Inductors

Abstract

The inductor (1) includes a wiring (35) and a magnetic layer (4) having a sheet shape and burying the wiring (35). The wiring (35) includes a conductor (2) and an insulating film (3) arranged on the conductor circumferential surface (7) of the conductor (2). The magnetic layer (4) contains 40% by volume or more of anisotropic magnetic particles (8). When observing at least two of the following first plane sections (11), second plane sections (12) and third plane sections (13) along the surface direction of the magnetic layer (4), in the first direction orthogonal to the flow direction and the thickness direction, in the vicinity (10) within 50 μm from the first direction outer end edge (30) of the insulating film (3) to the outside, an oriented region in which the anisotropic magnetic particles (8) are oriented in the flow direction is observed. The first plane section (11) passes through the midpoint (MP) of the line segment (L) of the conductor (2). The second plane section (12) passes through the first point (P1), which is located at a position where the distance from the midpoint (MP) to one side in the thickness direction is 1 / 4L. The third plane section (13) passes through the second point (P2), which is located at a position where the distance from the midpoint (MP) to the other side in the thickness direction is 1 / 4L.

Description

Technical Field

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

[0002] Conventionally, it is known that an inductor is mounted on electronic equipment or the like and used as a passive element such as a voltage conversion means.

[0003] For example, an inductor has been proposed that includes a rectangular parallelepiped substrate main body made of a magnetic material and an internal conductor buried inside the substrate main body (see, for example, Patent Document 1 listed below).

[0004] Prior art literature

[0005] Patent Literature

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

[0007] Problem that the invention aims to solve

[0008] In recent years, inductors have been required to have higher levels of inductance. However, the inductor disclosed in Patent Document 1 has a disadvantage that it cannot meet the above requirements.

[0009] The present invention provides an inductor having excellent inductance.

[0010] Solutions for solving problems

[0011] The present invention (1) includes an inductor, wherein the inductor includes: a wiring having a conductor and an insulating film arranged on the circumference of the conductor; and a magnetic layer in which the wiring is buried, the magnetic layer containing more than 40 volume % of anisotropic magnetic particles, and when observing at least two of the first plane section, the second plane section and the third plane section along the surface direction orthogonal to the thickness direction of the magnetic layer, in the first direction orthogonal to the current direction and the thickness direction, in the vicinity within 50 μm outward from the outer end edge of the insulating film, an orientation region in which the anisotropic magnetic particles are oriented along the current direction is observed.

[0012] The first planar cross-section passes through a midpoint of a line segment L connecting one end edge and the other end edge of the conductive wire in the thickness direction.

[0013] The second plane section passes through the first point, and the first point is located after advancing from the midpoint to one side in the thickness direction by 1 / 4 of the length of the line segment L, that is, 1 / 4L.

[0014] The third plane section passes through the second point, and the second point is located after advancing from the midpoint to the other side in the thickness direction by the length 1 / 4L.

[0015] In the inductor, when observing at least two of the first plane section, the second plane section, and the third plane section, an oriented region in which the anisotropic magnetic particles are oriented in the flow direction is observed in the vicinity. Therefore, a magnetic path along the flow direction is formed in the vicinity which has a strong influence on the inductance of the inductor.

[0016] In addition, the magnetic layer contains anisotropic magnetic particles at a high ratio of 40 volume % or more.

[0017] Therefore, the inductor has excellent inductance.

[0018] The present invention (2) includes the inductor described in (1), wherein when the magnetic layer is observed in the first planar cross section, the second planar cross section, and the third planar cross section, the orientation region is observed in all of the vicinity regions.

[0019] In the inductor 1 , the oriented region is observed in the vicinity of all the first planar cross sections, the second planar cross sections, and the third planar cross sections, and therefore the inductance of the inductor is further improved.

[0020] The present invention (3) comprises the inductor described in (1) or (2), wherein the conductive wire has a roughly circular shape when observed in a cross section perpendicular to the direction along the wiring, the anisotropic magnetic particles have a roughly plate-like shape, and in the orientation region, the surface direction of the anisotropic magnetic particles is along the circumferential direction of the conductive wire.

[0021] In the orientation region of the inductor, the plane direction of the anisotropic magnetic particles is oriented along the circumferential direction of the conductive wire, thereby forming a magnetic path surrounding the conductive wire. As a result, the inductance is further improved.

[0022] Effects of the Invention

[0023] The inductor of the present invention has excellent inductance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a processed image of a SEM photograph of a longitudinal section of Example 1, which is a specific example of one embodiment of the inductor of the present invention.

[0025] Figure 2 In Figure 2 A~ Figure 2 C is Figure 1 The image-processed image of the SEM photograph of the first cross section of the inductor shown in FIG. Figure 2 A represents the first plane section. Figure 2 B stands for Figure 2 A magnified image. Figure 2 C stands for Figure 2 Enlarged view of B.

[0026] Figure 3 In Figure 3 A~ Figure 3 C is Figure 1 The image-processed image of the SEM photograph of the second cross section of the inductor shown in FIG. Figure 3 A represents the second plane section, Figure 3 B stands for Figure 3 A magnified image. Figure 3 C stands for Figure 3 Enlarged view of B.

[0027] Figure 4 In Figure 4 A~ Figure 4 C is Figure 1 The image processing diagram of the SEM photograph of the third plane section of the inductor shown in FIG. Figure 4 A represents the third plane section. Figure 4 B stands for Figure 4 A magnified image. Figure 4 C stands for Figure 4 Enlarged view of B.

[0028] Figure 5 In Figure 5 A~ Figure 5 C is correct Figure 1 The process diagram for explaining the manufacturing process of the inductor is shown in FIG. Figure 5 A represents the process of preparing the first magnetic sheet and wiring. Figure 5 B represents the process of embedding wiring using the first magnetic sheet and the process of preparing the second magnetic sheet and the third magnetic sheet. Figure 5 C represents a step of sandwiching the wiring and the first magnetic sheet between the second magnetic sheet and the third magnetic sheet.

