Coil component

Abstract

A coil component 1 has an element body 10A internally provided with a coil 30, and external electrodes 21, 22 provided on the surface of the element body 10A. The external electrodes 21, 22 have a base electrode layer 25 and a plating layer 26. The base electrode layer 25 contains Ag as a main component and CuO and SiO2 as secondary components, the CuO and SiO2 both being present in the base electrode layer 25.

Description

Coil components

[0001] This invention relates to a coil component.

[0002] Patent Document 1 describes a common-mode noise filter comprising a plurality of rectangular insulating layers, first and second coils formed on the insulating layers, a rectangular parallelepiped-shaped laminate having the insulating layers and the first and second coils, and first to fourth external electrodes formed on the outside of the laminate.

[0003] Japanese Patent Publication No. 2019-36698

[0004] However, in the common-mode noise filter described in Patent Document 1, the adhesion strength between the laminate and the external electrode is insufficient. For example, due to thermal shock during mounting, there is a risk of reflow delamination, where the external electrode separates from the laminate (base material).

[0005] The present invention was made to solve the above problems and aims to provide a coil component that can improve the adhesion strength between the base body and the external electrode.

[0006] The coil component of the present invention comprises a base body with a coil provided inside, and an external electrode provided on the surface of the base body, wherein the external electrode has a base electrode layer and a plating layer, and the base electrode layer mainly contains Ag, as well as CuO and SiO ２ It contains as a minor component, and in the above-mentioned base electrode layer, CuO and SiO ２ They coexist.

[0007] According to the present invention, it is possible to provide a coil component that can improve the adhesion strength between the base body and the external electrode.

[0008] Figure 1 is a schematic perspective view showing an example of a coil component of Embodiment 1. Figure 2 is a schematic exploded perspective view showing an example of a laminate constituting the coil component shown in Figure 1. Figure 3 is a schematic side view showing an example of the internal structure of a laminate constituting the coil component shown in Figure 1, viewed through perspective. Figure 4 is a schematic cross-sectional view showing an example of a cross-section along line segment A-A of the coil component shown in Figure 1. Figure 5 is a schematic perspective view showing an example of a coil component of Embodiment 2. Figure 6 is a schematic cross-sectional view showing an example of a cross-section along line segment A1-A2 of the coil component shown in Figure 5. Figure 7 is a schematic cross-sectional view showing an example of a cross-section along line segment B1-B2 of the coil component shown in Figure 5. Figure 8 is a schematic cross-sectional view showing an example of a cross-section along line segment C1-C2 of the coil component shown in Figure 5. Figure 9 is a schematic perspective view showing an example of a disassembled state of the coil component (excluding the external electrodes) shown in Figure 5. Figure 10 is a schematic perspective view showing an example of a coil component of Embodiment 3. Figure 11 is a schematic cross-sectional view showing an example of a cross-section along the line segment A3-A4 of the coil component shown in Figure 10. Figure 12 is a mapping photograph (upper panel, Cu element detection result) obtained by surface analysis by WDX on the coil component of Example 1, and a graph (lower panel) showing the amount of Ag and Cu elements detected in the x direction on the coil component of Example 1. Figure 13 is a mapping photograph obtained by surface analysis by WDX on the coil component of Example 1, showing the Ag element detection result. Figure 14 is a mapping photograph obtained by surface analysis by WDX on the coil component of Example 1, showing the Si element detection result. Figure 15 is a graph showing the change in the amount of Ag element detected on the coil component of Example 1. Figure 16 is a graph (upper panel) showing the amount of Ag and Cu elements detected in the x direction on the coil component of Example 1, and a graph (lower panel) showing the change in the amount of Ag element detected on the coil component of Example 1. Figure 17 is a graph showing the relationship between the diffusion distance of Cu and the adhesive strength (tensile test strength) obtained by the tensile test. Figure 18 is a schematic diagram illustrating the method of the adhesion strength test, showing the coil component viewed from the second main surface (top surface) side. Figure 19 is a schematic diagram illustrating the method of the adhesion strength test, showing the coil component viewed from one end face side.

[0009] The coil components of the present invention will now be described. However, the present invention is not limited to the configuration described below, and may be modified as appropriate without departing from the spirit of the invention. Furthermore, a combination of several of the preferred configurations described below also constitutes the present invention.

[0010] The following diagrams are schematic representations, and their dimensions, aspect ratios, and scales may differ from those of the actual product. The same reference numerals are used for identical or equivalent parts in the diagrams. Furthermore, identical elements are denoted by the same reference numerals in each diagram, and redundant explanations are omitted.

[0011] In this specification, terms describing relationships between elements (e.g., "parallel," "orthogonal," etc.) and terms describing the shapes of elements mean not only their literal, exact forms, but also a range that is substantially equivalent, for example, a range that includes differences of a few percent.

[0012] The embodiments described below are illustrative, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. In the second and subsequent embodiments, descriptions of matters common to the first embodiment will be omitted, and only the differences will be explained. In particular, similar effects and advantages due to similar configurations will not be mentioned sequentially for each embodiment.

[0013] (Embodiment 1) Figure 1 is a schematic perspective view showing an example of a coil component of Embodiment 1.

[0014] The coil component 1 shown in Figure 1 is a laminated coil component, comprising a laminated body 10A as the base body, and a first external electrode 21 and a second external electrode 22 provided on the outer surface of the laminated body 10. The laminated body 10 has a rectangular parallelepiped shape with six faces. The structure of the laminated body 10 will be described later, but it consists of multiple insulating layers stacked in the stacking direction, with a coil provided inside. The coil is formed by stacking multiple coil conductors in the stacking direction. The first external electrode 21 and the second external electrode 22 are each electrically connected to the coil.

[0015] In this specification, "base body" refers to the insulating portion of a coil component excluding conductive parts such as external electrodes and coils (which may include fillers), and "base body" forms the outer shape of the portion of the coil component excluding the external electrodes.

[0016] In this specification, the coil components and base bodies are defined as the L direction, T direction, and W direction, respectively, as shown in Figure 1, etc. Here, the length direction L, the height direction T, and the width direction W are orthogonal to each other. Here, the length direction L is parallel to the stacking direction.

[0017] As shown in Figure 1, the laminate 10 (base body 10A) has a first end face 11 and a second end face 12 facing the length direction L, a first main face 13 and a second main face 14 facing the height direction T which is perpendicular to the length direction L, and a first side face 15 and a second side face 16 facing the width direction W which is perpendicular to the length direction L and the height direction T.

[0018] Although not shown in Figure 1, it is preferable that the laminate 10 has rounded corners and edges. Corners are the parts where three faces of the laminate intersect, and edges are the parts where two faces of the laminate intersect.

[0019] The first external electrode 21, for example as shown in Figure 1, covers the entire first end face 11 of the laminate 10 and extends from the first end face 11 to cover a part of the first main surface 13, a part of the second main surface 14, a part of the first side surface 15, and a part of the second side surface 16.

[0020] As shown in Figure 1, for example, the second external electrode 22 covers the entire second end face 12 of the laminate 10 and extends from the second end face 12 to cover a part of the first main surface 13, a part of the second main surface 14, a part of the first side surface 15, and a part of the second side surface 16.

[0021] When mounting the coil component 1, on which the first external electrode 21 and the second external electrode 22 are arranged as described above, onto a substrate, any of the first main surface 13, second main surface 14, first side surface 15, and second side surface 16 of the laminate 10 becomes the mounting surface.

[0022] However, the first external electrode 21 only needs to extend from at least a portion of the first end face 11 of the laminate 10 across the mounting surface of the laminate 10.

[0023] Similarly, the second external electrode 22 may extend from at least a portion of the second end face 12 of the laminate 10 across the mounting surface of the laminate 10.

[0024] The size of the coil component of the present invention is not particularly limited, but examples include 1608 size, 0603 size, 0402 size, or 1005 size.

[0025] Figure 2 is a schematic exploded perspective view showing an example of a laminate that constitutes the coil component shown in Figure 1.

[0026] As shown in Figure 2, the laminate 10 is constructed by stacking a plurality of insulating layers 31a, 31b, 31c, 31d, 31e, and 31f in the stacking direction (here, the length direction L) from the first end face 11 side to the second end face 12 side of the laminate 10. Hereafter, the insulating layers 31a, 31b, 31c, 31d, 31e, and 31f will be collectively referred to as insulating layer 31.

[0027] In this specification, the direction in which the multiple insulating layers constituting the laminate are stacked is referred to as the lamination direction.

[0028] In Figure 2, the insulating layer 31e is positioned on the lower side in the stacking direction (towards the first end face 11 of the laminate 10), and the insulating layer 31f is positioned on the upper side in the stacking direction (towards the second end face 12 of the laminate 10).

[0029] For example, the constituent material of each insulating layer 31 is SiO ２ Examples include non-magnetic materials such as glass ceramic materials (also called dielectric glass materials) whose main component is SiO, and magnetic materials such as ferrite materials. Thus, each insulating layer 31 is composed of SiO ２ It may also contain glass, ferrite, or both, with the main component being glass.

[0030] Thus, the base material 10A includes a non-magnetic phase, and at least a portion of the non-magnetic phase may contain Si. In this case, the base material 10A may further include a magnetic phase, or it may consist only of the non-magnetic phase. In the former case, the magnetic phase of the base material 10A preferably contains ferrite containing Cu. In the latter case, the base material 10A consists only of a non-magnetic phase, and at least a portion of the non-magnetic phase contains Si. In the latter case, the base material 10A does not contain a magnetic phase. By including a non-magnetic phase in the base material 10A, and at least a portion of the non-magnetic phase containing Si, magnetic saturation can be suppressed. When the base material 10A consists only of the non-magnetic phase, the entire non-magnetic phase of the base material 10A may contain Si, or the base material 10A may contain a non-magnetic phase containing Si and a non-magnetic phase that does not contain Si (for example, a non-magnetic phase containing Al).

[0031] More specifically, the base body 10A is SiO ２ The material may also include a ferrite glass composite material that contains both glass with SiO as its main component and ferrite containing Cu. In this case, the base material 10A is SiO ２ The resulting structure will consist of a non-magnetic phase containing glass with a main component of [unspecified material] and a magnetic phase containing ferrite containing Cu.

[0032] Furthermore, the element 10A may consist only of a magnetic phase, and this magnetic phase may include ferrite containing Cu. In this case, the element 10A will substantially not contain a non-magnetic phase. Magnetism can be ensured by including a magnetic phase in the element 10A.

[0033] However, in the coil component of the present invention, the statement that "the base body is composed solely of a magnetic phase" does not exclude the case in which non-magnetic materials inevitably get mixed into the base body during manufacturing, and minute portions of the non-magnetic phase caused by non-magnetic materials inevitably get mixed into the base body may be formed.

[0034] Each insulating layer 31 is made of SiO ２ The glass layer may contain glass with SiO as its main component, but may not contain ferrite. In addition, each insulating layer 31 may contain ferrite, while also containing SiO ２It may be a ferrite layer that does not contain glass having as a main component. Further, each insulating layer 31 may be a ferrite glass composite layer containing both glass having as a main component and ferrite. Thus, by forming the insulating layer from a composite material of glass (non-magnetic material) and ferrite (magnetic material), the glass contained in each base electrode layer of the first external electrode 21 and the second external electrode 22 becomes more likely to diffuse into the element body 10A. The ferrite glass composite layer includes a magnetic phase containing ferrite and a non-magnetic phase containing at least Si. ２ It may be a ferrite glass composite layer containing both glass having as a main component and ferrite. Thus, by forming the insulating layer from a composite material of glass (non-magnetic material) and ferrite (magnetic material), the glass contained in each base electrode layer of the first external electrode 21 and the second external electrode 22 becomes more likely to diffuse into the element body 10A. The ferrite glass composite layer includes a magnetic phase containing ferrite and a non-magnetic phase containing at least Si.

[0035] Note that the laminate 10 may include at least two types of layers among the above glass layer, ferrite glass composite layer, and ferrite layer.

