Laminated inductor

Abstract

The present invention provides a laminated inductor in which electrical characteristics are further improved by optimizing the shape of a via conductor in plan view. A laminated inductor according to the present disclosure is provided with: a hexahedral body formed by laminating magnetic layers; the external electrodes are at least respectively arranged at four corners of the bottom surface of the green body; a composite coil includes a first coil having a winding axis in the lamination direction and connecting a plurality of conductor layers disposed in the body in the lamination direction, and a second coil located above the first coil in the lamination direction and connecting a plurality of conductor layers disposed in the body in the lamination direction and having a winding axis in the lamination direction. A winding shaft is arranged in the stacking direction; and a through-hole conductor extending from the external electrode in the lamination direction, respectively connected to both ends of the first coil and both ends of the second coil, the through-hole conductor having a shape of a triangle in which both sides constituting an outer edge of the through-hole conductor are along an outer edge of the green body in plan view.

Description

Technical Field

[0001] The present disclosure relates to a stacked inductor. Background Art

[0002] Patent document 1 discloses a passive component (coil component), which comprises: an internal conductor built into a base portion, an external electrode provided on a mounting surface of the base portion and electrically connected to the internal conductor, and a lead conductor connecting the internal conductor and the external electrode, wherein the shape of the lead conductor is circular when viewed from above.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-176109

[0004] In the coil component described in Patent Document 1, if the diameter of the lead conductor (eg, via-hole conductor) which is circular in plan view is increased, the DC resistance decreases, but the volume of the base portion decreases, and the inductance value of the coil component decreases.

[0005] In addition, if the diameter of the lead conductor is reduced, the inductance value increases, but the resistance of the lead conductor, the connection resistance between the lead conductor and the internal conductor, and / or the connection resistance between the lead conductor and the external electrode increase, so the DC resistance of the coil component increases. In addition, if the diameter of the lead conductor is small, the connection area between the lead conductor and the external electrode decreases, so there is a concern that problems may arise in connection reliability. Summary of the invention

[0006] In view of this point, the present disclosure provides a laminated inductor having excellent reliability and further improved electrical characteristics of inductance value and direct current resistance by optimizing the shape of a through-hole conductor in a plan view.

[0007] The laminated inductor disclosed in the present invention comprises:

[0008] The blank is formed by stacking magnetic layers and has a hexahedral shape;

[0009] External electrodes are respectively arranged at least at four corners of the bottom surface of the blank;

[0010] A composite coil, comprising a first coil and a second coil, wherein the first coil is connected to a plurality of conductor layers arranged in the blank in a stacking direction and has a winding axis in the stacking direction, and the second coil is located above the first coil in the stacking direction, is connected to a plurality of conductor layers arranged in the blank in the stacking direction, and has a winding axis in the stacking direction; and

[0011] The through-hole conductors extend from the external electrodes in the stacking direction and are connected to both ends of the first coil and both ends of the second coil, respectively.

[0012] The through-hole conductor has a triangular shape in which two sides constituting an outer edge of the through-hole conductor are along an outer edge of the base body when viewed from above.

[0013] According to the present disclosure, since the shape of the through-hole conductor is optimized when viewed from above, a laminated inductor with further improved electrical characteristics and excellent reliability can be achieved. Specifically, since the shape of the through-hole conductor is a triangle whose two sides of the outer edge of the through-hole conductor are along the outer edge of the blank when viewed from above, the area between the outer edge of the blank and the outer edge of the composite coil can be effectively utilized to appropriately arrange the through-hole conductor. Therefore, the connection area between the through-hole conductor and the external electrode can be expanded, and the DC resistance of the laminated inductor can be further reduced. In addition, the connection reliability between the through-hole conductor and the external electrode can also be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a perspective view schematically showing an example of a laminated inductor according to the present disclosure.

[0015] Figure 2 This is a perspective view schematically showing an example of the internal structure of the laminated inductor according to the first embodiment.

[0016] Figure 3 This is an exploded perspective view schematically showing an example of the internal structure of the laminated inductor according to the first embodiment.

[0017] Figure 4A It is a perspective plan view of the laminated inductor according to the first embodiment.

[0018] Figure 4B It is a perspective plan view of a modified example of the laminated inductor according to the first embodiment.

[0019] Figure 5 This is a perspective view schematically showing an example of the internal structure of the laminated inductor according to the second embodiment.

[0020] Figure 6 It is a perspective plan view of a laminated inductor according to a second embodiment.

[0021] Figure 7 This is a perspective view schematically showing an example of the internal structure of the laminated inductor according to the third embodiment.

[0022] Fig. 8A It is a perspective plan view of a laminated inductor according to a third embodiment.

[0023] Figure 8B It is a perspective plan view of a modified example of the laminated inductor according to the third embodiment.

[0024] Description of Reference Numerals

[0025] 1A to 1C…laminated inductor; 10…body; 10L…long side; 10W…short side; 11…first principal surface; 12…second principal surface; 13…first end surface; 14…second end surface; 15…first side; 16…second side surface; C…composite coil; CL…width dimension; C1 to C2…first coil to second coil; E…external electrode; E1 to E4…first external electrode to fourth external electrode; G1 to G6…laminated group; TH…through-hole conductor; TH1 to TH4…first through-hole conductor to fourth through-hole conductor; TL1 to TL6…side; TO…hypotenuse; D1…first conductor layer; D2…second conductor; ML…magnetic layer; h1 to h7…portion; i1 to i7…portion; J1 to j7…portion; L1, L2, L3…imaginary straight line; 1 to θ4…angle. DETAILED DESCRIPTION

[0026] The following is an explanation of the laminated inductor of the present disclosure. In addition, the present disclosure is not limited to the following structure, and can be appropriately changed within the scope of the present disclosure. In addition, a structure obtained by combining a plurality of the preferred structures described below is also the present disclosure.

