Array-type inductor and inductor-embedded substrate equipped with array-type inductor

Abstract

To more reliably ensure insulation between external electrodes in an array type inductor.SOLUTION: An array-type inductor includes: a base, a first coil conductor provided inside the base; a second coil conductor provided inside the base; a first external electrode connected to one end of the first coil conductor; a second external electrode connected to the other end of the first coil conductor; a third external electrode connected to one end of the second coil conductor; and a fourth external electrode connected to the other end of the second coil conductor. The base has: a first surface; a second surface connected to the first surface via a first ridge portion; and a third surface connected to the first surface via a second ridge portion. The first external electrode, the second external electrode, the third external electrode, and the fourth external electrode are provided on the first surface of the base.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The disclosure of the present specification relates to an array-type inductor and an inductor-embedded substrate including the array-type inductor. [Background technology]

[0002] Array-type inductors including multiple inductors have been known for some time. In an array-type inductor, multiple inductors are packaged on a single chip. The array-type inductor includes a base, multiple coil conductors provided within the base and insulated from one another within the base, and multiple external electrodes. Each external electrode is connected to an end of one of the coil conductors. Conventional array-type inductors are described, for example, in Japanese Patent Laid-Open No. 2016-006830 (Patent Document 1) and Japanese Patent Laid-Open No. 2019-153649 (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-006830 [Patent Document 2] Japanese Patent Application Publication No. 2019-153649 Summary of the Invention [Problem to be solved by the invention]

[0004] In an array-type inductor, multiple inductor elements are arranged within a single chip, allowing for high-density mounting of these multiple inductor elements on a substrate. However, the inductor elements are spaced closely together, which can lead to a decrease in the reliability of insulation between the elements. In particular, because the external electrodes connected to the ends of one inductor element are arranged adjacent to the external electrodes connected to the ends of another inductor element at short intervals, short circuits are likely to occur between the adjacent external electrodes.

[0005] A soft magnetic substrate containing a large number of metal magnetic particles made of a soft magnetic material is used as the substrate for an array-type inductor. Soft magnetic substrates are less susceptible to magnetic saturation than magnetic substrates made of ferrite, making them particularly suitable for use in circuits through which large currents flow. In soft magnetic substrates, the surfaces of the metal magnetic particles are covered with an insulating film to ensure insulation between coil conductors and external electrodes. Because soft magnetic substrates have lower insulating properties than substrates made of ferrite, array-type inductors equipped with soft magnetic substrates are prone to short circuits between external electrodes.

[0006] One object of the present invention is to provide an array-type inductor that can more reliably ensure insulation between external electrodes. Other objects of the present invention will become apparent throughout the entire specification. The inventions disclosed in this specification may solve problems that are understood from sources other than those described in the "Problems to be Solved by the Invention" section. The various inventions disclosed in this specification may be collectively referred to as "the present invention." [Means for solving the problem]

[0007] An array-type inductor according to one aspect of the present invention comprises a base, a first coil conductor provided inside the base, a second coil conductor provided inside the base, a first external electrode connected to one end of the first coil conductor, a second external electrode connected to the other end of the first coil conductor, a third external electrode connected to one end of the second coil conductor, and a fourth external electrode connected to the other end of the second coil conductor. The base has a first surface, a second surface connected to the first surface via a first ridge portion, and a third surface connected to the first surface via a second ridge portion. The first external electrode, the second external electrode, the third external electrode, and the fourth external electrode are provided on the first surface of the base.

[0008] In one aspect, the first external electrode, the second external electrode, the third external electrode, and the fourth external electrode are all provided on the first surface at positions spaced apart from both the first ridge portion and the second ridge portion. [Effects of the Invention]

[0009] According to one aspect of the present invention, in an array type inductor, insulation between external electrodes can be more reliably ensured. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view schematically showing an array type inductor 1 according to one embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the array type inductor 1 of FIG. [Figure 3] 2 is a cross-sectional view schematically showing an LT cross section of the array type inductor 1 of FIG. 1 taken along line II. [Figure 4] FIG. 1 is a plan view schematically showing an array type inductor 101 according to another embodiment of the present invention. [Figure 5] 5 is a cross-sectional view schematically showing an LT cross section of the array type inductor 101 of FIG. 4. FIG. [Figure 6] FIG. 10 is a cross-sectional view schematically showing an LT cross section of an array type inductor 201 according to another embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view schematically showing an LT cross section of an array type inductor 301 according to another embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view schematically showing an LT cross section of an array type inductor 401 according to another embodiment of the present invention. [Figure 9a] 1A to 1C are diagrams schematically illustrating a part of a process for manufacturing an inductor-embedded substrate according to one embodiment. [Figure 9b] 1A to 1C are diagrams schematically illustrating a part of a process for manufacturing an inductor-embedded substrate according to one embodiment. [Figure 9c] 1A to 1C are diagrams schematically illustrating a part of a process for manufacturing an inductor-embedded substrate according to one embodiment. [Figure 9d] 1A to 1C are diagrams schematically illustrating a part of a process for manufacturing an inductor-embedded substrate according to one embodiment. [Figure 9e] 1A to 1C are diagrams schematically illustrating a part of a process for manufacturing an inductor-embedded substrate according to one embodiment. [Figure 9f] 1A to 1C are diagrams schematically illustrating a part of a process for manufacturing an inductor-embedded substrate according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Various embodiments of the present invention will be described below with appropriate reference to the drawings. Components common to multiple drawings are designated by the same or similar reference numerals throughout the drawings. Please note that the drawings are not necessarily drawn to scale for the sake of convenience. The embodiments described below do not necessarily limit the invention according to the claims. Elements described in the following embodiments are not necessarily essential to the solution of the invention.

