JP7743922B2 - Electronic components and their manufacturing method - Google Patents

Description

The present invention relates to electronic components and methods for manufacturing the same.

A conventional coil component is described in JP 2021-40160 A (Patent Document 1). This coil component has an element body and an external electrode provided on the surface of the element body. The external electrode comprises a metal electrode and a resin electrode that covers the entire surface of the metal electrode. In this case, taking into account an increase in DC resistance, the resin electrode is provided so that the end portions are thick and the remaining portions are thinner. This relieves stress and suppresses the occurrence of cracks.

Japanese Patent Application Laid-Open No. 2021-40160

However, in the above coil components, the highly resistive resin electrodes cover the entire surface of the metal electrodes, so the effect of reducing DC resistance is insufficient. In addition, it is difficult to precisely identify the path through which DC flows in coil components, making it difficult to reduce DC resistance by adjusting the thickness of the resin electrodes.

The present disclosure aims to provide an electronic component and a manufacturing method thereof that can reduce deflection stress while suppressing an increase in DC resistance.

In order to solve the above problems, an electronic component according to one aspect of the present disclosure comprises:
The base body and
an external electrode provided on the element body,
The element body is
A first end surface;
a second end surface facing the first end surface;
a bottom surface perpendicular to the first end surface and the second end surface,
The external electrode is
a first external electrode provided on the first end surface side;
a second external electrode provided on the second end surface side,
The first external electrode is
a metal electrode provided on at least a portion of the bottom surface;
a resin electrode that covers a part of the portion of the metal electrode that is provided on the bottom surface,
On the bottom surface, the metal electrode has an exposed portion that is exposed from the resin electrode.

The exposed portion of a metal electrode is the portion of the metal electrode that is not covered by the resin electrode. The exposed portion includes not only the portion of the metal electrode that is exposed to the outside, but also the portion that is covered by a material other than the resin electrode, such as a metal film or plating layer.

According to the above embodiment, only a portion of the metal electrode provided on the bottom surface is covered by the resin electrode, so when an electronic component is mounted on the bottom surface, the stress applied to the element body due to bending of the board (hereinafter referred to as bending stress) can be reduced while suppressing the increase in DC resistance caused by the provision of the resin electrode.

In one aspect, the electronic component further includes a plating layer on the bottom surface that covers at least a portion of the first external electrode.

According to the above embodiment, when electronic components are mounted on the bottom side, they are soldered via the plating layer, improving adhesion. Furthermore, the plating layer prevents the solder from penetrating into the electronic components.

In one aspect, the direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
On the bottom surface,
The exposed portion and the resin electrode are arranged side by side in the W direction.

According to the above embodiment, the deflection stress is further reduced.

In one aspect, the direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
The exposed portions are provided on both ends of the bottom surface in the W direction.

In one aspect, the direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
On the bottom surface,
The resin electrodes are provided so as to sandwich the exposed portion from both sides in the W direction.

According to the above embodiment, it is possible to increase the number of current paths that do not pass through the resin electrode, further suppressing the increase in DC resistance.

In one embodiment, the bottom surface
The maximum width of the resin electrode in the W direction is greater than the maximum width of the exposed portion adjacent to the resin electrode in the W direction.

According to the above embodiment, the deflection stress is further reduced.

In one embodiment, the bottom surface
The maximum width of the exposed portion sandwiched between the two resin electrodes is 10 μm or more and 160 μm or less.

According to the above embodiment, it is easy to balance the effect of reducing deflection stress and the effect of suppressing an increase in DC resistance.

In one aspect,
In the first external electrode,
the metal electrode is further provided on a portion of at least one of the first end surface and the second end surface,
The resin electrode further covers a part of a portion of the metal electrode provided on at least one of the first end surface and the second end surface.

According to the above embodiment, the deflection stress is further reduced.

In one aspect,
The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
In the first external electrode,
The resin electrode provided on a portion of at least one of the first end face and the second end face is provided in a region of the end face on which the resin electrode is provided, from the bottom side to 1/2 of the height of the element body in the T direction.

