Coil parts

Abstract

To provide a coil component capable of suppressing migration of metal atoms constituting a coil conductor.SOLUTION: A coil component includes: a laminate 10 including a plurality of metal magnetic particles 31; and a coil conductor 25 provided in the laminate 10 so as to be in contact with the laminate 10 and wound around a coil axis A. The laminate 10 includes an insulating part 30 including a non-metallic magnetic particle region R 2 defined by at least three metal magnetic particles 31 in a cross section of the laminate 10. In the insulating part 30, an atomic ratio of Si is highest among materials other than oxygen constituting the non-metallic magnetic particle region R 2.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a coil component. [Background technology]

[0002] A coil component such as a conventional inductor typically includes a magnetic base made of a magnetic material, a coil conductor provided in the magnetic base and wound around a coil axis, and an external electrode connected to an end of the coil conductor. Metallic magnetic materials made of metallic magnetic particles are known as materials for the magnetic base. In general, metallic magnetic materials have a higher saturation magnetic flux density than ferrite materials, and are therefore suitable as materials for the magnetic base of coil components through which a large current flows. A coil component using such a metallic magnetic material is disclosed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-121023 A Summary of the Invention [Problem to be solved by the invention]

[0004] A magnetic base made of a metal magnetic material has a higher saturation magnetic flux density than a magnetic base made of a ferrite material, but its insulating properties are lower. In addition, the heat treatment in the manufacturing process of the coil components can cause migration of metal atoms constituting the conductor, causing the metal atoms of the coil conductor to diffuse into the magnetic base. Such migration of metal atoms of the coil conductor can further reduce the insulating properties of the magnetic base made of a metal magnetic material.

[0005] It is an object of the present invention to provide a coil component capable of suppressing migration of metal atoms constituting a coil conductor. Other objects of the present invention will become apparent throughout the entire description of the present specification. [Means for solving the problem]

[0006] A coil component according to one embodiment of the present invention includes a base including a plurality of metal magnetic particles, and a coil conductor provided within the base so as to be in contact with the base, the base having an insulating portion including a non-metallic magnetic particle region defined by at least three metal magnetic particles in a cross section of the base, and the insulating portion has the highest atomic ratio of Si among materials other than oxygen constituting the non-metallic magnetic particle region. In one embodiment of the present invention, the coil conductor is wound around a coil axis.

[0007] In one embodiment of the present invention, the atomic ratio of Si may be highest among materials other than oxygen constituting the non-metallic magnetic particle region at the geometric center of the non-metallic magnetic particle region as viewed from a cross section along the coil axis.In one embodiment of the present invention, the atomic ratio of Si may be highest among materials other than oxygen constituting the non-metallic magnetic particle region at the geometric center of the non-metallic magnetic particle region in a cross section obtained by cutting the base along a plane passing through the coil conductor.

[0008] In one embodiment of the present invention, the surface of each metal magnetic particle is coated with a coating layer containing Si, and the material composition of the coating layer and the material composition of the non-metallic magnetic particle region at the geometric center may be different from each other.

[0009] In one embodiment of the present invention, the metal magnetic particles may be bonded to each other via a coating layer.

[0010] In one embodiment of the present invention, the atomic ratio of Si in the non-metallic magnetic grain region may be 50 at % or more and 95 at % or less.

[0011] In one embodiment of the present invention, the non-metallic magnetic particle regions may include Fe, Cr, and / or Al.

[0012] In one embodiment of the present invention, the metallic magnetic particles may be an alloy containing Fe, Si, Cr, or Al.

[0013] In one embodiment of the present invention, the coil conductor includes a first conductor pattern and a second conductor pattern extending along a planar direction perpendicular to the coil axis and spaced apart from each other in the direction of the coil axis, and the insulating portion may be disposed between the first conductor pattern and the second conductor pattern.

[0014] In one embodiment of the present invention, the coil component may further include an external electrode provided on the surface of the base and electrically connected to the coil conductor, and the insulating portion may be provided between the coil conductor and the external electrode.

[0015] In one embodiment of the present invention, the coil conductor may be provided inside the insulating portion.

[0016] In one embodiment of the present invention, the entire substrate may be an insulating portion.

[0017] In one embodiment of the present invention, the insulating portion may be formed by heat treating a metal magnetic paste containing metal magnetic particles and a silicone resin.