[0029] Figure 6 Indicate as Figure 1 This is a processed image of a SEM photograph of a longitudinal section of Example 2 which is a specific example of a modified example of the inductor shown.

[0030] Figure 7 This is a processed image of a SEM photograph of a longitudinal section of Example 3 which is a specific example of a modified example of the inductor of the present invention.

[0031] Figure 8 In Figure 8 A~ Figure 8 C is Figure 7 The image-processed images of the SEM photographs of the first to third plane sections of the inductor shown in FIG. Figure 8A represents the first plane section. Figure 8 B represents the second plane section. Figure 8 C represents a view of the third plane section.

[0032] Fig. 9 In Fig. 9 A~ Fig. 9 B is an image-processed image of the SEM photographs of the longitudinal section to the first planar section of Comparative Example 1, Fig. 9 A represents a longitudinal section. Fig. 9 B is a diagram showing the first planar section.

[0033] Fig.10 This is a processed image of the SEM photograph of the first cross section of Comparative Example 3. DETAILED DESCRIPTION

[0034] Based on Figure 1 to Figure 4 The SEM photograph shown in C illustrates one embodiment of the inductor of the present invention.

[0035] like Figure 1 As shown, the inductor 1 has a plane direction ( Figure 2 A~ Figure 4 The inductor 1 has a shape extending in the direction along the paper surface in C. The inductor 1 has one surface 5 and another surface 6 facing each other in the thickness direction. The one surface 5 and the other surface 6 are substantially parallel to each other and have a substantially flat shape.

[0036] The inductor 1 includes a wiring 35 and a magnetic layer 4 .

[0037] A plurality of wirings 35 are provided in the inductor 1 at intervals in the plane direction when viewed in a longitudinal section 16 perpendicular to a direction along the wiring 35. In the following description, one wiring 35 is described, but the same applies to the other wirings 35.

[0038] like Figure 2 As shown in A, the wiring 35 has a shape extending along one direction included in the surface direction of the inductor 1. Figure 1 As shown, the wiring 35 has a substantially circular shape when viewed in the longitudinal section 16 .

[0039] In addition, "observation in longitudinal section 16" includes the case where a cross section along longitudinal section 16 is prepared and observed by SEM. The same is true for observation in longitudinal section 16, first planar section 11, second planar section 12, and third planar section 13 described later.

[0040] The wiring 35 includes a conductive line 2 and an insulating film 3 .

[0041] The conductor 2 has a shape extending along the above-mentioned one direction. Figure 1 As shown, the conductor 2 has a substantially circular shape when viewed in a longitudinal section 16 along a direction perpendicular to the flow direction (downstream direction). Therefore, the conductor 2 has a conductor circumferential surface 7 when viewed in the longitudinal section 16 .

[0042] The material of the wire 2 includes metal conductors such as copper, silver, gold, aluminum, nickel, and alloys thereof, preferably copper. The wire 2 may be a single-layer structure or a multi-layer structure in which the surface of a core conductor (such as copper) is plated (such as nickel-plated).

[0043] The radius of the conductive wire 2 is, for example, greater than or equal to 25 μm, or preferably greater than or equal to 50 μm, and is, for example, less than or equal to 2000 μm, or preferably less than or equal to 200 μm.

[0044] The insulating film 3 is used to protect the conductor 2 from the influence of chemicals and water, and to prevent a short circuit between the conductor 2 and the magnetic layer 4. The insulating film 3 is arranged on the circumference of the conductor 2 when viewed in the longitudinal section 16. Specifically, the insulating film 3 covers the entire conductor circumference 7 (outer circumference) of the conductor 2 when viewed in the longitudinal section 16. In addition, the insulating film 3 has a substantially annular shape when viewed in cross section, sharing the central axis (center) with the conductor 2. Therefore, the insulating film 3 has an insulating circumferential surface 25 when viewed in the longitudinal section 16.

[0045] Examples of the material of the insulating film 3 include insulating resins such as polyvinyl formal, polyester, polyester imide, polyamide (including nylon), polyimide, polyamideimide, and polyurethane. These materials may be used alone or in combination of two or more.

[0046] The insulating film 3 may be composed of a single layer or a plurality of layers.

[0047] The thickness of the insulating film 3 is substantially uniform in the radial direction of the conductive wire 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.

[0048] The ratio of the radius of the conductive wire 2 to the thickness of the insulating film 3 is, for example, 1 or more, preferably 10 or more, and for example, 500 or less, preferably 100 or less.

[0049] The radius of the wiring 35 is, for example, greater than or equal to 25 μm, or preferably greater than or equal to 50 μm, and is, for example, less than or equal to 2000 μm, or preferably less than or equal to 200 μm.

[0050] The magnetic layer 4 increases the inductance of the inductor 1. The wiring 35 is embedded in the magnetic layer 4. The magnetic layer 4 is arranged on the peripheral surface of the insulating film 3 when viewed in the longitudinal section 16.

[0051] Specifically, the magnetic layer 4 covers the entire insulating circumferential surface 25 (outer circumferential surface) of the insulating film 3 .

[0052] In addition, the magnetic layer 4 forms the outer shape of the inductor 1. Specifically, the magnetic layer 4 has a sheet shape, and has a rectangular shape extending in the plane direction. More specifically, the magnetic layer 4 has one side and the other side facing each other in the thickness direction, and the one side of the magnetic layer 4 forms the one side 5 of the inductor 1, and the other side of the magnetic layer 4 forms the other side 6 of the inductor 1.