According to the above embodiment, when electronic components are mounted on the bottom side, the DC resistance can be further reduced while maintaining the effect of reducing deflection stress.

In one aspect,
The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
The resin electrode provided on the bottom surface protrudes outward in the T direction from the surface of the metal electrode provided on the bottom surface.

According to the above embodiment, when an electronic component is mounted on the bottom side, solder can penetrate into the irregularities formed by the resin electrodes, improving the connection strength between the circuit board and the electronic component. The plating layer is also less likely to peel off because solder can penetrate into the irregularities formed by the resin electrodes.

In one aspect, the electronic component further comprises a metal film covering at least the exposed portion of the metal electrode that is exposed from the resin electrode.

According to the above embodiment, it is possible to increase the number of current paths that do not pass through the resin electrode, further suppressing the increase in DC resistance.

In one aspect, at least on the bottom surface, the surface of the resin electrode and the surface of the metal film are flush.

According to the above embodiment, when electronic components are mounted on the bottom side, misalignment and tilt of the electronic components are reduced, allowing them to be mounted with high precision.

In one aspect, the resin electrode provided on the bottom surface is symmetrical with respect to a line that passes through the center of the bottom surface and extends in an L direction in which the first end surface and the second end surface face each other.
In one embodiment, the resin electrode provided on the bottom surface has a uniform thickness.

According to the above embodiment, when electronic components are mounted on the bottom side, rattle and tilt of the electronic components are reduced.

In one aspect,
The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
In a cross section of the resin electrode, the cross section is parallel to a T-W plane formed by a line extending in the W direction and a line extending in the T direction,
The width of a first surface of the resin electrode provided on the bottom surface on the metal electrode side is narrower than the width of a second surface of the resin electrode on the opposite side to the first surface.

According to the above embodiment, peeling of the plating layer from the contact area between the metal electrode and the resin electrode is suppressed. In addition, the anchor effect acts, improving the solder joint strength between the circuit board and the electronic component.

In one aspect, the electronic component may further include a coil provided inside the element body. The coil is electrically connected to the first external electrode and the second external electrode.

According to the above embodiment, the increase in DC resistance is suppressed, so that even in coil components through which large currents may flow, heat generation, etc. can be suppressed while bending stress is reduced.

Furthermore, a method for manufacturing an electronic component according to one aspect of the present disclosure includes:
preparing an element body having a first end surface, a second end surface opposite to the first end surface, and a bottom surface perpendicular to the first end surface and the second end surface;
providing a first external electrode on the first end surface side;
and providing a second external electrode on the second end surface side, wherein the step of providing the first external electrode includes:
forming a metal electrode on at least a portion of the bottom surface on the first end surface side;
forming a resin electrode that covers a portion of the portion of the metal electrode that is provided on the bottom surface;
In the step of forming the resin electrode, an exposed portion of the metal electrode that is exposed from the resin electrode is formed.

According to the above embodiment, in an electronic component having a metal electrode and a resin electrode, an exposed portion of the metal electrode can be formed that is exposed from the resin electrode.

The step of forming the resin electrode includes:
applying a conductive resin composition containing a photosensitive resin to at least a portion of the portion of the metal electrode provided on the bottom surface;
irradiating a portion of the applied resin composition with laser light;
The method may further comprise the step of removing the part or remainder of the resin composition after the irradiating step.

According to the above embodiment, resin electrodes of the desired shape and thickness can be formed with high precision.

After the step of forming the resin electrode,
The method may further comprise the step of forming a metal film that covers at least the portion of the metal electrode that is exposed from the resin electrode.

According to the above embodiment, electronic components with lower DC resistance can be obtained.

An electronic component according to one aspect of the present disclosure can reduce the stress on the element body due to bending of the substrate while suppressing an increase in DC resistance.