[0036] As the glass having as a main component SiO contained in the glass layer or the ferrite glass composite layer, borosilicate glass is preferable. The borosilicate glass preferably contains 70% by weight or more and 85% by weight or less of Si in terms of SiO, 10% by weight or more and 25% by weight or less of B in terms of B O, 0.5% by weight or more and 5% by weight or less of alkali metal A in terms of A O, and 0% by weight or more and 5% by weight or less of Al in terms of Al O. Examples of the alkali metal A include K and Na. ２ As the glass having as a main component SiO contained in the glass layer or the ferrite glass composite layer, borosilicate glass is preferable. The borosilicate glass preferably contains 70% by weight or more and 85% by weight or less of Si in terms of SiO, 10% by weight or more and 25% by weight or less of B in terms of B O, 0.5% by weight or more and 5% by weight or less of alkali metal A in terms of A O, and 0% by weight or more and 5% by weight or less of Al in terms of Al O. Examples of the alkali metal A include K and Na. ２ It is preferably contained in a ratio of 70% by weight or more and 85% by weight or less of Si in terms of SiO, 10% by weight or more and 25% by weight or less of B in terms of B O, 0.5% by weight or more and 5% by weight or less of alkali metal A in terms of A O, and 0% by weight or more and 5% by weight or less of Al in terms of Al O. Examples of the alkali metal A include K and Na. ２ O ３ It is preferably contained in a ratio of 70% by weight or more and 85% by weight or less of Si in terms of SiO, 10% by weight or more and 25% by weight or less of B in terms of B O, 0.5% by weight or more and 5% by weight or less of alkali metal A in terms of A O, and 0% by weight or more and 5% by weight or less of Al in terms of Al O. Examples of the alkali metal A include K and Na. ２ O to 0.5% by weight or more and 5% by weight or less of Al in terms of Al O. Examples of the alkali metal A include K and Na. ２ O ３ It is preferably contained in a ratio of 70% by weight or more and 85% by weight or less of Si in terms of SiO, 10% by weight or more and 25% by weight or less of B in terms of B O, 0.5% by weight or more and 5% by weight or less of alkali metal A in terms of A O, and 0% by weight or more and 5% by weight or less of Al in terms of Al O. Examples of the alkali metal A include K and Na.

[0037] The ferrite contained in the ferrite glass composite layer contains Cu as a main component. In addition, as main components, it may contain at least Fe, Ni, and Zn. The ferrite contained in the ferrite glass composite layer may further contain Co, Bi, Sn, Mn, etc.

[0038] The ferrite contained in the ferrite glass composite layer may be a Ni-Cu-Zn-based ferrite material. The Ni-Cu-Zn-based ferrite material may further contain additives such as Co, Bi, Sn, Mn, etc., and unavoidable impurities.

[0039] The ferrite contained in the ferrite glass composite layer is Fe ２ O ３ It is preferable that the mixture contains 40 mol% or more and 49.5 mol% or less of Fe (converted to ZnO), 2 mol% or more and 35 mol% or less of Zn (converted to ZnO), 6 mol% or more and 13 mol% or less of Cu (converted to CuO), and 10 mol% or more and 45 mol% or less of Ni (converted to NiO).

[0040] The ferrite constituting the ferrite layer contains Cu as its main component. It may also contain at least Fe, Ni, and Zn as other main components. Preferably, the ferrite constituting the ferrite layer is a Ni-Cu-Zn ferrite.

[0041] In the ferrite that constitutes the ferrite layer, the Fe content is Fe ２ O ３ Converted to this, it is preferably 40.0 mol% or more and 49.5 mol% or less (based on the total amount of main components, the same applies hereinafter), and more preferably 45.0 mol% or more and 49.5 mol% or less.

[0042] In the ferrite constituting the ferrite layer, the Zn content is preferably 5.0 mol% or more and 35.0 mol% or less (based on the total amount of main components; the same applies hereinafter) when converted to ZnO, and more preferably 10.0 mol% or more and 30.0 mol% or less.

[0043] In the ferrite constituting the ferrite layer, the Cu content is preferably 4.0 mol% or more and 12.0 mol% or less (based on the total amount of main components; the same applies hereinafter), and more preferably 7.0 mol% or more and 10.0 mol% or less, when converted to CuO.

[0044] In the ferrite constituting the ferrite layer, the Ni content is not particularly limited and can be the remainder of the other main components, Fe, Zn, and Cu, as described above. For example, the Ni content is preferably 8.0 mol% or more and 44.0 mol% or less when converted to NiO.

[0045] In the ferrite that constitutes the ferrite layer, Fe is Fe ２ O ３The amounts may be 40.0 mol% or more and 49.5 mol% or less when converted to ZnO, 5.0 mol% or more and 35.0 mol% or less when converted to CuO, 4.0 mol% or more and 13.0 mol% or less when converted to CuO, and 8.0 mol% or more and 44.0 mol% or less when converted to NiO.

[0046] The ferrite constituting the ferrite layer may further contain additive components. Examples of additive components in ferrite include, but are not limited to, Mn, Co, Sn, Bi, and Si. The content (amount added) of Mn, Co, Sn, Bi, and Si is determined by the ratio of the main component (Fe(Fe) ２ O ３ For a total of 100 parts by weight of Zn (ZnO equivalent), Cu (CuO equivalent), and Ni (NiO equivalent), Mn ３ O ４ Co ３ O ４ , SnO ２ , Bi ２ O ３ and SiO ２ Preferably, the amount is between 0.1 parts by weight and 1 part by weight. Furthermore, the ferrite constituting the ferrite layer may contain impurities that are unavoidable during manufacturing. Furthermore, the ferrite constituting the ferrite layer may contain non-magnetic materials that are unavoidable during manufacturing as described above.

[0047] Body 10A contains forsterite (2MgO・SiO₂) as a filler. ２ ), quartz (SiO ２ ), alumina (Al ２ O ３ ) may further contain the following. In this case, forsterite and quartz constitute a non-magnetic phase containing Si in the base material 10A, and alumina constitutes a non-magnetic phase containing Al but not Si in the base material 10A.

[0048] Insulating layers 31a, 31b, 31c, and 31d are provided with coil conductors 32a, 32b, 32c, and 32d, and via conductors 33a, 33b, 33c, and 33d, respectively. Insulating layer 31e is provided with a via conductor 33e and a land 35e. Insulating layer 31f is provided with a via conductor 33f and a land 35f. Insulating layer 31e may consist of one layer or two or more layers. Similarly, insulating layer 31f may consist of one layer or two or more layers. Hereinafter, coil conductors 32a, 32b, 32c, and 32d will be collectively referred to as coil conductor 32.

[0049] The coil conductors 32a, 32b, 32c, and 32d are provided on the main surfaces of the insulating layers 31a, 31b, 31c, and 31d, respectively, and are laminated together with the insulating layers 31a, 31b, 31c, 31d, 31e, and 31f. In Figure 2, each coil conductor 32 has a 3 / 4 turn shape, and the four insulating layers 31 arranged in the order of insulating layers 31a, 31b, 31c, and 31d are repeatedly laminated as one unit (3 turns).

[0050] Furthermore, the coil conductors 32a, 32b, 32c, and 32d each include annular circumferential portions 34a, 34b, 34c, and 34d, which are partially missing in one place and have a gap, and lands 35a, 35b, 35c, and 35d. Lands 35a, 35b, 35c, and 35d are provided at both ends of each circumferential portion 34a, 34b, 34c, and 34d, respectively. Hereinafter, the circumferential portions 34a, 34b, 34c, and 34d will be collectively referred to as circumferential portion 34.

[0051] The via conductors 33a, 33b, 33c, 33d, 33e, and 33f are provided so as to penetrate the insulating layers 31a, 31b, 31c, 31d, 31e, and 31f in the lamination direction, respectively. Hereinafter, the via conductors 33a, 33b, 33c, 33d, 33e, and 33f will be collectively referred to as via conductor 33.

[0052] Lands 35e and 35f are provided directly above via conductors 33e and 33f, respectively. It is preferable that the lands 35a, 35b, 35c, 35d, 35e, and 35f are slightly larger than the line width of the surrounding portions 34a, 34b, 34c, and 34d. Hereinafter, lands 35a, 35b, 35c, 35d, 35e, and 35f will be collectively referred to as land 35. Land 35 is larger than the adjacent via conductor 33, and when viewed from the stacking direction (length direction L), the via conductor 33 adjacent to land 35 is contained within the area of ​​land 35.

[0053] Examples of materials used to construct each coil conductor 32, including the circumferential portion 34 and the land 35, and each via conductor 33 include Ag, Au, Cu, Pd, Ni, Al, and alloys containing at least one of these metals.

[0054] The multiple insulating layers 31a, 31b, 31c, 31d, 31e, and 31f configured as described above are stacked in the stacking direction. This forms a laminate 10, and the multiple coil conductors 32a, 32b, 32c, and 32d are electrically connected via via conductors 33a, 33b, 33c, and 33d. As a result, a solenoid-shaped coil having a coil axis parallel to the stacking direction is formed within the laminate 10.

[0055] Furthermore, the via conductor 33e and the land 35e become a first lead conductor within the laminate 10 and are exposed on the first end face 11 of the laminate 10. That is, the first lead conductor includes the via conductor 33e and the land 35e. As will be described later, the first lead conductor connects the first external electrode 21 and the coil conductor 32a facing it within the laminate 10.

[0056] The via conductor 33f and land 35f become a second lead conductor within the laminate 10 and are exposed on the second end face 12 of the laminate 10. That is, the second lead conductor includes the via conductor 33f and land 35f. As will be described later, the second lead conductor connects the second external electrode 22 and the coil conductor 32c facing it within the laminate 10.

[0057] When viewed from the stacking direction (length direction L), it is preferable that the coil conductors 32 overlap each other. Also, when viewed from the stacking direction, the coil may have a shape composed of straight sections (for example, a polygonal shape such as a rectangle) as shown in Figure 2, a shape composed of curved sections (for example, a circular shape), or a shape composed of both straight and curved sections.

[0058] Figure 3 is a schematic side view showing an example of the internal structure of a laminate that constitutes the coil component shown in Figure 1, viewed through perspective.

[0059] As shown in Figure 3, in the coil component 1, multiple insulating layers 31 are stacked in the longitudinal direction L, so the longitudinal direction L is the stacking direction. Furthermore, the stacking direction of the laminate 10 and the coil axis A of the coil 30 are parallel to one of the mounting surfaces, the first main surface 13, the second main surface 14, the first side surface 15, or the second side surface 16, for example, the first main surface 13. In other words, the coil component 1 is a transversely wound laminated inductor in which the coil 30 is provided so that the coil axis A is parallel to the mounting surface.

[0060] As shown in Figure 3, in reality, no boundary is visible between adjacent insulating layers 31.

[0061] The first lead conductor 41 extends in the stacking direction within the laminate 10 and linearly connects the first external electrode 21 provided on the first end face 11 and the coil conductor 32a facing it. Similarly, the second lead conductor 42 extends in the stacking direction within the laminate 10 and linearly connects the second external electrode 22 provided on the second end face 12 and the coil conductor 32c facing it.

[0062] When viewed from the stacking direction (length direction L), it is preferable that the via conductors constituting the lead conductors overlap each other, but the via conductors constituting the lead conductors do not necessarily have to be aligned in a strictly straight line.

[0063] Furthermore, while Figures 2 and 3 illustrate the case where the number of layers of coil conductors 32 to constitute three turns of coil 30 is four, that is, the repeating shape is a 3 / 4 turn shape, the number of layers of coil conductors 32 to constitute one turn of coil 30 is not particularly limited. For example, the number of layers of coil conductors 32 to constitute one turn of coil 30 may be two, that is, the repeating shape may be a 1 / 2 turn shape.

[0064] Furthermore, the number of layers of coil conductors 32, that is, the total number of layers of coil conductors 32 included in the laminate 10, is not particularly limited as long as it is three or more layers, but it is preferably 10 or more and 60 or less.