[0053] The magnetic layer 4 contains anisotropic magnetic particles 8. Specifically, the material of the magnetic layer 4 is a magnetic composition containing anisotropic magnetic particles 8 and a binder 9. Preferably, the magnetic layer 4 is a cured product of a thermosetting resin composition (a composition containing anisotropic magnetic particles 8 and a thermosetting component described below).

[0054] Examples of the magnetic material constituting the anisotropic magnetic particles 8 include soft magnetic materials and hard magnetic materials. From the viewpoint of inductance, soft magnetic materials are preferred.

[0055] As the soft magnetic body, for example, a single metal body containing one metal element in a pure state, for example, a eutectic body (mixture) of one or more metal elements (the first metal element) and one or more metal elements (the second metal element) and / or non-metallic elements (carbon, nitrogen, silicon, phosphorus, etc.), i.e., an alloy body, can be cited. These materials can be used alone or in combination.

[0056] As a single metal body, for example, a metal monomer consisting of only one metal element (the first metal element) can be cited. As the first metal element, for example, iron (Fe), cobalt (Co), nickel (Ni), and other metal elements that can be contained as the first metal element of the soft magnetic body can be appropriately selected.

[0057] In addition, as a single metal body, for example, a core containing only one metal element and a surface layer containing inorganic and / or organic substances that partially or completely modify the surface of the core can be cited, for example, an organic metal compound containing a first metal element, a form after decomposition (thermal decomposition, etc.) of an inorganic metal compound, etc. As the latter form, more specifically, iron powder (sometimes referred to as carbonyl iron powder) after thermal decomposition of an organic iron compound (specifically carbonyl iron) containing iron as the first metal element can be cited. In addition, the position of the layer including the inorganic and / or organic substances that modify the portion containing only one metal element is not limited to the surface as described above. In addition, as an organic metal compound or inorganic metal compound that can obtain a single metal body, there is no particular limitation, but it can be appropriately selected from the known or commonly used organic metal compounds or inorganic metal compounds that can obtain a single metal body of a soft magnetic body.

[0058] The alloy body is a fusion body of one or more metal elements (first metal element) and one or more metal elements (second metal element) and / or non-metal elements (carbon, nitrogen, silicon, phosphorus, etc.), and there is no particular restriction as long as it can be used as an alloy body of a soft magnetic body.

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

[0060] The second metal element is an element (auxiliary component) auxiliaryly contained in the alloy body and is a metal element compatible (eutectic) with the first metal element, and examples thereof include iron (Fe) (when the first metal element is an element other than Fe), cobalt (Co) (when the first metal element is an element other than Co), nickel (Ni) (when the first metal element is an element other than Ni), chromium (Cr), aluminum (Al), silicon (Si), copper (Cu), silver (Ag), manganese (Mn), calcium (Ca), barium (Ba), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), molybdenum (Mo), tungsten (W), ruthenium (Ru), rhodium (Rh), zinc (Zn), gallium (Ga), indium (In), germanium (Ge), tin (Sn), lead (Pb), scandium (Sc), yttrium (Y), strontium (Sr), various rare earth elements, etc. These elements can be used alone or in combination of two or more.

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

[0062] As an example of an Fe alloy of an alloy body, for example, magnetic stainless steel (Fe-Cr-Al-Si alloy) (including electromagnetic stainless steel), sendust (Fe-Si-Al alloy) (including super sendust), permalloy (Fe-Ni alloy), Fe-Ni-Mo alloy, Fe-Ni-Mo-Cu alloy, Fe-Ni-Co alloy, Fe-Cr alloy, Fe-Cr-Al alloy, Fe-Ni-Cr alloy, Fe-Ni-Cr-Si alloy, copper silicon alloy (Fe-Cu-Si alloy), Fe-Si alloy, Fe-Si-B (-Cu-Nb alloy), Fe-B -Si-Cr alloy, Fe-Si-Cr-Ni alloy, Fe-Si-Cr alloy, Fe-Si-Al-Ni-Cr alloy, Fe-Ni-Si-Co alloy, Fe-N alloy, Fe-C alloy, Fe-B alloy, Fe-P alloy, ferrite (including stainless steel ferrite, and soft magnetic ferrite such as Mn-Mg ferrite, Mn-Zn ferrite, Ni-Zn-Cu ferrite, Cu-Zn ferrite, Cu-Mg-Zn ferrite, etc.), Permind iron cobalt alloy (Fe-Co alloy), Fe-Co-V alloy, Fe-based amorphous alloy, etc.

[0063] As a Co-based alloy which is an example of an alloy body, for example, Co-Ta-Zr, a cobalt (Co)-based amorphous alloy, etc. can be cited.

[0064] As a Ni-based alloy which is an example of an alloy body, for example, Ni—Cr alloy etc. can be cited.

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

[0066] As the shape of the anisotropic magnetic particles 8, from the viewpoint of anisotropy (or orientation), for example, a flat shape (plate shape), a needle shape, etc. can be cited. From the viewpoint that the relative magnetic permeability is good in the plane direction (two-dimensional), a flat shape is preferably cited. In addition, the magnetic layer 4 can also contain non-anisotropic magnetic particles in addition to the anisotropic magnetic particles 8. The non-anisotropic magnetic particles can also have shapes such as spheres, particles, blocks, pellets, etc. 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.

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

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

[0069] The proportion of the anisotropic magnetic particles 8 in the magnetic layer 4 is 40% by volume or more, preferably 45% by volume or more, more preferably 50% by volume or more, further preferably 55% by volume or more, and particularly preferably 60% by volume or more. If the proportion of the anisotropic magnetic particles 8 in the magnetic layer 4 does not satisfy the above lower limit, the inductor 1 cannot obtain excellent inductance.

[0070] The ratio of anisotropic magnetic particles 8 in magnetic layer 4 is, for example, 95 volume % or less, or preferably 90 volume % or less. When the ratio of anisotropic magnetic particles 8 is equal to or less than the above upper limit, inductor 1 has excellent mechanical strength.

