Coil components

Abstract

To provide a coil component in which a characteristic of a surface of an external electrode can be improved.SOLUTION: A multilayer coil component 1 includes an element assembly 2, a coil 7 disposed in the element assembly 2, and a first external electrode 4 and a second external electrode 5 disposed on the element assembly 2. The first external electrode 4 and the second external electrode 5 include a bonding surface S1 to be bonded to the element assembly 2, and a plating surface S2 opposing the bonding surface S1 and formed of plating. At least a part includes an electrode part embedded in the element assembly 2.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a coil component.

Background Art

[0002] Patent Document 1 discloses an electronic component including a ceramic laminate, an internal electrode layer disposed within the ceramic laminate, and an external electrode disposed on the surface of the ceramic laminate. In the electronic component described in Patent Document 1, the external electrode has an external electrode layer disposed on the surface of the ceramic laminate and a plating layer disposed on the external electrode layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One aspect of the present invention aims to provide a coil component capable of improving the characteristics of the surface of an external electrode.

Means for Solving the Problems

[0005] (1) A coil component according to one aspect of the present invention includes a body, a coil disposed within the body, and an external electrode disposed on the body. The external electrode has a bonding surface bonded to the body and a plating surface facing the bonding surface and formed by plating, and has an electrode portion at least partially embedded in the body.

[0006] In a coil component according to one aspect of the present invention, the electrode portion has a bonding surface that is joined to the base body and a plated surface that faces the bonding surface and is formed by plating. Thus, in the coil component, the surface of the electrode portion that faces the bonding surface, i.e., the surface of the electrode portion, is the plated surface, so the surface of the electrode portion has few voids (gaps), etc. Therefore, the surface of the electrode portion becomes a dense surface with few irregularities and defects. Even when a plating layer is placed on the surface of the electrode portion, the surface of the plating layer also becomes a dense surface with few irregularities and defects. Consequently, the surface characteristics of the external electrode can be improved in the coil component. As a result, when soldering the coil component, the wettability of the solder can be improved.

[0007] (2) In the coil component described in (1) above, the external electrode may have one or more plating layers arranged on the plated surface of the electrode portion. In this configuration, since the plated surface of the electrode portion is a dense surface with few irregularities and few defects, the thickness of the plating layer arranged on the plated surface can be reduced. As a result, the stress generated during the formation of the plating layer can be reduced, and thus the peeling of the external electrode from the base material can be suppressed.

[0008] (3) In the coil component described in (1) or (2) above, the base body may be constructed by laminating a base body layer containing multiple metallic magnetic particles of a soft magnetic material. In this configuration, the electrode portion can be formed by plating.

[0009] (4) In any one of the coil components described in (1) to (3) above, the surface roughness of the bonding surface may be greater than the surface roughness of the plated surface. In this configuration, the bonding strength between the base body and the external electrode can be improved by the anchoring effect. Therefore, in the coil component, peeling of the external electrode can be suppressed.

[0010] (5) In any one of the coil components described in (1) to (4) above, the electrode portion may have a bonding surface and a baked electrode layer containing a glass component. This configuration can improve the bonding strength between the base body and the electrode portion. [Effects of the Invention]

[0011] According to one aspect of the present invention, the surface characteristics of the external electrode can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a perspective view showing a laminated coil component according to the first embodiment. [Figure 2] Figure 2 shows the cross-sectional configuration of the laminated coil component shown in Figure 1. [Figure 3] Figure 3 is an exploded perspective view of a laminated coil component. [Figure 4] Figure 4 shows a cross-sectional view of a portion of the external electrode. [Figure 5] Figure 5 shows a cross-sectional view of a part of the external electrode in a modified example. [Figure 6] Figure 6 is an exploded perspective view of a laminated coil component according to the second embodiment. [Figure 7] Figure 7 is an exploded perspective view of the laminated coil component shown in Figure 6. [Figure 8] Figure 8 shows the cross-sectional configuration of a laminated coil component according to the third embodiment. [Figure 9] Figure 9 is an exploded perspective view of the laminated coil component shown in Figure 8. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0014] [First Embodiment] As shown in Figure 1, the laminated coil component 1 according to the first embodiment comprises a base body 2 and a first external electrode 4 and a second external electrode 5 arranged at both ends of the base body 2, respectively.

[0015] The base body 2 has a substantially rectangular parallelepiped shape. The rectangular parallelepiped shape includes a shape of a rectangular parallelepiped with chamfered corner portions and ridge line portions, and a shape of a rectangular parallelepiped with rounded corner portions and ridge line portions. As its outer surface, the base body 2 has a pair of end faces 2a and 2b facing each other, a pair of main faces 2c and 2d facing each other, and a pair of side faces 2e and 2f facing each other. The facing direction in which the pair of main faces 2c and 2d face each other is the first direction D1. The facing direction in which the pair of end faces 2a and 2b face each other is the second direction D2. The facing direction in which the pair of side faces 2e and 2f face each other is the third direction D3. In the present embodiment, the first direction D1 is the height direction of the base body 2. The second direction D2 is the longitudinal direction of the base body 2 and is orthogonal to the first direction D1. The third direction D3 is the width direction of the base body 2 and is orthogonal to both the first direction D1 and the second direction D2.