[0018] An embodiment of the present invention relates to a circuit board including any one of the above electronic components. Also, an embodiment of the present invention relates to an electronic device including the above circuit board. Effect of the Invention

[0019] According to the present invention, there is provided a coil component capable of suppressing migration of metal atoms that constitute a coil conductor. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a coil component according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the coil component of FIG. [Diagram 3] 2 is a diagram showing a schematic cross section of the coil component taken along line II in FIG. 1. [Figure 4] 4 is an enlarged cross-sectional view showing a schematic view of a partial region of the insulating part of FIG. 3. [Diagram 5] FIG. 13 is a schematic cross-sectional view of a coil component according to another embodiment of the present invention. [Figure 6] FIG. 13 is a schematic cross-sectional view of a coil component according to another embodiment of the present invention. [Figure 7] FIG. 13 is a schematic cross-sectional view of a coil component according to another embodiment of the present invention. [Figure 8] FIG. 13 is a schematic cross-sectional view of a coil component according to another embodiment of the present invention. [Figure 9] FIG. 13 is a perspective view of a coil component according to another embodiment of the present invention. [Figure 10] 10 is a diagram showing a schematic cross section of the coil device taken along line II-II in FIG. 9. [Figure 11] 11 is a diagram illustrating a modified example of the coil conductor in FIG. 10. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, various embodiments of the present invention will be described with reference to the drawings as appropriate. Note that components common to multiple drawings are designated by the same reference numerals throughout the multiple drawings. Please note that the drawings are not necessarily drawn to scale for the sake of convenience of explanation.

[0022] FIG. 1 is a perspective view of a coil component 1 according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the coil component 1 of FIG. 1. FIGS. 1 and 2 show, as an example of the coil component 1, a laminated inductor used as a passive element in various circuits. The laminated inductor is an example of a laminated coil component to which the present invention can be applied. In addition to laminated inductors, the present invention can also be applied to coil components produced by, for example, compression molding or thin film molding. The present invention can be applied to power inductors incorporated in power lines and various other coil components.

[0023] The coil component 1 in the illustrated embodiment includes a laminate (base) 10 including a plurality of metal magnetic particles, a coil conductor 25 provided inside the laminate 10 and wound around a coil axis A, an external electrode 21 electrically connected to one end of the coil conductor 25, and an external electrode 22 electrically connected to the other end of the coil conductor 25. The laminate 10 is formed by stacking magnetic layers made of a magnetic material. The coil conductor 25 has a plurality of conductor patterns C11 to C16. The plurality of conductor patterns C11 to C16 extend along a planar direction perpendicular to the coil axis A and are spaced apart from each other in the direction of the coil axis A. Each of the conductor patterns C11 to C16 is electrically connected to an adjacent conductor pattern through vias V1 to V5, which will be described later. In this manner, the coil conductor 25 is formed by the conductor patterns C11 to C16 and the vias V1 to V5. The conductor pattern C11 is electrically connected to the external electrode 21, and the conductor C16 is electrically connected to the external electrode 22.

[0024] As shown in the figure, in one embodiment of the present invention, the laminate 10 is formed, for example, in a rectangular parallelepiped shape. The laminate 10 has a first main surface 10e, a second main surface 10f, a first end surface 10a, a second end surface 10c, a first side surface 10b, and a second side surface 10d. The outer surface of the laminate 10 is defined by these six surfaces. The first main surface 10e and the second main surface 10f face each other, the first end surface 10a and the second end surface 10c face each other, and the first side surface 10b and the second side surface 10d face each other. When the laminate 10 is formed in a rectangular parallelepiped shape, the first main surface 10e and the second main surface 10f are parallel, the first end surface 10a and the second end surface 10c are parallel, and the first side surface 10b and the second side surface 10d are parallel.

[0025] In the embodiment of FIG. 1, the first main surface 10e is on the upper side of the laminate 10, and therefore the first main surface 10e may be referred to as the "upper surface" in this specification. Similarly, the second main surface 10f may be referred to as the "lower surface". The coil component 1 is disposed so that the second main surface 10f faces a circuit board (not shown), and therefore the second main surface 10f may be referred to as the "mounting surface" in this specification. Furthermore, when referring to the up-down direction of the coil component 1, the up-down direction in FIG. 1 is used as the reference.

[0026] In this specification, unless otherwise understood in the context, the "length" direction, "width" direction, and "thickness" direction of the coil component 1 are respectively the "L axis" direction, the "W axis" direction, and the "T axis" direction in FIG. 1. The L axis, the W axis, and the T axis are perpendicular to each other. The coil axis A extends along the T direction. The direction in which the plane including the W direction and the L direction extends corresponds to the planar direction.

[0027] In one embodiment of the present invention, the coil component 1 is formed so that the length dimension (dimension in the L-axis direction) is 0.2 to 6.0 mm, the width dimension (dimension in the W-axis direction) is 0.1 to 4.5 mm, and the thickness dimension (dimension in the T-axis direction) is 0.1 to 4.0 mm. These dimensions are merely examples, and the coil component 1 to which the present invention is applicable may have any dimensions as long as they are not contrary to the spirit of the present invention. In one embodiment, the coil component 1 is formed to have a low height. For example, the coil component 1 is formed so that its width dimension is larger than its thickness dimension.

[0028] Fig. 2 is an exploded perspective view of the coil device 1 of Fig. 1. For convenience of illustration, the external electrodes 21 and 22 are omitted in Fig. 2. As shown in Fig. 2, the laminate 10 includes a main body portion 20, an upper cover layer 18 provided on the upper surface of the main body portion 20, and a lower cover layer 19 provided on the lower surface of the main body portion 20. The main body portion 20 includes stacked magnetic layers 11 to 16, and the upper cover layer 18, the magnetic layer 11, the magnetic layer 12, the magnetic layer 13, the magnetic layer 14, the magnetic layer 15, the magnetic layer 16, the magnetic layer 17, and the lower cover layer 19 are stacked in this order from top to bottom in Fig. 2.