[0071] The binder 9 is a matrix for dispersing the anisotropic magnetic particles 8 in the magnetic layer 4. The binder 9 is dispersed in the magnetic layer 4 in a predetermined direction.

[0072] Specifically, as the binder 9, thermoplastic components such as acrylic resins and thermosetting components such as epoxy resin compositions can be cited. Acrylic resins include, for example, carboxyl-containing acrylate copolymers. The epoxy resin composition includes, for example, epoxy resins (cresol novolac type epoxy resins, etc.) as a main agent, epoxy resin curing agents (phenolic resins, etc.), epoxy resin curing accelerators (imidazole compounds, etc.). Preferably, the binder 9 contains a cured product of a thermosetting component. The proportion of the binder 9 in the magnetic composition is the remainder excluding the proportion of the anisotropic magnetic particles 8 in the magnetic composition.

[0073] In addition, when the magnetic layer 4 is observed in the longitudinal section 16, the anisotropic magnetic particles 8 covering the insulating circumferential surface 25 of the insulating film 3 are oriented, for example, along the circumferential direction of the conductive wire 2. Furthermore, if the anisotropic magnetic particles 8 are flat, when the magnetic layer 4 is observed in the longitudinal section 16, the anisotropic magnetic particles 8 covering the insulating circumferential surface 25 are oriented in the circumferential direction.

[0074] In respectively Figure 2 A~ Figure 2 The first plane section 11 shown in C, Figure 3 A~ Figure 3 The second plane section 12 shown in B and Figure 4 A~ Figure 4 When observing the three planar sections, such as the third planar section 13 shown in B, the vicinity region 10 and the outer region 20 are observed in the magnetic layer 4. That is, in the first planar section 11, the second planar section 12, and the third planar section 13, the magnetic layer 4 has the vicinity region 10 and the outer region 20.

[0075] The first plane section 11 , the second plane section 12 , and the third plane section 13 are defined as follows.

[0076] like Figure 1 As shown, the first plane section 11 is a central plane section passing through the midpoint MP of the line segment L, and the line segment L connects one end edge 36 and the other end edge 37 in the thickness direction of the conductor 2. The first plane section 11 is along the surface direction of the inductor 1. Specifically, the first plane section 11 is substantially parallel to at least the other surface 6 of the inductor 1 in the thickness direction.

[0077] The second plane section 12 is a plane section passing through the first point P1, which is located at a position after advancing from the midpoint MP to one side in the thickness direction by 1 / 4 length (1 / 4L) of the line segment L. The second plane section 12 is along the surface direction of the inductor 1. Specifically, the second plane section 12 is parallel to the first plane section 11.

[0078] The third plane section 13 is another plane section passing through the second point P2, which is located at a position after advancing the length (1 / 4L) from the midpoint MP to the other side in the thickness direction. The third plane section 13 is along the plane direction of the inductor 1. Specifically, the third plane section 13 is parallel to the first plane section 11.

[0079] like Figure 2 B. Figure 3 B and Figure 4 As shown in FIG. 1B , the vicinity region 10 and the outer region 20 are arranged in this order in the first direction (equivalent to the direction perpendicular to the flow direction and the thickness direction). Figure 2 A~ Figure 4 C) are sequentially arranged from the outer edge 30 of the insulating film 3 toward the outside in the first direction, and the nearby region 10 and the outer region 20 are continuous with each other without a gap.

[0080] The vicinity region 10 is a region within 50 μm from the first direction outer edge 30 of the insulating film 3 in the first direction and is a band-shaped region along the flow direction. The vicinity region 10 is a portion that has a greater influence on the inductance of the inductor 1 than the outer region 20 described below.

[0081] The outer region 20 includes a first outer region 17, a second outer region 18, and a third outer region 19. The first outer region 17, the second outer region 18, and the third outer region 19 are arranged in this order in parallel toward the outer side in the first direction.

[0082] The first outer region 17 is adjacent to the first direction outer portion of the neighboring region 10. Specifically, the first outer region 17 is a region that is more than 50 μm and less than 75 μm outward from the first direction outer edge 30 of the insulating film 3 in the first direction, and is a band-shaped region along the flow direction. That is, the first outer region 17 is a region that is within 25 μm from the first direction outer edge of the neighboring region 10.

[0083] The second outer region 18 is adjacent to the first outer region 17 in the first direction. Specifically, the second outer region 18 is a region extending from the first direction outer edge 30 of the insulating film 3 to the outside by more than 75 μm and less than 95 μm in the first direction, and is a band-shaped region along the flow direction. That is, the second outer region 18 is a region within 20 μm from the first direction outer edge of the first outer region 17.

[0084] The third outer region 19 is adjacent to the portion of the second outer region 18 outside in the first direction. Specifically, the third outer region 19 is a region extending from the first direction outer edge 30 of the insulating film 3 to the outside by more than 95 μm and less than 105 μm in the first direction, and is a band-shaped region along the flow direction. That is, the third outer region 19 is a region within 10 μm from the first direction outer edge of the second outer region 18.

[0085] like Figure 2 A~ Figure 4 As shown in C, when observing any of the first planar section 11, the second planar section 12 and the third planar section 13, an oriented region in which the anisotropic magnetic particles 8 are oriented in a substantially linear shape along the current direction is observed at least in the vicinity 10.

[0086] When observed in the above-mentioned cross-section, the case where the angle between the straight direction of the anisotropic magnetic particles 8 and the current direction is less than 15 degrees is defined as "the anisotropic magnetic particles 8 are oriented along the flow direction". On the other hand, the case where the above-mentioned angle exceeds 15 degrees is defined as "the anisotropic magnetic particles 8 are not oriented along the flow direction".