[0065] Figure 4 is a schematic cross-sectional view showing an example of a cross-section along the line segment A-A of the coil component shown in Figure 1. Note that Figure 4 shows a cross-section of the circumferential portion 34 of the coil conductor 32.

[0066] As shown in Figure 4, when viewing a cross-section perpendicular to the direction in which the coil conductor 32 extends, the cross-sectional shape of the coil conductor 32 is flattened (longitudinal shape), and its longitudinal direction is perpendicular to the stacking direction (length direction L). In the example shown in Figure 4, the cross-sectional shape of the coil conductor 32 is an ellipse with its major axis perpendicular to the stacking direction, but the cross-sectional shape of the coil conductor 32 is not particularly limited, and may be a rectangle with a pair of sides of equal length opposite to the stacking direction, or a trapezoid with a pair of sides of different lengths opposite to the stacking direction, etc.

[0067] Furthermore, as shown in Figure 4, the first external electrode 21 and the second external electrode 22 each have a base electrode layer 25 and a plating layer 26. Each external electrode has the base electrode layer 25 and the plating layer 26 in order from the surface side of the laminate 10.

[0068] The base electrode layer 25 mainly contains Ag, as well as CuO and SiO ２ It contains as a minor component. And in the base electrode layer 25, CuO and SiO ２ They coexist. That is, in the base electrode layer 25, SiO ２CuO is dissolved in the glass, which is composed of the following components. By adding Cu to the glass in the base electrode layer 25 of the first external electrode 21 and the second external electrode 22 in this way, the softening point of the glass can be lowered. As a result, gaps are less likely to form between the base body 10A and the base electrode layer 25 when the base electrode layer 25 is baked, and the adhesion strength (adhesion force) between the base body 10A and each external electrode can be improved by the anchoring effect.

[0069] Furthermore, if the base material 10A includes a non-magnetic phase, and at least a portion of the non-magnetic phase includes Si, the glass softened in the base electrode layer 25 during baking of the base electrode layer 25 will more easily diffuse into the glass of the base material 10A. As a result, the adhesion strength between the first external electrode 21 and the second external electrode 22 and the base material 10A is further improved, and the occurrence of defects in which each external electrode peels off from the base material 10A can be effectively suppressed. For example, the occurrence of reflow peeling can be suppressed.

[0070] Furthermore, if the base body 10A contains a magnetic phase, and the magnetic phase contains ferrite containing Cu, the Cu in the ferrite contained in the base body 10A and the Cu contained in the base electrode layer 25 improve the compatibility between the materials, and the glass of the base electrode layer 25 diffuses more easily into the base body 10A during the baking of the base electrode layer 25. As a result, the adhesion strength between the first external electrode 21 and the second external electrode 22 and the base body 10A is further improved, and the occurrence of defects in which each external electrode peels off from the base body 10A can be effectively suppressed.

[0071] CuO and SiO in the present invention ２ The state in which CuO and SiO coexist is that CuO and SiO are present in a portion of the underlying electrode layer 25. ２ They may be mixed together, and within a portion of the base electrode layer 25, CuO and SiO ２ They may exist separately. Note that CuO and SiO ２ In the region where they coexist, CuO and SiO ２ Other substances may or may not be present. If the region where the Cu component is present and the region where the Si component is present overlap or are close together within the same region in elemental mapping by wavelength-dispersive X-ray analysis (WDX) described later, then "CuO and SiO ２It can be said that they coexist.

[0072] The distance over which Cu from the external electrode (underlay electrode layer 25) diffuses from the interface between each external electrode and the base body 10A to the base body 10A (hereinafter sometimes simply referred to as the Cu diffusion distance) is preferably 9 μm or less. This makes it possible to achieve strength in tensile tests that is suitable for practical use. The Cu diffusion distance is more preferably 8.5 μm or less, and even more preferably 7 μm or less.

[0073] The lower limit of the diffusion distance of Cu is not particularly limited, but it may be, for example, 1 μm or more.

[0074] Examples of the plating layer 26 include a Ni plating layer, an Sn plating layer, and the like.

[0075] The coil component 1 is manufactured, for example, by the following method.

[0076] <Ferrite material manufacturing process> When the insulating layer is a ferrite glass composite layer or a ferrite layer, Fe ２ O ３ ZnO, CuO, and NiO are weighed in predetermined ratios. Each oxide may contain unavoidable impurities. Next, these weighed materials are mixed wet and then ground to prepare a slurry. At this time, Mn ３ O ４ , Bi ２ O ３ Co ３ O ４ SiO ２ , SnO ２ Additives such as the above may be added. After drying the obtained slurry, it is calcined. The calcination temperature should be, for example, 700°C or higher and 800°C or lower. The calcination time should be, for example, 2 hours or more and 5 hours or less. In this way, powdered ferrite material is produced as a magnetic material. The additives will integrate with other oxides during calcination and form a magnetic phase.

[0077] Ferrite materials include, for example, those containing 40 mol% or more and 49.5 mol% or less of Fe ２ O ３It may also contain ZnO in an amount of 2 mol% or more and 35 mol% or less, CuO in an amount of 6 mol% or more and 13 mol% or less, and NiO in an amount of 10 mol% or more and 45 mol% or less.

[0078] <Process for manufacturing glass ceramic material> When the insulating layer is to be a ferrite glass composite layer or a glass layer, the glass ceramic material powder is weighed. A glass powder containing alkali metals such as potassium, boron, silicon, and aluminum in predetermined proportions is prepared as a non-magnetic material as borosilicate glass. Forsterite powder is also prepared as a filler. Quartz powder may be further prepared as a filler. Alumina powder may also be prepared as a filler.

[0079] Borosilicate glass is made by saturating Si with SiO ２ Converted to 70% or more by weight, and 85% or less by weight, B to B ２ O ３ Converted to A, alkali metal A is present in an amount of 10% or more by weight and 25% or less by weight. ２ Converted to O, 0.5% by weight or more, and 5% by weight or less, Al to Al ２ O ３ It is preferable that it be included in a proportion of 0% or more and 5% or less by weight when converted to a certain amount.

[0080] The glass ceramic material preferably contains forsterite powder as a filler in an amount of 1.5% to 20% by volume.

[0081] <Conductive Paste Preparation Process> Ag powder is prepared, mixed with a predetermined amount of solvent (such as eugenol), resin (such as ethylcellulose), and dispersant in a planetary mixer, and then dispersed in a three-roll mill to produce a conductive paste for the internal conductor.

[0082] <Green Sheet Manufacturing Process> Weigh the glass ceramic material and / or ferrite material. If the insulating layer is to be a ferrite glass composite layer, weigh the ferrite material and glass ceramic material in a predetermined ratio. Next, mix these weighed materials with an organic binder such as polyvinyl butyral resin, an organic solvent such as ethanol or toluene, a plasticizer, etc., and then pulverize the mixture to produce a slurry. Then, form the obtained slurry into a sheet of a predetermined thickness using a doctor blade method or the like, and then punch out a predetermined shape, such as a rectangle, to produce a green sheet. The thickness of the green sheet is preferably 15 μm or more and 30 μm or less.

[0083] When the insulating layer is a glass layer, the green sheet is made using only glass ceramic material.

[0084] When using a ferrite layer as the insulating layer, the green sheet is manufactured using only ferrite material.

[0085] When the insulating layer is a ferrite glass composite layer, the volume ratio of the ferrite material to the total volume of the ferrite material and glass ceramic material is preferably 10% to 80%, more preferably 15% to 70%, and even more preferably 20% to 60%. If the volume ratio of the ferrite material to the total volume of the ferrite material and glass ceramic material is less than 10%, the strength of the laminate may be weakened. If the volume ratio of the ferrite material to the total volume of the ferrite material and glass ceramic material exceeds 80%, the ferrite material and glass ceramic material may become difficult to sinter.

[0086] <Conductor pattern formation process> First, via holes are formed by irradiating predetermined locations on the green sheet with a laser.

[0087] Next, conductive paste is applied to the surface of the green sheet by screen printing or the like, filling the via holes. This forms a conductor pattern for via conductors in the via holes of the green sheet, and a conductor pattern for coil conductors connected to the via conductor pattern is formed on the surface. In this way, a coil sheet is produced in which the conductor pattern for coil conductors and the conductor pattern for via conductors are formed on the green sheet. Multiple coil sheets are produced, and each coil sheet is formed with a conductor pattern for coil conductors corresponding to the coil conductors shown in Figure 2, and a conductor pattern for via conductors corresponding to the via conductors shown in Figure 2.

[0088] Furthermore, conductive paste is applied to the surface of the green sheet while filling the via holes using a screen printing method or the like. This creates via sheets, separate from the coil sheets, in which conductor patterns for via conductors and conductor patterns for lands are formed on the green sheet. Multiple via sheets are also produced, and each via sheet is formed with a conductor pattern for via conductors corresponding to the via conductors shown in Figure 2, and a conductor pattern for lands corresponding to the lands shown in Figure 2.

[0089] <Laminated Block Fabrication Process> After stacking coil sheets and via sheets in the stacking direction (length direction L) in the order corresponding to Figure 2, a laminated block is fabricated by heat-pressing them together.

[0090] <Laminate and coil manufacturing process> First, the laminate block is cut to a predetermined size using a dicer or similar tool to produce individual chips.

[0091] Next, the individual chips are fired. The firing temperature should be, for example, 900°C or higher and 920°C or lower. The firing time should be, for example, 2 hours or more and 4 hours or less.

[0092] By firing the individual chips, the green sheets of the coil sheet and via sheet become insulating layers. As a result, a laminate is produced in which multiple insulating layers are stacked in the stacking direction, in this case, the length direction. When the insulating layer is a ferrite glass composite layer, a magnetic phase composed of ferrite material and a non-magnetic phase composed of glass ceramic material are formed in the laminate.

[0093] Furthermore, by firing the individualized chips, the conductor patterns for coil conductors, via conductors, and lands become coil conductors, via conductors, and lands, respectively. As a result, a coil is fabricated in which multiple coil conductors, laminated together with an insulating layer, are electrically connected via via conductors.

[0094] As a result, a laminate is fabricated in which multiple insulating layers are stacked in the stacking direction, and a coil is embedded inside.

[0095] For the laminate, for example, the corners and edges may be rounded by barrel polishing.

[0096] <External electrode formation process> First, Ag powder, CuO powder, glass frit, and organic binder resin are prepared as electrode paste materials for the base electrode layer.

[0097] Next, CuO powder is added to the glass frit in an amount of 0.2 mol% to 20 mol%, heated to melt, and then cooled and pulverized to the desired size. The heating temperature is, for example, 500°C to 2000°C.

[0098] Next, the obtained pulverized material, Ag powder, and organic binder resin are mixed to form a paste, thereby preparing an electrode paste for the base electrode layer. By adding Cu to the electrode paste in this way, the softening point of the electrode paste can be lowered. For example, when Cu is added, the softening point of the electrode paste can be lowered to less than 700°C, making it possible to bake it at a baking temperature of 600°C to 800°C. On the other hand, when Cu is not added to the electrode paste, the softening point of the electrode paste exceeds, for example, 700°C, and it is necessary to bake it at around 800°C.

[0099] The mixing ratio of Ag powder, CuO powder-added glass frit, and organic binder resin in this electrode paste is not particularly limited, but it is preferable that the electrode paste contains 60% to 80% by weight of Ag powder, 5% to 20% by weight of CuO powder-added glass frit, and 10% to 20% by weight of organic binder resin, when the total amount is 100% by weight.

[0100] Next, the prepared electrode paste is applied to the first and second end faces of the laminate's outer surface, from which the coils are drawn out, and baked to form a base electrode layer for the external electrodes. The baking temperature is set to 600°C or higher and 800°C or lower. Since increasing the baking temperature increases the diffusion distance of Cu, it is possible to adjust the diffusion distance of Cu by adjusting the baking temperature. The thickness of the base electrode layer is set to, for example, 30 μm.

[0101] The baking temperature is preferably less than 720°C, and more preferably 710°C or lower. If the baking temperature is 720°C or higher, the diffusion distance of Cu becomes 8 μm or more, and the tensile test strength tends to decrease. From the viewpoint of further promoting glass diffusion during the baking of the base electrode layer and making the diffusion distance of Cu 4 μm or more, the baking temperature is preferably 640°C or higher.