[0029] The upper cover layer 18 includes four magnetic layers 18a to 18d. In the upper cover layer 18, the magnetic layer 18a, the magnetic layer 18b, the magnetic layer 18c, and the magnetic layer 18d are stacked in this order from bottom to top in FIG.

[0030] The lower cover layer 19 includes four magnetic layers 19a to 19d. In the lower cover layer 19, the magnetic layer 19a, the magnetic layer 19b, the magnetic layer 19c, and the magnetic layer 19d are stacked in this order from top to bottom in FIG.

[0031] The magnetic layers 11-16 constituting the main body 20, the magnetic layers 18a-18d constituting the upper cover layer 18, and the magnetic layers 19a-19d constituting the lower cover layer 19 each contain a metal magnetic particle and an insulating resin material. The metal magnetic particles applicable to the present invention are materials in which magnetism is manifested in the non-oxidized metal portion, such as particles containing non-oxidized metal particles and alloy particles. The magnetic particles applicable to the present invention, for example, contain Fe and at least one of Al and Mn as alloy components. As the material of the magnetic particles applicable to the present invention, for example, alloy-based Fe-Si-Cr-Al, Fe-Si-Cr-Mn, Fe-Si-Al, Fe-Si-Mn, or Fe-Ni, amorphous Fe-Si-Cr-BC, or Fe-Si-B-Cr, Fe, or particles of a mixture of these materials can be used. The resin material contained in each magnetic layer will be described later.

[0032] The coil component 1 may include any number of magnetic layers as necessary in addition to the magnetic layers 11 to 16, 18a to 18d, and 19a to 19d. Some of the magnetic layers 11 to 16, 18a to 18d, and 19a to 19d may be omitted as appropriate.

[0033] Corresponding conductor patterns C11 to C16 are embedded in the magnetic layers 11 to 16, respectively. Before the magnetic layers 11 to 16 are laminated, the upper surfaces of the conductor patterns C11 to C16 are exposed from the upper surfaces of the magnetic layers 11 to 16, respectively. Each of the conductor patterns C11 to C16 is formed so as to extend around the coil axis A. In the illustrated embodiment, the coil axis A extends in the T-axis direction, which coincides with the lamination direction of the magnetic layers 11 to 16.

[0034] Vias V1 to V5 are formed at predetermined positions of the magnetic layers 11 to 15, respectively. The vias V1 to V5 are formed by forming through holes penetrating the magnetic layers 11 to 15 in the T-axis direction at predetermined positions of the magnetic layers 11 to 15 and filling the through holes with a metal material.

[0035] The conductive patterns C11 to C16 and the vias V1 to V5 are formed so as to contain a metal having excellent conductivity, for example, Ag, Pd, Cu, Al, or an alloy thereof.

[0036] In one embodiment, the external electrode 21 is provided on the first end surface 10a of the laminate 10, and the external electrode 22 is provided on the second end surface 10c of the laminate 10. The external electrode 21 and the external electrode 22 may extend to the upper surface 10e, the lower surface 10f, the first side surface 10b, and the second side surface 10d of the laminate 10 as shown in the figure. In this case, the external electrode 21 is provided so as to cover the entire first end surface 10a of the laminate 10 and parts of the upper surface 10e, the lower surface 10f, the first side surface 10b, and the second side surface 10d, and the external electrode 22 is provided so as to cover the entire second end surface 10c of the laminate 10 and parts of the upper surface 10e, the lower surface 10f, the first side surface 10b, and the second side surface 10d. The shapes of the external electrode 21 and the external electrode 22 are not particularly limited and can be changed as appropriate. For example, the external electrode 21 may be L-shaped to cover a portion of each of the first end face 10a and the lower face 10f, or may be plate-shaped to cover a portion of the lower face 10f. Similarly, the external electrode 22 may be L-shaped to cover a portion of each of the second end face 10c and the lower face 10f, or may be plate-shaped to cover a portion of the lower face 10f.

[0037] Next, the laminate 10 of the coil device 1 will be described in more detail with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram showing a schematic cross section of the coil device 1 taken along line II in Fig. 1. In Fig. 3, some of the magnetic layers included in the laminate 10 are omitted. Fig. 4 is an enlarged cross-sectional view showing a schematic partial region of the insulating section 30 in Fig. 3.