[0012] 1 First embodiment (array-type inductor 1) 1-1 Basic structure of array inductor 1 An array inductor 1 according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a perspective view schematically showing the array inductor 1, Fig. 2 is a plan view of the array inductor 1, and Fig. 3 is a schematic cross-sectional view showing an enlarged portion of the cross section of the array inductor 1 taken along line II.

[0013] For ease of explanation, each figure may include an L-axis, a W-axis, and a T-axis that are perpendicular to each other. In this specification, the dimensions, arrangement, shape, and other features of each component of the array inductor 1 may be explained based on the L-axis, W-axis, and T-axis.

[0014] The array inductor 1 can be surface-mounted on a substrate. The substrate is provided with land portions. The array inductor 1 is mounted on the substrate by joining each external electrode to a corresponding land portion of the substrate. The substrate on which the array inductor 1 is mounted can be installed in various electronic devices. Electronic devices that can be equipped with a substrate on which the array inductor 1 is mounted include smartphones, tablets, game consoles, automotive electrical components, servers, and various other electronic devices.

[0015] The array-type inductor 1 is used in electronic circuits, for example, to remove noise. The array-type inductor 1 may be a power inductor incorporated in a power line, or an inductor used in a signal line. As will be described later, the coil component 1 may be built into a substrate.

[0016] The array type inductor 1 comprises a base 10, a plurality of coil conductors provided inside the base 10, and a plurality of external electrodes provided on the surface of the base 10. In the illustrated embodiment, the array type inductor 1 comprises eight external electrodes, namely, a first external electrode 21 to an eighth external electrode.

[0017] 1-2 Base 10 The substrate 10 is an insulating structure. The substrate 10 may contain a plurality of metal magnetic particles. The surfaces of the metal magnetic particles are coated with an insulating insulating film. Adjacent metal magnetic particles contained in the substrate 10 are bonded to each other via the insulating film on their surfaces. Adjacent metal magnetic particles are electrically insulated from each other by their respective insulating films.

[0018] The metal magnetic particles contained in the substrate 10 may be, for example, (1) metal particles such as Fe or Ni; (2) crystalline alloy particles such as Fe-Si-Cr alloy, Fe-Si-Al alloy, or Fe-Ni alloy; (3) amorphous alloy particles such as Fe-Si-Cr-BC alloy or Fe-Si-Cr-B alloy; or (4) mixed particles of these. The composition of the metal magnetic particles contained in the substrate 10 is not limited to those described above. For example, the metal magnetic particles contained in the substrate 10 may be a Co-Nb-Zr alloy, an Fe-Zr-Cu-B alloy, an Fe-Si-B alloy, an Fe-Co-Zr-Cu-B alloy, an Ni-Si-B alloy, or an Fe-Al-Cr alloy. The Fe-based metal magnetic particles contained in the substrate 10 may contain 80 wt% or more of Fe. The insulating film formed on the surface of each metal magnetic particle may be an oxide film formed by oxidation of the above metal or alloy. The insulating film provided on the surface of each metal magnetic particle may be, for example, a silicon oxide film coated by a sol-gel method. The metal magnetic particles contained in the base 10 have an average particle size of 1.0 to 20 μm. The average particle size of the metal magnetic particles contained in the base 10 may be smaller than 1.0 μm or larger than 20 μm. The base 10 may contain two or more types of metal magnetic particles with different average particle sizes.

[0019] The base 10 may include a resin binder that bonds the metal magnetic particles together. The binder is made of, for example, a thermosetting resin with excellent insulating properties. The resin material used as the binder has a lower magnetic permeability than the first magnetic material. Examples of resin materials that can be used for the binder include epoxy resin, polyimide resin, polystyrene (PS) resin, high-density polyethylene (HDPE) resin, polyoxymethylene (POM) resin, polycarbonate (PC) resin, polyvinylidene fluoride (PVDF) resin, phenolic resin, polytetrafluoroethylene (PTFE) resin, and polybenzoxazole (PBO) resin.

[0020] In one embodiment, the base body 10 is configured to have a generally rectangular parallelepiped shape. The base body 10 has six surfaces: an upper surface 10a, a lower surface 10b, a first end surface 10c, a second end surface 10d, a first side surface 10e, and a second side surface 10f. All six surfaces are generally flat. In the illustrated embodiment, the upper surface 10a corresponds to the "first surface" described in the claims.

[0021] Adjacent surfaces of the six surfaces constituting the base 10 are connected via ridges. In the illustrated embodiment, the upper surface 10a and the first end surface 10c are connected via ridge R11, the upper surface 10a and the second end surface 10d are connected via ridge R12, the upper surface 10a and the first side surface 10e are connected via ridge R13, and the upper surface 10a and the second side surface 10f are connected via ridge R14. The lower surface 10b and the first end surface 10c are connected via ridge R21, the lower surface 10b and the second end surface 10d are connected via ridge R22, the lower surface 10b and the first side surface 10e are connected via ridge R23, and the lower surface 10b and the second side surface 10f are connected via ridge R24. Furthermore, first end face 10c and first side face 10e are connected via ridge R31, first side face 10e and second end face 10d are connected via ridge R32, second end face 10d and second side face 10f are connected via ridge R33, and second side face 10f and first end face 10c are connected via ridge R34. In this way, the outer surface of base 10 is defined by six faces (10a to 10f) and twelve ridges (R11 to R14, R21 to R24, R31 to R34).

[0022] Each ridge of the base 10 has a curved shape. For example, in the manufacturing process of the array type inductor 1, each ridge of the base 10 can be formed by barrel polishing chips formed into rectangular parallelepiped shapes by dicing. Barrel polishing allows each ridge to be formed so as to have a desired radius of curvature. The radius of curvature of each ridge is, for example, 20 μm to 100 μm.