[0087] The oriented region is a region where the ratio of the number of anisotropic magnetic particles 8 oriented along the flow direction to the sum of the number of anisotropic magnetic particles 8 oriented along the flow direction and the number of anisotropic magnetic particles 8 not oriented along the flow direction is greater than 50%, preferably greater than 60%, more preferably greater than 70%, further preferably greater than 75%, and particularly preferably greater than 80%.

[0088] Preferably, when observing in any of the first planar cross section 11 , the second planar cross section 12 , and the third planar cross section 13 , the alignment region can be observed in the vicinity region 10 and the first outer region 17 .

[0089] More preferably, when observing with one of the first cross-section 11, the second cross-section 12 and the third cross-section 13 (the first cross-section 11 or the second cross-section 12), or even with two cross-sections (for example, the first cross-section 11 and the second cross-section 12), orientation regions are observed in the nearby area 10, the first outer area 17 and the second outer area 18.

[0090] It is particularly preferred that when observing with one of the first plane section 11, the second plane section 12 and the third plane section 13 (specifically the first plane section 11), the orientation region is observed in the nearby area 10, the first outer area 17, the second outer area 18 and the third outer area 19.

[0091] In addition, preferably, referring to the column of Example 1 in Table 2, Figure 2 As shown in FIG. 1B, when observing the first planar section 11, the orientation regions are observed in the vicinity region 10, the first outer region 17, the second outer region 18, and the third outer region 19. Figure 3 As shown in FIG. 1B , when observing the second planar section 12 , an oriented region is observed in the vicinity 10 , the first outer region 17 , and the second outer region 18 , but no oriented region is observed in the third outer region 19 . Figure 4 As shown in FIG. 1B , when observing the third plane section 13, an orientation region is observed in the vicinity region 10 and the first outer region 17, but no orientation region is observed in the second outer region 18 and the third outer region 19. That is, it is preferred that Figure 2 B. Figure 3 B and Figure 4 As shown in B, alignment regions can be observed in both the nearby region 10 and the outer region 20.

[0092] In addition, in the orientation regions observed in the first planar section 11, the second planar section 12, and the third planar section 13, it is observed that the anisotropic magnetic particles 8 are oriented along the flow direction, and referring to the longitudinal section 16, the anisotropic magnetic particles 8 are oriented along the circumferential direction of the conductive wire 2. If the aspect ratio of the anisotropic magnetic particles 8 themselves is 100, and if the aspect ratio observed in the first planar section 11, specifically, the aspect ratio (longitudinal length l / lateral length w) of the anisotropic magnetic particles 8 in the above-mentioned cross-section (refer to Figure 2 C. Figure 3 C and Figure 4 C) is, for example, 50 or more, preferably 75 or more, which can be defined as the orientation of the anisotropic magnetic particles 8 along the flow direction and the circumferential direction of the conductive wire 2 .

[0093] When the anisotropic magnetic particles 8 are oriented in both the flow direction and the circumferential direction, a magnetic path surrounding the conductive wire 2 and following the current is formed in the magnetic layer 4 , thereby increasing the inductance of the inductor 1 .

[0094] Furthermore, when observing the first planar section 11 , the second planar section 12 , and the third planar section 13 , an alignment region may be observed in a portion of the outer region 20 that is outside the third outer region 19 , or no alignment region may be observed.

[0095] In addition, if Figure 1 As shown in the figure, when viewed in the longitudinal section 16, the intersection (top) 50 is formed by two kinds of anisotropic magnetic particles 8 having different orientation directions. In this embodiment, the intersection 50 is located at a position closer to the other side in the thickness direction than the third planar section 13. In addition, the intersection 50 is located at a position on the thickness direction side of the fifth section (not shown) that passes through the other end edge 37 of the wire 2 and is parallel to the third planar section 13. That is, the intersection 50 is located between the third planar section 13 and the fifth section (not shown).

[0096] The thickness of the magnetic layer 4 is, for example, 2 times or more, preferably 3 times or more, and for example, 20 times or less of the radius of the conductor 2. Specifically, the thickness of the magnetic layer 4 is, for example, 100 μm or more, preferably 200 μm or more, and for example, 2000 μm or less, preferably 1000 μm or less. In addition, the thickness of the magnetic layer 4 is the distance between one surface 5 and the other surface 6 of the magnetic layer 4.

[0097] The thickness of the inductor 1 is the same as the thickness of the magnetic layer 4 described above.

[0098] To obtain the inductor 1, for example, Figure 5 As shown in A, first, the wiring 35 is prepared, and the magnetic sheet 24 is prepared, as shown in FIG. Figure 5As shown in B, next, the wirings 35 are buried collectively using the magnetic sheet 24 to form the magnetic layer 4.

[0099] The magnetic sheet 24 may be a single sheet or may include a plurality of sheets. Specifically, the magnetic sheet 24 includes at least a first magnetic sheet 21 ( Figure 5 A), preferably independently including the first magnetic sheet 21 and the second magnetic sheet 22 ( Figure 5 B) and the third magnetic sheet 23 ( Figure 5 B).

[0100] The materials of the first magnetic sheet 21, the second magnetic sheet 22 and the third magnetic sheet 23 each include the above-mentioned anisotropic magnetic particles 8 and the binder 9, and have a sheet shape extending in the plane direction. Preferably, the first magnetic sheet 21, the second magnetic sheet 22 and the third magnetic sheet 23 are prepared as B-stage sheets respectively. Each of the first magnetic sheet 21, the second magnetic sheet 22 and the third magnetic sheet 23 can be a single layer, and can also be composed of multiple layers (specifically, an inner sheet and an outer sheet located on the side opposite to the side where the conductor 2 is located relative to the inner sheet). As the first magnetic sheet 21, the second magnetic sheet 22 and the third magnetic sheet 23, for example, soft magnetic thermosetting adhesive films described in Japanese Patent Application No. 2014-165363, Japanese Patent Application No. 2015-92544, etc. can be cited.