[0027] The laminated inductor of the present disclosure can be used, for example, as a power inductor of a DC-DC converter. The laminated inductor of the present disclosure can also be used for purposes other than power inductors.

[0028] In this specification, the terms indicating the relationship between elements (e.g., "parallel", "orthogonal", etc.) and the terms indicating the shape of elements do not only mean the strict manner of the words, but also mean the range of being substantially equivalent, such as the range containing a difference of about a few percent. In addition, in this specification, the direction of stacking the magnetic layers and coil conductors constituting the blank is referred to as the "stacking direction". In addition, the so-called top view refers to the top view of the blank observed from the upper surface (height direction).

[0029] The drawings shown below are schematic diagrams, and their dimensions, aspect ratios, and other aspects may differ from those of actual products.

[0030] <Multilayer Inductor According to First Embodiment>

[0031] First, refer to Figure 1 to Figure 4B An embodiment of the laminated inductor according to the first embodiment of the present disclosure will be described. Figure 1 is a perspective view schematically showing an example of a laminated inductor of the present disclosure, Figure 2 is a perspective view schematically showing an example of the internal structure of the laminated inductor according to the first embodiment. Figure 3is an exploded perspective view schematically showing an example of the internal structure of the laminated inductor according to the first embodiment, Figure 4A is a plan perspective view of the laminated inductor according to the first embodiment, Figure 4B It is a perspective plan view of a modified example of the laminated inductor according to the first embodiment.

[0032] like Figure 1 to Figure 4B As shown, the multilayer inductor 1A includes an element 10, external electrodes E (first to fourth external electrodes E1 to E4), a composite coil C (first coil C1 and second coil C2), and through-hole conductors TH (first to fourth through-hole conductors TH1 to TH4). Each component will be described in detail below.

[0033] -Body-

[0034] The blank 10 is, for example, a hexahedron having six faces. As an example, it can be a rectangular parallelepiped or a substantially rectangular parallelepiped. The blank 10 can also have rounded corners and ridges. The corner is the portion where three faces of the blank 10 intersect, and the ridge is the portion where two faces of the blank 10 intersect.

[0035] exist Figure 1 In FIG. 1 , the long side direction, short side direction, and height direction of the laminated inductor 1A and the base body 10 are respectively represented as L direction, W direction, and T direction. The long side direction L, the short side direction W, and the height direction T are orthogonal to each other.

[0036] Figure 1 The blank 10 shown has a first main surface 11 and a second main surface 12 opposite to each other in the height direction T, a first end surface 13 and a second end surface 14 opposite to each other in the longitudinal direction L, and a first side surface 15 and a second side surface 16 opposite to each other in the transverse direction W. Figure 1 In the example shown, a first external electrode E1, a second external electrode E2, a third external electrode E3, and a fourth external electrode E4 are respectively formed at the four corners of the first main surface 11 of the blank 10, and the first main surface 11 of the blank 10 corresponds to the mounting surface (the bottom surface of the blank) of the stacked inductor 1A.

[0037] Figure 3 FIG. 1 is an exploded perspective view schematically showing an example of the internal structure of the laminated inductor of the present disclosure. Figure 3 As shown, the blank 10 is formed by stacking a plurality of magnetic layers ML in the height direction. In addition, a first coil C1 having a first conductor layer D1 and a second coil C2 having a second conductor layer D2 described later may be arranged inside the blank 10. In this embodiment, as shown in FIG. Figure 3As shown, the green body 10 is formed by stacking stacking groups G1 to G6 and forming the first external electrode E1 to the fourth external electrode E4 on the lower side of the stacking group G6. In addition, the boundaries of each layer of the stacking structure of the green body 10 may disappear. In addition, each stacking group G1 to G6 may be formed by stacking a plurality of the same pattern.

[0038] (Layer Group G1)

[0039] The laminate group G1 may include a magnetic layer ML constituting the second main surface 12 of the body 10 .

[0040] (Layer Group G2)

[0041] The stacked group G2 may include a magnetic layer ML and a second conductive layer D2.

[0042] When the end corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the second conductor layer D2 of the stacking group G2 may include a portion h1 arranged along the long side of the green body 10 from the one end S, a portion h2 arranged obliquely at a predetermined angle from the end of the portion h1, a portion h3 arranged along the short side of the green body 10 from the end of the portion h2, a portion h4 arranged obliquely at a predetermined angle from the end of the portion h3, a portion h5 arranged along the long side of the green body 10 from the end of the portion h4, a portion h6 arranged obliquely at a predetermined angle from the end of the portion h5, and a portion h7 arranged along the short side of the green body 10 from the end of the portion h6. Furthermore, the one end S may be electrically connected to the fourth through-hole conductor TH4 of the stacking group G3, and the other end F may be electrically connected to the second conductor layer D2 of the stacking group G3 via a via conductor (not shown).

[0043] (Layer Group G3)

[0044] The stacked group G3 may include a magnetic layer ML, a second conductive layer D2 , and a fourth through-hole conductor TH4 .