[0023] 1-3 Coil conductor The array inductor 1 includes multiple coil conductors. Each coil conductor is disposed inside the base 10 so that both ends thereof are exposed from the surface of the base 10. One end of each coil conductor is electrically connected to one of the external electrodes of the array inductor 1, and the other end of the coil conductor is connected to another external electrode of the array inductor 1. FIG. 3 shows a coil conductor 35 as an example of the coil conductor included in the array inductor 1. As shown in the figure, both ends of the coil conductor 35 are exposed to the outside of the base 10 from the upper surface 10a of the base 10. One end of the coil conductor 35 is electrically connected to the first external electrode 21, and the other end of the coil conductor 35 is electrically connected to the second external electrode 22. The illustrated array inductor 1 includes four coil conductors, including the coil conductor 35. Coil conductors other than the coil conductor 35 are not shown. One end of one coil conductor included in the array inductor 1 is connected to the third external electrode 23, and the other end is connected to the fourth external electrode 24. Another coil conductor included in the array type inductor 1 has one end connected to the fifth external electrode 25 and the other end connected to the sixth external electrode 26. Another coil conductor included in the array type inductor 1 has one end connected to the seventh external electrode 27 and the other end connected to the eighth external electrode 28.

[0024] Each coil conductor may have various shapes. Each coil conductor is configured to have a shape that generates a desired inductance. For example, each coil conductor is wound a predetermined number of turns around a coil axis extending in the T-axis direction. The coil conductor may have a linear shape, an elliptical shape, a meandering shape, or any other shape.

[0025] 1-4 External electrode In the illustrated embodiment, the array inductor 1 has eight external electrodes. The number of external electrodes included in the array inductor 1 may be any even number equal to or greater than four. For example, the array inductor 1 may have four, six, ten, twelve, or any other even number of external electrodes. Each external electrode is electrically insulated from the other external electrodes.

[0026] The illustrated array-type inductor 1 includes a first external electrode 21, a second external electrode 22, a third external electrode 23, a fourth external electrode 24, a fifth external electrode 25, a sixth external electrode 26, a seventh external electrode 27, and an eighth external electrode 28. All eight of these external electrodes are provided on the upper surface 10a of the base 10. The first external electrode 21 is located in the lower left corner of the page in FIG. 2. The second external electrode 22 is provided at a position spaced apart from the first external electrode 21 in the L1 direction along the L axis. The third external electrode 23 is provided at a position spaced apart from the first external electrode 21 in the W1 direction along the W axis. The fourth external electrode 24 is provided at a position spaced apart from the third external electrode 23 in the L1 direction along the L axis. The fifth external electrode 25 is provided at a position spaced apart from the third external electrode 23 in the W1 direction. The sixth external electrode 26 is provided at a position spaced apart in the L1 direction from the fifth external electrode 25. The seventh external electrode 25 is provided at a position spaced apart in the W1 direction from the fifth external electrode 25. The eighth external electrode 28 is provided at a position spaced apart in the L1 direction from the seventh external electrode 27.

[0027] In one aspect, each external electrode included in the array type inductor 1 is disposed at a position spaced apart from any of the ridge lines of the base 10. In the illustrated embodiment, the first external electrode 21, second external electrode 22, third external electrode 23, fourth external electrode 24, fifth external electrode 25, sixth external electrode 26, seventh external electrode 27, and eighth external electrode 28 are all disposed on the upper surface 10a of the base 10 so as to be spaced apart from any of the ridge lines R11 to R14 that surround this upper surface 10a. In other words, in a plan view, the first external electrode 21, second external electrode 22, third external electrode 23, fourth external electrode 24, fifth external electrode 25, sixth external electrode 26, seventh external electrode 27, and eighth external electrode 28 are all disposed so as not to overlap with the ridge lines R11 to R14. In this specification, for the sake of simplicity, each of the first external electrode 21, the second external electrode 22, the third external electrode 23, the fourth external electrode 24, the fifth external electrode 25, the sixth external electrode 26, the seventh external electrode 27, and the eighth external electrode 28 may be simply referred to as "each external electrode."

[0028] The shape of each external electrode provided in the array inductor 1 in a plan view will be described mainly with reference to Fig. 2. Each external electrode has a straight line portion that extends linearly in a plan view (i.e., when viewed from a direction normal to the upper surface 10a or when viewed from the T axis). For example, the first external electrode 21 has straight line portions L11, L12, L13, and L14. The straight line portions L11 and L13 extend in a direction along the L axis, and the straight line portions L12 and L14 extend in a direction along the W axis.

[0029] The second external electrode 22 has straight line portions L21, L22, L23, and L24. The straight line portions L21 and L23 extend in the direction along the L axis, and the straight line portions L22 and L24 extend in the direction along the W axis. The straight line portion L22 of the second external electrode 22 faces the straight line portion L14 of the first external electrode 21 in the L axis direction. The third external electrode 23 has straight line portions L31, L32, L33, and L34. The fourth external electrode 24 has straight line portions L41, L42, L43, and L44. The fifth external electrode 25 has straight line portions L51, L52, L53, and L54. The sixth external electrode 26 has straight line portions L61, L62, L63, and L64. The seventh external electrode 27 has straight line portions L71, L72, L73, and L74. The eighth external electrode 28 has straight line portions L81, L82, L83, and L84.