[0038] In one or more embodiments of the present invention, the laminate 10 has an insulating portion 30 at least in a part thereof. Alternatively, the entire laminate 10 may be the insulating portion 30. In the embodiment shown in FIG. 3, the insulating portion 30 is provided so as to surround the coil conductor 25. That is, in the illustrated coil component 1, the coil conductor 25 is provided inside the insulating portion 30. The coil conductor 125 is provided in the laminate 10 so as to contact the insulating portion 30. More specifically, in the illustrated embodiment, the magnetic layers 11 to 16 (see FIG. 2) constituting the main body portion 20, the magnetic layer 18a of the upper cover layer 18, and the magnetic layer 19a of the lower cover layer 19 are the insulating portion 30.

[0039] Each magnetic layer of the laminate 10 is formed using a metal magnetic paste containing metal magnetic particles and a resin material having insulating properties, and the magnetic layers 11-16, 18a, and 19a constituting the insulating section 30 use a metal magnetic paste containing a silicon resin as a resin material. The ratio of the silicon resin in the metal magnetic paste can be, for example, 5 vol% or more and 50 vol% or less. Examples of the resin material of the metal magnetic paste used for the magnetic layers not constituting the insulating section 30 (in this embodiment, the magnetic layers 18b-18d, 19b-19d) include polyvinyl butyral (PVB) resin, ethyl cellulose resin, polyvinyl alcohol resin, and acrylic resin. In addition, a thermosetting resin with excellent insulating properties can also be used as the resin material used for the magnetic layers 18b-18d, 19b-19d not constituting the insulating section 30. Examples of the thermosetting resin that can be used 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.

[0040] As shown in FIG. 4, the insulating part 30 includes a metal magnetic particle region R1 composed of a plurality of metal magnetic particles 31, and a non-metal magnetic particle region R2 defined by at least three metal magnetic particles 31 in a cross section of the laminate 10 along an arbitrary direction. In the cross section of the laminate 10, the three metal magnetic particles 31 defining one non-metal magnetic particle region R2 are in contact with each other. The non-metal magnetic particle region R2 may be defined by four or more metal magnetic particles 31. In the non-metal magnetic particle region R2, the proportion of Si is the highest among the materials other than oxygen that constitute the non-metal magnetic particle region R2. The non-metal magnetic particle region R2 is filled with Si oxide. The non-metal magnetic particle region R2 may contain, for example, Fe and / or Cr in addition to Si and oxygen. As an example, the proportion of Si among the materials other than oxygen in the non-metal magnetic particle region R2 is 50 at% or more and 95 at% or less.

[0041] The proportion of Si in the non-metallic magnetic particle region R2 is based on the geometric center C of the non-metallic magnetic particle region R2 as viewed from a cross section along the coil axis A. That is, among materials other than oxygen, the atomic proportion of Si is the highest at the geometric center C of the non-metallic magnetic particle region R2 as viewed from a cross section along the coil axis A. The proportion of Si is measured, for example, by EDS (Energy Dispersive X-ray Spectroscopy) analysis.

[0042] The surface of each metal magnetic particle 31 may be covered with a coating layer 32. The coating layer 32 may be, for example, an oxide coating formed by oxidizing the surface of the metal magnetic particle 31, a coating film containing Si, or a coating film containing an element other than Si. The oxide coating or coating film may be an insulating film. The metal magnetic particles 31 are bonded to each other via the coating layer 32. When the coating layer 32 is formed on the surface of the metal magnetic particle 31, the coating layer 32 is a part of the metal magnetic particle 31 and is included in the metal magnetic particle region R1. In this case, the composition of the material of the coating layer 32 may be different from the composition of the material of the non-metal magnetic particle region R2 at the geometric center C.

[0043] Next, an example of a method for manufacturing the coil component 1 will be described. First, an upper laminate that becomes the upper cover layer 18, an intermediate laminate, and a lower laminate that becomes the lower cover layer 19 are formed. The upper laminate is formed by stacking a plurality of magnetic sheets that become the magnetic layers 18a to 18d. Similarly, the lower laminate is formed by stacking a plurality of magnetic sheets that become the magnetic layers 19a to 19d. The magnetic sheets are obtained, for example, by applying a metal magnetic paste to the surface of a plastic base film, drying it, and cutting the dried metal magnetic paste to a predetermined size. The metal magnetic paste is prepared, for example, by adding a solvent to a resin material containing metal magnetic particles. Silicon resin is used as the resin material used for the magnetic sheets that become the magnetic layers (magnetic layers 11 to 16, 18a, and 19a in the illustrated embodiment) that constitute the insulating part 30. Examples of resin materials that can be used for the magnetic sheets that become the magnetic layers (in the illustrated embodiment, the magnetic layers 18b-18d, 19b-19d) that do not constitute the insulating section 30 include resin materials with excellent insulating properties, such as polyvinyl butyral (PVB) resin and epoxy resin.

[0044] The intermediate laminate is formed by stacking a plurality of sheets including a conductor pattern, a magnetic layer, and an insulating material. When each sheet is prepared, first, a green sheet is formed on a base film. At this time, through holes are formed in the green sheet in the stacking direction to form vias. Next, a conductor pattern is formed on the green sheet by screen printing or the like. As a result, the metal material constituting the conductor pattern is embedded in the through holes to form vias. Then, a magnetic layer is printed on the portion where the conductor pattern is not formed. After each sheet including the conductor patterns C11 to C16 is formed, the base film is removed, and the sheets are stacked in order from the sheet including the conductor pattern C16 to the sheet including the conductor pattern C11. Since there is no other conductor pattern below the conductor pattern C16, it is not necessary to provide a through hole for forming a via when preparing the sheet including the conductor pattern C16.