[0045] The second conductor layer D2 of the stacking group G3 corresponds to the second conductor layer D2 of the stacking group G2 described above. In addition, when the upper surface is viewed from above, the second conductor layer D2 of the stacking group G3 and the second conductor layer D2 of the stacking group G2 may overlap at least in part. One end of the second conductor layer D2 may be electrically connected to the second conductor layer D2 of the stacking group G2 via a through-hole conductor (not shown), and the other end of the second conductor layer D2 may be electrically connected to the third through-hole conductor TH3 of the stacking group G4. If the second conductor layer D2 of the stacking group G2 and the stacking group G3 is viewed from above, it is roughly octagonal. In addition, the roughly octagonal shape is mainly intended to contribute to the inductance characteristics, and the connection portion with the through-hole conductor is not included in the roughly octagonal shape.

[0046] The fourth through-hole conductor TH4 of the stacking group G3 can be electrically connected to the fourth external electrode E4 by connecting to the fourth through-hole conductor TH4 adjacent to the stacking direction. Therefore, the fourth through-hole conductor TH4 can be arranged above the fourth external electrode E4. In addition, the details of the through-hole conductor will be described in detail item by item later.

[0047] (Layer Group G4)

[0048] The multilayer group G4 may include a magnetic layer ML, a first conductive layer D1 , a third through-hole conductor TH3 , and a fourth through-hole conductor TH4 .

[0049] When the end corresponding to the start of winding is defined as one end S and the end corresponding to the end of winding is defined as the other end F, the first conductor layer D1 of the stacking group G4 may include a portion i1 arranged along the long side of the green body 10 from the one end S, a portion i2 arranged at an angle from the end of the portion i1, a portion i3 arranged along the short side of the green body 10 from the end of the portion i2, a portion i4 arranged at an angle from the end of the portion i3, a portion i5 arranged along the long side of the green body 10 from the end of the portion i4, a portion i6 arranged at an angle from the end of the portion i5, and a portion i7 arranged along the short side of the green body 10 from the end of the portion i6. Furthermore, the one end S may be electrically connected to the second through-hole conductor TH2 of the stacking group G5, and the other end F may be electrically connected to the first conductor layer D1 of the stacking group G5 via a via conductor (not shown).

[0050] The third through-hole conductor TH3 and the fourth through-hole conductor TH4 of the stack group G4 can be electrically connected to the third through-hole conductor TH3 and the fourth through-hole conductor TH4 of the stack group G5, respectively. Thus, the third through-hole conductor TH3 can be arranged above the third external electrode E3 for electrical conduction with the third external electrode E3, and the fourth through-hole conductor TH4 can be arranged above the fourth external electrode E4 for electrical conduction with the fourth external electrode E4.

[0051] (Layer Group G5)

[0052] The laminate group G5 may include a magnetic layer ML, a first conductor layer D1 formed by winding a conductor, a second through-hole conductor TH2 , a third through-hole conductor TH3 , and a fourth through-hole conductor TH4 .

[0053] The first conductor layer D1 of the stacking group G5 corresponds to the first conductor layer D1 of the stacking group G4 described above. In addition, when the upper surface is viewed from above, the first conductor layer D1 of the stacking group G5 and the first conductor layer D1 of the stacking group G4 may overlap at least in part. One end of the first conductor layer D1 may be electrically connected to the first conductor layer D1 of the stacking group G4 via a via conductor (not shown), and the other end of the first conductor layer D1 may be electrically connected to the first through-hole conductor TH1 of the stacking group G6. When the first conductor layer D1 of the stacking groups G4 and G5 is viewed from above, it is approximately octagonal.

[0054] The second through-hole conductor TH2, the third through-hole conductor TH3, and the fourth through-hole conductor TH4 of the stacking group G5 can be electrically connected to the second through-hole conductor TH2, the third through-hole conductor TH3, and the fourth through-hole conductor TH4 of the stacking group G6, respectively. Thus, the second through-hole conductor TH2 can be arranged above the second external electrode E2 for electrical conduction with the second external electrode E2, the third through-hole conductor TH3 can be arranged above the third external electrode E3 for electrical conduction with the third external electrode E3, and the fourth through-hole conductor TH4 can be arranged above the fourth external electrode E4 for electrical conduction with the fourth external electrode E4.

[0055] (Laminated Group G6)

[0056] The laminate group G6 may include a magnetic layer ML, a first through-hole conductor TH1, a second through-hole conductor TH2, a third through-hole conductor TH3, and a fourth through-hole conductor TH4. The first through-hole conductor TH1 to the fourth through-hole conductor TH4 of the laminate groups G1 to G6 may have substantially the same area in a plan view.

[0057] (Optional addition to the stacking group)

[0058] As a preferred stacking group, an additional stacking group may be provided below the stacking group G6. The additional stacking group may include first to fourth through-hole conductors having a larger area than the first to fourth through-hole conductors TH1 to TH4 of the stacking groups G1 to G6 when viewed from above. According to such a structure, when the external electrode is to be arranged at a desired position of the green body, even if the position of the through hole is shifted due to shrinkage caused by firing, poor connection will not occur. Since the additional stacking group is provided to buffer the positional shift of the through-hole conductors, its thickness may be thinner than that of the stacking groups G1 to G6.