[0030] In each external electrode, each straight line segment may be connected to an adjacent straight line segment via a curved corner segment. For example, in the example of FIG. 2, straight line segment L11 and straight line segment L12 are connected by a curved corner segment. Similarly, straight line segment L12 and straight line segment L13, straight line segment L13 and straight line segment L14, and straight line segment L14 and straight line segment L11 are each connected by a curved corner segment. Therefore, the outer edge of the first external electrode 21 has an oval shape with curved corner segments connecting the straight line segments L11, L12, L13, and L14 and adjacent straight line segments. In the second external electrode 22, straight line segment L21 and straight line segment L22, straight line segment L22 and straight line segment L23, straight line segment L23 and straight line segment L24, and straight line segment L24 and straight line segment L21 are each connected by a curved corner segment. Therefore, the outer edge of the second external electrode 22 has an elliptical shape having these straight line portions L21, L22, L23, L24 and curved corner portions connecting adjacent straight line portions.

[0031] The third external electrode 23, the fourth external electrode 24, the fifth external electrode 25, the sixth external electrode 26, the seventh external electrode 27, and the eighth external electrode 28 each have the same shape as the first external electrode 21 in a plan view. That is, the second external electrode 22, the third external electrode 23, the fourth external electrode 24, the fifth external electrode 25, the sixth external electrode 26, the seventh external electrode 27, and the eighth external electrode 28 each have an oval shape in a plan view.

[0032] The first external electrode 21, the second external electrode 22, the third external electrode 23, the fourth external electrode 24, the fifth external electrode 25, the sixth external electrode 26, the seventh external electrode 27, and the eighth external electrode 28 each have a shape without corners in a plan view. An oval is an example of a shape without corners. Each external electrode may be configured to have an elliptical shape other than an oval shape.

[0033] In the array-type inductor 1, the external electrodes may be arranged so that the distance between an external electrode connected to one coil conductor and an external electrode connected to a coil conductor other than the one coil conductor is smaller than the distance between an external electrode connected to one end of the one coil conductor and an external electrode connected to the other end of the one coil conductor. In the embodiment shown in FIG. 2, adjacent external electrodes in the W-axis direction are connected to different coil conductors. The distance between adjacent external electrodes in the W-axis direction may be smaller than the distance between adjacent external electrodes in the L-axis direction. For example, the distance DW1 between the first external electrode 21 connected to one end of the coil conductor 35 and the third external electrode 23 connected to one end of a coil conductor other than the coil conductor 35 may be smaller than the distance DL1 between the first external electrode 21 and the second external electrode 22 connected to the other end of the coil conductor 35. In the array-type inductor 1, since the coil conductors are aligned along the W-axis direction, increasing the number of coil conductors increases the dimension in the W-axis direction. By making the distance DW1 smaller than the distance DL1, the dimension of the array-type inductor 1 in the W-axis direction can be made more compact.

[0034] The first external electrode 21 has a first base electrode layer 21A and a first plating layer 21B covering the first base electrode layer 21A. The second external electrode 22 has a second base electrode layer 22A and a second plating layer 22B covering the second base electrode layer 22A. Like the first external electrode 21 and the second external electrode 22, each external electrode other than the first external electrode 21 and the second external electrode 22 also has a base electrode layer and a plating layer covering the base electrode layer.

[0035] The first and second underlying electrode layers 21A and 22A are formed, for example, by applying a paste-like conductive material to the surface of the insulator body 10 and then hardening the applied conductive material. Examples of conductive materials that can be used for the first and second underlying electrode layers 21A and 22A include metal materials such as copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), and gold (Au), as well as alloy materials containing one or more of these metal materials. An example of such an alloy material is a Cu-Ni alloy.

[0036] The first plating layer 21B is formed on the surface of the first base electrode layer 21A so as to cover the first base electrode layer 21A. The first plating layer 21B is formed, for example, by electrolytic plating. When the first plating layer 21B is formed by electrolytic plating, the first plating layer 21B extends along the conductive first base electrode layer 21A to the edge of the first base electrode layer 21A. Therefore, when the array type inductor 1 is viewed from above (in other words, when viewed from the normal direction of the upper surface 10a (in the illustrated embodiment, the direction along the T-axis)), the shape of the first plating layer 21B is equal to or similar to the shape of the first base electrode layer 21A. At least one of the first plating layer 21B and the second plating layer 22B may have a two-layer structure. When first plating layer 21B has a two-layer structure, the first plating layer in contact with first base electrode layer 21A may be a nickel plating layer, and the second plating layer formed on the first plating layer may be a tin plating layer. When second plating layer 22B has a two-layer structure, the first plating layer in contact with second base electrode layer 22A may be a nickel plating layer, and the second plating layer formed on the first plating layer may be a tin plating layer.

[0037] The second plating layer 22B is formed so as to cover the second base electrode layer 22A by, for example, electrolytic plating on the surface of the second base electrode layer 22A. A plating layer is provided so as to cover the surface of each base electrode layer in the third external electrode 23 to the eighth external electrode 28. The explanation regarding the first plating layer 21B also applies to the second plating layer 22B of the second external electrode 22 and the plating layers of each of the third external electrode 23 to the eighth external electrode 28.

[0038] Each external electrode is designed and manufactured to have an area equal to or greater than a predetermined area in order to ensure the bonding strength with the coil conductor and to reduce electrical resistance. In the embodiment shown in Fig. 2, the straight line portion L14 of the first external electrode 21 and the straight line portion L22 of the second external electrode 22 are arranged to face each other in the L-axis direction. This allows for a larger distance between the first external electrode 21 and the second external electrode 22 than when the first external electrode 21 and the second external electrode 22 are formed in a circular shape in a plan view or when the first external electrode 21 and the second external electrode 22 have curved surfaces that protrude toward each other. This makes it possible to prevent short circuits from occurring between the first external electrode 21 and the second external electrode 22. Similarly, since the straight portion L11 of the first external electrode 21 and the straight portion L33 of the third external electrode 23 are arranged to face each other in the W-axis direction, the distance between the first external electrode 21 and the third external electrode 23 can be made larger than when the first external electrode 21 and the third external electrode 23 are formed into a circular shape in a planar view or when the first external electrode 21 and the third external electrode 23 have curved surfaces that protrude toward each other.