FIG. 1 is a perspective view showing a first embodiment of a coil component. 2 is a cross-sectional view taken along the line XX in FIG. 1. 2 is a cross-sectional view taken along the line YY in FIG. 1. FIG. 2 is an exploded plan view of the coil component. FIG. 10 is a perspective view showing a coil component soldered to a pad provided on a circuit board. 2 is a cross-sectional view showing a modified example of the coil component according to the first embodiment, the cross-sectional view corresponding to the YY cross-sectional view of FIG. 1. FIG. 1. FIG. 4 is a cross-sectional view showing another modified example of the coil component according to the first embodiment, corresponding to the YY cross-sectional view of FIG. 1. FIG. 4 is a cross-sectional view showing yet another modified example of the coil component according to the first embodiment, the cross-sectional view corresponding to the YY cross-sectional view of FIG. FIG. 10 is a perspective view showing a comparative coil component. FIG. 10 is a perspective view showing another comparative coil component. FIG. 10 is a perspective view showing a second embodiment of the coil component. FIG. 10 is a perspective view showing a third embodiment of a coil component. FIG. 10 is a perspective view showing a fourth embodiment of a coil component. FIG. 10 is a perspective view showing a fifth embodiment of a coil component. FIG. 10 is a perspective view showing a sixth embodiment of a coil component. FIG. 13 is a perspective view showing another modified example of the coil component according to the sixth embodiment. FIG. 13 is a perspective view showing yet another modified example of the coil component according to the sixth embodiment. FIG. 10 is a perspective view showing a seventh embodiment of a coil component. FIG. 13 is a perspective view showing an eighth embodiment of the coil component.

The electronic component, which is one aspect of the present disclosure, will be described in detail below with reference to the illustrated embodiments. The drawings include some schematic illustrations and may not reflect actual dimensions or proportions.

[First embodiment]
<Configuration>
FIG. 1 is a perspective view showing a first embodiment of a coil component, with the resin electrodes hatched for convenience. FIG. 2A is an X-X cross-sectional view of FIG. 1, which is an LT cross-sectional view of the resin electrode. FIG. 2B is a Y-Y cross-sectional view of FIG. 1, which is a TW cross-sectional view of the resin electrode. FIG. 3 is an exploded plan view of the coil component, showing a view along the T direction from the bottom to the top. For convenience, the external electrodes are omitted from FIG. 3.

The L direction is the length direction of the coil component 1, the W direction is the width direction of the coil component 1, and the T direction is the height direction of the coil component 1. Hereinafter, the forward direction of the T direction will be referred to as the upper side, and the reverse direction of the T direction will also be referred to as the lower side. The LT cross-section shown in Figure 2A is obtained by cutting the resin electrode along a plane parallel to the plane formed by a line extending in the L direction and a line extending in the T direction. The TW cross-section shown in Figure 2B is obtained by cutting the resin electrode along a plane parallel to the plane formed by a line extending in the T direction and a line extending in the W direction.

As shown in Figures 1, 2A, 2B and 3, the coil component 1 has a base body 10, a coil 20 provided inside the base body 10, and a first external electrode 30A and a second external electrode 30B provided on the surface of the base body 10 and electrically connected to the coil 20.

Coil component 1 is electrically connected to wiring on a circuit board (not shown) via first and second external electrodes 30A and 30B. Coil component 1 is used, for example, as a noise removal filter in electronic devices such as personal computers, DVD players, digital cameras, TVs, mobile phones, and car electronics.

The coil 20 has a plurality of coil wirings 22 stacked along the T direction, via wirings 24 extending along the T direction and connecting adjacent coil wirings 22 in the T direction, a first lead conductor 23A connected to the coil wiring 22 in the top layer, and a second lead conductor 23B connected to the coil wiring 22 in the bottom layer.

Each coil wiring 22 is provided in each of the multiple magnetic layers 21 except for the topmost magnetic layer 21 and the bottommost magnetic layer 21. Each coil wiring 22 is wound along a plane parallel to the WL plane, arranged side by side in the T direction, and electrically connected in series to form a spiral. Each coil wiring 22 is wound with less than one turn. Via wiring 24 penetrates the magnetic layer 21 in the T direction. Coil wiring 22 adjacent in the T direction are electrically connected in series via the via wiring 24.