[0059] The thickness of the first conductor layer D1 and / or the second conductor layer D2 in each stacked group may be the same. As an example of their materials, the first conductor layer D1, the second conductor layer D2, the first through-hole conductor TH1 to the fourth through-hole conductor TH4 and / or the via conductor may be metal conductors such as Ag and / or Cu, and the same material or different materials may be used. The first conductor layer D1 and / or the second conductor layer D2, the first through-hole conductor TH1 to the fourth through-hole conductor TH4 and / or the via conductor may be formed, for example, by printing a conductive paste on the magnetic layer ML and then printing the magnetic layer ML outside the conductive paste.

[0060] As described above, if the laminated structure in which the base body 10 includes the laminated groups G1 to G6 is provided, the degree of freedom in designing the laminated inductor 1A is further improved. For example, when the laminated inductor 1A is manufactured in which the first external electrode E1 to the fourth external electrode E4 are provided on the bottom surface (first main surface 11) of the base body 10, it is easy to lead the first conductor layer D1 and the second conductor layer D2 to the bottom surface side. In addition, the laminated structure including the laminated groups G1 to G6 can be formed by repeatedly printing the material constituting the magnetic layer ML, the material constituting the first conductor layer D1 or the second conductor layer D2, and the material constituting the through-hole conductor and / or the via-hole conductor in sequence from the second main surface 12 side or the first main surface 11 side of the base body 10 by screen printing or the like until the desired thickness of the via-hole conductor is reached, or can be formed by sputtering, inkjet method, or other known methods.

[0061] Further additional elements related to the blank 10 are described. The magnetic layer ML may include metal magnetic particles made of a magnetic material. The metal magnetic particles may include Fe and / or Si. More specifically, they may be Fe particles or Fe alloy particles. As Fe alloys, they may be Fe-Si alloys, Fe-Si-Cr alloys, Fe-Si-Al alloys, Fe-Si-B-P-Cu-C alloys, Fe-Si-B-Nb-Cu alloys, etc. In addition, the metal magnetic particles may also contain impurities such as Cr, Mn, Cu, Ni, P, S or Co that are not desirable in manufacturing. In addition, the metal magnetic particles may also be contained in the magnetic slurry. Therefore, the metal magnetic particles may also contain elements that are more easily oxidized than Fe added when manufacturing the magnetic slurry (for example, Cr, Al, Li, Zn, Zr).

[0062] The surface of the above-mentioned metal magnetic particles can be covered with an insulating film. If the surface of the metal magnetic particles is covered with an insulating film, the insulation between the metal magnetic particles can be improved, the withstand voltage of the inductor can be improved, and the eddy current generated in the metal magnetic particles can be suppressed. As a method for forming an insulating film on the surface of the metal magnetic particles, a sol-gel method, a mechanochemical method, etc. can be used. The material constituting the insulating film can be an oxide of P, Si, etc., zinc phosphate, manganese phosphate. In addition, the insulating film can also be an oxide film formed by oxidation of the surface of the metal magnetic particles by oxygen in the atmosphere, or an oxide film of an element that is easier to oxidize than Fe. The thickness of the insulating film is preferably more than 1nm and less than 50nm, more preferably more than 1nm and less than 30nm, and further preferably more than 1nm and less than 20nm. For example, a cross-section obtained by grinding a sample of an inductor can be photographed using a scanning electron microscope (SEM), and the thickness of the insulating film covering the surface of the metal magnetic particles can be measured based on the obtained SEM photograph.

[0063] The average particle size of the metal magnetic particles in the magnetic layer ML is preferably greater than 1 μm and less than 30 μm, more preferably greater than 1 μm and less than 20 μm, and further preferably greater than 1 μm and less than 10 μm. The average particle size of the metal magnetic particles in the magnetic layer can be measured by the steps described below. Cut the sample of the inductor to obtain a sample cross section. Specifically, the sample cross section is obtained by cutting through the center of the blank and orthogonally to the mounting surface and end surface of the stacked inductor. For the obtained cross section, multiple (for example, 5) areas (for example, 130 μm × 100 μm) are photographed using SEM, and the obtained SEM image is analyzed using image analysis software (for example, image analysis software WinROOF2021 (manufactured by Mitani Shoji Co., Ltd.)) to determine the equivalent circular diameter of the metal magnetic particles. The average value of the equivalent circular diameter obtained is taken as the average particle size of the metal magnetic particles.

[0064] Heat treatment is performed when forming the blank 10. In this case, the metal magnetic particles contained in the blank 10 have an oxide film on the surface. The oxide film originates from the metal magnetic particles and is formed by heat treatment. In the blank 10, adjacent metal magnetic particles can be bonded to each other via the oxide film.

[0065] In order to further improve the green body strength, a resin material may be impregnated into the green body 10 after firing the green body 10. As an example of a resin for improving the green body strength, epoxy resin and / or phenolic resin and / or silicone resin may be used.

[0066] - External Electrode -

[0067] The external electrodes E are provided on the bottom surface of the green body 10. The external electrodes E include a first external electrode E1, a second external electrode E2, a third external electrode E3, and a fourth external electrode E4. The first external electrode E1 and the second external electrode E2 can be electrically connected to the first conductor layer D1. In addition, the third external electrode E3 and the fourth external electrode E4 can be electrically connected to the second conductor layer D2. If the external electrodes E are provided on the bottom surface (first main surface 11) of the green body 10, the laminated inductor 1A can be appropriately mounted on a mounting substrate or the like.