[0016] The pair of end faces 2a and 2b extend in the first direction D1 so as to connect between the pair of main faces 2c and 2d. The pair of end faces 2a and 2b also extend in the third direction D3 (the short side direction of the pair of main faces 2c and 2d). The pair of side faces 2e and 2f extend in the first direction D1 so as to connect between the pair of main faces 2c and 2d. The pair of side faces 2e and 2f also extend in the second direction D2 (the long side direction of the pair of end faces 2a and 2b). The main face 2d can be defined as a mounting surface that faces another electronic device (for example, a circuit board or an electronic component) when mounting the multilayer coil component 1 on the other electronic device.

[0017] As shown in FIG. 3, the base body 2 is configured by laminating a plurality of base body layers 10a to 10k. Each of the base body layers 10a to 10k is laminated in the first direction D1. That is, the first direction D1 is the lamination direction. The base body 2 has a plurality of laminated base body layers 10a to 10k. In the actual base body 2, the plurality of base body layers 10a to 10k are integrated to such an extent that the boundaries between the layers are not visible.

[0018] Each base layer 10a to 10k contains a plurality of metal magnetic particles. The metal magnetic particles are composed of a soft magnetic alloy (soft magnetic material). The soft magnetic alloy is, for example, an Fe-Si alloy. When the soft magnetic alloy is an Fe-Si alloy, the soft magnetic alloy may contain P. The soft magnetic alloy may be, for example, an Fe-Ni-Si-M alloy. "M" contains one or more elements selected from Co, Cr, Mn, P, Ti, Zr, Hf, Nb, Ta, Mo, Mg, Ca, Sr, Ba, Zn, B, Al, and rare earth elements.

[0019] In the base layers 10a to 10k, the metal magnetic particles are bonded to each other. The bonding between the metal magnetic particles is realized, for example, by the bonding of oxide films formed on the surfaces of the metal magnetic particles. In the base layers 10a to 10k, the metal magnetic particles are electrically insulated from each other by the bonding of the oxide films. The thickness of the oxide film is, for example, 5 to 60 nm or less. The oxide film may be composed of one or more layers.

[0020] The base 2 contains a resin. The resin exists between the plurality of metal magnetic particles. The resin is a resin having electrical insulation properties (insulating resin). The insulating resin includes, for example, silicone resin, phenolic resin, acrylic resin, or epoxy resin.

[0021] As shown in FIG. 2, in the base 2, a part of the main surface 2c forms a step. Specifically, each of the end face 2a side and the end face 2b side of the main surface 2c is recessed toward the main surface 2d side from the central part. In the base 2, a part of the main surface 2d forms a step. Specifically, each of the end face 2a side and the end face 2b side of the main surface 2d is recessed toward the main surface 2c side from the central part.

[0022] The first external electrode 4 is positioned on one end face 2a. The first external electrode 4 includes five electrode portions: a first electrode portion 4a located on the end face 2a, a second electrode portion 4b located on the main surface 2c, a third electrode portion 4c located on the main surface 2d, a fourth electrode portion 4d located on the side surface 2e, and a fifth electrode portion 4e located on the side surface 2f. The first electrode portion 4a extends along the first direction D1 and the third direction D3 and has a rectangular shape when viewed from the second direction D2. The second electrode portion 4b extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The third electrode portion 4c extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The fourth electrode portion 4d extends along the first direction D1 and the second direction D2 and has a rectangular shape when viewed from the third direction D3. The fifth electrode portion 4e extends along the first direction D1 and the second direction D2, and has a rectangular shape when viewed from the third direction D3.

[0023] The first electrode portion 4a, the second electrode portion 4b, the third electrode portion 4c, the fourth electrode portion 4d, and the fifth electrode portion 4e are connected at the edges of the base body 2 and are electrically connected to each other. The first external electrode 4 is formed on five surfaces: one end face 2a, a pair of main faces 2c and 2d, and a pair of side faces 2e and 2f. The first electrode portion 4a, the second electrode portion 4b, the third electrode portion 4c, the fourth electrode portion 4d, and the fifth electrode portion 4e are integrally formed. In this embodiment, the surface of the second electrode portion 4b is flush with the main face 2c, and the surface of the third electrode portion 4c is flush with the main face 2d. Also, the surface of the fourth electrode portion 4d is flush with the side face 2e, and the surface of the fifth electrode portion 4e is flush with the side face 2f. With this configuration, it can be said that a part of the first external electrode 4 is embedded in the base body 2.

[0024] As shown in Figure 3, the first external electrode 4 is formed by stacking multiple first external electrode layers 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, 12i, 12j, and 12k in the first direction D1. In other words, the stacking direction of the first external electrode layers 12a to 12k is the first direction D1. In the actual first external electrode 4, the multiple first external electrode layers 12a to 12k are integrated to such an extent that the boundaries between the layers are not visible.

[0025] As shown in Figure 2, the second external electrode 5 is positioned on one end face 2b. The second external electrode 5 includes five electrode portions: a first electrode portion 5a located on the end face 2b, a second electrode portion 5b located on the main surface 2c, a third electrode portion 5c located on the main surface 2d, a fourth electrode portion 5d located on the side surface 2e, and a fifth electrode portion 5e located on the side surface 2f. The first electrode portion 5a extends along the first direction D1 and the third direction D3 and has a rectangular shape when viewed from the second direction D2. The second electrode portion 5b extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The third electrode portion 5c extends along the second direction D2 and the third direction D3 and has a rectangular shape when viewed from the first direction D1. The fourth electrode portion 5d extends along the first direction D1 and the second direction D2 and has a rectangular shape when viewed from the third direction D3. The fifth electrode portion 5e extends along the first direction D1 and the second direction D2, and has a rectangular shape when viewed from the third direction D3.