[0101] like Figure 5 The arrow of A and Figure 5 As shown in B, for example, first, the wiring 35 is embedded in the first magnetic sheet 21 indicated by the solid line (preferably, the wiring 35 is thermally pressed). Thus, the intersection 50 is formed in the first magnetic sheet 21.

[0102] like Figure 5 The arrow of B and Figure 5 C, then, as required, the second magnetic sheet 22 and the third magnetic sheet 23 are respectively arranged (preferably hot pressed) on one side and the other side in the thickness direction of the first magnetic sheet 21 in such a manner that the wiring 35 and the first magnetic sheet 21 are clamped in the thickness direction. Thus, a magnetic layer 4 having one side 5 and the other side 6 is formed.

[0103] Then, if the magnetic layer 4 is in the B-stage, it is changed to the C-stage.

[0104] In addition, Figure 5 In C, the boundary between the first magnetic sheet 21 and the second magnetic sheet 22, and the boundary between the first magnetic sheet 21 and the third magnetic sheet 23 are shown, but according to Figure 1 As can be seen from the SEM photos, these boundaries may not be clear.

[0105] Furthermore, in the inductor 1, when observing at least two of the first planar cross section 11, the second planar cross section 12, and the third planar cross section 13, an oriented region in which the anisotropic magnetic particles 8 are oriented in the flow direction is observed in the vicinity 10 that has a strong influence on the inductance of the inductor 1. Therefore, in the vicinity 10, a magnetic path is formed along the flow direction.

[0106] Furthermore, the conductor 2 has the conductor circumferential surface 7 when viewed in a longitudinal section. Therefore, in the magnetic layer 4 facing the conductor circumferential surface 7, the anisotropic magnetic particles 8 are more likely to be oriented in the flow direction.

[0107] Furthermore, the magnetic layer 4 contains 40 volume % or more of the anisotropic magnetic particles 8 .

[0108] Therefore, the inductor 1 has excellent inductance.

[0109] In particular, in the inductor 1 of this embodiment, when the magnetic layer 4 is observed in three planar sections, namely the first planar section 11 , the second planar section 12 , and the third planar section 13 , an oriented region is observed in the vicinity region 10 , and thus the inductor 1 has further excellent inductance.

[0110] Furthermore, in the orientation region of the inductor 1, the plane direction of the anisotropic magnetic particles 8 is oriented along the circumferential direction of the conductive wire 2. Therefore, a magnetic path surrounding the conductive wire 2 is formed. As a result, the inductance is further improved.

[0111] <Modification>

[0112] In the modification, the same reference numerals are used for the same components and processes as those in the first embodiment, and detailed description thereof is omitted. In addition, the modification can have the same effects as those in the first embodiment except for the contents specially described. Furthermore, the first embodiment and its modification can be appropriately combined.

[0113] In one embodiment, if Figure 2 B. Figure 3 B and Figure 4 As shown in B, an orientation region can be observed in the vicinity 10 of any of the first planar section 11, the second planar section 12, and the third planar section 13.

[0114] However, the cross-sections where the orientation region is observed are not limited to all (three) of the three cross-sections described above, and may be two. For example, although not drawn as the first cross-section 11, the second cross-section 12, and the third cross-section 13, referring to the Example 2 column of Table 1, when observing with the second cross-section 12 and the third cross-section 13, the orientation region is observed in the vicinity 10 (and the first outer region 17 and the second outer region 18), on the other hand, when observing with the first cross-section 11, the orientation region is not observed in the vicinity 10. In addition, in the above-mentioned modification examples, as Figure 6 As shown, the intersection portion 50 is located on the first planar section 11 , for example.

[0115] In the above-mentioned modification, in the second plane section 12 and the third plane section 13, an orientation region is observed in the vicinity 10, which is not shown in the figure. However, two of the three plane sections are not limited to the second plane section 12 and the third plane section 13, and may be the first plane section 11 and the second plane section 12 (see the following description). Figure 7-8 C) or the first plane section 11 and the third plane section 13.

[0116] Furthermore, when an orientation region is observed in the vicinity 10 when observing with the first planar section 11 and the second planar section 12, no orientation region is observed in the vicinity 10 when observing with the third planar section 13. Furthermore, when an orientation region is observed in the vicinity 10 when observing with the first planar section 11 and the third planar section 13, no orientation region is observed in the vicinity 10 when observing with the second planar section 12.

[0117] Preferably, if Figure 1 to Figure 4 As in one embodiment shown in C, when observing from the first planar section 11, the second planar section 12, and the third planar section 13, an orientation region is observed in the vicinity region 10. Figure 1 to Figure 4 The inductor 1 of one embodiment shown in C and Figure 6-7 The inductance is more excellent than that of the inductor 1 according to the modified example shown.

[0118] In addition, in one embodiment, if Figure 1 As shown, the wiring 35 and the conductor 2 are generally circular when viewed in longitudinal section 16, but for example Figure 7 As shown, it may also be roughly rectangular.

[0119] The inductor 1 includes a conductor pattern 38 as an example of a wire, an insulating film 3, and a magnetic layer 4. The inductor 1 is a modified example in which an orientation region is observed in the vicinity region 10 in two of the three plane sections, namely, the first plane section 11 and the second plane section 12.

[0120] When viewed in the longitudinal section 16 , the conductor pattern 38 integrally includes one surface 39 and another surface 40 facing each other in the thickness direction, and two connecting surfaces 41 connecting both end edges in the first direction of the one surface 39 and the other surface 40 .

[0121] One surface 39 and the other surface 40 are both flat surfaces and parallel to each other.

[0122] Moreover, in Figure 7 In the illustrated modification, the insulating film 3 may cover the entire outer peripheral surface of the conductive wire 2 .