[0068] The first external electrode E1 to the fourth external electrode E4 can also be arranged only on the first main surface 11 of the blank 10, or can be arranged across the first main surface 11 of the blank 10 and the surface adjacent to the first main surface 11 (any one or two surfaces of the first end surface 13, the second end surface 14, the first side surface 15, and the second side surface 16).

[0069] As a preferred form of the external electrode E, the planar area of ​​the external electrode E viewed from the mounting surface side of the multilayer inductor 1A may be larger than the planar areas of the first through-hole conductor TH1 to the fourth through-hole conductor TH4 of the multilayer group G6. By making the planar area of ​​the external electrode E larger than the first through-hole conductor TH1 to the fourth through-hole conductor TH4 of the multilayer group G13, it is possible to easily align the through-hole conductors and the external electrode when electrically connecting them.

[0070] As an example, various materials such as Cu and / or Au can be used for the external electrode E. The external electrode E can be formed by any method, but as an example, it can be a plated electrode formed by plating (for example, electroless plating method, sputtering method), or after the external electrode E is formed, a plating layer such as Ni and Sn can be further formed on the external electrode E by plating method to form a stacked structure of more than two layers.

[0071] - Composite coil -

[0072] The composite coil C includes a first coil C1 and a second coil C2.

[0073] As a preferred composite coil method, for example Figure 4AAs shown, when viewed from above, the winding shape of the composite coil C can be an octagon. As an example, the shape of the outline (inner outline and / or outer outline) of the composite coil C can be an octagon. The "octagon" mentioned in this specification is not limited to an octagon in the strict sense, but is intended to include a roughly octagonal structure with eight sides or eight corners. For example, it may also include a situation where eight corners protrude from the sides, or have rounded corners, or are flat, or where eight sides are bent and / or curved. By making the shape of the composite coil C into an octagon or a shape similar thereto, a roughly triangular area can be provided between the outer periphery of the composite coil C and the blank 10, and the through-hole conductor TH described later can be appropriately provided in this area.

[0074] In addition, if Figure 4B As shown, when viewed from above, the winding shape of the composite coil C may also be a hexagon. As an example, the shape of the outline (inner outline and / or outer outline) of the composite coil C may be a hexagon. The "hexagon" mentioned in this specification is not limited to a hexagon in the strict sense, but is intended to include a roughly hexagonal structure with six sides or six corners. For example, it may include a situation where six corners protrude from the sides, or have rounded corners, or are flat, or six sides are bent and / or curved. Even if the shape of the composite coil C is made into a hexagon or a shape similar thereto, a roughly triangular area can be provided between the outer periphery of the composite coil C and the blank 10, and the through-hole conductor TH described later can be appropriately provided in this area.

[0075] The first coil C1 connects the plurality of first conductor layers D1 disposed in the blank 10 in the stacking direction and has a winding axis along the stacking direction. As an example, as described above, the first coil C1 may be provided over two stacking groups (stacking groups G4 and G5). Thus, the first coil C1 may have 1.75 turns.

[0076] The second coil C2 is located above the first coil C1 in the stacking direction, connects the plurality of second conductor layers D2 disposed in the blank 10 in the stacking direction, and has a winding axis along the stacking direction. As an example, the second coil C2 can be arranged over two stacking groups (stacking groups G2 and G3). Thus, the second coil C2 can be 1.75 turns.

[0077] -Through-hole conductors-

[0078] The through-hole conductors extend from the external electrodes in the stacking direction, and are connected to both ends of the first coil C1 and both ends of the second coil C2 . In the present embodiment, first to fourth through-hole conductors TH1 to TH4 may be provided.

[0079] The first through-hole conductor TH1 can electrically connect the end of the first coil C1 closest to the bottom surface (first main surface 11) of the body 10 to the first external electrode E1. The second through-hole conductor TH2 can electrically connect the other end of the first coil C1 to the second external electrode E2. The third through-hole conductor TH3 can electrically connect the end of the second coil C2 closest to the bottom surface (first main surface 11) of the body 10 to the third external electrode E3. The fourth through-hole conductor TH4 can connect the other end of the second coil C2 to the fourth external electrode E4.

[0080] When viewed from above, the shape of the through-hole conductor is a triangle with two sides along the outer edge of the blank 10. As an example, the shape of the outer contour of the through-hole conductor can be a triangle. The "triangle" mentioned in this specification is not limited to a triangle in the strict sense, but is intended to include a roughly triangle with a structure equivalent to three sides or three corners. For example, it can include a situation where three corners protrude from the side, or have rounded corners, or are flat, and a situation where three sides are bent and / or curved. Therefore, according to the stacked inductor 1A disclosed in the present invention, the area between the outer edge of the blank 10 and the outer edge of the composite coil C can be effectively utilized to appropriately set the through-hole conductor TH. As a result, the connection area between the through-hole conductor TH and the external electrode E can be expanded, and the DC resistance of the stacked inductor 1A can be further reduced. In addition, the connection reliability between the through-hole conductor TH and the external electrode E can also be further improved.

[0081] As a preferred shape of the through-hole conductor, the lengths of the two sides of the through-hole conductor TH may be different from each other when viewed from above. As an example, Figure 4A In the laminated inductor 1A shown, the side TL1 of the through-hole conductor TH along the long side of the base body 10 is longer than the side TL2 of the through-hole conductor TH along the short side of the base body 10. According to this embodiment, the through-hole conductor TH can be appropriately arranged according to the shape of the region between the outer edge of the base body 10 and the outer edge of the composite coil C. Figure 4B As in the multilayer inductor 1A shown in the figure, the side TL3 of the through-hole conductor TH along the long side of the base body 10 may be shorter than the side TL4 of the through-hole conductor TH along the short side of the base body 10. According to this embodiment, the through-hole conductor TH can be appropriately provided in accordance with the shape of the region between the outer edge of the base body 10 and the outer edge of the composite coil C.