The first extraction conductor 23A extends linearly from the end of the top layer coil wiring 22 opposite the end to which the via wiring 24 is connected to the first end surface 15A of the element body 10. The first extraction conductor 23A is exposed from the first end surface 15A and is electrically connected to the first external electrode 30A. The second extraction conductor 23B extends linearly from the end of the bottom layer coil wiring 22 opposite the end to which the via wiring 24 is connected to the second end surface 15B of the element body 10. The second extraction conductor 23B is exposed from the second end surface 15B and is electrically connected to the second external electrode 30B.

The coil wiring 22 and the first and second lead conductors 23A, 23B are formed of a conductive material such as Ag or Cu. Neither the coil wiring 22 nor the first and second lead conductors 23A, 23B are formed on the magnetic layer 21 located at the outermost side of the laminate in the T direction.

The number of layers of the coil wiring 22 is not particularly limited. By firing this laminate, a coil 20 that forms a spiral along the T direction is obtained. The number of layers of the magnetic layer 21 arranged at the outermost position in the T direction of the laminate, i.e., the magnetic layer 21 on which neither the coil wiring 22 nor the first and second lead conductors 23A, 23B are formed, is also not particularly limited, and may be two or more layers each.

Element body 10 is formed in a generally rectangular parallelepiped shape. The surface of element body 10 has a first end face 15A, a second end face 15B opposite first end face 15A, a bottom face 16 perpendicular to first and second end faces 15A and 15B, a top face 17 opposite bottom face 16, and a first side face 18A and a second side face 18B located between first end face 15A and second end face 15B and other than bottom face 16 and top face 17.

When the bottom surface 16 is perpendicular to the first and second end surfaces 15A and 15B, the angle formed between the bottom surface 16 and the first end surface 15A and the second end surface 15B is greater than or equal to 80° and less than or equal to 100°.

The first end surface 15A and the second end surface 15B face each other in the L direction. The bottom surface 16 and the top surface 17 face each other in the T direction. The first side surface 18A and the second side surface 18B face each other in the W direction.

The L direction is specifically a direction perpendicular to the first end face 15A and the second end face 15B. The W direction is specifically a direction perpendicular to the first side face 18A and the second side face 18B. The W direction is perpendicular to the L direction at the bottom face. The W direction is also perpendicular to the L direction and is parallel to the mounting surface of the coil component 1 (typically, the bottom face 16). The T direction is specifically a direction perpendicular to the bottom face 16 and the top face 17. The T direction is perpendicular to the L direction and the W direction.

The bottom surface 16 is the area visible when the element body 10 is viewed from below. The bottom surface 16 is located between the first end surface 15A and the second end surface 15B, and is continuous with both the first end surface 15A and the second end surface 15B. The top surface 17 is the area visible when the element body 10 is viewed from above. In the illustrated example, the bottom surface 16 and the top surface 17 each have curved portions at the ends facing the first and second end surfaces 15A and 15B and the first and second side surfaces 18A and 18B. The first side surface 18A is the area visible when the element body 10 is viewed from the W direction, excluding the bottom surface 16 and the top surface 17. The second side surface 18B is similar to the first side surface 18A. In the illustrated example, the first and second side surfaces 18A and 18B each have a curved portion at the end on the side of the first and second end surfaces 15A and 15B. The first end surface 15A is the area visible when the element body 10 is viewed from the L direction, excluding the bottom surface 16, the top surface 17, and the two side surfaces 18A and 18B. The second end surface 15B is similar to the first end surface 15A.

The height T of the base body 10 is the distance from the lowest end of the bottom surface 16 to the highest end of the top surface 17 along the T direction.