[0102] Then, on the surface of the base electrode layer, plating layers, such as a Ni plating layer and a Sn plating layer, are sequentially formed by electroplating or the like. This forms an external electrode having the base electrode layer, Ni plating layer, and Sn plating layer in that order.

[0103] The coil component 1 is manufactured as described above.

[0104] (Embodiment 2) In the coil component of Embodiment 2 and the coil component of Embodiment 3 described later, the base material is SiO ２ It is a laminate in which glass layers containing glass as the main component and magnetic layers containing ferrite are alternately stacked.

[0105] Here, "glass layers and magnetic layers are stacked alternately" means that at least three layers of glass layers and magnetic layers are stacked alternately, and includes cases where at least three layers of magnetic layer / glass layer / magnetic layer are stacked, and cases where at least three layers of glass layer / magnetic layer / glass layer are stacked.

[0106] Figure 5 is a schematic perspective view showing an example of a coil component of Embodiment 2.

[0107] The coil component 101A shown in Figure 5 comprises a base body 110A, a first external electrode 121, a second external electrode 122, a third external electrode 123, and a fourth external electrode 124. Although not shown in Figure 5, as will be described later, the coil component 101A also includes a first coil and a second coil provided inside the base body 110A.

[0108] The coil component 101A is also called a common-mode choke coil, which is a type of noise filter for circuits.

[0109] The base body 110A has a first end face 111a and a second end face 111b facing in the length direction L, a first main face 112a and a second main face 112b facing in the height direction T, and a first side face 113a and a second side face 113b facing in the width direction W, and is, for example, rectangular parallelepiped or substantially rectangular parallelepiped.

[0110] The first end face 111a and the second end face 111b of the base body 110A do not need to be strictly perpendicular to the length direction L. Also, the first main face 112a and the second main face 112b of the base body 110A do not need to be strictly perpendicular to the height direction T. Furthermore, the first side surface 113a and the second side surface 113b of the base body 110A do not need to be strictly perpendicular to the width direction W.

[0111] When mounting the coil component 101A onto the circuit board, the first main surface 112a of the base body 110A becomes the mounting surface.

[0112] It is preferable that the base body 110A has rounded corners and edges. The corners of the base body 110A are the parts where the three faces of the base body 110A intersect. The edges of the base body 110A are the parts where the two faces of the base body 110A intersect.

[0113] The base body 110A has a first glass layer 115a as a non-magnetic layer, a first ferrite layer 116a as a magnetic layer, and a second ferrite layer 116b as a magnetic layer, arranged in a stacking direction. In the base body 110A, the stacking direction of the first glass layer 115a, etc., is parallel to the height direction T. In other words, in the base body 110A, the stacking direction of the first glass layer 115a, etc., is perpendicular to the first main surface 112a of the base body 110A, which is the mounting surface.

[0114] In the stacking direction (here, the height direction T), the first ferrite layer 116a is adjacent to one main surface side of the first glass layer 115a, and the second ferrite layer 116b is adjacent to the other main surface side of the first glass layer 115a. In other words, in the base body 110A, in the stacking direction (here, the height direction T), the first glass layer 115a is sandwiched between the first ferrite layer 116a and the second ferrite layer 116b.

[0115] Here, the stacking direction (here, the height direction) is defined as the vertical direction, with the first main surface of the base body shown as the lower side and the second main surface of the base body shown as the upper side. However, the configuration is not limited to these directions and can be appropriately changed depending on how the coil components are installed. For example, the base body 110A may be configured such that the first ferrite layer 116a is located on the lower side in the vertical direction and the second ferrite layer 116b is located on the upper side in the vertical direction, or the first ferrite layer 116a is located on the upper side in the vertical direction and the second ferrite layer 116b is located on the lower side in the vertical direction.

[0116] Although not shown in Figure 5, as will be described later, a first coil and a second coil are provided inside the first glass layer 115a.

[0117] The first glass layer 115a has a multilayer structure in which multiple insulating layers are stacked in the stacking direction (here, the height direction T), as will be described later.

[0118] The base material 110A includes a non-magnetic phase, and at least a portion of the non-magnetic phase contains Si. Furthermore, the base material 110A contains SiO ２ It includes.

[0119] Specifically, the first glass layer 115a contains Si, for example, SiO２ It is composed of a glass ceramic material (also called a dielectric glass material) with as its main component. The first glass layer 115a may consist only of a non-magnetic phase, in which case it is preferable that at least a part of the non-magnetic phase of the first glass layer 115a contains Si. As a result, the first glass layer 115a does not contain a magnetic phase. In this case, the entire non-magnetic phase of the first glass layer 115a may contain Si, or the first glass layer 115a may contain a non-magnetic phase containing Si and a non-magnetic phase that does not contain Si (for example, a non-magnetic phase containing Al).

[0120] The first glass layer 115a preferably contains a glass material containing K, B, and Si. In other words, the glass ceramic material constituting the first glass layer 115a preferably contains a glass material containing K, B, and Si.

[0121] The glass material contained in the first glass layer 115a, when the total amount is 100% by weight, has a ratio of K to K ２ In terms of O equivalent, 0.5% or more by weight and 5% or less by weight, B is B ２ O ３ Converted to 10% or more by weight and 25% or less by weight, Si to SiO ２ Converted to 70% or more by weight, and 85% or less by weight, Al to Al ２ O ３ Preferably, it contains 0% or more and 5% or less by weight.

[0122] The first glass layer 115a is made of quartz (SiO ２ ) and alumina (Al ２ O ３It is preferable that the glass ceramic material constituting the first glass layer 115a contains a filler containing at least one of quartz and alumina. In other words, it is preferable that the glass ceramic material constituting the first glass layer 115a contains a filler containing at least one of quartz and alumina. Including quartz as a filler in the glass ceramic material constituting the first glass layer 115a makes it easier to improve the high-frequency characteristics of the coil component 101A. Also, including alumina as a filler in the glass ceramic material constituting the first glass layer 115a makes it easier to improve the mechanical strength of the base body 110A. When the glass ceramic material constituting the first glass layer 115a contains quartz as a filler, the quartz constitutes a non-magnetic phase containing Si in the first glass layer 115a. When the glass ceramic material constituting the first glass layer 115a contains alumina as a filler, the alumina constitutes a non-magnetic phase containing Al without containing Si in the first glass layer 115a.

[0123] When the glass ceramic material constituting the first glass layer 115a contains quartz and alumina as fillers, it is preferable that the glass ceramic material, when the total amount is 100% by weight, contains 60% to 66% by weight of glass material, 34% to 37% by weight of quartz as a filler, and 0.5% to 4% by weight of alumina as a filler.

[0124] The first ferrite layer 116a and the second ferrite layer 116b each have a multilayer structure in which multiple insulating layers are stacked in the stacking direction (here, the height direction T), for example, as will be described later.

[0125] Furthermore, the base body 110A includes a magnetic phase, and this magnetic phase includes ferrite containing Cu.

[0126] More specifically, it is preferable that the first ferrite layer 116a and the second ferrite layer 116b are each composed of a Ni-Cu-Zn ferrite material. In this case, the inductance of the coil component 101A tends to be large. Thus, the first ferrite layer 116a and the second ferrite layer 116b are each composed of a magnetic phase containing at least ferrite. The first ferrite layer 116a and the second ferrite layer 116b may each be composed only of a magnetic phase, and the magnetic phase may contain ferrite containing Cu. In this case, the first ferrite layer 116a and the second ferrite layer 116b will each substantially not contain a non-magnetic phase. However, even in this case, as described above, the first ferrite layer 116a and the second ferrite layer 116b may each contain non-magnetic material that is unavoidable during manufacturing, and minute portions of non-magnetic phase caused by non-magnetic material that is unavoidable during manufacturing may be formed.

[0127] The Ni-Cu-Zn ferrite material constituting the first ferrite layer 116a and the second ferrite layer 116b each has a total amount of Fe at 100 mol%. ２ O ３ It is preferable that the mixture contains 40 mol% or more and 49.5 mol% or less in terms of conversion, Zn in terms of 5 mol% or more and 35 mol% or less in terms of ZnO conversion, Cu in terms of 6 mol% or more and 12 mol% or less in terms of CuO conversion, and Ni in terms of 8 mol% or more and 40 mol% or less in terms of NiO conversion.

[0128] The Ni-Cu-Zn ferrite material constituting the first ferrite layer 116a and the second ferrite layer 116b is, respectively, Mn ３ O ４ Co ３ O ４ , SnO ２ , Bi ２ O ３ SiO ２ The following additives may be further included.

[0129] The Ni-Cu-Zn ferrite materials constituting the first ferrite layer 116a and the second ferrite layer 116b may each further contain unavoidable impurities. Furthermore, the Ni-Cu-Zn ferrite materials constituting the first ferrite layer 116a and the second ferrite layer 116b may each contain non-magnetic materials that are unavoidable during manufacturing as described above.

[0130] The dimensions of the first glass layer 115a, the first ferrite layer 116a, and the second ferrite layer 116b in the height direction T may be the same, different, or partially different. If the dimensions of the first glass layer 115a, the first ferrite layer 116a, and the second ferrite layer 116b in the height direction T are different or partially different, their relative sizes are not particularly limited.

[0131] The glass layer and the ferrite layer are distinguished as follows. First, the coil component is sealed with resin as needed, and then the coil component is polished in a first direction (e.g., the width direction) perpendicular to the stacking direction (e.g., the height direction). This exposes the cross-sections along the stacking direction and the second direction (e.g., the length direction) perpendicular to the stacking direction, approximately in the center of the first direction. Next, the composition (the ratio of detected elements) is determined for the region in the exposed cross-section of the base material where it can be estimated that different layers exist (e.g., a region where different layers can be estimated to exist due to differences in color tone, etc.) using scanning transmission electron microscopy-energy dispersive X-ray analysis (STEM-EDX). Then, the glass layer and the ferrite layer are distinguished by determining whether the constituent material of each layer is a glass ceramic material or a ferrite material from the obtained composition.

[0132] The first external electrode 121 is provided on the surface of the base body 110A. In the example shown in Figure 5, the first external electrode 121 extends from a part of the first side surface 113a of the base body 110A to parts of the first main surface 112a and the second main surface 112b.

[0133] The second external electrode 122 is provided on the surface of the base body 110A. In the example shown in Figure 5, the second external electrode 122 extends from a part of the second side surface 113b of the base body 110A across parts of the first main surface 112a and the second main surface 112b. The second external electrode 122 is also provided at a position opposite to the first external electrode 121 in the width direction W.

[0134] The third external electrode 123 is provided on the surface of the base body 110A. In the example shown in Figure 5, the third external electrode 123 extends from a part of the first side surface 113a of the base body 110A to parts of the first main surface 112a and the second main surface 112b, at a position separated from the first external electrode 121 in the longitudinal direction L.

[0135] The fourth external electrode 124 is provided on the surface of the base body 110A. In the example shown in Figure 5, the fourth external electrode 124 is located at a position separated from the second external electrode 122 in the length direction L, and extends from a part of the second side surface 113b of the base body 110A to parts of each surface of the first main surface 112a and the second main surface 112b. The fourth external electrode 124 is also provided at a position opposite the third external electrode 123 in the width direction W.

[0136] As described above, the first external electrode 121, the second external electrode 122, the third external electrode 123, and the fourth external electrode 124 are provided on the surface of the base body 110A at positions spaced apart from each other.

[0137] As described above, if a portion of each of the first external electrode 121, the second external electrode 122, the third external electrode 123, and the fourth external electrode 124 is provided on the first main surface 112a of the base body 110A which serves as the mounting surface, the mountability of the coil component 101A is easily improved.

[0138] The arrangement of the first external electrode 121, the second external electrode 122, the third external electrode 123, and the fourth external electrode 124 is not limited to the configuration shown in Figure 5.