[0045] Next, the intermediate laminate prepared as described above is sandwiched between an upper laminate and a lower laminate from above and below, and the upper laminate and the lower laminate are thermocompressed to the intermediate laminate to obtain a main laminate. Next, the main laminate is divided into pieces of a desired size using a cutting device such as a dicing machine or a laser processing machine, to obtain a chip laminate corresponding to the laminate 10. Next, the chip laminate is degreased, and the degreased chip laminate is heated at a predetermined temperature. By this heating process, the silicon resin contained in the metal magnetic paste is thermally decomposed into Si oxide, and the Si oxide is filled in the non-metallic magnetic particle region R2 of the insulating part 30. In addition, when the metal magnetic particles contain at least one of Al and Mn as an alloy component, at least one of an oxide of Al and an oxide of Mn is generated in the heating process, and the non-metallic magnetic particle region R2 of the insulating part 30 is filled with at least one of the oxide of Al and the oxide of Mn. In this way, the non-metallic magnetic particle region R2 may contain a mixture of an oxide of Si and at least one of an oxide of Al and an oxide of Mn. By including at least one of Al and Mn in the metal magnetic particles, the voids in the non-metallic magnetic particle region R2 can be reduced compared to when the metal magnetic particles do not include Al and Mn. Furthermore, by including at least one of an oxide of Al and an oxide of Mn in the non-metallic magnetic particle region R2, adjacent metal magnetic particles are firmly bonded to each other, improving the mechanical strength of the base 10. Next, a conductive paste is applied to both ends of the heat-treated chip stack to form the external electrodes 21 and 22. Through the above steps, the coil component 1 is obtained.

[0046] Next, another embodiment of the present invention will be described with reference to FIG. 5. FIG. 5 shows a cross-sectional view of a coil component according to another embodiment of the present invention cut along a cross section corresponding to the cross section of FIG. 3. As shown in FIG. 5, a coil component 100 according to another embodiment of the present invention includes, like the coil component 1, a laminate 10 containing a plurality of metal magnetic particles, a coil conductor 25 provided inside the laminate 10 and wound around a coil axis A, an external electrode 21 electrically connected to one end of the coil conductor 25, and an external electrode 22 electrically connected to the other end of the coil conductor 25. The coil component 100 differs from the coil component 1 in that the insulating portion 30 of the laminate 10 is provided only in the inter-conductor pattern regions between the conductor patterns C11 to C16 adjacent to each other in the direction of the coil axis A. The inter-conductor pattern regions extend throughout the entire laminate 10 in planar directions along the L-axis direction and the W-axis direction.

[0047] Next, another embodiment of the present invention will be described with reference to FIG. 6. FIG. 6 shows a cross-sectional view of a coil component according to another embodiment of the present invention cut along a cross section corresponding to the cross section of FIG. 3. As shown in FIG. 6, a coil component 200 according to another embodiment of the present invention includes, like the coil component 1, a laminate 10 containing a plurality of metal magnetic particles, a coil conductor 25 provided inside the laminate 10 and wound around a coil axis A, an external electrode 21 electrically connected to one end of the coil conductor 25, and an external electrode 22 electrically connected to the other end of the coil conductor 25. In the coil component 200, an insulating portion 30 is provided in a region between the conductor pattern C11 and the upper surface 10e of the laminate 10 and in a region between the conductor pattern C16 and the lower surface 10f of the laminate 10 in the direction of the coil axis A. That is, in the coil part 200, the upper cover layer 18 (magnetic layers 18a to 18d) and the lower cover layer 19 (magnetic layers 19a to 19d) correspond to the insulating portion 30.

[0048] Next, another embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 shows a cross-sectional view of a coil component according to another embodiment of the present invention cut along a cross section corresponding to the cross section of FIG. 3. As shown in FIG. 7, a coil component 300 according to another embodiment of the present invention includes, like the coil component 1, a laminate 10 containing a plurality of metal magnetic particles, a coil conductor 25 provided inside the laminate 10 and wound around a coil axis A, an external electrode 21 electrically connected to one end of the coil conductor 25, and an external electrode 22 electrically connected to the other end of the coil conductor 25. In the coil component 300, the external electrodes 21 and 22 are provided only on the lower surface 10f of the laminate 10. The coil conductor 25 further includes a lead conductor 25A electrically connecting one end of the coil conductor 25 to the external electrode 21, and a lead conductor 25B electrically connecting the other end of the coil conductor 25 to the external electrode 22. More specifically, the lead conductor 25A is led out from the conductor pattern C11 along the direction of the coil axis A and connected to the external electrode 21. The lead conductor 25B is led out from the conductor pattern C16 along the direction of the coil axis A and connected to the external electrode 22. The insulating portion 30 of the coil component 300 is formed so as to cover the entire coil conductor 25 (i.e., the conductor patterns C11 to C16, the vias V1 to V5, and the lead conductors 25A and 25B). That is, in the coil component 300, the magnetic layers 11 to 16 included in the main body 20, the magnetic layer 18a included in the upper cover layer 18, and the magnetic layers 19a to 19d included in the lower cover layer 19 correspond to the insulating portion 30. As a result, the insulating portion 30 exists in a region where the conductor pattern C16 and the lead conductor 25A, which have the largest potential difference, face each other. The insulating portion 30 also exists in a region where the conductor patterns C12 to C15 and the vias V1 to V5 face the lead conductor 25A, where a potential difference exists but is smaller than the potential difference between the conductor pattern C16 and the lead conductor 25A.