The element body 10 is provided with at least a first external electrode 30A and a second external electrode 30B. The first external electrode 30A is provided on the first end face 15A side, and the second external electrode 30B is provided on the second end face 15B side.

The first external electrode 30A comprises a metal electrode 31 provided on at least a portion of the bottom surface, and a resin electrode 32 covering a portion of the portion of the metal electrode 31 provided on the bottom surface. The metal electrode 31 is further provided on at least a portion of one of the first end surfaces 15A. The resin electrode 32 further covers a portion of the portion of the metal electrode 31 provided on at least one of the first end surfaces 15A. The first external electrode 30A is electrically connected to one end of the coil 20.

The second external electrode 30B comprises a metal electrode 31 provided on at least a portion of the bottom surface, and a resin electrode 32 covering a portion of the portion of the metal electrode 31 provided on the bottom surface. The metal electrode 31 is further provided on at least a portion of one of the second end surfaces 15B. The resin electrode 32 further covers a portion of the portion of the metal electrode 31 provided on at least one of the second end surfaces 15B. The second external electrode 30B is electrically connected to the other end of the coil 20.

The first external electrode 30A and the second external electrode 30B are plane-symmetric with respect to the TW cross section passing through the center of the element body 10, and are point-symmetric with respect to the center of the element body 10.

The configuration of the first external electrode 30A is described below. The description of the first external electrode 30A can be applied to the second external electrode 30B by replacing the first end surface 15A with the second end surface 15B.

<Configuration of First External Electrode>
The first external electrode 30A comprises a metal electrode 31 that covers the entire first end face 15A, the bottom face 16, the top face 17, and the ends of the first side face 18A and the second side face 18B on the first end face 15A side, and a resin electrode 32 that covers a portion of the metal electrode 31.

The metal electrode 31 has a first exposed portion 311, a second exposed portion 312, and a third exposed portion 313. The resin electrode 32 has a first resin electrode 321 and a second resin electrode 322.

Figure 4 shows a perspective view of a coil component soldered to a pad on a circuit board. As shown in Figure 4, the coil component 1 is soldered to a pad 6 arranged on a circuit board (not shown) with the bottom surface 16 serving as the mounting surface. Current flows, for example, from the circuit board through the first external electrode 30A, coil 20, and second external electrode 30B of the coil component 1 in this order. It has been found that the current density is higher on the bottom surface 16 side than on the first end surface 15A side. Therefore, by having the first, second, and third exposed portions 311, 312, and 313 of the metal electrode 31 exposed from the resin electrode 32 at least on the bottom surface 16, the increase in DC resistance that may arise from the first and second resin electrodes 321 and 322 is more effectively suppressed.

Furthermore, as shown in Figure 4, when the coil component 1 is soldered to a circuit board on the first and second end faces 15A and 15B of the bottom surface 16, the flexural stress acts in a direction that causes the element body 10 to bend in the T direction, starting from the first and second end faces 15A and 15B of the bottom surface 16. Therefore, by providing the first and second resin electrodes 321 and 322 on the bottom surface 16, the flexural stress can be more effectively reduced.

In other words, by providing the first and second resin electrodes 321, 322 at least on the bottom surface 16 and providing the first, second, and third exposed portions 311, 312, and 313 on the bottom surface 16, it is possible to effectively reduce the bending stress while suppressing the increase in DC resistance caused by the provision of the first and second resin electrodes 321, 322.

The first and second resin electrodes 321, 322 can also suppress cracking of the element body 10 due to the difference in thermal expansion between the element body 10 and the metal electrode 31, and cracking of the solder due to the difference in thermal expansion between the solder and the element body 10 after mounting.

The metal electrode 31 is obtained by firing a conductive paste containing, for example, conductive particles such as Ag powder and glass. The metal electrode 31 is also called the base electrode and is directly connected to the coil 20. The metal electrode 31 is usually made of the same material as the coil wiring 22 and the first and second lead conductors 23A and 23B.