[0026] The first electrode portion 5a, the second electrode portion 5b, the third electrode portion 5c, the fourth electrode portion 5d, and the fifth electrode portion 5e are connected at the edges of the base body 2 and are electrically connected to each other. The second external electrode 5 is formed on five surfaces: one end face 2b, a pair of main faces 2c and 2d, and a pair of side faces 2e and 2f. The first electrode portion 5a, the second electrode portion 5b, the third electrode portion 5c, the fourth electrode portion 5d, and the fifth electrode portion 5e are integrally formed. In this embodiment, the surface of the second electrode portion 5b is flush with the main face 2c, and the surface of the third electrode portion 5c is flush with the main face 2d. Also, the surface of the fourth electrode portion 5d is flush with the side face 2e, and the surface of the fifth electrode portion 5e is flush with the side face 2f. With this configuration, it can be said that a part of the second external electrode 5 is embedded in the base body 2.

[0027] As shown in Figure 3, the second external electrode 5 is formed by stacking multiple second external electrode layers 14a, 14b, 14c, 14d, 14e, 14f, 14g, 14h, 14i, 14j, and 14k in the first direction D1. In other words, the stacking direction of the second external electrode layers 14a to 14k is the first direction D1. In the actual second external electrode 5, the multiple second external electrode layers 14a to 14k are integrated to such an extent that the boundaries between the layers are not visible.

[0028] As shown in Figure 4, the first external electrode 4 and the second external electrode 5 each have a first plating layer (electrode portion) M1, a second plating layer M2, and a third plating layer M3. The first plating layer M1, the second plating layer M2, and the third plating layer M3 are arranged in the order of first plating layer M1, second plating layer M2, and third plating layer M3 from the base body 2 side.

[0029] The first plating layer M1 is an Ag plating layer formed by Ag plating. The second plating layer M2 is a Ni plating layer formed by Ni plating. The third plating layer M3 is a Sn plating layer formed by Sn plating. The outer surface of the third plating layer M3 constitutes the surface of the first external electrode 4 and the second external electrode 5. The first plating layer M1 is formed by a transfer method described later. In other words, the first plating layer M1 is not formed by electroplating. The second plating layer M2 and the third plating layer M3 are formed by electroplating.

[0030] The first plating layer M1 has a bonding surface S1 that is bonded to the base body 2, and a plating surface S2 that is opposite to the bonding surface S1. The bonding surface S1 is formed along the shape (uneven shape) of the surface of the base body 2. The plating surface S2 is a flat surface. The surface roughness of the bonding surface S1 is greater than the surface roughness of the plating surface S2. In other words, the surface roughness of the plating surface S2 is less than the surface roughness of the bonding surface S1. The surface roughness (arithmetic mean roughness Ra) of the bonding surface S1 is 1.1 to 10 times the surface roughness of the top surface of the plating surface S2.

[0031] In this embodiment, the thickness of the first plating layer M1 is, for example, 5 to 50 μm. The thickness of the second plating layer M2 is, for example, 5 to 10 μm. The thickness of the third plating layer M3 is, for example, 1 to 10 μm.

[0032] In this embodiment, when the area of ​​the voids in the cross-section is measured in the first plating layer M1, the second plating layer M2, and the third plating layer M3, the porosity (area of ​​voids / total area of ​​conductor) is, for example, 98% or more. The porosity is obtained as follows.

[0033] Cross-sectional photographs are taken of the laminated coil component 1, which includes the first plating layer M1, the second plating layer M2, and the third plating layer M3. The cross-sectional photographs are obtained, for example, by taking a photograph of the cross-section when the laminated coil component 1 is cut by a plane that is parallel to a pair of end faces 2a and 2b and is located at a predetermined distance from one of the end faces 2a. The plane may be located at an equidistant distance from the pair of end faces 2a and 2b. The cross-sectional photographs may also be obtained by taking a photograph of the cross-section when the laminated coil component 1 is cut by a plane that is parallel to a pair of side surfaces 2e and 2f and is located at a predetermined distance from one of the side surfaces 2e. On the obtained cross-sectional photographs, the area of ​​the voids in the cross-sections of the first plating layer M1, the second plating layer M2, and the third plating layer M3 is measured, and the void ratio is calculated.

[0034] As shown in Figure 2, the laminated coil component 1 has a coil 7 arranged within a base body 2. As shown in Figure 3, the coil 7 is constructed by connecting coil conductor layers 20c, 20d, 20e, 20f, 20g, 20h, and 20i to each other. The coil axis of the coil 7 is provided along the first direction D1. The coil conductor layers 20c to 20i are arranged so that at least a portion of them overlap each other when viewed from the first direction D1.

[0035] The coil conductor layers 20c to 20i are made of a conductive material (for example, Ag or Pd). Each of these layers may be made of the same material or different materials.