[0039] 1-5 Manufacturing method The array inductor 1 is fabricated by, for example, a sheet lamination method, a print lamination method, a thin film process method, a slurry build method, or other known fabrication methods. In these fabrication methods, as known to those skilled in the art, a structure containing precursors of a plurality of array inductors 1 is created, and this structure is then cut into individual pieces using a cutting machine such as a dicing machine or a laser processing machine. The individual chips are subjected to a polishing process such as barrel polishing to form each ridge portion of the base 10.

[0040] 1-6 Summary When forming the plating layer of each external electrode by electroplating, a stronger electric field is generated at each ridge line of the base 10 than in other regions (each surface), making plating extension more likely to occur at the ridge line of the base 10. When plating extension occurs at the ridge line of the base 10, the insulation reliability between the adjacent external electrodes arranged along that ridge line decreases. To address this issue, in the array-type inductor 1 according to the first embodiment of the present invention, each external electrode is arranged on the upper surface 10a of the base 10, spaced apart from any of the ridge lines R11 to R14 that surround the upper surface 10a. For example, the first external electrode 21 is arranged on the upper surface 10a of the base 10 at a position spaced apart from the ridge line R11 (and also from the other ridge lines R12 to R14), thereby preventing plating extension from occurring along the ridge line R11 when forming the first plating layer 21B of the first external electrode 21. This makes it possible to prevent the first plating layer 21B from growing excessively in the W-axis direction along the ridge portion R11, thereby ensuring insulation reliability between the first external electrode 21 and the third external electrode 23. A similar mechanism also ensures insulation reliability between other external electrodes adjacent in the W-axis direction, i.e., between the third external electrode 23 and the fifth external electrode 25, between the fifth external electrode 25 and the seventh external electrode 27, between the second external electrode 22 and the fourth external electrode 24, between the fourth external electrode 24 and the sixth external electrode 26, and between the sixth external electrode 26 and the eighth external electrode 28.

[0041] The base 10 made of metal magnetic particles has lower insulating properties than a base made of ferrite, and is therefore more susceptible to plating elongation on its surface than on the surface of a base made of ferrite. In the array-type inductor 1, the external electrodes are arranged on the top surface 10a of the base 10 at a distance from any of the ridges R11 to R14 that surround the top surface 10a, so even when the base 10 is made of metal magnetic particles, plating elongation can be suppressed, ensuring reliable insulation between the external electrodes.

[0042] In the array inductor 1, multiple elements are arranged along the W-axis direction, so as the number of elements built into the base 10 increases, the demand for compactness in the W-axis direction becomes stronger. In the array inductor 1, the insulation reliability between adjacent external electrodes in the W-axis direction is improved, so the distance between adjacent external electrodes in the W-axis direction can be made smaller than the distance between adjacent external electrodes in the L-axis direction. This allows the dimensions of the array inductor 1 in the W-axis direction to be compact.

[0043] In the array-type inductor 1, each external electrode has a shape without corners in a plan view, which makes it possible to prevent a strong electric field from being generated in some areas on the base electrode layer when forming the plating layer of each external electrode (e.g., first plating layer 21B or second plating layer 22B). This makes it possible to prevent plating from growing more excessively in some areas of the base electrode layer than in other areas. Therefore, the plating layer of each external electrode provided in the array-type inductor 1 is formed to have a more uniform thickness compared to the surface of conventional external electrodes that have corners in a plan view. Therefore, when the array-type inductor 1 is surface-mounted on a substrate, the array-type inductor 1 can be held in a stable position on the substrate.

[0044] 2. Second embodiment (array-type inductor 101) Next, an array inductor 101 according to a second embodiment will be described with reference to Fig. 4 and Fig. 5. The array inductor 101 differs from the array inductor 1 in that it includes an insulating film 31. Fig. 4 is a plan view of the array inductor 101 according to the second embodiment, and Fig. 5 is a cross-sectional view of the array inductor 101 cut along a plane that passes through the first external electrode 21 and the second external electrode 22 and is parallel to the LT plane. The following mainly describes the insulating film 31 included in the array inductor 101, and a description of the points in the magnetically coupled coil component 101 that are common to the magnetically coupled coil component 1 will be omitted.

[0045] The array type inductor 101 includes an insulating film 31 provided on the upper surface 10a of the base 10. The insulating film 31 is provided so as to cover the area of ​​the upper surface 10a of the base 10 where no external electrodes are provided. Thus, the insulating film 31 is provided on the upper surface 10a of the base 10 so as to surround each of the first to eighth external electrodes 21 to 28. The insulating film 31 is made of an insulating material with excellent insulating properties. The insulating film 31 has a higher electrical resistivity than the base 10. Examples of materials for the insulating film 31 include resin materials such as silicone resin, epoxy resin, and phenol resin, glasses such as borosilicate glass, and metal oxides such as Al oxide.

[0046] The insulating film 31 is provided across adjacent external electrodes, and therefore further improves the insulation reliability between the adjacent external electrodes. For example, as shown in Fig. 5, the insulating film 31 extends between the first external electrode 21 and the second external electrode 22 adjacent to the first external electrode 21 in the L-axis direction. This allows the insulating film 31 to improve the insulation reliability between the first external electrode 21 and the second external electrode 22.