The thickness of the metal electrode 31 is, for example, 1 μm or more and 100 μm or less, and may be 5 μm or more and 80 μm or less. The thickness of the metal electrode 31 is the thickness at approximately the center of the metal electrode 31.

The approximate center of the metal electrode 31 refers to the center in the W direction of the metal electrode 31 in a TW cross section that bisects the metal electrode 31 provided on the bottom surface 16 or the top surface 17 of the first external electrode 30A in the L direction, or the center in the T direction of the metal electrode 31 in an LT cross section that bisects the metal electrode 31 provided on the first end surface 15A of the first external electrode 30A in the W direction. The thickness of the metal electrode 31 can be measured using an image of the TW cross section or LT cross section exposed by polishing the coil component 1, taken with a scanning electron microscope (SEM).

The metal electrode 31 in the first external electrode 30A and the metal electrode 31 in the second external electrode 30B may be the same or different in material and thickness.

The resin electrode 32 contains an organic material and is conductive. The resin electrode 32 is formed, for example, from a resin composition containing conductive particles such as Ag powder and a photosensitive resin.

The thickness of the resin electrode 32 is, for example, 1 μm or more and 100 μm or less, and may be 5 μm or more and 20 μm or less. The thickness of the resin electrode 32 is the thickness at approximately the center of the resin electrode 32.

The approximate center of the resin electrode 32 refers to the center in the W direction of any one resin electrode 32 provided on the bottom surface 16 or top surface 17 of the first external electrode 30A in a TW cross section that bisects the resin electrode 32 in the L direction, or the center in the T direction of any one resin electrode 32 provided on the first end surface 15A of the first external electrode 30A in an LT cross section that bisects the resin electrode 32 in the W direction. The thickness of the resin electrode 32 can be measured using an SEM image of the TW cross section or LT cross section exposed by polishing the coil component 1.

The thickness of the resin electrode 32 is uniform. In particular, if the thickness of the resin electrode 32 provided on the bottom surface 16 is uniform, rattle and tilt of the coil component 1 are suppressed when the coil component 1 is mounted on the bottom surface 16.

"Uniform thickness" means that the thickness of the end of any one resin electrode 32 on any surface is within ±20% of the thickness at the approximate center. The end of the resin electrode 32 refers to one of three points on the TW cross section used to determine the approximate center of the resin electrode 32, which divides the resin electrode 32 into four equal parts in the W direction, excluding the middle (corresponding to the approximate center of the resin electrode 32). Alternatively, on the LT cross section used to determine the approximate center of the resin electrode 32, one of three points on the LT cross section used to determine the approximate center of the resin electrode 32, which divides the resin electrode 32 into four equal parts in the T direction, excluding the middle (corresponding to the approximate center of the resin electrode 32).

When multiple resin electrodes 32 are provided on the same surface, the materials and thicknesses of the multiple resin electrodes 32 may be the same or different. In this embodiment, the thicknesses of the first resin electrode 321 and the second resin electrode 322 are the same on any surface and are the same on all surfaces.

The thickness of multiple resin electrodes 32 on any given surface means that the thickness of any one resin electrode 32 on that surface is within ±20% of the average thickness of the multiple resin electrodes 32 on that surface.

The coil component 1 may include a plating layer 40 on the bottom surface 16 that covers at least a portion of the first external electrode 30A. The plating layer 40 is not directly connected to the coil 20, but is electrically connected to the first external electrode 30A via the first, second, and third exposed portions 311, 312, and 313 and/or the first and second resin electrodes 321 and 322. The plating layer 40 is typically formed of a material different from that of the coil wiring 22 and the first and second lead conductors 23A and 23B. The plating layer 40 is a thin metal film formed by surface treatment (typically, a wet plating method).

The metal contained in the plating layer 40 is, for example, nickel and tin. The plating layer 40 may be a single layer, or may be two or more layers. The plating layer 40 may have a laminated structure of a nickel plating layer and a tin plating layer. The thickness of each plating layer 40 is not particularly limited, and is, for example, 2 μm or more and 15 μm or less.