[0036] As shown in Figure 3, the laminated coil component 1 comprises multiple layers La, Lb, Lc, Ld, Le, Lf, Lg, Lh, Li, Lj, and Lk. The laminated coil component 1 is constructed, for example, by stacking layers La, two Lb layers, Lc layer, Ld layer, Le layer, Lf layer, Lg layer, Lh layer, Li layer, two Lj layers, and Lk layer in that order from the main surface 2c side.

[0037] Layer La is composed of a base layer 10a and a first external electrode layer 12a and a second external electrode layer 14a. The base layer 10a has a shape corresponding to the shapes of the first external electrode layer 12a and the second external electrode layer 14a, and is provided with a defect Ra into which the first external electrode layer 12a and the second external electrode layer 14a are fitted. The base layer 10a and the first external electrode layer 12a and the second external electrode layer 14a as a whole have a complementary relationship with each other.

[0038] Layer Lb is composed of a base layer 10b and a first external electrode layer 12b and a second external electrode layer 14b, which are combined with each other. The base layer 10b has a shape corresponding to the shapes of the first external electrode layer 12b and the second external electrode layer 14b, and is provided with a defect Rb into which the first external electrode layer 12b and the second external electrode layer 14b are fitted. The base layer 10b and the first external electrode layer 12b and the second external electrode layer 14b as a whole have a complementary relationship with each other.

[0039] Layer Lc is composed of a base layer 10c, a first external electrode layer 12c, a second external electrode layer 14c, and a coil conductor layer 20c, all of which are combined with each other. The base layer 10c has a shape corresponding to the shapes of the first external electrode layer 12c, the second external electrode layer 14c, and the coil conductor layer 20c, and is provided with a recess Rc into which the first external electrode layer 12c, the second external electrode layer 14c, and the coil conductor layer 20c are fitted. The base layer 10c and the entirety of the first external electrode layer 12c, the second external electrode layer 14c, and the coil conductor layer 20c are complementary to each other.

[0040] Layer Ld is composed of a base layer 10d, a first external electrode layer 12d, a second external electrode layer 14d, and a coil conductor layer 20d, all of which are combined together. The base layer 10d has a shape corresponding to the shapes of the first external electrode layer 12d, the second external electrode layer 14d, and the coil conductor layer 20d, and is provided with a recess Rd into which the first external electrode layer 12d, the second external electrode layer 14d, and the coil conductor layer 20d are fitted. The base layer 10d and the entirety of the first external electrode layer 12d, the second external electrode layer 14d, and the coil conductor layer 20d are complementary to each other.

[0041] Layer Le is composed of a base layer 10e, a first external electrode layer 12e, a second external electrode layer 14e, and a coil conductor layer 20e, all of which are combined with each other. The base layer 10e has a shape corresponding to the shapes of the first external electrode layer 12e, the second external electrode layer 14e, and the coil conductor layer 20e, and is provided with a recess Re into which the first external electrode layer 12e, the second external electrode layer 14e, and the coil conductor layer 20e are fitted. The base layer 10e and the entirety of the first external electrode layer 12e, the second external electrode layer 14e, and the coil conductor layer 20e are complementary to each other.

[0042] Layer Lf is composed of a base layer 10f, a first external electrode layer 12f, a second external electrode layer 14f, and a coil conductor layer 20f, all of which are combined with each other. The base layer 10f has a shape corresponding to the shapes of the first external electrode layer 12f, the second external electrode layer 14f, and the coil conductor layer 20f, and is provided with a recess Rf into which the first external electrode layer 12f, the second external electrode layer 14f, and the coil conductor layer 20f are fitted. The base layer 10f and the entirety of the first external electrode layer 12f, the second external electrode layer 14f, and the coil conductor layer 20f have a complementary relationship with each other.

[0043] Layer Lg is composed of a base layer 10g, a first external electrode layer 12g, a second external electrode layer 14g, and a coil conductor layer 20g, all of which are combined together. The base layer 10g has a shape corresponding to the shapes of the first external electrode layer 12g, the second external electrode layer 14g, and the coil conductor layer 20g, and is provided with a recess Rg into which the first external electrode layer 12g, the second external electrode layer 14g, and the coil conductor layer 20g are fitted. The base layer 10g and the entirety of the first external electrode layer 12g, the second external electrode layer 14g, and the coil conductor layer 20g have a complementary relationship with each other.

[0044] Layer Lh is composed of a base layer 10h, a first external electrode layer 12h, a second external electrode layer 14h, and a coil conductor layer 20h, all of which are combined with each other. The base layer 10h has a shape corresponding to the shapes of the first external electrode layer 12h, the second external electrode layer 14h, and the coil conductor layer 20h, and is provided with a defect Rh into which the first external electrode layer 12h, the second external electrode layer 14h, and the coil conductor layer 20h are fitted. The base layer 10h and the entirety of the first external electrode layer 12h, the second external electrode layer 14h, and the coil conductor layer 20h are complementary to each other.

[0045] Layer Li is composed of a base layer 10i, a first external electrode layer 12i, a second external electrode layer 14i, and a coil conductor layer 20i, all of which are combined together. The base layer 10i has a shape corresponding to the shapes of the first external electrode layer 12i, the second external electrode layer 14i, and the coil conductor layer 20i, and is provided with a recessed portion Ri into which the first external electrode layer 12i, the second external electrode layer 14i, and the coil conductor layer 20i are fitted. The base layer 10i and the entirety of the first external electrode layer 12i, the second external electrode layer 14i, and the coil conductor layer 20i are complementary to each other.