[0047] The insulating film 31 is also provided on the upper surface 10a of the base 10 between each external electrode and the ridge line portion. For example, a portion of the insulating film 31 is interposed between the first external electrode 21, the third external electrode 23, the fifth external electrode 25, and the seventh external electrode 27 and the ridge line portion R11. Another portion of the insulating film 31 is interposed between the second external electrode 22, the fourth external electrode 24, the sixth external electrode 26, and the seventh external electrode 28 and the ridge line portion R12. The insulating film 31 may be provided so as to cover each ridge line portion. This can further suppress plating elongation at the ridge line portion covered by the insulating film 31. For example, by having the insulating film 31 cover the ridge line portion R11, plating elongation at the ridge line portion R11 can be further suppressed.

[0048] In one embodiment of the present invention, the surface roughness of the upper surface 10a of the substrate 10 is smaller than the surface roughness of the first end surface 10c, the second end surface 10d, the first side surface 10e, and the second side surface 10f. By reducing the surface roughness of the upper surface 10a, the insulating film 31 provided on the upper surface 10a, which is necessary to ensure insulation between the external electrodes, can be made thinner. The surface roughness of the substrate 10 can be expressed as an arithmetic surface roughness Sa calculated using a measuring instrument conforming to ISO 25178. The arithmetic surface roughness Sa can be measured using a commercially available instrument capable of measuring arithmetic surface roughness Sa, such as a shape analysis laser microscope (VK-X250) manufactured by Keyence Corporation.

[0049] 3 Third embodiment (array type inductor 201) Next, an array inductor 201 according to the third embodiment will be described with reference to Fig. 6. The array inductor 201 differs from the array inductor 101 in that an insulating film 31 covers a portion of the base electrode layer. Fig. 6 is a cross-sectional view of the array inductor 201 cut along a plane that passes through the first external electrode 21 and the second external electrode 22 and is parallel to the LT plane. Below, differences between the array inductor 201 and the array inductor 101 will be described, and descriptions of the commonalities between the magnetically coupled coil component 201 and the magnetically coupled coil component 101 will be omitted.

[0050] 6, the insulating film 31 provided in the array-type inductor 201 is provided so as to cover a portion of the upper surface of each of the first base electrode layer 21A and the second base electrode layer 22A. The insulating film 31 covers a ring-shaped region along the peripheral edge 21C of the first base electrode layer 21A and a ring-shaped region along the peripheral edge 22C of the upper surface of the second base electrode layer 22A. Although not shown in the figure, a portion (peripheral edge) of the upper surface of each base electrode layer provided in each external electrode other than the first external electrode 21 and the second external electrode 22 may also be covered by the insulating film 31.

[0051] 6, the upper surface 10a of the base 10 is covered with the insulating film 31, the first base electrode layer 21A, and the second base electrode layer 22A, so that the upper surface 10a of the base 10 is not exposed when the first plating layer 21B and the second plating layer 22B are formed. This makes it possible to prevent moisture from penetrating into the base 10 when the first plating layer 21B and the second plating layer 22B are formed by plating. For example, it is possible to prevent a cleaning solution or a plating solution used in the plating process from penetrating into the base 10.

[0052] In the array-type inductor 201, by covering the peripheral portion of the upper surface of the base electrode layer of each external electrode with the insulating film 31, it is possible to prevent the plating from extending beyond the upper surface of each base electrode layer when forming a plating layer on the upper surface of each base electrode layer, which further improves the insulation reliability between adjacent external electrodes in the array-type inductor 201.

[0053] 4 Fourth embodiment (array type inductor 301) Next, an array inductor 301 according to a fourth embodiment will be described with reference to Fig. 7. The array inductor 301 differs from the array inductor 201 in that a base electrode layer is embedded in the base 10. Fig. 7 is a cross-sectional view of the array inductor 301 cut along a plane that passes through the first external electrode 21 and the second external electrode 22 and is parallel to the LT plane. Below, differences between the array inductor 301 and the array inductor 201 will be described, and descriptions of the commonalities between the magnetically coupled coil component 301 and the magnetically coupled coil component 201 will be omitted.

[0054] In the array-type inductor 301, the base electrode layer of each external electrode is embedded in the base 10 so that only its upper surface is exposed. A plating layer is provided on the upper surface of the base electrode layer exposed from the base 10. For example, as shown in FIG. 7 , the first base electrode layer 21A of the first external electrode 21 and the second base electrode layer 22A of the second external electrode 22 are both embedded in the base 10. A first plating layer 21B is provided on the upper surface of the first base electrode layer 21A that is exposed from the base 10 and the insulating film 31. A second plating layer 22B is provided on the upper surface of the second base electrode layer 22A that is exposed from the base 10 and the insulating film 31. For each of the other external electrodes, the base electrode layer is embedded inside the base 10, and a plating layer is provided on the upper surface of the base electrode layer.

[0055] The dimensions of the array type inductor 301 in the T-axis direction can be made compact.

[0056] 5 Fifth embodiment (array type inductor 301) Next, an array inductor 401 according to a fifth embodiment will be described with reference to Fig. 8. The array inductor 401 differs from the array inductor 301 in the shape of the base electrode layer. Fig. 8 is a cross-sectional view of the array inductor 401 cut along a plane that passes through the first external electrode 21 and the second external electrode 22 and is parallel to the LT plane. Below, differences between the array inductor 401 and the array inductor 301 will be described, and descriptions of commonalities between the magnetically coupled coil component 401 and the magnetically coupled coil component 301 will be omitted.