[0123] Conductor pattern 38 has two corners 42 formed by one surface 39 and connecting surface 41. The two corners 42 constitute curved portions (curved surfaces). The curvature radius of the curved surface of corner 42 is, for example, 5 μm or more and 30 μm or less.

[0124] The thickness of the conductor pattern 38 is the distance between one surface 39 and the other surface 40. The width of the conductor pattern 38 is the average distance between two connection surfaces 41, and is, for example, not less than 20 μm and not more than 1000 μm.

[0125] The insulating film 3 is disposed on one surface 39 , the other surface 40 , and the connecting surface 41 of the conductive pattern 38 .

[0126] The magnetic layer 4 includes a first magnetic layer 45 and a second magnetic layer 46 .

[0127] The first magnetic layer 45 has a substantially plate shape extending in the plane direction. The material of the first magnetic layer 45 is the above-mentioned magnetic composition. In the first magnetic layer 45, the anisotropic magnetic particles 8 are oriented in the flow direction and the plane direction.

[0128] The second magnetic layer 46 has a sheet shape extending in the plane direction. One side of the second magnetic layer 46 in the thickness direction is exposed toward one side in the thickness direction, and the other side of the second magnetic layer 46 covers one side 39 and the connecting surface 41 of the conductor pattern 38 and contacts one side of the first magnetic layer 45 exposed from the conductor pattern 38.

[0129] In the second magnetic layer 46, the anisotropic magnetic particles 8 opposite to one surface 39 are oriented in the surface direction and the flow direction, the anisotropic magnetic particles 8 opposite to the connecting surface 41 are oriented in the thickness direction and the flow direction as described later, and the anisotropic magnetic particles 8 opposite to the corner 42 are oriented in the circumferential direction centered on the corner 42 and the flow direction.

[0130] In this modification, when observing from the first and second plane sections 11 and 12, the alignment region is observed at least in the vicinity 10, which is not shown. However, when observing from the third plane section 13, it is permitted that the alignment region is not observed in the vicinity 10.

[0131] In addition, the corner 42 of the conductor pattern 38 may not be a curved portion, that is, may not have a curved surface, which is not shown in the figure. The corner 42 may also be a curved portion bent at an angle of, for example, 45 degrees or more, 60 degrees or more, or 75 degrees or more, and, for example, 135 degrees or less, 120 degrees or less, or 105 degrees or less (more specifically, 90 degrees).

[0132] In one embodiment, the inductor 1 includes a plurality of wirings 35 , but may also include, for example, one wiring 35 .

[0133] In the above description, the definition of the vicinity region 10 is expressed using the absolute distance from the first direction outer edge 30, but it can be expressed using a relative distance. For example, if the anisotropic magnetic particles 8 are flat, it can be defined as a region within 0.08 of the average thickness of the anisotropic magnetic particles 8 from the first direction outer edge 30 to the outside in the first direction. That is, the ratio of the above distance to the average thickness of the anisotropic magnetic particles 8 can be set to 0.08. In addition, similarly to the vicinity region 10, the first outer region 17 can be defined as a region exceeding 0.08 and within 0.13 from the first direction outer edge 30 to the outside in the first direction, the second outer region 18 can be defined as a region exceeding 0.13 and within 0.175 from the first direction outer edge 30, and the third outer region 19 can be defined as a region exceeding 0.175 and within 0.225 from the first direction outer edge 30 to the outside in the first direction.

[0134] The ratio of the anisotropic magnetic grains 8 in the magnetic layer 4 may be uniform in the magnetic layer 4 , or may be higher or lower as the distance from each wiring 2 increases.

[0135] In order to manufacture the inductor 1 in which the ratio of the anisotropic magnetic particles 8 in the magnetic layer 4 increases as the distance from the wiring 35 increases, for example, Figure 5 As shown in FIG. 2B , the abundance ratio of the anisotropic magnetic particles 8 in the second magnetic sheet 22 and the abundance ratio of the anisotropic magnetic particles 8 in the third magnetic sheet 23 are set higher than the abundance ratio of the anisotropic magnetic particles 8 in the first magnetic sheet 21 .

[0136] [Example]

[0137] Embodiment and comparative example are shown below, and the present invention is further specifically described. In addition, the present invention is not limited to any embodiment and comparative example. In addition, the specific numerical values ​​such as the allotment ratio (containing ratio), physical property value, parameter used in the following description can be replaced by the upper limit (defined as "below", "less than") or the lower limit (defined as "above", "exceeding") of the corresponding records of the allotment ratio (containing ratio), physical property value, parameter, etc. recorded in the above-mentioned "specific embodiments".

[0138] Example 1

[0139] exist Figure 1 to Figure 4 Example drawn in C

[0140] <Inductor according to one embodiment>

[0141] According to one embodiment, an inductor 1 is manufactured. Specifically, a wiring 35 having a wire 2 made of copper with a radius of 100 μm and an insulating film 3 with a thickness of 10 μm is prepared. In addition, a first magnetic sheet 21 is prepared as a B-stage sheet. Table 1 shows the layer structure and processing method of the first magnetic sheet 21.

[0142] like Figure 5 As shown in A, next, the first magnetic sheet 21 is attached (thermocompression-coated) to the wiring 35 .

[0143] like Figure 5 As shown in B, the second magnetic sheet 22 and the third magnetic sheet 23 are prepared as B-stage sheets. Table 1 shows the layer structures and processing methods of the second magnetic sheet 22 and the third magnetic sheet 23.

[0144] If Figure 5 As shown by the arrow B, the wiring 35 and the first magnetic sheet 21 are sandwiched between the second magnetic sheet 22 and the third magnetic sheet 23, and they are attached (thermal-pressed) together.

[0145] Then, the thermosetting components in the first magnetic sheet 21 , the second magnetic sheet 22 , and the third magnetic sheet 23 are brought to a C-stage.