[0046] Layer Lj is composed of a base layer 10j and a first external electrode layer 12j and a second external electrode layer 14j, which are combined with each other. The base layer 10j has a shape corresponding to the shapes of the first external electrode layer 12j and the second external electrode layer 14j, and is provided with a recess Rj into which the first external electrode layer 12j and the second external electrode layer 14j are fitted. The base layer 10j and the first external electrode layer 12j and the second external electrode layer 14j as a whole have a complementary relationship with each other.

[0047] Layer Lk is composed of a base layer 10k, a first external electrode layer 12k, and a second external electrode layer 14k. The base layer 10k has a shape corresponding to the shapes of the first external electrode layer 12k and the second external electrode layer 14k, and is provided with a defect Rk into which the first external electrode layer 12k and the second external electrode layer 14k are fitted. The base layer 10k and the first external electrode layer 12k and the second external electrode layer 14k as a whole have a complementary relationship with each other.

[0048] An example of a manufacturing method for the laminated coil component 1 according to this embodiment is described below.

[0049] Conductor patterns, which will form the first external electrode layers 12a to 12k, the second external electrode layers 14a to 14k, and the coil conductor layers 20c to 20i, are formed on a substrate (for example, a PET film) by plating. The conductor patterns for the coil conductor layers 20c to 20i may also be formed by screen printing. Next, enamel is applied to the substrate, for example by screen printing, to fill in the area around the conductor patterns. That is, enamel is applied to fill in the steps (margins) created by the conductor patterns. Then, multiple green sheets, which will form the base layers 10a to 10k, are transferred and laminated in this order along with the conductor patterns. A laminate of green sheets is formed by pressing from the lamination direction.

[0050] As described above, a laminate constituting the laminated coil component 1 is formed on a support after heat treatment. Next, the obtained laminate is cut to a predetermined size. After that, the cut laminate is subjected to a binder removal treatment and then heat treatment. The heat treatment temperature is, for example, about 650 to 750°C. After heat treatment, electroplating is applied to the first external electrode 4 and the second external electrode 5 to form the second plating layer M2 and the third plating layer M3. This gives the laminated coil component 1.

[0051] As described above, in the laminated coil component 1 according to this embodiment, the first plating layer M1 has a bonding surface S1 that is bonded to the base body 2, and a plating surface S2 that faces the bonding surface S1 and is formed by plating. Thus, in the laminated coil component 1, the surface of the first plating layer M1 that faces the bonding surface S1, i.e., the surface of the first plating layer M1, is the plating surface S2, so the surface of the first plating layer M1 has few voids (gaps), etc. Therefore, the surface of the first plating layer M1 is a dense surface with few irregularities and defects. Consequently, the surface characteristics of the first external electrode 4 and the second external electrode 5 can be improved in the laminated coil component 1. As a result, when soldering the laminated coil component 1, the wettability of the solder can be improved. Surface characteristics refer to the flatness and density of the surface.

[0052] In the laminated coil component 1 according to this embodiment, the first external electrode 4 and the second external electrode 5 each have a second plating layer M2 and a third plating layer M3, which are arranged on the plating surface S2 of the first plating layer M1. In this configuration, since the plating surface S2 of the first plating layer M1 is a dense surface with few irregularities and few defects, the thickness of the second plating layer M2 and the third plating layer M3 arranged on the plating surface S2 can be reduced. Therefore, the stress generated during the formation of the second plating layer M2 and the third plating layer M3 can be reduced, and thus the peeling of the first external electrode 4 and the second external electrode 5 from the base body 2 can be suppressed.

[0053] In the laminated coil component 1 according to this embodiment, the surface roughness of the bonding surface S1 of the first plating layer M1 is greater than the surface roughness of the plating surface S2 of the first external electrode 4 and the second external electrode 5. In this configuration, the bonding strength between the base body 2 and the first external electrode 4 and the second external electrode 5 can be improved by the anchoring effect. Therefore, in the laminated coil component 1, peeling of the first external electrode 4 and the second external electrode 5 can be further suppressed.

[0054] Furthermore, because the surface roughness of the plated surface S2 is small (it is a flat surface), the surface area of ​​the second plating layer M2 and the third plating layer M3 formed on the plated surface S2 can be reduced. As a result, the area in contact with air of the third plating layer M3 can be reduced, and oxidation of the surface of the third plating layer M3 can be suppressed. Therefore, it is possible to suppress a decrease in the reliability of the laminated coil component 1.

[0055] In this embodiment, the laminated coil component 1 has the first external electrode 4 and the second external electrode 5 formed by a transfer method. As a result, the first plating layer M1 of the first external electrode 4 and the second external electrode 5 can have a bonding surface S1 that conforms to the irregularities of the base body 2, and the plating surface S2 can have a dense surface with few irregularities.

[0056] In the above embodiment, as shown in Figure 4, a configuration in which the first external electrode 4 and the second external electrode 5 each have a first plating layer M1, a second plating layer M2, and a third plating layer M3 was described as an example. As shown in Figure 5, the first external electrode 4 and the second external electrode 5 each have a baked electrode layer E, a first plating layer M1, a second plating layer M2, and a third plating layer M3. The baked electrode layer E and the first plating layer M1 constitute the electrode portion. The electrode portion has a bonding surface S1 that is joined to the base body 2 and a plating surface S2 that faces the bonding surface S1.