[0139] Figure 6 is a schematic cross-sectional view showing an example of a cross-section along line segment A1-A2 of the coil component shown in Figure 5. Figure 7 is a schematic cross-sectional view showing an example of a cross-section along line segment B1-B2 of the coil component shown in Figure 5. Figure 8 is a schematic cross-sectional view showing an example of a cross-section along line segment C1-C2 of the coil component shown in Figure 5.

[0140] As shown in Figures 6 to 8, the first glass layer 115a is formed by sequentially stacking insulating layers 115aa, 115ab, 115ac, 115ad, and 115ae in the stacking direction (here, the height direction T). More specifically, in the first glass layer 115a, insulating layers 115aa, 115ab, 115ac, 115ad, and 115ae are stacked sequentially from the first main surface 112a side of the base material 110A toward the second main surface 112b side.

[0141] The constituent materials of insulating layer 115aa, insulating layer 115ab, insulating layer 115ac, insulating layer 115ad, and insulating layer 115ae are preferably the same, but they may be different from each other, or they may be different in some respects.

[0142] Note that in Figures 6 to 8, for the sake of explanation, the boundaries between the insulating layers constituting the first glass layer 115a are shown, but in reality, these boundaries are not clearly visible.

[0143] As shown in Figures 6 to 8, the first ferrite layer 116a is formed by stacking insulating layers 116aa and 116ab in the stacking direction (here, the height direction T). More specifically, in the first ferrite layer 116a, insulating layers 116aa and 116ab are stacked in order from the first glass layer 115a side.

[0144] Note that in Figures 6 to 8, for the sake of explanation, the boundaries between the insulating layers constituting the first ferrite layer 116a are shown, but in reality, these boundaries are not clearly visible.

[0145] As shown in Figures 6 to 8, the second ferrite layer 116b is formed by stacking insulating layers 116ba and 116bb in the stacking direction (here, the height direction T). More specifically, in the second ferrite layer 116b, insulating layers 116ba and 116bb are stacked in order from the first glass layer 115a side.

[0146] Note that in Figures 6 to 8, for the sake of explanation, the boundaries between the insulating layers constituting the second ferrite layer 116b are shown, but in reality, these boundaries are not clearly visible.

[0147] As shown in Figures 7 and 8, the first external electrode 121, the second external electrode 122, the third external electrode 123, and the fourth external electrode 124 each have a base electrode layer 125 and a plating layer 126. Each external electrode has the base electrode layer 125 and the plating layer 126 in order from the surface side of the base body 110A.

[0148] The base electrode layer 125 contains Ag as the main component, along with CuO and SiO ２ It contains each of these as minor components. And in the base electrode layer 125, CuO and SiO ２ These coexist. Therefore, similar to Embodiment 1, the adhesion strength (adhesion force) between the base body 110A and each external electrode can be improved. Furthermore, for example, the occurrence of reflow delamination can be suppressed.

[0149] The distance over which Cu from the external electrode (underlay electrode layer 125) diffuses from the interface between each external electrode and the base body 110A to the base body 110A (Cu diffusion distance) is preferably 9 μm or less, more preferably 8.5 μm or less, and even more preferably 7 μm or less, similar to Embodiment 1.

[0150] The lower limit of the diffusion distance of Cu is not particularly limited, but it may be, for example, 1 μm or more.

[0151] Examples of the plating layer 126 include a Ni plating layer, an Sn plating layer, and the like.

[0152] Inside the first glass layer 115a, a first coil 131 and a second coil 132 are provided.

[0153] The first coil 131 and the second coil 132 are insulated from each other.

[0154] The first coil 131, more specifically, one end of the first coil 131, is electrically connected to the first external electrode 121 via the first lead conductor 151 shown in Figure 7. In the example shown in Figure 7, the first lead conductor 151 is exposed on the first side surface 113a of the base body 110A, and the first external electrode 121 is connected to the exposed portion of the first lead conductor 151.

[0155] The first coil 131, more specifically, the other end of the first coil 131, is electrically connected to the second external electrode 122 via the second lead conductor 152 shown in Figure 7. In the example shown in Figure 7, the second lead conductor 152 is exposed on the second side surface 113b of the base body 110A, and the second external electrode 122 is connected to the exposed portion of the second lead conductor 152.

[0156] The second coil 132, more specifically, one end of the second coil 132, is electrically connected to the third external electrode 123 via the third lead conductor 153 shown in Figure 8. In the example shown in Figure 8, the third lead conductor 153 is exposed on the first side surface 113a of the base body 110A, and the third external electrode 123 is connected to the exposed portion of the third lead conductor 153.

[0157] The second coil 132, more specifically, the other end of the second coil 132, is electrically connected to the fourth external electrode 124 via the fourth lead conductor 154 shown in Figure 8. In the example shown in Figure 8, the fourth lead conductor 154 is exposed on the second side surface 113b of the base body 110A, and the fourth external electrode 124 is connected to the exposed portion of the fourth lead conductor 154.

[0158] As described above, the coil component 101A is a common mode choke coil provided with a first coil 131 and a second coil 132 insulated from the first coil 131.

[0159] As shown in Figure 6, the first coil 131 has a coil axis D1. In the example shown in Figure 6, the coil axis D1 of the first coil 131 penetrates between the first main surface 112a and the second main surface 112b of the base body 110A along the height direction T. In other words, the direction of the coil axis D1 of the first coil 131 is perpendicular to the first main surface 112a of the base body 110A, which is the mounting surface.

[0160] As shown in Figure 6, the second coil 132 has a coil axis D2. In the example shown in Figure 6, the coil axis D2 of the second coil 132 penetrates between the first main surface 112a and the second main surface 112b of the base body 110A along the height direction T. In other words, the direction of the coil axis D2 of the second coil 132 is perpendicular to the first main surface 112a of the base body 110A, which is the mounting surface.

[0161] Note that the coil axis D1 of the first coil 131 and the coil axis D2 of the second coil 132 pass through the inner circumference of the first coil 131 and the inner circumference of the second coil 132, respectively, when viewed from the height direction T, but for the sake of explanation, this is shown in Figure 6.

[0162] From the above, the lamination direction of the insulating layer constituting the first glass layer 115a, the direction of the coil axis D1 of the first coil 131, and the direction of the coil axis D2 of the second coil 132 are all perpendicular to the first main surface 112a of the base body 110A, which serves as the mounting surface, along the same height direction T.

[0163] Figure 9 is a schematic perspective view showing an example of the disassembled state of the coil components (excluding the external electrodes) shown in Figure 5.

[0164] As shown in Figure 9, the first coil 131 includes a coil conductor 141a and a coil conductor 141b.

[0165] The coil conductor 141a is provided on the main surface of the insulating layer 115aa. The coil conductor 141a has a land portion 161a at one end and is connected to the first lead conductor 151 at the other end.

[0166] The coil conductor 141b is provided on the main surface of the insulating layer 115ab. The coil conductor 141b has a land portion 161b at one end and is connected to the second lead conductor 152 at the other end.

[0167] The land portion 161a of the coil conductor 141a and the land portion 161b of the coil conductor 141b overlap when viewed from the height direction T.

[0168] The insulating layer 115ab is provided with via conductors 171a that penetrate in the height direction T, at positions that overlap with the land portions 161a and 161b when viewed from the height direction T.

[0169] In the coil component 101A, the insulating layers 115aa and 115ab are stacked in the stacking direction (here, the height direction T), so that the coil conductors 141a and 141b are stacked together with these insulating layers in the height direction T and electrically connected. More specifically, the land portion 161a of the coil conductor 141a and the land portion 161b of the coil conductor 141b are electrically connected via the via conductor 171a. In this way, the first coil 131 is formed by the electrical connection of the coil conductors 141a and 141b.

[0170] As shown in Figure 9, the second coil 132 includes a coil conductor 142a and a coil conductor 142b.

[0171] The coil conductor 142a is provided on the main surface of the insulating layer 115ac. The coil conductor 142a has a land portion 162a at one end and is connected to the fourth lead conductor 154 at the other end.

[0172] The coil conductor 142b is provided on the main surface of the insulating layer 115ad. The coil conductor 142b has a land portion 162b at one end and is connected to the third lead conductor 153 at the other end.

[0173] The land portion 162a of the coil conductor 142a and the land portion 162b of the coil conductor 142b overlap when viewed from the height direction T.

[0174] The insulating layer 115ad is provided with via conductors 172a that penetrate in the height direction T, at positions that overlap with the land portions 162a and 162b when viewed from the height direction T.

[0175] In the coil component 101A, the insulating layers 115ac and 115ad are stacked in the stacking direction (here, the height direction T), so that the coil conductors 142a and 142b are stacked together with these insulating layers in the height direction T and electrically connected. More specifically, the land portion 162a of the coil conductor 142a and the land portion 162b of the coil conductor 142b are electrically connected via the via conductor 172a. The second coil 132 is formed by the electrical connection of the coil conductors 142a and 142b in this way.

[0176] In the first glass layer 115a, an insulating layer 115ae, which does not have conductors such as coil conductors, lead conductors, or via conductors, is further laminated on the second main surface 112b side of the base body 110A, relative to the laminated portion of insulating layers 115aa, 115ab, 115ac, and 115ad. As a result, the first coil 131 and the second coil 132 (especially the second coil 132) are provided inside the first glass layer 115a.

[0177] Furthermore, in the first glass layer 115a, at least one insulating layer without conductors such as coil conductors, lead conductors, or via conductors may be further laminated on at least one side of the first main surface 112a side and the second main surface 112b side of the base body 110A, relative to the laminated portion of insulating layer 115aa, insulating layer 115ab, insulating layer 115ac, insulating layer 115ad, and insulating layer 115ae. In other words, the number of insulating layers constituting the first glass layer 115a is not limited to the configuration shown in Figure 9 (five layers).

[0178] The number of coil conductors constituting each of the first coil 131 and the second coil 132 is not limited to the configuration shown in Figure 9 (two).

[0179] When viewed from the stacking direction (here, the height direction T), each coil conductor may have a shape consisting only of straight sections as shown in Figure 9, a shape consisting only of curved sections, or a shape consisting of both straight and curved sections. In other words, when viewed from the height direction T, the first coil 131 and the second coil 132 may each have a shape consisting only of straight sections as shown in Figure 9, a shape consisting only of curved sections, or a shape consisting of both straight and curved sections.

[0180] When viewed from the stacking direction (here, the height direction T), each land portion may be circular in shape as shown in Figure 9, or it may be polygonal in shape.

[0181] Each coil conductor does not necessarily have to have a land portion at its end.

[0182] Examples of constituent materials for each coil conductor, each lead conductor, and each via conductor include Ag, Au, Cu, Pd, Ni, Al, and alloys containing at least one of these metals.

[0183] As described above, the first ferrite layer 116a is formed by stacking insulating layers 116aa and 116ab in the stacking direction (here, the height direction T).

[0184] The number of insulating layers constituting the first ferrite layer 116a is not limited to the configuration shown in Figure 9 (two layers). In other words, the number of insulating layers constituting the first ferrite layer 116a may be one or multiple.

[0185] As described above, the second ferrite layer 116b is formed by stacking insulating layer 116ba and insulating layer 116bb in the stacking direction (here, the height direction T).

[0186] The number of insulating layers constituting the second ferrite layer 116b is not limited to the configuration shown in Figure 9 (two layers). In other words, the number of insulating layers constituting the second ferrite layer 116b may be one or multiple.

[0187] The coil component 101A is manufactured, for example, by the following method.

[0188] <Process of manufacturing glass-ceramic material> First, weigh K ２ O, B ２ O ３ SiO ２ and Al ２ O ３ so that they are in a predetermined ratio, and mix them in a platinum crucible or the like.

[0189] Next, melt the obtained mixture by heat treatment. Regarding the heat treatment temperature, for example, set it to 1500 °C or higher and 1600 °C or lower.

[0190] Then, produce a glass material by rapidly cooling the obtained melt.