[0146] Thus, the wiring 35 is embedded in the magnetic layer 4 composed of the first magnetic sheet 21, the second magnetic sheet 22 and the third magnetic sheet 23 of the C stage. Figure 1 As shown, the inductor 1 having the wiring 35 and the magnetic layer 4 is manufactured.

[0147] Then, the longitudinal section 16, the first planar section 11, the second planar section 12, and the third planar section 13 of the obtained inductor 1 were observed by SEM, and observation of the orientation region was attempted. Figure 1 to Figure 4 C shows these image processing images, and Table 2 describes the observation results of the alignment regions.

[0148] Example 2

[0149] exist Figure 6 Example drawn in

[0150] <Manufacturing Example of Inductor Based on Modification of One Embodiment>

[0151] The same method as in Example 1 was used except that the first magnetic sheet 21 was not used and only the second magnetic sheet 22 and the third magnetic sheet 23 were used to clamp the wiring 35. Figure 6 The inductor 1 shown was subjected to SEM observation of each of the first cross-section 11 , the second cross-section 12 , and the third cross-section 13 .

[0152] Table 2 shows the observation results of the alignment regions.

[0153] Example 3

[0154] exist Figure 7-8 Example drawn in C

[0155] <Manufacturing Example of Inductor Based on Modification of One Embodiment>

[0156] The cross-sectional area (normal cross-sectional area) of the longitudinal section 16 is the same as that of Example 1. The inductor 1 is obtained in the same manner as Example 1 except that a substantially rectangular wire 2 is used, and SEM observations of the first planar section 11, the second planar section 12, and the third planar section 13 are each performed. In addition, the first magnetic layer 45 covers the wire 2 via the insulating film 3 using a B-stage sheet.

[0157] Table 2 shows the observation results of the alignment regions.

[0158] Comparative Example 1

[0159] exist Fig. 9 A~ Fig. 9 The example drawn in B

[0160] The inductor 1 was obtained in the same manner as in Example 2 except that the second magnetic sheet 22 and the third magnetic sheet 23 when attached to the wiring 35 were changed to C-stage cured bodies, and the first planar section 11 , the second planar section 12 , and the third planar section 13 were each observed by SEM.

[0161] Table 3 shows the results of observation of the alignment regions.

[0162] Comparative Example 2

[0163] The inductor 1 was obtained in the same manner as in Example 3 except that the second magnetic sheet 22 and the third magnetic sheet 23 at the time of pasting were changed to C-stage cured bodies, and the first planar section 11 , the second planar section 12 , and the third planar section 13 were each observed by SEM.

[0164] Table 3 shows the results of observation of the alignment regions.

[0165] Comparative Example 3

[0166] exist Fig.10 Example drawn in

[0167] The inductor 1 was obtained in the same manner as in Example 11 except that spherical magnetic particles (average particle size 20 μm, Fe—Si—Al alloy) were used instead of the anisotropic magnetic particles 8 , and SEM observations of the first cross section 11 , the second cross section 12 , and the third cross section 13 were performed.

[0168] Table 3 shows the results of observation of the alignment regions.

[0169] <Inductor>

[0170] One end edge 36 of both ends of the wire 2 in the flow direction was exposed from the insulating film 3 and the magnetic layer 4 , and both ends of the wire 2 in the flow direction were connected to an impedance analyzer (Agilent: 4294A) to obtain the inductance of the inductor 1 .

[0171] These results are shown in Tables 2 and 3.

[0172] [Table 1]

[0173]

[0174] [Table 2]

[0175]

[0176] [Table 3]

[0177]

[0178] In addition, the above invention is provided as an exemplary embodiment of the present invention, but this is only an example and is not to be interpreted as limiting. Modifications of the present invention that are obvious to those skilled in the art are included in the above claims.

[0179] Industrial Applicability

[0180] Inductors are mounted on, for example, electronic devices and the like.

[0181] Description of Reference Numerals

[0182] 1. Inductor; 2. Conductor; 3. Insulating film; 4. Magnetic layer; 8. Anisotropic magnetic particles; 10. Nearby area; 16. Longitudinal section; 11. First plane section; 12. Second plane section; 13. Third plane section; 16. Longitudinal section; 25. Insulating circumferential surface; 35. Wiring; 38. Conductor pattern; L, line segment; MP, midpoint; P1, first point; P2, second point.

Claims

1. An inductor, characterized in that: The inductor includes: a wiring having a conductive wire and an insulating film disposed on a peripheral surface of the conductive wire; and a magnetic layer in which the wiring is buried, The magnetic layer contains more than 40 volume % of anisotropic magnetic particles, When observing at least two of the first plane section, the second plane section and the third plane section along the plane direction perpendicular to the thickness direction of the magnetic layer, in the first direction perpendicular to the current direction and the thickness direction, in the vicinity within 50 μm outward from the outer edge of the insulating film, an oriented region in which the anisotropic magnetic particles are oriented along the current direction is observed, The first plane section passes through the midpoint of a line segment L connecting one end edge and the other end edge of the conductive wire in the thickness direction. The second plane section passes through the first point, which is located at a position after advancing from the midpoint to one side in the thickness direction by 1 / 4 of the length of the line segment L, that is, 1 / 4L, The third plane section passes through the second point, and the second point is located after advancing from the midpoint to the other side in the thickness direction by the length 1 / 4L.

2. The inductor according to claim 1, characterized in that When observing the first plane section, the second plane section, and the third plane section, respectively, the alignment region is observed in the vicinity.

3. The inductor according to claim 1 or 2, characterized in that: The conductive wire has a substantially circular shape when viewed in a cross section perpendicular to the direction along the wiring. The anisotropic magnetic particles have a substantially plate-like shape, In the orientation region, the plane direction of the anisotropic magnetic particles is along the circumferential direction of the wire.

Images