[0057] The baked electrode layer E contains a conductive material (for example, Ag or Pd). In this embodiment, the conductive material is Ag. The baked electrode layer E is constructed as a sintered body of a conductive paste containing conductive metal powder (for example, Ag powder) and glass frit (glass component).

[0058] In the configuration of the first external electrode 4 and the second external electrode 5 shown in Figure 5, a baked electrode layer E having a bonding surface S1 that is bonded to the base body 2 is provided, and the baked electrode layer E contains glass frit. Therefore, the bonding strength between the base body 2 and the baked electrode layer E can be ensured. Consequently, delamination of the first external electrode 4 and the second external electrode 5 from the base body 2 can be suppressed.

[0059] [Second Embodiment] Next, a second embodiment will be described. As shown in Figure 6, the laminated coil component 1A according to the second embodiment comprises a base body 2A and a first external electrode 4A and a second external electrode 5B arranged at both ends of the base body 2A, respectively.

[0060] The first external electrode 4A is positioned on one end face 2a. The first external electrode 4A includes two electrode portions: a first electrode portion 4Aa located on the end face 2a and a second electrode portion 4Ac located on the main surface 2d. The first electrode portion 4Aa and the second electrode portion 4Ac are connected at the ridge of the base body 2A and are electrically connected to each other. The first external electrode 4A is formed on two surfaces: one end face 2a and the main surface 2d. The first electrode portion 4Aa and the second electrode portion 4Ac are formed integrally. In this embodiment, the surface of the second electrode portion 4Ac is flush with the main surface 2d. With this configuration, it can be said that a part of the first external electrode 4 is embedded in the base body 2A.

[0061] As shown in Figure 7, the first external electrode 4A is formed by stacking multiple first external electrode layers 12b, 12c, 12d, 12e, 12f, 12g, 12h, 12i, 12j, and 12k in the first direction D1. In other words, the stacking direction of the first external electrode layers 12b to 12k is the first direction D1. In the actual first external electrode 4A, the multiple first external electrode layers 12b to 12k are integrated to such an extent that the boundaries between the layers are not visible.

[0062] As shown in Figure 6, the second external electrode 5A is positioned on one end face 2b. The second external electrode 5A includes two electrode portions: a first electrode portion 5Aa located on the end face 2b and a second electrode portion 5Ac located on the main surface 2d. The first electrode portion 5Aa and the second electrode portion 5Ac are connected at the ridge of the base body 2A and are electrically connected to each other. The second external electrode 5A is formed on two surfaces: one end face 2b and the main surface 2d. The first electrode portion 5Aa and the second electrode portion 5Ac are formed integrally. In this embodiment, the surface of the second electrode portion 5Ac is flush with the main surface 2d. With this configuration, it can be said that a part of the second external electrode 5 is embedded in the base body 2A.

[0063] As shown in Figure 7, the second external electrode 5A is formed by stacking multiple second external electrode layers 14b, 14c, 14d, 14e, 14f, 14g, 14h, 14i, 14j, and 14k in the first direction D1. In other words, the stacking direction of the second external electrode layers 14b to 14k is the first direction D1. In the actual second external electrode 5A, the multiple second external electrode layers 14b to 14k are integrated to such an extent that the boundaries between the layers are not visible.

[0064] Each of the first external electrode 4A and the second external electrode 5A has the same configuration as each of the first external electrode 4 and the second external electrode 5 of the laminated coil component 1. That is, each of the first external electrode 4A and the second external electrode 5A has a first plating layer M1, a second plating layer M2, and a third plating layer M3. Alternatively, each of the first external electrode 4A and the second external electrode 5A has a baked electrode layer E, a first plating layer M1, a second plating layer M2, and a third plating layer M3.

[0065] As shown in Figure 6, the laminated coil component 1A has a coil 7 arranged within the base body 2A. As shown in Figure 7, the coil 7 is constructed by connecting coil conductor layers 20c, 20d, 20e, 20f, 20g, 20h, and 20i to each other. The coil axis of the coil 7 is provided along the first direction D1. The coil conductor layers 20c to 20i are arranged so that at least a portion of them overlap each other when viewed from the first direction D1.

[0066] The laminated coil component 1A comprises multiple layers LAa, LAb, Lac, Lad, LAe, Laf, LAg, LAh, Lai, LAj, and LAk. For example, the laminated coil component 1A is constructed by stacking layers LAa, two layers LAb, Lac, Lad, Lae, Laf, Lag, Lah, Lai, two layers Lai, and Lak in that order from the main surface 2c side.

[0067] Layers LAb, LAc, LAd, LAe, LAf, LAg, LAh, LAi, LAi, and LAk have the same configuration as layers Lb, Lc, Ld, Le, Lf, Lg, Lh, Li, Li, and Lk of the laminated coil component 1A according to the first embodiment. Layer LAa is composed of a base layer 10a.