[0082] In addition, as a preferred form of the through-hole conductor, the hypotenuse TO of the through-hole conductor TH may be parallel to one side of the outer edge of the composite coil C in a plan view. The "hypotenuse of the through-hole conductor" in this specification refers to a side of the triangular through-hole conductor TH that is different from the two sides along the outer edge of the base body 10. According to such a form, the interval between the through-hole conductor TH and the composite coil C is constant, and the through-hole conductor TH can be provided as large as possible in the area between the outer edge of the base body 10 and the outer edge of the composite coil C.

[0083] In addition, as a preferred form of through-hole conductor, the shape of the through-hole conductor TH when viewed from above can be a right scalene triangle. The "right scalene triangle" mentioned in this specification refers to a triangle in which the lengths of the three sides constituting the triangle are different from each other and one angle of the triangle is a right angle. In addition, the "right angle" mentioned in this specification does not need to strictly constitute 90°, and can also include an error of about ±5°. By making the shape of the through-hole conductor TH a right triangle with three sides of different lengths, the degree of freedom of the length of the three sides of the triangle is increased, and the through-hole conductor TH can be appropriately arranged in the area between the outer edge of the blank 10 and the outer edge of the composite coil C.

[0084] As a preferred form of the through-hole conductor, the long side TL1 of the right angle constituting the right-angled scalene triangle (see Figure 4A ), TL4 (refer to Figure 4B ) and the short side TL2 (refer to Figure 4A )、TL3(reference Figure 4B ) may correspond to the ratio of the long side 10L and the short side 10W constituting the outer edge of the blank 10 when viewed from above. More specifically, the ratio of the lengths of the long sides TL1 and TL4 and the short sides TL2 and TL3 constituting the right angle of the right scalene triangle may be equal to (or be the same as) the ratio of the lengths of the long side 10L and the short side 10W constituting the outer edge of the blank 10 when viewed from above. If the long side and the short side dimensions of the blank 10 and the long side and the short side dimensions of the through-hole conductor TH are designed in this way, the balance between the magnetic flux inside the composite coil C and the magnetic flux outside the composite coil C can be improved, thereby improving the inductance value.

[0085] In addition, as a preferred form of the through-hole conductor TH, the size of the short sides TL2 and TL3 constituting the right angle of the right scalene triangle may be smaller than the width dimension CL of the composite coil C when viewed from above, and the size of the long sides TL1 and TL4 constituting the right angle of the right scalene triangle may be smaller than 1 / 2 of the size of the short side 10W constituting the outer edge of the blank 10 when viewed from above. By making the size of the short sides TL2 and TL3 of the through-hole conductor TH larger than the width dimension CL of the composite coil C, the connection area between the through-hole conductor TH and the composite coil C can be increased, and the connection reliability between the composite coil C and the through-hole conductor TH can be improved. In addition, by making the size of the long sides TL1 and TL4 of the through-hole conductor TH smaller than 1 / 2 of the size of the short side 10W of the blank 10, a composite coil C with a large plane area can be built into the blank 10, thereby improving the inductance value. In addition, here, the width dimension CL refers to the minimum width on one side of the coil winding adjacent to the hypotenuse of the right scalene triangle.

[0086] <Multilayer Inductor According to Second Embodiment>

[0087] Next, refer to Figure 5 and Figure 6 A multilayer inductor 1B according to the second embodiment will be described. Figure 5 is a perspective view schematically showing an example of the internal structure of the laminated inductor according to the second embodiment. Figure 6 1B is a perspective view of a laminated inductor according to the second embodiment. The internal structure of the base body 10 of the laminated inductor 1B according to the second embodiment is different from that of the laminated inductor 1A according to the first embodiment. The following description will focus on the differences from the laminated inductor described in the above embodiment.

[0088] - Composite coil -

[0089] The composite coil C of this embodiment can be symmetrical with respect to the center point of the blank. Figure 6 In the plan view, the composite coil C is point-symmetrical with respect to the intersection of the imaginary straight line L1 and the imaginary straight line L2 which pass through the center of the base body 10 and are parallel to the outer edge of the base body 10. If the composite coil C is point-symmetrical in the plan view, the magnetic flux formed inside the composite coil C can be dispersed compared with the laminated inductor 1A of the first embodiment. For example, in the case of Figure 8B In the case of the structure of the laminated inductor 1C of the third embodiment shown, the positions where the magnetic flux is concentrated can be made inconsistent by arranging the composite coils C alternately, so the dispersion of the magnetic flux is useful. In addition, if the above structure is determined from another angle, the composite coils C in a plan view may be non-line symmetric with respect to the imaginary straight line L1 and the imaginary straight line L2.