[0191] When the total amount of the glass material is 100% by weight, it preferably contains K in terms of K ２ O conversion of 0.5% by weight or more and 5% by weight or less, B in terms of B ２ O ３ conversion of 10% by weight or more and 25% by weight or less, Si in terms of SiO ２ [[ID=3l]]conversion of 70% by weight or more and 85% by weight or less, and Al in terms of Al ２ O ３ conversion of 0% by weight or more and 5% by weight or less.

[0192] Next, prepare glass powder by pulverizing the glass material. Regarding the median diameter D ５０ of the glass powder, for example, set it to 1 μm or more and 3 μm or less. Also, prepare quartz powder and alumina powder as fillers. Regarding the median diameter D ５０ of the quartz powder and alumina powder, for example, set it to 0.5 μm or more and 2.0 μm or less. Here, the median diameter D ５０ of the glass powder, quartz powder, and alumina powder is the particle diameter when the cumulative probability based on volume is 50%.

[0193] Then, produce a glass-ceramic material (dielectric glass material: non-magnetic material) by adding quartz powder and alumina powder as fillers to the glass powder.

[0194] <Process for manufacturing glass ceramic sheets> First, glass ceramic material, an organic binder such as polyvinyl butyral resin, an organic solvent such as ethanol or toluene, a plasticizer, etc. are mixed together with PSZ media in a ball mill to produce a glass ceramic slurry.

[0195] Next, the glass-ceramic slurry is formed into a sheet of a predetermined thickness using a doctor blade method or the like, and then punched out into a predetermined shape to produce a glass-ceramic sheet. The thickness of the glass-ceramic sheet is, for example, 20 μm or more and 30 μm or less. The shape of the glass-ceramic sheet is, for example, rectangular.

[0196] <Process for producing ferrite material> First, Fe ２ O ３ Weigh out ZnO, CuO, and NiO in predetermined ratios. Each oxide may contain unavoidable impurities. In this case, Mn ３ O ４ Co ３ O ４ , SnO ２ , Bi ２ O ３ SiO ２ Additives such as those listed above may be added. These additives will integrate with other oxides during firing, forming a magnetic phase.

[0197] Next, these weighed materials, along with pure water, a dispersant, etc., are placed in a ball mill with the PSZ media and mixed, then ground.

[0198] Then, the resulting pulverized material is dried and calcined. The calcination temperature is, for example, 700°C or higher and 800°C or lower. The calcination time is, for example, 2 hours or more and 3 hours or less.

[0199] In this way, powdered ferrite material (magnetic material) is prepared.

[0200] When the total amount of ferrite material is 100 mol%, Fe is Fe ２ O ３It is preferable that the mixture contains 40 mol% or more and 49.5 mol% or less in terms of conversion, Zn in terms of 5 mol% or more and 35 mol% or less in terms of ZnO conversion, Cu in terms of 6 mol% or more and 12 mol% or less in terms of CuO conversion, and Ni in terms of 8 mol% or more and 40 mol% or less in terms of NiO conversion.

[0201] <Process for producing ferrite sheets> First, powdered ferrite material, an organic binder such as polyvinyl butyral resin, and an organic solvent such as ethanol or toluene are mixed together with PSZ media in a ball mill and then pulverized to produce a ferrite slurry.

[0202] Next, the ferrite slurry is formed into a sheet of a predetermined thickness using a doctor blade method or the like, and then punched out into a predetermined shape to produce a ferrite sheet. The shape of the ferrite sheet is, for example, rectangular.

[0203] <Process for forming conductor patterns> Conductive paste such as Ag paste is applied to each glass ceramic sheet by screen printing or the like to form a conductor pattern for coil conductors corresponding to the coil conductors shown in Figure 9, a conductor pattern for lead conductors corresponding to the lead conductors shown in Figure 9, and a conductor pattern for via conductors corresponding to the via conductors shown in Figure 9. When forming the conductor patterns for via conductors, via holes are formed in advance by irradiating predetermined locations on the glass ceramic sheet with a laser, and then the conductive paste is filled into these via holes.

[0204] <Process for manufacturing the laminated block> First, each glass ceramic sheet with a conductor pattern formed on it is laminated in the order shown in Figure 9, that is, in the order of insulating layer 115aa, insulating layer 115ab, insulating layer 115ac, and insulating layer 115ad as shown in Figure 9, in the lamination direction (here, the height direction). Then, as shown in Figure 9, a glass ceramic sheet without a conductor pattern is laminated on one of the main surfaces of the obtained laminate in the lamination direction (here, the height direction), that is, at the position of insulating layer 115ae as shown in Figure 9.

[0205] Next, a predetermined number of ferrite sheets are laminated on both main surfaces of the resulting glass-ceramic sheet laminate in the lamination direction (here, the height direction). In this case, for example, the first ferrite sheet and the second ferrite sheet are laminated on both main surfaces of the glass-ceramic sheet laminate, starting from the glass-ceramic sheet laminate side. More specifically, the first ferrite sheet is laminated at the positions of insulating layer 116aa and insulating layer 116ba shown in Figure 9, and the second ferrite sheet is laminated at the positions of insulating layer 116ab and insulating layer 116bb shown in Figure 9.

[0206] Then, the resulting laminate of glass ceramic sheets and ferrite sheets is compressed using a warm isostatic pressing (WIP) process or the like to produce a laminate block.

[0207] <Process for manufacturing the base body and coil> First, the laminated block is cut to a predetermined size using a dicer or the like to produce individual chips.

[0208] Next, the individual chips are fired. The firing temperature should be, for example, 860°C or higher and 920°C or lower. The firing time should be, for example, 1 hour or more and 2 hours or less.

[0209] By firing the individual chips, the glass-ceramic sheet and the ferrite sheet each become insulating layers. As a result, the laminated portion of the glass-ceramic sheet becomes the first glass layer. Furthermore, the two laminated portions of the ferrite sheet that sandwich the laminated portion of the glass-ceramic sheet in the lamination direction (here, the height direction) become the first ferrite layer and the second ferrite layer, respectively. In addition, the conductor pattern for the coil conductor, the conductor pattern for the lead conductor, and the conductor pattern for the via conductor become the coil conductor, the lead conductor, and the via conductor, respectively.

[0210] In this way, a base body having a structure in which the first glass layer is sandwiched between the first ferrite layer and the second ferrite layer in the stacking direction (here, the height direction), a first coil provided inside the first glass layer, and a second coil provided inside the first glass layer and insulated from the first coil are manufactured. Here, the first side surface of the base body exposes the first lead conductor connected to one end of the first coil and the third lead conductor connected to one end of the second coil. Furthermore, the second side surface of the base body exposes the second lead conductor connected to the other end of the first coil and the fourth lead conductor connected to the other end of the second coil.

[0211] For the base material, for example, the base material may be placed in a rotary barrel machine together with the media and barrel polished to round off the corners and edges.

[0212] <Process for forming the external electrode> First, Ag powder, CuO powder, glass frit, and organic binder resin are prepared as electrode paste materials for the base electrode layer.

[0213] Next, CuO powder is added to the glass frit in an amount of 0.2 mol% to 20 mol%, heated to melt, and then cooled and pulverized to the desired size. The heating temperature is, for example, 500°C to 2000°C.

[0214] Next, the obtained pulverized material, Ag powder, and organic binder resin are mixed to form a paste, thereby preparing an electrode paste for the base electrode layer.

[0215] The mixing ratio of Ag powder, CuO powder-added glass frit, and organic binder resin in this electrode paste is not particularly limited, but it is preferable that the electrode paste contains 60% to 80% by weight of Ag powder, 5% to 20% by weight of CuO powder-added glass frit, and 10% to 20% by weight of organic binder resin, when the total amount is 100% by weight.

[0216] Next, the prepared electrode paste is applied to at least four locations on the base body: the area on the first side surface where the first lead conductor is exposed, the area on the second side surface where the second lead conductor is exposed, the area on the first side surface where the third lead conductor is exposed, and the area on the second side surface where the fourth lead conductor is exposed.

[0217] Next, the obtained coating films are baked to form a base electrode on the surface of the substrate. The baking temperature is set to 600°C or higher and 800°C or lower. Since increasing the baking temperature increases the diffusion distance of Cu, it is possible to adjust the diffusion distance of Cu by adjusting the baking temperature. The thickness of the base electrode layer is set to, for example, 30 μm.

[0218] The baking temperature is preferably less than 720°C, and more preferably 710°C or lower. If the baking temperature is 720°C or higher, the diffusion distance of Cu becomes 8 μm or more, and the tensile test strength tends to decrease. From the viewpoint of further promoting glass diffusion during the baking of the base electrode layer and making the diffusion distance of Cu 4 μm or more, the baking temperature is preferably 640°C or higher.

[0219] Then, by electroplating or the like, plating layers, for example, a Ni plating layer and a Sn plating layer, are sequentially formed on the surface of each underlying electrode layer.

[0220] In this way, a first external electrode electrically connected to one end of the first coil via a first lead conductor, a second external electrode electrically connected to the other end of the first coil via a second lead conductor, a third external electrode electrically connected to one end of the second coil via a third lead conductor, and a fourth external electrode electrically connected to the other end of the second coil via a fourth lead conductor are formed on the surface of the base body.

[0221] The coil component 101A is manufactured as described above.

[0222] (Embodiment 3) In the coil component of Embodiment 3, the base further comprises a second glass layer adjacent to the first ferrite layer on the opposite side from the first glass layer, and a third glass layer adjacent to the second ferrite layer on the opposite side from the first glass layer. Except for this point, the coil component of Embodiment 3 is the same as the coil component of Embodiment 2.

[0223] Figure 10 is a schematic perspective view showing an example of a coil component of Embodiment 3. Figure 11 is a schematic cross-sectional view showing an example of a cross-section along line segment A3-A4 of the coil component shown in Figure 10.

[0224] In the coil component 101B shown in Figures 10 and 11, the base body 110B has the same configuration as the base body 110A, namely the first glass layer 115a as a non-magnetic layer, the first ferrite layer 116a as a magnetic layer, and the second ferrite layer 116b as a magnetic layer, in addition to the second glass layer 115b as a non-magnetic layer and the third glass layer 115c as a non-magnetic layer.

[0225] In the stacking direction (here, the height direction T), the second glass layer 115b is adjacent to the first ferrite layer 116a on the opposite side from the first glass layer 115a, and the third glass layer 115c is adjacent to the second ferrite layer 116b on the opposite side from the first glass layer 115a. In other words, in the base body 110B, in the stacking direction (here, the height direction T), the first ferrite layer 116a is sandwiched between the first glass layer 115a and the second glass layer 115b, and the second ferrite layer 116b is sandwiched between the first glass layer 115a and the third glass layer 115c.

[0226] The number of insulating layers constituting the second glass layer 115b is not particularly limited and may be one or more.

[0227] The base material 110B includes a non-magnetic phase, and at least a portion of the non-magnetic phase contains Si. Furthermore, the base material 110B contains SiO ２ It includes.

[0228] Specifically, the second glass layer 115b, like the first glass layer 115a, contains Si, for example, SiO ２It is composed of a glass ceramic material with as its main component. The second glass layer 115b may consist only of a non-magnetic phase, in which case it is preferable that at least a part of the non-magnetic phase of the second glass layer 115b contains Si. As a result, the second glass layer 115b does not contain a magnetic phase. In this case, the entire non-magnetic phase of the second glass layer 115b may contain Si, or the second glass layer 115b may contain a non-magnetic phase containing Si and a non-magnetic phase that does not contain Si (for example, a non-magnetic phase containing Al).

[0229] The second glass layer 115b preferably contains a glass material containing K, B, and Si. In other words, the glass ceramic material constituting the second glass layer 115b preferably contains a glass material containing K, B, and Si.

[0230] The glass material contained in the second glass layer 115b, when the total amount is 100% by weight, has a ratio of K to K ２ In terms of O equivalent, 0.5% or more by weight and 5% or less by weight, B is B ２ O ３ Converted to 10% or more by weight and 25% or less by weight, Si to SiO ２ Converted to 70% or more by weight, and 85% or less by weight, Al to Al ２ O ３ Preferably, it contains 0% or more and 5% or less by weight.