[0068] As described above, in the laminated coil component 1A according to this embodiment, the first plating layer M1 has a bonding surface S1 that is bonded to the base body 2, and a plating surface S2 that faces the bonding surface S1 and is formed by plating. Thus, in the laminated coil component 1A, the surface of the first plating layer M1 that faces the bonding surface S1, i.e., the surface of the first plating layer M1, is the plating surface S2, so the surface of the first plating layer M1 has few voids (gaps), etc. Therefore, the surface of the first plating layer M1 is a dense surface with few irregularities and defects. Consequently, the surface characteristics of the first external electrode 4A and the second external electrode 5A can be improved in the laminated coil component 1A.

[0069] [Third Embodiment] Next, a third embodiment will be described. As shown in Figure 8, the laminated coil component 1B according to the third embodiment comprises a base body 2B, a first external electrode 4B, and a second external electrode 5B.

[0070] As shown in Figure 9, the base body 2B is constructed by stacking multiple base body layers 30a to 30i. Each base body layer 30a to 30i is stacked in the first direction D1. That is, the first direction D1 is the stacking direction. Base body 2B has multiple stacked base body layers 30a to 30i. In the actual base body 2B, the multiple base body layers 30a to 30i are integrated to such an extent that the boundaries between the layers are not visible.

[0071] Each of the elemental layers 30a to 30i contains multiple metallic magnetic particles. The metallic magnetic particles are composed of a soft magnetic alloy (soft magnetic material). The soft magnetic alloy is, for example, an Fe-Si alloy. If the soft magnetic alloy is an Fe-Si alloy, it may also contain P. The soft magnetic alloy may also be, for example, an Fe-Ni-Si-M alloy. "M" includes one or more elements selected from Co, Cr, Mn, P, Ti, Zr, Hf, Nb, Ta, Mo, Mg, Ca, Sr, Ba, Zn, B, Al, and rare earth elements.

[0072] In the base layers 30a to 30i, the metallic magnetic particles are bonded to each other. This bonding is achieved, for example, by bonding between oxide films formed on the surfaces of the metallic magnetic particles. In the base layers 30a to 30i, the metallic magnetic particles are electrically insulated from each other by bonding between the oxide films. The thickness of the oxide film is, for example, 5 to 60 nm or less. The oxide film may consist of one or more layers.

[0073] Body 2B contains a resin. The resin is present between multiple metallic magnetic particles. The resin is an electrically insulating resin (insulating resin). Insulating resins include, for example, silicone resin, phenolic resin, acrylic resin, or epoxy resin.

[0074] As shown in Figure 8, in the base body 2B, a step is formed on a portion of the main surface 2d. Specifically, both the end face 2a and end face 2b sides of the main surface 2d are recessed towards the main surface 2c side compared to the central part.

[0075] The first external electrode 4B is positioned on one end face 2a side of the main surface 2d. The first external electrode 4B extends along the second direction D2 and the third direction D3, and has a rectangular shape when viewed from the first direction D1. In this embodiment, the surface of the first external electrode 4B is flush with the main surface 2d. With this configuration, it can be said that a part of the first external electrode 4B is embedded in the base body 2. As shown in Figure 9, the first external electrode 4B is composed of a first external electrode layer 44.

[0076] As shown in Figure 8, the second external electrode 5B is positioned on one end face 2b side of the main surface 2d. The second external electrode 5B extends along the second direction D2 and the third direction D3, and has a rectangular shape when viewed from the first direction D1. In this embodiment, the surface of the second external electrode 5B is flush with the main surface 2d. With this configuration, it can be said that a part of the second external electrode 5B is embedded in the base body 2. As shown in Figure 9, the second external electrode 5B is composed of a second external electrode layer 46.

[0077] Each of the first external electrode 4B and the second external electrode 5B has the same configuration as each of the first external electrode 4 and the second external electrode 5 of the laminated coil component 1. That is, each of the first external electrode 4B and the second external electrode 5B has a first plating layer M1, a second plating layer M2, and a third plating layer M3. Alternatively, each of the first external electrode 4B and the second external electrode 5B has a baked electrode layer E, a first plating layer M1, a second plating layer M2, and a third plating layer M3.

[0078] As shown in Figure 8, the laminated coil component 1B has a coil 7B arranged within the base body 2B. As shown in Figure 9, the coil 7B is constructed by connecting coil conductor layers 40b, 40c, 40d, 40e, 40f, 40g, 40h and coil conductor layers 42c, 42d, 42e, 42f, 42g, 42h to each other. The coil axis of the coil 7B is provided along the first direction D1.

[0079] The coil conductor layers 40b to 40h and the coil conductor layers 42c to 42h are composed of a conductive material (for example, Ag or Pd). Each of these layers may be composed of the same material or different materials.

[0080] The laminated coil component 1B comprises multiple layers LBa, LBb, LBc, LBd, LBe, LBf, LBg, LBh, and LBi. For example, the laminated coil component 1B is constructed by stacking two layers LBa, layer LBb, layer LBc, layer LBd, layer LBe, layer LBf, layer LBg, two layers LBh, and layer LBi in that order from the main surface 2c side.

[0081] Layer LBa is composed of a base layer 30a.

[0082] Layer LBb is formed by combining a base layer 30b and a coil conductor layer 40b. The base layer 30b has a shape corresponding to the shape of the coil conductor layer 40b, and is provided with a recess RBb into which the coil conductor layer 40b is fitted. The base layer 30b and the coil conductor layer 40b as a whole have a complementary relationship with each other.