[0090] As a more specific embodiment of the composite coil C (refer to Figure 6 ), it may include a portion j1 ​​arranged along the long side of the blank 10, a portion j2 arranged at an angle from the end of the portion j1, a portion j3 arranged along the short side of the blank 10 from the end of the portion j2, a portion j4 arranged at an angle from the end of the portion j3, a portion j5 arranged along the long side of the blank 10 from the end of the portion j4, a portion j6 arranged at an angle from the end of the portion j5, and a portion j7 arranged along the short side of the blank 10 from the end of the portion j6. Moreover, the angle θ1 formed by the portion j1 ​​and the portion j2 and the angle θ2 formed by the portion j5 and the portion j4 may be different angles. In addition, the angle θ3 formed by the portion j3 and the portion j2 and the angle θ4 formed by the portion j3 and the portion j4 may be different angles. In addition, the above description assumes that the composite coil is an octagonal shape when viewed from above, but the winding shape of the composite coil may be a hexagonal shape when viewed from above.

[0091] -Through-hole conductors-

[0092] In a plan view, the through-hole conductor TH of the present embodiment may be a shape obtained by rotating two through-hole conductors (for example, the first through-hole conductor TH1 and the second through-hole conductor TH2) arranged along one side of the outer edge of the base body 10 by 90 degrees. Figure 6 In the embodiment, the shape may be such that the short side of another through-hole conductor (for example, the short side TL6 of the second through-hole conductor TH2) is arranged on the extension line of the long side of one through-hole conductor (for example, the long side TL5 of the first through-hole conductor TH1). If each through-hole conductor is formed into such a shape, the through-hole conductor TH can be appropriately provided in the region between the above-mentioned point-symmetrical and non-line-symmetrical composite coil C and the base body 10.

[0093] <Multilayer Inductor According to Third Embodiment>

[0094] Next, refer to Figure 7 to Figure 8B A multilayer inductor according to a third embodiment will be described. Figure 7 is a perspective view schematically showing an example of the internal structure of the laminated inductor according to the third embodiment. Fig. 8A is a plan perspective view of a laminated inductor according to a third embodiment, Figure 8B 1 is a perspective view of a modified example of the laminated inductor of the third embodiment. The laminated inductor 1C of the third embodiment is different from the laminated inductor 1A of the first embodiment and the laminated inductor 1B of the second embodiment in that a plurality of composite coils C are provided in the base body 10. The following description will focus on the differences from the laminated inductor described in the above embodiments.

[0095] The laminated inductor 1C of the third embodiment includes a plurality of composite coils C in the base body 10. In a plan view, one composite coil C may be arranged in a direction intersecting the stacking direction with respect to one composite coil C. In addition, the laminated inductor 1C of the third embodiment may further include a plurality of through-hole conductors TH and external electrodes E corresponding to the plurality of composite coils C. Figure 7 and Fig. 8A In the W direction (a direction intersecting the stacking direction), three composite coils C may be arranged. Furthermore, twelve through-hole conductors TH and external electrodes E may be provided corresponding to the three composite coils C. Furthermore, the composite coils C arranged in the W direction may have substantially the same structure.

[0096] By providing a plurality of composite coils C in a direction intersecting the stacking direction in the element 10 as in the laminated inductor 1C of the third embodiment, it is possible to contribute to increasing the current and improving the efficiency of the DC-DC converter.

[0097] Furthermore, as a modified example of the laminated inductor 1C of the third embodiment, one composite coil C and another composite coil C may be arranged alternately in a direction intersecting the lamination direction in a plan view (see FIG. 1 ). Figure 8B ). The term "interlaced" as used herein means that when an imaginary straight line L3 is drawn that divides one composite coil C into two equal parts, the composite coils C and the composite coils C are in a line symmetric relationship with respect to the imaginary straight line L3. Specifically, it means that when folded along the imaginary straight line L3, the composite coils C and the composite coils C are in an overlapping relationship with each other. Fig. 8A Unlike the laminated inductor shown, it is possible to prevent the location where the magnetic flux is concentrated in one composite coil C from being aligned with the location where the magnetic flux is concentrated in another composite coil C. Therefore, by preventing the locations where the magnetic flux is concentrated from being aligned, it is possible to obtain a laminated inductor that reduces mutual interference between one composite coil and another composite coil and further improves the inductance characteristics.

[0098] In addition, if Figure 8B As in the laminated inductor shown in FIG. 1 , in a plan view, the through-hole conductors TH connected to one composite coil C and the through-hole conductors TH connected to another composite coil C can be arranged alternately in a direction intersecting the stacking direction. According to such a modification of the third embodiment, the through-hole conductors TH can be appropriately arranged in the region between the composite coils C and the base body 10 that are arranged alternately.

[0099] In addition, the embodiments disclosed this time are illustrative at all points and are not the basis for restrictive interpretation. Therefore, the technical scope of the present disclosure is not interpreted only by the above-mentioned embodiments, but is defined based on the records of the claims. In addition, within the technical scope of the present disclosure, all changes within the meaning and scope equivalent to the claims are included.

[0100] The embodiment of the laminated inductor disclosed in the present invention is as follows.

[0101] <1> A laminated inductor comprising:

[0102] The blank is formed by stacking magnetic layers and has a hexahedral shape;

[0103] External electrodes are respectively arranged at least at four corners of the bottom surface of the blank;

[0104] A composite coil, comprising a first coil and a second coil, wherein the first coil is connected to a plurality of conductor layers arranged in the blank in a stacking direction and has a winding axis in the stacking direction, and the second coil is located above the first coil in the stacking direction, is connected to a plurality of conductor layers arranged in the blank in the stacking direction, and has a winding axis in the stacking direction; and

[0105] The through-hole conductors extend from the external electrodes in the stacking direction and are connected to both ends of the first coil and both ends of the second coil, respectively.