[0057] In the array-type inductor 401, the first base electrode layer 21A is configured so that the upper surface of its peripheral portion 21C is flush with the upper surface 10a of the base body 10 or is recessed more inward into the base body 10 than the upper surface 10a of the base body 10. Furthermore, the first base electrode layer 21A has an inner region surrounded by the peripheral portion 21C recessed more inward into the base body 10 than the peripheral portion 21C. Furthermore, the second base electrode layer 22A has an upper surface of its peripheral portion 22C flush with the upper surface 10a of the base body 10 or is recessed more inward into the base body 10 than the upper surface 10a of the base body 10. Furthermore, the second base electrode layer 22A has an inner region surrounded by the peripheral portion 22C recessed more inward into the base body 10 than the peripheral portion 22C. The depth of the recessed inner region of the first underlying electrode layer 21A and the depth of the recessed inner region of the second underlying electrode layer 22A may be less than half the thickness of the insulating film 31, or may be less than the thickness of the insulating film 31.

[0058] The dimension in the T-axis direction of the arrayed inductor 401 can be further reduced. Also, the portions of the insulating film 31 that cover the peripheral edge portion 21C of the first base electrode layer 21A and the peripheral edge portion 22C of the second base electrode layer 22A can be prevented from protruding outward beyond the other portions.

[0059] 6 Manufacturing method for inductor-embedded substrate Next, an example of a method for manufacturing an inductor-embedded substrate that incorporates the array type inductor 1 will be described with reference to FIGS. 9a to 9f.

[0060] First, as shown in FIG. 9a, an insulating layer 52 is formed on a film 51, and a cavity H1 is formed in this insulating layer 52. Then, the array inductor 1 is placed in the cavity H1 so that the first external electrode 21 and the second external electrode 22 are in contact with the film 51. The film 51 is a film for temporarily attaching the array inductor 1 during the manufacturing process of an inductor-embedded substrate. The insulating layer 52 is part of a multilayer printed circuit board. Although not shown, multiple wiring patterns and via conductors connecting the wiring patterns may be formed inside the insulating layer 52. The insulating layer 52 is made of an insulating material such as glass epoxy. The material of the insulating layer 52 is not limited to glass epoxy and can be made of various materials suitable for insulating layers in multilayer printed circuit boards.

[0061] Next, as shown in FIG. 9b, a first resin layer 53 is formed in the cavity H1 in which the array inductor 1 is placed so as to cover the array inductor 1. The first resin layer 53 is made of, for example, a thermosetting resin. The first resin layer 53 may be formed by injecting uncured thermosetting resin into the cavity H1 and heating and curing the injected thermosetting resin. In this way, an intermediate body is produced in which the array inductor 1 is sealed in the cavity H1 by the first resin layer 53.

[0062] 9c, the intermediate body is turned upside down, and then the film 51 is removed. A second resin layer 54 is formed on the upper surface of the intermediate body from which the film 51 has been removed. The second resin layer 54 may be made of the same thermosetting resin as the first resin layer 53. The second resin layer 54 is formed so as to cover the first external electrode 21 and the second external electrode 22 that are exposed when the film 51 is removed.

[0063] Next, as shown in FIG. 9d, a first via hole VH1 and a second via hole VH2 are formed in the second resin layer 54 to expose a portion of the first external electrode 21 and a portion of the second external electrode 22. The first via hole VH1 is formed by irradiating a laser beam from above the paper toward the first external electrode 21. Similarly, the second via hole VH2 is formed by irradiating a laser beam from above the paper toward the second external electrode 22. The irradiated laser is, for example, a carbon dioxide laser. By using two carbon dioxide laser processing machines, the laser can be simultaneously irradiated toward the upper surface 21 a of the first external electrode 21 and the upper surface 22 a of the second external electrode 22, so that the first via hole VH1 and the second via hole VH2 can be formed in parallel. This shortens the manufacturing time.

[0064] As described above, the first external electrode 21 and the second external electrode 22 have a shape without corners in a plan view, and therefore the upper surfaces 21a and 22a of the first external electrode 21 and the second external electrode 22 are smoother than those of conventional external electrodes. Therefore, diffuse reflection of the laser irradiated toward the first external electrode 21 and the second external electrode 22 to form the first via hole VH1 and the second via hole VH2 is suppressed at the upper surfaces 21a and 22a, and the first via hole VH1 and the second via hole VH2 can be formed with high precision.

[0065] 9e, the bottom and wall surfaces defining the first via hole VH1 and the bottom and wall surfaces defining the second via hole VH2 are plated to form via conductors 61 in the first via hole VH1 and via conductors 62 in the second via hole VH2. In addition, the surface of the second resin layer 54 is plated to form a conductor layer 70 on the surface of the second resin layer 54.

[0066] Next, as shown in Figure 9f, the region of the conductor layer 70 between the first external electrode 21 and the second external electrode 22 in the L-axis direction is etched to form a first wiring pattern 71 connected to the first external electrode 21 and a second wiring pattern 72 connected to the second external electrode 22.

[0067] In this way, an inductor-embedded substrate 81 with the array type inductor 1 embedded therein is fabricated.

[0068] The inductor-built-in substrate 81 may have various electronic components built in other than the illustrated array-type inductor 1. The electronic components built in the inductor-built-in substrate 81 other than the array-type inductor 1 may be passive elements such as inductors, capacitors, resistors, etc., or may be active elements such as semiconductor ICs.

[0069] The inductor-built-in substrate 81 can be mounted in a variety of electronic devices, including smartphones, tablets, game consoles, automotive electrical components, servers, and various other electronic devices.

[0070] 7 Notes The dimensions, materials, and arrangements of each component described in the various embodiments above are not limited to those explicitly described in each embodiment, and each component can be modified to have any dimensions, materials, and arrangements that may fall within the scope of the present invention.

[0071] Components not explicitly described in this specification may be added to each of the above-described embodiments, and some of the components described in each embodiment may be omitted.

[0072] The designations "first," "second," "third," etc. in this specification are used to identify components and do not necessarily limit the number, order, or content thereof. Furthermore, numbers used to identify components are used in different contexts, and numbers used in one context do not necessarily indicate the same configuration in another context. Furthermore, this does not prevent a component identified by a certain number from also serving the function of a component identified by another number.