[0049] Next, another embodiment of the present invention will be described with reference to FIG. 8. FIG. 8 shows a cross-sectional view of a coil component according to another embodiment of the present invention cut along a cross section corresponding to the cross section of FIG. 3. As shown in FIG. 8, a coil component 400 according to another embodiment of the present invention includes, similarly to the coil component 300, a laminate 10 including a plurality of metal magnetic particles, a coil conductor 25 provided inside the laminate 10 and wound around a coil axis A, an external electrode 21 electrically connected to one end of the coil conductor 25, and an external electrode 22 electrically connected to the other end of the coil conductor 25. Similarly to the coil component 300, the external electrodes 21 and 22 of the coil component 400 are provided only on the lower surface 10f of the laminate 10, and the coil conductor 25 further includes a lead conductor 25A electrically connecting one end of the coil conductor 25 to the external electrode 21 and a lead conductor 25B electrically connecting the other end of the coil conductor 25 to the external electrode 22. More specifically, the lead conductor 25A is led out from the conductor pattern C11 along the coil axis A and connected to the external electrode 21. The lead conductor 25B is led out from the conductor pattern C16 along the coil axis A and connected to the external electrode 22. In the coil component 400, an insulating section 30 is provided in a region between the pattern C16 and the lower surface 10f of the laminate 10 in the coil axis A direction. That is, in the coil part 400, the lower cover layer 19 (magnetic layers 19a to 19d) corresponds to the insulating section 30. As a result, the insulating section 30 exists between the conductor pattern C16 and the external electrode 21, which have a large potential difference.

[0050] Next, another embodiment of the present invention will be described with reference to Fig. 9 and Fig. 10. Fig. 9 shows a perspective view of a coil component according to another embodiment of the present invention. As shown in Fig. 9, a coil component 500 according to another embodiment of the present invention includes a laminate 10, similar to the coil component 1. The coil component 500 also includes a coil conductor 125 provided inside the laminate 10, an external electrode 21 electrically connected to one end of the coil conductor 25, and an external electrode 22 electrically connected to the other end of the coil conductor 25.

[0051] The coil conductor 125 is disposed in the laminate 10 so as to be surrounded by the insulating portion 30. The coil conductor 125 is provided in the laminate 10 so as to be in contact with the insulating portion 30. One end of the coil conductor 125 is exposed from the first end face 10c toward the outside of the magnetic base 10, and is connected to the external electrode 21 at this end. The other end of the coil conductor 125 is exposed from the second end face 10d toward the outside of the magnetic base 10, and is connected to the external electrode 22 at this other end. In this manner, one end of the coil conductor 125 is connected to the external electrode 21, and the other end is connected to the external electrode 22.

[0052] The coil conductor 125 extends linearly from the external electrode 21 to the second external electrode 22 in a plan view (from the viewpoint of the T-axis). That is, the coil conductor 125 does not have any parts that are arranged opposite to each other in the laminate 10 in a plan view. In this specification, when the coil conductor 125 does not have any parts that are opposed to each other in a plan view in the laminate 10, the coil conductor 125 can be said to extend linearly from the external electrode 21 to the external electrode 22. In the illustrated embodiment, the coil conductor 125 has a rectangular parallelepiped shape. The coil conductor 125 may have only a single conductor pattern, or may have multiple conductor patterns that are electrically insulated from each other in the laminate 10. When the coil conductor 125 has multiple conductor patterns, the conductor patterns have the same shape, and adjacent conductor patterns are separated by a part of the insulating portion 30 of the laminate 10.

[0053] In the embodiment shown in FIG. 9 and FIG. 10, the insulating part 30 is also configured as shown in FIG. 4. That is, the insulating part 30 includes a metal magnetic particle region R1 composed of a plurality of metal magnetic particles 31, and a nonmetallic magnetic particle region R2 defined by at least three metal magnetic particles 31 in a cross section of the laminate 10 along an arbitrary direction. In the nonmetallic magnetic particle region R2, the proportion of Si is the highest among the materials other than oxygen constituting the nonmetallic magnetic particle region R2. The proportion of Si in the nonmetallic magnetic particle region R2 is based on the geometric center C of the nonmetallic magnetic particle region R2 in a cross section cut by a plane passing through the coil conductor 125 (for example, a plane passing through the coil conductor 125 and parallel to the LT plane). That is, in the geometric center C of the nonmetallic magnetic particle region R2 in a cross section cut by a plane passing through the coil conductor 125, the atomic proportion of Si is the highest among the materials other than oxygen.