[0106] In a plan view, the through-hole conductor has a triangular shape with two sides along the outer edge of the base body.

[0107] <2> The laminated inductor according to <1>, wherein:

[0108] The two sides of the via-hole conductor have different lengths from each other in a plan view.

[0109] <3> The laminated inductor according to <1> or <2>, wherein:

[0110] In a plan view, one side of the via-hole conductor different from the two sides of the via-hole conductor is parallel to one side of the outer edge of the composite coil in a plan view.

[0111] <4> The multilayer inductor according to any one of <1> to <3>, wherein

[0112] When viewed from above, the winding shape of the composite coil is hexagonal or octagonal.

[0113] <5> The laminated inductor according to any one of <1> to <4>, wherein

[0114] The through-hole conductor has a right-angled scalene triangle shape when viewed from above.

[0115] <6> The laminated inductor according to <5>, wherein:

[0116] The ratio of the long side and the short side constituting the right angle of the right scalene triangle corresponds to the ratio of the long side and the short side constituting the outer edge of the blank in a plan view.

[0117] <7> The laminated inductor according to <5> or <6>, wherein:

[0118] The short side of the right angle constituting the right-angled scalene triangle is smaller than the width of the composite coil in a plan view.

[0119] The dimension of the long side of the right angle constituting the right scalene triangle is smaller than 1 / 2 of the dimension of the short side constituting the outer edge of the blank in a plan view.

[0120] <8> The laminated inductor according to any one of <1> to <7>, wherein

[0121] The two through-hole conductors arranged along one side of the outer edge of the base body are in a positional relationship obtained by rotating the through-hole conductors by 90 degrees in a plan view.

[0122] <9> The laminated inductor according to <8>, wherein:

[0123] The composite coil is symmetrical with respect to the center point of the blank when viewed from above.

[0124] <10> The laminated inductor according to any one of <1> to <9>, wherein

[0125] A plurality of the composite coils are arranged in the blank.

[0126] In a plan view, the other composite coil is arranged in a direction intersecting the stacking direction with respect to the one composite coil.

[0127] <11> The laminated inductor according to <10>, wherein:

[0128] In a plan view, one of the composite coils and the other composite coils are arranged alternately in a direction intersecting the stacking direction.

[0129] <12> The laminated inductor according to <11>, wherein:

[0130] The via-hole conductor connected to one of the composite coils and the via-hole conductor connected to the other composite coil are arranged alternately in a direction intersecting the stacking direction in a plan view.

[0131] The multilayer inductor disclosed in the present invention can be suitably used as an electronic component in which the electrical characteristics are further improved by optimizing the shape of the via-hole conductor in a plan view.

Claims

1. A stacked inductor comprising: The blank is formed by stacking magnetic layers and has a hexahedral shape; External electrodes are respectively arranged at least at four corners of the bottom surface of the blank; The composite coil comprises a first coil and a second coil, wherein: The first coil is connected to a plurality of conductor layers arranged in the body in a stacking direction and has a winding axis in the stacking direction, and the second coil is located above the first coil in the stacking direction, is connected to a plurality of conductor layers arranged in the body in the stacking direction and has a winding axis in the stacking direction; and The through-hole conductors extend from the external electrodes in the stacking direction and are connected to both ends of the first coil and both ends of the second coil, respectively. The through-hole conductor has a triangular shape in which two sides constituting an outer edge of the through-hole conductor are along an outer edge of the base body when viewed from above.

2. The laminated inductor according to claim 1, wherein: The two sides of the via-hole conductor have different lengths from each other in a plan view.

3. The laminated inductor according to claim 1 or 2, wherein: In a plan view, one side of the via-hole conductor different from the two sides of the via-hole conductor is parallel to one side of the outer edge of the composite coil in a plan view.

4. The laminated inductor according to any one of claims 1 to 3, wherein: When viewed from above, the winding shape of the composite coil is hexagonal or octagonal.

5. The laminated inductor according to any one of claims 1 to 4, wherein: The through-hole conductor has a right-angled scalene triangle shape when viewed from above.

6. The stacked inductor according to claim 5, wherein: The ratio of the long side and the short side constituting the right angle of the right scalene triangle corresponds to the ratio of the long side and the short side constituting the outer edge of the blank in a plan view.

7. The laminated inductor according to claim 5 or 6, wherein: The short side of the right angle constituting the right-angled scalene triangle is smaller than the width of the composite coil in a plan view. The dimension of the long side of the right angle constituting the right scalene triangle is smaller than 1 / 2 of the dimension of the short side constituting the outer edge of the blank in a plan view.

8. The laminated inductor according to any one of claims 1 to 7, wherein: The two through-hole conductors arranged along one side of the outer edge of the base body have a shape obtained by rotating the through-hole conductors by 90 degrees in a plan view.

9. The stacked inductor according to claim 8, wherein: The composite coil is symmetrical with respect to the center point of the blank.

10. The laminated inductor according to any one of claims 1 to 9, wherein: A plurality of the composite coils are arranged in the blank. In a plan view, the other composite coil is arranged in a direction intersecting the stacking direction with respect to the one composite coil.

11. The stacked inductor according to claim 10, wherein: In a plan view, one of the composite coils and the other composite coils are arranged alternately in a direction intersecting the stacking direction.

12. The stacked inductor according to claim 11, wherein: The via-hole conductor connected to one of the composite coils and the via-hole conductor connected to the other composite coil are arranged alternately in a direction intersecting the stacking direction in a plan view.

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