[0073] In this specification, when a certain component is referred to as "comprising" another component, it does not mean that other components are excluded, but that other components may be further included, unless it is inconsistent with the content of the present invention.

[0074] 8. Supplementary Notes The embodiments disclosed herein also include the following:

[0075] [Appendix 1] a base (10) having a first surface (10a), a second surface (10c) connected to the first surface via a first ridge portion (R11), and a third surface (10d) facing the second surface in a first direction (L) and connected to the first surface via a second ridge portion (R12); a first coil conductor (25) provided inside the base; a second coil conductor provided inside the base; a first external electrode (21) provided on the first surface of the base and connected to one end of the first coil conductor; a second external electrode (22) provided on the first surface of the base body and spaced apart from the first external electrode in the first direction, and connected to the other end of the first coil conductor; a third external electrode (23) provided on the first surface of the base body and spaced apart from the first external electrode in a second direction perpendicular to the first direction, and connected to one end of the second coil conductor; a fourth external electrode (24) provided on the first surface of the base body and spaced apart from the third external electrode in the first direction, and connected to the other end of the second coil conductor; An array type inductor comprising:

[0076] [Appendix 2] the first external electrode, the second external electrode, the third external electrode, and the fourth external electrode are all provided at positions on the first surface that are spaced apart from both the first ridge portion and the second ridge portion; An array type inductor as described in [Appendix 1].

[0077] [Appendix 3] When viewed from the normal direction of the first surface, the outer edge of the first external electrode has a first linear portion (L12) extending along the second direction (W). An array type inductor according to [Appendix 1] or [Appendix 2].

[0078] [Appendix 4] The first external electrode has a first base electrode layer (21A) and a first plating layer (21B) provided on the first base electrode layer. An array type inductor according to any one of [Appendix 1] to [Appendix 3].

[0079] [Appendix 5] The semiconductor device further includes an insulating film (31) provided on the first surface of the base and surrounding the first external electrode, the second external electrode, the third external electrode, and the fourth external electrode. An array type inductor according to any one of [Appendix 1] to [Appendix 4].

[0080] [Appendix 6] the insulating film (31) is provided on the first surface of the base body so as to cover a peripheral portion (21C) of the base electrode layer; An array type inductor as described in [Appendix 5].

[0081] [Appendix 7] When viewed from the second direction, both the first ridge portion and the second ridge portion are curved. An array type inductor according to any one of [Appendix 1] to [Appendix 6].

[0082] [Appendix 8] the substrate includes a plurality of metal magnetic particles; An array type inductor according to any one of [Appendix 1] to [Appendix 7].

[0083] [Appendix 9] The second external electrode has a second base electrode layer (22A) and a second plating layer (22B) provided on the first base electrode layer. An array type inductor according to any one of [Appendix 1] to [Appendix 8].

[0084] [Appendix 10] The first plating layer and the second plating layer are formed by an electrolytic plating method. An array type inductor according to any one of [Appendix 1] to [Appendix 9].

[0085] [Appendix 11] An inductor-embedded substrate incorporating the array-type inductor described in any one of [Appendix 1] to [Appendix 10]. [Explanation of symbols]

[0086] 1, 101, 201, 301, 401 Array type inductor 10 Base 21 1st external electrode 22 2nd external electrode 23 Third external electrode 24 4th external electrode 25 5th external electrode 26 6th external electrode 27 7th external electrode 28 8th external electrode 35 Coil conductor 81 Inductor built-in board R11~R14, R21~R24, R31~R34 Ridge line

Claims

1. a base body having a first surface, a second surface connected to the first surface via a first ridge portion, and a third surface facing the second surface in a first direction and connected to the first surface via a second ridge portion; a first coil conductor provided inside the base; a second coil conductor provided inside the base; a first external electrode provided on the first surface of the base and connected to one end of the first coil conductor; a second external electrode provided on the first surface of the base body and spaced apart from the first external electrode in the first direction, and connected to the other end of the first coil conductor; a third external electrode provided on the first surface of the base body and spaced apart from the first external electrode in a second direction perpendicular to the first direction, and connected to one end of the second coil conductor; a fourth external electrode provided on the first surface of the base body and spaced apart from the third external electrode in the first direction, and connected to the other end of the second coil conductor; An array type inductor comprising:

2. the first external electrode, the second external electrode, the third external electrode, and the fourth external electrode are all provided at positions on the first surface that are spaced apart from both the first ridge portion and the second ridge portion; The array type inductor according to claim 1 .

3. When viewed from the normal direction of the first surface, an outer edge of the first external electrode has a first linear portion extending along the second direction.

3. The array type inductor according to claim 1 or 2.

4. The first external electrode has a first base electrode layer and a first plating layer provided on the first base electrode layer.

3. The array type inductor according to claim 1 or 2.

5. an insulating film provided on the first surface of the base and surrounding the first external electrode, the second external electrode, the third external electrode, and the fourth external electrode; 3. The array type inductor according to claim 1 or 2.

6. the insulating film is provided on the first surface of the base body so as to cover a peripheral portion of the base electrode layer; The array type inductor according to claim 5 .

7. When viewed from the second direction, both the first ridge portion and the second ridge portion are curved.

3. The array type inductor according to claim 1 or 2.

8. the substrate includes a plurality of metal magnetic particles; 3. The array type inductor according to claim 1 or 2.

9. The second external electrode has a second base electrode layer and a second plating layer provided on the first base electrode layer. The array type inductor according to claim 4 .

10. The first plating layer and the second plating layer are formed by an electrolytic plating method. The array type inductor according to claim 9 .

11. 3. An inductor-built-in substrate incorporating the coil component according to claim 1.

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