[0231] The second glass layer 115b preferably contains a filler containing at least one of quartz and alumina. In other words, the glass ceramic material constituting the second glass layer 115b preferably contains a filler containing at least one of quartz and alumina. Including quartz as a filler in the glass ceramic material constituting the second glass layer 115b makes it easier to improve the high-frequency characteristics of the coil component 101B. Furthermore, including alumina as a filler in the glass ceramic material constituting the second glass layer 115b makes it easier to improve the mechanical strength of the base body 110B. When the glass ceramic material constituting the second glass layer 115b contains quartz as a filler, the quartz constitutes a non-magnetic phase containing Si in the second glass layer 115b. When the glass ceramic material constituting the second glass layer 115b contains alumina as a filler, the alumina constitutes a non-magnetic phase containing Al without containing Si in the second glass layer 115b.

[0232] When the glass ceramic material constituting the second glass layer 115b contains quartz and alumina as fillers, it is preferable that the glass ceramic material, when the total amount is 100% by weight, contains 60% to 66% by weight of glass material, 34% to 37% by weight of quartz as a filler, and 0.5% to 4% by weight of alumina as a filler.

[0233] The number of insulating layers constituting the third glass layer 115c is not particularly limited and may be one or more.

[0234] The third glass layer 115c, like the first glass layer 115a and the second glass layer 115b, contains Si, for example, SiO ２It is composed of a glass ceramic material with as its main component. The third glass layer 115c may consist only of a non-magnetic phase, in which case it is preferable that at least a part of the non-magnetic phase of the third glass layer 115c contains Si. As a result, the third glass layer 115c does not contain a magnetic phase. In this case, the entire non-magnetic phase of the third glass layer 115c may contain Si, or the third glass layer 115c may contain a non-magnetic phase containing Si and a non-magnetic phase that does not contain Si (for example, a non-magnetic phase containing Al).

[0235] The third glass layer 115c preferably contains a glass material containing K, B, and Si. In other words, the glass ceramic material constituting the third glass layer 115c preferably contains a glass material containing K, B, and Si.

[0236] The glass material contained in the third glass layer 115c, when the total amount is 100% by weight, has a ratio of K to K ２ In terms of O equivalent, 0.5% or more by weight and 5% or less by weight, B is B ２ O ３ Converted to 10% or more by weight and 25% or less by weight, Si to SiO ２ Converted to 70% or more by weight, and 85% or less by weight, Al to Al ２ O ３ Preferably, it contains 0% or more and 5% or less by weight.

[0237] The third glass layer 115c preferably contains a filler containing at least one of quartz and alumina. In other words, the glass ceramic material constituting the third glass layer 115c preferably contains a filler containing at least one of quartz and alumina. Including quartz as a filler in the glass ceramic material constituting the third glass layer 115c makes it easier to improve the high-frequency characteristics of the coil component 101B. Furthermore, including alumina as a filler in the glass ceramic material constituting the third glass layer 115c makes it easier to improve the mechanical strength of the base body 110B. When the glass ceramic material constituting the third glass layer 115c contains quartz as a filler, the quartz constitutes a non-magnetic phase containing Si in the third glass layer 115c. When the glass ceramic material constituting the third glass layer 115c contains alumina as a filler, the alumina constitutes a non-magnetic phase containing Al without containing Si in the third glass layer 115c.

[0238] When the glass ceramic material constituting the third glass layer 115c contains quartz and alumina as fillers, it is preferable that the glass ceramic material, when the total amount is 100% by weight, contains 60% to 66% by weight of glass material, 34% to 37% by weight of quartz as a filler, and 0.5% to 4% by weight of alumina as a filler.

[0239] The glass ceramic materials constituting the first glass layer 115a, the second glass layer 115b, and the third glass layer 115c are preferably the same, but they may be different from each other, or they may be different in some respects.

[0240] The dimensions of the first glass layer 115a, the second glass layer 115b, the third glass layer 115c, the first ferrite layer 116a, and the second ferrite layer 116b in the height direction T may be the same, different from each other, or partially different. If the dimensions of the first glass layer 115a, the second glass layer 115b, the third glass layer 115c, the first ferrite layer 116a, and the second ferrite layer 116b in the height direction T may be different from each other or partially different, their relative sizes are not particularly limited.

[0241] The coil component 101B is manufactured in the same manner as the coil component 101A, except that the process of manufacturing the laminated block is carried out as follows.

[0242] <Process for manufacturing a laminated block> First, each glass-ceramic sheet with a conductive pattern formed on it is stacked in the stacking direction (here, the height direction) in the order shown in Figure 9. At this time, a predetermined number of glass-ceramic sheets without a conductive pattern are stacked on at least one main surface in the stacking direction (here, the height direction) of the resulting laminate.

[0243] Next, a predetermined number of ferrite sheets are laminated onto both main surfaces of the resulting glass-ceramic sheet laminate in the lamination direction (here, the height direction). In this case, for example, a first ferrite sheet, a second ferrite sheet, and a first ferrite sheet are laminated onto both main surfaces of the glass-ceramic sheet laminate in order from the glass-ceramic sheet laminate side.

[0244] Next, a predetermined number of glass-ceramic sheets without a conductive pattern are stacked on the two stacked portions of the obtained ferrite sheet in the stacking direction (here, the height direction).

[0245] Then, the resulting laminate of glass ceramic sheets and ferrite sheets is compressed by a warm isostatic pressing process or the like to produce a laminate block.

[0246] Subsequently, in the process of manufacturing the base body and coil, the individualized chips are fired, and the laminated portion of the glass-ceramic sheet provided on the inside becomes the first glass layer. Furthermore, the two laminated portions of the ferrite sheet sandwiching the above-mentioned glass-ceramic sheet laminated portion in the lamination direction (here, the height direction) become the first ferrite layer and the second ferrite layer, respectively. In addition, the two laminated portions of the glass-ceramic sheet provided on the outside of the two laminated portions of the ferrite sheet become the second glass layer and the third glass layer, respectively.

[0247] The following examples more specifically disclose the coil components of the present invention, particularly the coil components of Embodiment 1. However, the present invention is not limited to these embodiments.

[0248] [Examples 1-6] The coil components of Examples 1-6 were manufactured by the following method.

[0249] <Ferrite material manufacturing process> Fe ２ O ３ The main components were weighed out in the following proportions: 48.0 mol% of nitrate, 30.0 mol% of ZnO, 14.0 mol% of NiO, and 8.0 mol% of CuO. Next, these weighed materials, along with pure water and a dispersant, were placed in a ball mill with PSZ media and mixed, then pulverized to produce a slurry. The resulting slurry was dried and then calcined at 800°C for 2 hours. In this way, a powdered ferrite material was produced as a magnetic material.

[0250] <Glass Ceramic Material Preparation Process> Borosilicate glass powder containing Si, B, K, and Al in predetermined proportions, along with forsterite powder and quartz powder as fillers, were prepared. The borosilicate glass powder, forsterite powder, and quartz powder were weighed in a volume ratio of borosilicate glass:forsterite:quartz = 93:6:1. Next, these weighed materials, along with pure water and a dispersant, were placed in a ball mill with PSZ media and mixed, then pulverized to produce a slurry. The resulting slurry was then dried to produce a powdered glass ceramic material as a non-magnetic material.

[0251] <Green Sheet Manufacturing Process> Ferrite material and glass ceramic material were weighed so that the volume ratio of ferrite material to glass ceramic material was 40:60. Next, these weighed materials, along with polyvinyl butyral resin as an organic binder and ethanol and toluene as organic solvents, were placed in a ball mill with PSZ media and mixed, then pulverized to produce a slurry. The obtained slurry was then formed into a sheet of a predetermined thickness using the doctor blade method, and then punched out into a predetermined shape to produce a green sheet.

[0252] <Conductor Pattern Formation Process> A conductive paste was prepared by mixing Ag powder, a predetermined amount of solvent (eugenol), resin (ethylcellulose), and a dispersant in a planetary mixer, and then dispersing it in a three-roll mill. Via holes were formed at predetermined locations on a green sheet, and the conductive paste was filled to form via conductors. After that, a coil conductor pattern was printed to obtain a coil sheet. Separately, via holes were formed at predetermined locations on a green sheet by irradiating them with a laser. After filling the via holes with conductive paste to form via conductors, a land pattern was printed to obtain a via sheet.

[0253] <Laminated Block Fabrication Process> A laminated block was fabricated by stacking coil sheets and via sheets in the stacking direction in the order corresponding to Figure 2, and then heat-pressing them together.

[0254] <Laminate and Coil Fabrication Process> The laminate block was cut into individual pieces using a dicer to produce individual chips. Subsequently, the individual chips were fired at 910°C for 4 hours to form a laminate. A magnetic phase and a non-magnetic phase were formed in the laminate.

[0255] <External electrode formation process> First, Ag powder, CuO powder, glass frit, and organic binder resin were prepared as electrode paste materials for the base electrode layer.

[0256] Next, CuO powder was added to the glass frit in an amount of 0.2 mol% to 20 mol%, heated to melt, and then cooled and pulverized to the desired size. The heating temperature was 1000°C.

[0257] Next, the obtained pulverized material was mixed with Ag powder and organic binder resin to form a paste, which was then used to prepare an electrode paste for the base electrode layer.

[0258] Next, the prepared electrode paste was applied to the first and second end faces of the laminate's outer surface, from which the coils were drawn out, and baked to form a base electrode layer for the external electrodes. The baking temperature was set to a range of 600°C to 800°C. The diffusion distance of Cu in Examples 1 to 6 was adjusted by changing the baking temperature in Examples 1 to 6. The thickness of the base electrode layer was approximately 30 μm.

[0259] Then, a Ni plating layer and a Sn plating layer were sequentially formed on the surface of the base electrode layer by electroplating or the like. This created an external electrode having the base electrode layer, Ni plating layer, and Sn plating layer in that order.

[0260] Based on the above, coil components of Examples 1 to 6 according to Embodiment 1 were manufactured. The dimensions of the manufactured coil components were 1.0 mm in the length direction, 0.5 mm in the height direction, and 0.5 mm in the width direction.

[0261] [Comparative Example 1] A coil component of Comparative Example 1 was manufactured in the same manner as the coil components of Examples 1 to 6. However, as the electrode paste for the base electrode layer, an electrode paste prepared by mixing Ag powder and an organic binder resin to form a paste was used. The curing temperature was set to 800°C.

[0262] [Example 7] The coil component of Example 7 was manufactured in the same manner as the coil components of Examples 1 to 6, except for the following points.

[0263] In this embodiment, the green sheet was manufactured using only the glass ceramic material described in Example 1 during the green sheet manufacturing process.

[0264] Furthermore, in this embodiment, the baking temperature of the base electrode layer of the external electrode was set to 630°C during the external electrode formation process.

[0265] [Example 8] The coil component of Example 8 was manufactured in the same manner as the coil components of Examples 1 to 6, except for the following points.

[0266] In this embodiment, the green sheet was manufactured using only the ferrite material described in Example 1 during the green sheet manufacturing process.

[0267] Furthermore, in this embodiment, the baking temperature of the base electrode layer of the external electrode was set to 630°C during the external electrode formation process.

[0268] [Example 9] The coil component of Example 9 was manufactured in the same manner as the coil components of Examples 1 to 6, except for the following points.

[0269] In this embodiment, during the green sheet manufacturing process, the ferrite material and glass ceramic material described in Example 1 were weighed so that their volume ratio was ferrite material:glass ceramic material = 40:60. Next, these weighed materials, along with a polyvinyl butyral resin as an organic binder and ethanol and toluene as organic solvents, were placed in a ball mill with PSZ media and mixed, then pulverized to produce a slurry. The obtained slurry was then formed into a sheet of a predetermined thickness using the doctor blade method, and then punched out into a predetermined shape to produce a green sheet.

[0270] Furthermore, in this embodiment, the baking temperature of the base electrode layer of the external electrode was set to 630°C during the external electrode formation process.