[0054] The shape of the coil conductor 125 is not limited to that shown in the figure. The coil conductor 125 may be configured such that both ends are exposed from the mounting surface 10b of the laminate 10, as shown in FIG. 11. The coil conductor 125 shown in FIG. 11 has a first portion 125a1, one end of which is exposed from the mounting surface 10b and extends from the one end in the positive direction of the T axis and the positive direction of the L axis, a second portion 125a2, one end of which is exposed from the mounting surface 10b and extends from the one end in the positive direction of the T axis and the negative direction of the L axis, and a third portion 125a3 connecting the upper end of the first portion 125a1 and the upper end of the second portion 125a2. The lower end of the first portion 25a1 is connected to the external electrode 21, and the lower end of the second portion 25a2 is connected to the external electrode 22. In the illustrated embodiment, the third portion 25a3 extends parallel to the upper surface 10a.

[0055] In one or more embodiments of the present invention, the laminate 10 of the coil component has an insulating part 30 including a non-metallic magnetic particle region R2 defined by at least three metal magnetic particles 31, and the atomic ratio of Si is the highest among the materials other than oxygen that constitute the non-metallic magnetic particle region R2. In a conventional coil component, the resin contained in the metal magnetic paste is thermally decomposed into carbon dioxide or the like by a heat treatment in the manufacturing process, so that voids are formed in the region defined by the multiple metal magnetic particles (i.e., the region corresponding to the non-metallic magnetic particle region R2). When such voids are formed, the metal magnetic particles are more likely to come into contact with oxygen, and Fe, Si, Cr, and the like contained in the metal magnetic particles are more likely to be oxidized. As a result, ionized substances contained in the metal material of the coil conductor are more likely to receive electrons, which may cause migration of metal atoms in the coil conductor. In contrast, in the coil component 1 according to one embodiment of the present invention, as described above, Si oxide is present in the non-metallic magnetic particle region R2. This is because silicon resin is used as the resin contained in the metal magnetic paste, and when the silicon resin is thermally decomposed by heat treatment, the Si contained in the silicon resin remains even after the thermal decomposition, and the remaining Si is oxidized to become Si oxide. The presence of Si oxide in the non-metallic magnetic particle region R2 makes it difficult for voids to be formed by heat treatment, so oxidation of Fe, Si, Cr, etc. contained in the metal magnetic particles is suppressed. Therefore, it is possible to suppress migration of metal atoms in the coil conductor 25 due to heat treatment.

[0056] In one or more embodiments of the present invention, migration of metal atoms in the coil conductor 25 may occur when metal atoms move through the non-metallic magnetic particle region R2 as a result of application of a voltage to the coil conductor 25. In the insulating portion 30 of the coil component 1 according to one embodiment of the present invention, the formation of voids in the non-metallic magnetic particle region R2 is suppressed, and therefore migration of metal atoms in the coil conductor 25 due to application of a voltage can be suppressed even after the coil component 1 is mounted on a substrate or the like.

[0057] In one or more embodiments of the present invention, the coil conductor 25 is provided inside the insulating part 30. With this configuration, it is possible to suppress migration of the metal material of the coil conductor 25 between the conductor patterns C11 to C16 of the coil conductor 25 and between the coil conductor 25 and the external electrodes 21, 22. Therefore, it is possible to more reliably suppress the occurrence of short circuit defects inside the coil component 1.

[0058] In one or more embodiments of the present invention, the insulating portion 30 is formed by heat-treating a metal magnetic paste containing metal magnetic particles 31 and silicon resin. Since silicon resin is more easily supplied to the gaps between the metal magnetic particles 31 than particulate Si oxide, the filling rate of the Si oxide in the non-metal magnetic particle region R2 can be increased. Therefore, it is possible to more effectively suppress migration of metal atoms of the coil conductor 25 due to heat treatment.

[0059] In one or more embodiments of the present invention, the coil conductor 25 may include conductor patterns C11-C16 extending along a plane direction perpendicular to the coil axis A and spaced apart from one another in the direction of the coil axis A, and the insulating portion 30 may be provided between adjacent conductor patterns C11-C16. With this configuration, migration of the metal material of the coil conductor 25 between adjacent conductor patterns C11-C16 can be suppressed.

[0060] In one or more embodiments of the present invention, the coil component may further include external electrodes 21, 22 provided on the surface of the laminate 10 and electrically connected to the coil conductor 25, and the insulating portion 30 may be provided between the coil conductor 25 and the external electrodes 21, 22. With this configuration, migration of the metal material of the coil conductor 25 between the coil conductor 25 and the external electrodes 21, 22 can be suppressed.

