. 4B, the proportion of magnetic particles in the second magnetic sheet 22 and the proportion of magnetic particles in the third magnetic sheet 23 are set higher than the proportion of magnetic particles in the first magnetic sheet 21.

[0148] <Second embodiment> In the following second embodiment, the same reference numerals are used for the same components and steps as those in the first embodiment and its modified examples, and detailed descriptions thereof will be omitted. In addition, the second embodiment can achieve the same effects as those in the first embodiment and its modified examples, unless otherwise specified. Furthermore, the first embodiment, its modified examples, and the second embodiment can be appropriately combined.

[0149] In the first embodiment, the wiring 2 (see FIG. 1A) shown in FIG. 1A and prepared in a first step, and the wiring 2 in the inductor 30 (FIG. 1C) shown in FIG. 1C and fabricated in a second step, have an approximately U-shape when viewed in a plane.

[0150] However, the shape of the wiring 2 in a plan view is not limited to the above.

[0151] For example, as shown in FIG. 12, in the second embodiment, the wiring 2 has a generally zigzag shape in plan view.

[0152] The intermediate portion 10 of the wiring 2 also has a generally zigzag shape in plan view, and more specifically, has bent portions 14 that are bent in plan view. A plurality of bent portions 14 are arranged in the intermediate portion 10 at intervals from each other in the direction of electrical current flow.

[0153] In the inductor 30, of the four peripheral end faces of the magnetic layer 3, a first end 8 and a second end 9 are exposed from one end face (front end face) 16 and the other end face (rear end face) 17 which face each other with a gap between them.

[0154] <Third embodiment> In the following third embodiment, the same reference numerals are used for the same members and steps as those in the first embodiment, its modified example, and the second embodiment, and detailed description thereof will be omitted. In addition, the third embodiment can achieve the same effects as those in the first embodiment, its modified example, and the second embodiment, unless otherwise specified. Furthermore, the first embodiment, its modified example, the second embodiment, and the third embodiment can be appropriately combined.

[0155] As shown in FIG. 1C, in the first embodiment, in the inductor 30, the entire flow direction of the midsection 10 is embedded in the magnetic layer 3.

[0156] As shown in FIG. 13, in the third embodiment, a part of the midsection 10 in the flow direction can be exposed from the magnetic layer 3.

[0157] Specifically, in the inductor 30, the curved portion 11 corresponding to the approximate center portion 18 in the flow direction of the intermediate portion 10 (the wiring 2) is exposed from the other end surface 17 of the magnetic layer 3.

[0158] In the evaluation and inspection step, the terminal 25 is not brought into contact with the curved portion 11, but is brought into contact with the first end portion 8 and the second end portion 9.

[0159] In the third step, the wiring 2 and the magnetic layer 3 are cut so that the first end 8 and the second end 9 are removed while the curved portion 11 remains. That is, the curved portion 11 is attached to the inductor 1.

[0160] In this way, an inductor 1 is obtained, which includes the magnetic layer 3, the curved portion 11 exposed from the magnetic layer 3, and the wiring 2 having a portion embedded in the magnetic layer 3 (the portion of the intermediate portion 10 other than the curved portion 11). EXAMPLES

[0161] The present invention will be described in more detail below with reference to examples and comparative examples. The present invention is not limited to the examples and comparative examples. The specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "not more than" or "less than") or lower limit (a numerical value defined as "not less than" or "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Form for carrying out the invention".

[0162] Example 1 As shown in FIGS. 1A to 2D, the first and second steps were carried out in this order to obtain the inductor 30 shown in FIGS. 1C and 1D.

[0163] 1A and 1B, in the first step, a plurality of wirings 2 each having a diameter D of 220 μm (radius R2 of 110 μm) were prepared. More specifically, a plurality of wirings 2 each including a conductor 6 having a radius R1 of 100 μm and an insulating layer 7 having a thickness T1 of 10 μm were prepared and placed on a horizontal stand (not shown) so as to form a U-shape in plan view.

[0164] Separately, the middle portion 10 of the conductive wire 6 was covered with a magnetic sheet 20 containing magnetic particles and a binder (more specifically, a laminated sheet of a first magnetic sheet 21, a second magnetic sheet 22, and a third magnetic sheet 23 (see Figures 4A to 4C)). The magnetic sheet 20 was formed into a sheet shape so that the first end portion 8 and the second end portion 9 were exposed.

[0165] As shown in FIG. 1C, the length L of each of the first end 8 and the second end 9 was 10 mm.

[0166] As shown in FIGS. 2E to 2H, the fourth step and the third step were then carried out in this order to obtain the inductor 1.

[0167] Example 2 to Comparative Example 2 Except for changing the length L according to Table 1, the same process as in Example 1 was carried out to produce the inductor 30, and then the inductor 1 was obtained.

[0168] [Ease of inspection in the inspection and evaluation process] The inductors 30 of the examples and comparative examples were evaluated for inspectability during manufacture according to the following criteria. The results are shown in Table 1. Both the needle-shaped terminal 25 having a diameter of 5 mm and the cylindrical terminal 25 having a diameter of 5 mm were able to come into contact with the first end 8 and the second end 9, the inductance of the inductor 1 was able to be measured, and a continuity test of the wiring 2 was able to be performed. △ Needle-shaped terminal 25 with a diameter of 5 mm was able to come into contact with first end 8 and second end 9, and was able to measure the inductance of inductor 1 and perform a continuity test of wiring 2. However, cylindrical terminal 25 with a diameter of 5 mm was not able to come into contact with first end 8 and second end 9, and was unable to measure the inductance of inductor 1 and was also unable to perform a continuity test of wiring 2. × Neither the needle-shaped terminal 25 with a diameter of 5 mm nor the cylindrical terminal 25 with a diameter of 5 mm could come into contact with the first end 8 and the second end 9, so the inductance of the inductor 1 could not be measured, and no continuity test of the wiring 2 could be performed.

[0169] [Manufacturing cost] The amount of removal of the first end 8 and the second end 9 in the fourth step of each of the examples and comparative examples was measured, and the manufacturing cost was evaluated according to the following criteria. The results are shown in Table 1. The length L of each of the first end 8 and the second end 9 of the wiring 2 is 40 mm or less. △ The length L of each of the first end 8 and the second end 9 of the wiring 2 is more than 40 mm and less than 100 mm. × The length L of each of the first end 8 and the second end 9 of the wiring 2 is 100 mm or more.

[0170] [Table 1] [Explanation of symbols]

[0171] 1 Inductor 2 Wiring 3 magnetic layer 6 conductors 7 Insulating layer 8 First end 9 Second end 10 Middle part 13 Second outer peripheral surface 30 Inductor L End length D: Diameter of a wire with a circular cross section T2 Thickness of wiring with a rectangular cross section

Claims

1. An inductor comprising a plurality of wirings each having a conductor and an insulating layer covering the conductor, the insulating layer being made of an insulating resin, and a magnetic layer, The magnetic layer contains magnetic particles, each of the plurality of wirings has an intermediate portion covered by the magnetic layer and an end portion exposed within a range of 2 mm or more and less than 100 mm from the magnetic layer; An inductor, characterized in that, at each of the ends exposed from the magnetic layer, only one end in the thickness direction of the conductor is exposed from the insulating layer.

2. The thickness direction length of the wiring in the inductor is 300 μm or less, 2. The inductor according to claim 1, wherein the thickness of the inductor is 1000 μm or less.

3. An inductor as described in claim 1, characterized in that the magnetic layer is a laminate of multiple magnetic sheets.

Images