[0271] [Comparative Example 2] The coil component of Comparative Example 2 was manufactured in the same manner as the coil component of Example 7. However, as the electrode paste for the base electrode layer, an electrode paste prepared by mixing Ag powder and an organic binder resin to form a paste was used. The curing temperature was set to 720°C.

[0272] [Comparative Example 3] The coil component of Comparative Example 3 was manufactured in the same manner as the coil component of Example 8. However, as the electrode paste for the base electrode layer, an electrode paste prepared by mixing Ag powder and an organic binder resin to form a paste was used. The curing temperature was set to 720°C.

[0273] [Comparative Example 4] The coil component of Comparative Example 4 was manufactured in the same manner as the coil component of Example 9. However, as the electrode paste for the base electrode layer, an electrode paste prepared by mixing Ag powder and an organic binder resin to form a paste was used. The curing temperature was set to 720°C.

[0274] <Measurement of Cu diffusion distance> The diffusion distance of Cu was measured for the prepared samples (coil components of Examples 1 to 9 and Comparative Examples 1 to 4) using the following method.

[0275] (1) WDX data acquisition and data processing 1. The sample was placed upright so that the width direction (W direction) was vertical, and the area around the sample was solidified with resin.

[0276] 2. The sample was polished using a polishing machine in the width direction until the approximate center of the width direction was exposed.

[0277] 3. Using wavelength-dispersive X-ray spectroscopy (WDX) on the cross-section of the obtained sample, the distance over which Cu contained in the underlying electrode layer of the external electrode diffused from the interface between the external electrode and the laminate was measured as follows.

[0278] (2) Calculation of the boundary (coordinates) between the base material and the external electrode 4. In order to determine the position for taking mapping photographs, the approximate boundary between the base material and the external electrode, which can be seen on the polished surface, was aligned to approximately 32 μm in the x-direction. Surface analysis of Ag, Cu, and Si elements was performed on a 46 μm section from the 0 μm position of the laminate to the 46 μm position on the external electrode side, and on a 46 μm section near the center of the laminate in the y-direction. In detail, the aforementioned square area was divided into 256 × 256 unit square areas, and the amount of Ag, Cu, and Si elements detected was measured for each unit square. An example of the results is shown in Figures 12 to 14. Figure 12 is a mapping photograph obtained by surface analysis of the coil component of Example 1 using WDX (upper panel, Cu element detection result) and a graph showing the amount of Ag and Cu elements detected in the x-direction of the coil component of Example 1 (lower panel). Figure 13 is a mapping photograph obtained by surface analysis of the coil component of Example 1 using WDX, showing the Ag element detection result. Figure 14 is a mapping photograph obtained by surface analysis using WDX on the coil component of Example 1, showing the detection results of Si elements. As shown in Figures 12 to 14, in the rightmost region where Ag elements are abundant, i.e., the underlying electrode layer, Cu elements and Si elements overlap, and CuO and SiO ２ It can be seen that they coexist. Also, the underlying electrode layer contains CuO and SiO in the Ag phase. ２ It can be seen that the phases in which these coexist have a dispersed sea-island structure.

[0279] 5. By taking the average of the detected amounts of Ag and Cu elements for every 1 unit square in the x-direction, and for every 256 unit squares in the y-direction, and then taking the average of the elemental detection amounts at a total of 5 points including the two points to the left and right of each x coordinate (5-point average), it becomes easier to grasp the trend of change. This 5-point average value is defined as the detected amount of Ag and Cu elements in the x-direction. An example is shown in the lower part of Figure 12.

[0280] 6. The interface position almost always has a range (varies) in the x-direction, and the boundary cannot be determined by appearance alone. Therefore, the boundary between the substrate and the external electrode is determined by the change in the amount of Ag element detected in the x-direction. The change in the amount of Ag element detected is the difference between the amount of Ag detected next to it, divided by the size of one unit square, which is 0.18 μm. An example of this is shown in Figure 15. Figure 15 is a graph showing the change in the amount of Ag element detected in the coil component of Example 1.

[0281] 7. As shown in Figure 15, it is desirable to extract the X-coordinate where the change in the amount of Ag detected first falls below the reference value, using the peak of the change in the amount of Ag detected as a reference, and to use the average of the X-coordinates of the two extracted points as the boundary between the element and the external electrode. The reference value on the element side and the reference value on the external electrode side are set by the absolute average of the change in the amount of Ag detected in the area with only element and the area with only external electrode, respectively. The area with only element and the area with only external electrode can be reliably determined from the mapping photograph and WDX data. The area with only external electrode is the range where Ag first disappears from the edge of the mapping photograph, and similarly, the area with only element is the range where element first disappears from the edge of the mapping photograph.

[0282] (3) Calculation of Cu diffusion range 8. Next, in order to calculate the Cu diffusion range, the average amount of Cu detected in the range where only the element is definitely present is calculated, and this average amount of Cu detected is used as the reference amount of Cu originally contained in the element. The range where only the element is definitely present can be determined by comparing the mapping photograph with the amount of Cu detected. An example of this is shown in Figure 16. Figure 16 is a graph (upper panel) showing the amount of Ag and Cu elements detected in the x direction in the coil component of Example 1, and a graph (lower panel) showing the amount of change in the amount of Ag element detected in the coil component of Example 1.

[0283] Based on the X-coordinate of the boundary between the substrate and the external electrode calculated in 9.7 (see the lower graph in Figure 16), the X-coordinate at which the initial detection amount of Cu contained in the substrate falls below the reference amount is the destination coordinate of the Cu that has diffused into the substrate (see the upper graph in Figure 16). The difference between the boundary position and the destination position of the Cu is the distance over which the Cu from the external electrode (underlying electrode layer) has diffused into the substrate (the diffusion distance of Cu).

[0284] <Reflow Test> Multiple samples were prepared for each of the fabricated samples (coil components from Examples 1 and 3, and Comparative Example 1), and a reflow test (solder heat resistance test) was performed on each sample using a general method. More specifically, each sample was soldered onto a substrate, and the substrate was heated six times in a reflow oven. After that, it was checked whether the external electrodes had detached from the substrate. Here, 100 samples were tested for each example. The results are shown in Table 1 below.

[0285]

[0286] These results suggest that adding Cu to the underlying electrode layer of the external electrodes suppressed the occurrence of reflow delamination. This is likely because adding Cu to the underlying electrode layer of the external electrodes improved the adhesion strength between the substrate and each external electrode.

[0287] <Tensile Test> A slurry containing ferrite material and glass ceramic material was prepared in the same manner as in Examples 2 to 6. The obtained slurry was then formed into a sheet of a predetermined thickness using the doctor blade method, and then punched out into a predetermined shape to produce a ferrite glass composite substrate. Subsequently, a 2 mm square pad and a 0.5 mm wide line were formed on the prepared ceramic glass composite substrate using the electrode paste for the base electrode layer obtained in the same manner as in Examples 2 to 6 by the screen printing method, and the sample was prepared by firing at 600°C to 800°C (varied depending on the example) for 10 minutes.

[0288] Then, an L-shaped Sn-plated copper wire (0.8 mm in diameter) was soldered to a 2 mm square pad, and the copper wire was pulled perpendicular to the substrate. The load at which the adhesive joint between the pad and the substrate broke was defined as the adhesive strength. The results are shown in Table 2 and Figure 17 below. Figure 17 is a graph showing the relationship between the Cu diffusion distance and the adhesive strength (tensile test strength) obtained by the tensile test. In this test, the Cu diffusion distance into the ceramic glass composite substrate was not directly determined, but since the ferrite glass composite substrate was manufactured under the same conditions as the base material in Examples 2 to 6, and the formation conditions such as the baking temperature of the underlay electrode layer were set in the same way as in Examples 2 to 6, it is considered that the Cu diffusion distance is the same as in Examples 2 to 6.

[0289]

[0290] These results showed that when the diffusion distance of Cu was 9 μm or less (preferably 8.5 μm or less), the tensile strength was 4 N or higher, which is sufficient for use. Furthermore, when the diffusion distance of Cu was 7 μm or less, it was found that the strength improved as the diffusion distance of Cu increased.

[0291] The results of the above tests are summarized in Table 3 below.

[0292]

[0293] The results of measuring the Cu diffusion distance for the coil components of Examples 7 to 9 and Comparative Examples 2 to 4 are shown in Table 4 below.

[0294]

[0295] These results show that, regardless of the base material, adding Cu to the underlying electrode layer of the external electrode causes the Cu to diffuse into the base material.

[0296] <Adhesion Force Test> Figure 18 is a schematic diagram illustrating the method of the adhesion force test, showing the coil component viewed from the second main surface (top surface). Figure 19 is a schematic diagram illustrating the method of the adhesion force test, showing the coil component viewed from one end face.

[0297] Fifteen samples were prepared for each of the fabricated coil components (Examples 7 and 8, and Comparative Examples 2 and 3), and a bonding force test was performed on each sample. More specifically, as shown in Figures 18 and 19, each sample 200 was mounted on a substrate 210. That is, a pair of external electrodes 201 of each sample 200 were soldered to a pair of pads 211. Then, the sample 200 was pressed from the side with a pressing jig 230, and the force at which the sample 200 detached from the pads 211 was measured and defined as the bonding force. The pressing jig 230 was positioned at a height such that the distance between the lower end of the pressing jig 230 and the surface of the substrate 210 was 1 / 4 or less of the height of the sample 200. For each example, a Weilbull plot was created from the results of 15 samples, with the bonding force on the horizontal axis, and the value F(t) = 1% (the bonding force at which the cumulative failure rate = 1%) was calculated to determine the bonding force for each example. The results are shown in Table 5 below.

[0298]

[0299] These results show that even when the insulating layer of the base material is composed solely of a non-magnetic phase, with at least a portion of the non-magnetic phase containing Si, or when it is composed solely of a magnetic phase, with the magnetic phase containing Cu ferrite, adding Cu to the underlying electrode layer of the external electrodes improves the adhesion strength. This is thought to be because adding Cu to the underlying electrode layer of the external electrodes improves the adhesion strength between the base material and each external electrode.

[0300] 1 Coil component 10 Laminate 10A Base body 11 First end face 12 Second end face 13 First main face 14 Second main face 15 First side face 16 Second side face 21 First external electrode 22 Second external electrode 25 Underlay electrode layer 26 Plating layer 30 Coil 31, 31a, 31b, 31c, 31d, 31e, 31f Insulating layer 32, 32a, 32b, 32c, 32d Coil conductor 33, 33a, 33b, 33c, 33d, 33e, 33f Via conductor 34, 34a, 34b, 34c, 34d Peripheral part 35, 35a, 35b, 35c, 35d, 35e, 35f Land 41 First lead conductor 42 Second lead conductor A Coil shaft

Claims

1. The device comprises a base body with a coil inside, and an external electrode provided on the surface of the base body, wherein the external electrode has a base electrode layer and a plating layer, and the base electrode layer mainly contains Ag, as well as CuO and SiO ２ It contains as a minor component, and in the aforementioned under electrode layer, CuO and SiO ２ These are coil components that coexist.

2. The coil component according to claim 1, wherein the base body includes a non-magnetic phase, and at least a portion of the non-magnetic phase includes Si.

3. The coil component according to claim 2, wherein the base body includes a magnetic phase, and the magnetic phase includes a ferrite containing Cu.

4. The coil component according to claim 2, wherein the base body is composed solely of the non-magnetic phase.

5. The coil component according to claim 1, wherein the element is composed only of a magnetic phase, and the magnetic phase includes ferrite containing Cu.

6. The above-mentioned substrate is SiO ２ The coil component according to claim 1, comprising a ferrite glass composite material that includes both glass with a main component and ferrite containing Cu.

7. The coil component according to any one of claims 1 to 6, wherein the base body is a laminate formed by stacking insulating layers.

8. The coil component according to any one of claims 1 to 7, wherein the base body is a laminate in which glass layers containing Si and magnetic layers containing ferrite are alternately stacked.

9. The coil component according to any one of claims 1 to 8, wherein the distance over which the Cu of the external electrode diffuses from the interface between the external electrode and the substrate to the substrate is 9 μm or less.

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