[0061] In one or more embodiments of the present invention, the metal magnetic particles 31 may contain Al. With this configuration, the coating layer 32 of the metal magnetic particles 31 is likely to become thick, and the gaps in the non-metallic magnetic particle regions R2 defined by the metal magnetic particles 31 become smaller. Therefore, the path along which the metal elements constituting the coil conductor 25 are ionized and move becomes narrower, and migration of the metal elements is likely to be suppressed.

[0062] In one or more embodiments of the present invention, metal magnetic particles 31 may contain Cr. Cr suppresses oxidation of Fe contained in metal magnetic particles 31, and therefore can suppress ionization of metal elements in coil conductor 25 that accompanies oxidation of Fe. Therefore, migration of the metal material of coil conductor 25 can be suppressed.

[0063] 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 can be included in the scope of the present invention. Also, components not explicitly described in this specification can be added to each of the above-mentioned embodiments, and some of the components described in each embodiment can be omitted.

[0064] For example, in the above embodiments, various examples were shown regarding the position at which the insulating portion 30 is provided, but it is sufficient that the insulating portion 30 is provided in at least a portion of the laminate 10, and the position at which the insulating portion 30 is provided is not limited to the above embodiments. [Explanation of symbols]

[0065] 1, 100, 200, 300, 400, 500... coil component, 10... laminate (base), 21, 22... external electrode, 25, 125... coil conductor, 30... insulating portion, 31... metal magnetic particle, 32... coating layer, A... coil shaft, C11 to C16... conductor pattern, R1... metal magnetic particle region, R2... non-metal magnetic particle region.

Claims

1. A substrate including a plurality of metal magnetic particles; a coil conductor provided within the base so as to be in contact with the base and wound around a coil axis; the substrate has an insulating portion including a non-metallic magnetic particle region defined by at least three of the metallic magnetic particles in a cross section of the substrate; In the insulating portion, the atomic ratio of Si is the highest among materials other than oxygen constituting the non-metallic magnetic particle region, The surface of each of the metal magnetic particles is coated with a coating layer containing Si, the coating layer is an oxide coating containing an oxide of an element contained in the metal magnetic particles, the metal magnetic particles are bonded to each other by the coating layer, A coil component, wherein the material composition of the coating layer is different from the material composition of the non-metallic magnetic particle region at the geometric center of the non-metallic magnetic particle region in a cross section taken along the coil axis.

2. The coil component according to claim 1 , wherein at the geometric center, an atomic ratio of Si is the highest among materials other than oxygen constituting the non-metallic magnetic grain region.

3. A substrate including a plurality of metal magnetic particles; a coil conductor provided within the base so as to be in contact with the base, the substrate has an insulating portion including a non-metallic magnetic particle region defined by at least three of the metallic magnetic particles in a cross section of the substrate; In the insulating portion, the atomic ratio of Si is the highest among materials other than oxygen constituting the non-metallic magnetic particle region, The surface of each of the metal magnetic particles is coated with a coating layer containing Si, the coating layer is an oxide coating containing an oxide of an element contained in the metal magnetic particle, the metal magnetic particles are bonded to each other by the coating layer, A coil component, wherein the material composition of the coating layer is different from the material composition of the non-metallic magnetic particle region at the geometric center of the non-metallic magnetic particle region in a cross section of the base cut along a plane passing through the coil conductor.

4. The coil component according to claim 3 , wherein at the geometric center, an atomic ratio of Si is the highest among materials other than oxygen constituting the non-metallic magnetic grain region.

5. The coil component according to any one of claims 1 to 4, wherein an atomic ratio of Si in the non-metallic magnetic particle region is 50 at % or more and 95 at % or less.

6. The coil component according to claim 1 , wherein the non-metallic magnetic particle region contains Fe, Cr, and / or Al.

7. The coil component according to claim 6 , wherein the metal magnetic particles are an alloy containing Fe, Si, Cr, or Al.

8. The coil component according to claim 1 , wherein the non-metallic magnetic particle region contains at least one of Al and Mn.

9. The coil component according to any one of claims 1 to 8, wherein the metal magnetic particles contain at least one of Al and Mn.

10. the coil conductor includes a first conductor pattern and a second conductor pattern extending along a plane direction perpendicular to the coil axis and spaced apart from each other in the direction of the coil axis, The coil component according to claim 1 , wherein the insulating portion of the base is disposed between the first conductor pattern and the second conductor pattern.

11. an external electrode provided on a surface of the base and electrically connected to the coil conductor; The coil component according to claim 1 , wherein the insulating portion is provided between the coil conductor and the external electrode.

12. The coil component according to claim 1 , wherein the coil conductor is provided inside the insulating portion.

13. The coil component according to any one of claims 1 to 12, wherein the entire base body is the insulating portion.

14. A circuit board comprising the coil component according to any one of claims 1 to 13.

15. An electronic component comprising the circuit board according to claim 14.

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