[0083] Layer LBc is composed of a base layer 30c and coil conductor layers 40c and 42c, which are combined with each other. The base layer 30c has a shape corresponding to the shape of the coil conductor layers 40c and 42c, and is provided with a recess RBc into which the coil conductor layers 40c and 42c are fitted. The base layer 30c and the coil conductor layers 40c and 42c as a whole have a complementary relationship with each other.

[0084] Layer LBd is composed of a base layer 30d and coil conductor layers 40d and 42d, which are combined with each other. The base layer 30d has a shape corresponding to the shape of the coil conductor layers 40d and 42d, and is provided with a recess RBd into which the coil conductor layers 40d and 42d are fitted. The base layer 30d and the coil conductor layers 40d and 42d as a whole have a complementary relationship with each other.

[0085] Layer LBe is composed of a base layer 30e and coil conductor layers 40e and 42e, which are combined with each other. The base layer 30e has a shape corresponding to the shape of the coil conductor layers 40e and 42e, and is provided with a recessed portion RBe into which the coil conductor layers 40e and 42e are fitted. The base layer 30e and the coil conductor layers 40e and 42e as a whole have a complementary relationship with each other.

[0086] Layer LBf is composed of a base layer 30f and coil conductor layers 40f and 42f, which are combined with each other. The base layer 30f has a shape corresponding to the shape of the coil conductor layers 40f and 42f, and is provided with a recess RBf into which the coil conductor layers 40f and 42f are fitted. The base layer 30f and the coil conductor layers 40f and 42f as a whole have a complementary relationship with each other.

[0087] Layer LBg is composed of a base layer 30g and coil conductor layers 40g and 42g, which are combined with each other. The base layer 30g has a shape corresponding to the shape of the coil conductor layers 40g and 42g, and is provided with a recess RBg into which the coil conductor layers 40g and 42g are fitted. The base layer 30g and the coil conductor layers 40g and 42g as a whole have a complementary relationship with each other.

[0088] Layer LBh is composed of a base layer 30h and coil conductor layers 40h and 42h combined together. The base layer 30h has a shape corresponding to the shape of the coil conductor layers 40h and 42h, and is provided with a recess RBh into which the coil conductor layers 40h and 42h are fitted. The base layer 30h and the coil conductor layers 40h and 42h as a whole have a complementary relationship with each other.

[0089] Layer LBi is composed of a base layer 30i and a first external electrode layer 44 and a second external electrode layer 46, which are combined with each other. The base layer 30i has a shape corresponding to the shapes of the first external electrode layer 44 and the second external electrode layer 46, and is provided with a recessed portion RBi into which the first external electrode layer 44 and the second external electrode layer 46 are fitted. The base layer 30i and the entirety of the first external electrode layer 44 and the second external electrode layer 46 are complementary to each other.

[0090] As described above, in the laminated coil component 1B according to this embodiment, the first plating layer M1 has a bonding surface S1 that is bonded to the base body 2, and a plating surface S2 that faces the bonding surface S1 and is formed by plating. Thus, in the laminated coil component 1, the surface of the first plating layer M1 that faces the bonding surface S1, i.e., the surface of the first plating layer M1, is the plating surface S2, so the surface of the first plating layer M1 has few voids (gaps), etc. Therefore, the surface of the first plating layer M1 is a dense surface with few irregularities and defects. Consequently, in the laminated coil component 1B, the surface characteristics of the first external electrode 4B and the second external electrode 5B can be improved.

[0091] While embodiments of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0092] The element 2 does not necessarily have to be composed of metallic magnetic particles, and may be composed of ferrite (for example, Ni-Cu-Zn ferrite, Ni-Cu-Zn-Mg ferrite, Cu-Zn ferrite) or dielectric materials.

[0093] In the above embodiment, a configuration in which the first external electrode 4 and the second external electrode 5 each have a first plating layer M1, a second plating layer M2, and a third plating layer M3 was described as an example. However, each of the first external electrode 4 and the second external electrode 5 may further have a plated portion (for example, a Cu plating layer), or the plated portion may be only one layer (for example, an Ag plating layer). When there is only one plated portion, the electrical resistivity of the DC resistance can be reduced.

[0094] The number of coil conductors is not limited to the values ​​mentioned above. [Explanation of symbols]

[0095] 1,1A,1B...Laminated coil component, 2,2A,2B...Base body, 4...First external electrode, 5...Second external electrode, 7,7B...Coil, 10a~10k,30a~30i...Base body layer, E...Baked electrode layer, M1...First plating layer (electrode part), M2...Second plating layer (plating layer), M3...Third plating layer (plating layer), S1...Bonding surface, S2...Plated surface.

Claims

1. The base body and, A coil arranged within the aforementioned body, The body comprises an external electrode arranged on the aforementioned body, The external electrode has a bonding surface that is joined to the base body, and a plated surface that faces the bonding surface and is formed by plating, and has an electrode portion that is embedded in the base body, at least a part of it. The electrode portion has the bonding surface and a baked electrode layer containing glass components, which is a coil component.

2. The coil component according to claim 1, wherein the external electrode has one or more plating layers disposed on the plated surface of the electrode portion.

3. The coil component according to claim 1 or 2, wherein the base body is constructed by laminating base layers containing a plurality of metallic magnetic particles of a soft magnetic material.

4. The coil component according to claim 1 or 2, wherein the surface roughness of the bonding surface is greater than the surface roughness of the plated surface.

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