In Figure 2A, the plating layer 40 is indicated by a two-dot chain line. In Figure 2A, the plating layer 40 covers the entire first external electrode 30A and is electrically connected to the first external electrode 30A. Therefore, the plating layer 40 causes current that tends to concentrate on the bottom surface 16 side to also flow to the first end surface 15A side, and to the circuit board, for example, via the solder fillet. This reduces the impact of increased DC resistance due to the provision of the first and second resin electrodes 321, 322. The plating layer 40 may cover only a portion of the first external electrode 30A.

<Detailed Configuration of First External Electrode>
The resin electrode 32 and the metal electrode 31 of the first external electrode 30A will be described in detail below.
The resin electrode 32 has two strip-shaped first and second resin electrodes 321 and 322. The strip-shaped first and second resin electrodes 321 and 322 extend continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The first resin electrode 321 and the second resin electrode 322 are arranged side by side in the W direction with a gap between them.

The metal electrode 31 has first, second, and third exposed portions 311, 312, and 313 exposed from the resin electrode 32. The first exposed portion 311 is located at the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and facing the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second exposed portion 312 is located between the first resin electrode 321 and the second resin electrode 322 and is a strip-like portion that extends continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The third exposed portion 313 is located at the end of the second side surface 18B on the first end surface 15A side, the end of the bottom surface 16 on the first end surface 15A side and the second side surface 18B side, the end of the top surface 17 on the first end surface 15A side and the second side surface 18B side, and the end of the first end surface 15A on the second side surface 18B side.

The first exposed portion 311, the first resin electrode 321, the second exposed portion 312, the second resin electrode 322 and the third exposed portion 313 are arranged in a row in the W direction in this order from the first side surface 18A side, so that the resin electrodes and exposed portions alternate.

The first and second resin electrodes 321, 322 are provided in a strip shape from the bottom surface 16 to the top surface 17, which further enhances the effect of reducing flexural stress. Furthermore, the second exposed portion 312 is provided between the first resin electrode 321 and the second resin electrode 322, which further reduces the increase in DC resistance. In addition, the first exposed portion 311 and the third exposed portion 313 are provided on the first and second side surfaces 18A, 18B of the element body 10, respectively, which further reduces the increase in DC resistance.

By providing the first and second resin electrodes 321, 322 on the first end surface 15A as well, cracking of the solder is more easily suppressed when the coil component 1 is mounted using the bottom surface 16 as the mounting surface, as shown in FIG. 4. The fillet of the solder 5 is typically formed to cover at least a portion of the first external electrode 30A on the first end surface 15A. The first and second resin electrodes 321, 322 can suppress cracking of the solder 5 due to the difference in thermal expansion between the solder 5 and the element body 10.

The first resin electrode 321 and the second resin electrode 322 are arranged symmetrically with respect to the LT cross section passing through the center of the base body 10. This helps to suppress rattle and tilt of the coil component 1 during mounting.

The first, second, and third exposed portions 311, 312, and 313 each include a first metal portion 3101 provided on the bottom surface 16, a second metal portion 3102 provided on the first end surface 15A, and a third metal portion 3103 provided on the top surface 17. The first and third exposed portions 311 and 313 are also provided on the first end surface 15A side of the first and second side surfaces 18A and 18B, respectively. The first and second resin electrodes 321 and 322 each include a first resin portion 3201 provided on the bottom surface 16, a second resin portion 3202 provided on the first end surface 15A, and a third resin portion 3203 provided on the top surface 17. In the first external electrode 30A in FIG. 2A, the boundary between the first resin portion 3201 and the second resin portion 3202, and the boundary between the second resin portion 3202 and the third resin portion 3203 are indicated by dashed lines.

(First metal portion and first resin portion)
The first metal portion 3101 and the first resin portion 3201 will be described below.
Three first metal portions 3101 are provided. The three first metal portions 3101 are part of the first, second, and third exposed portions 311, 312, and 313, respectively. Two first resin portions 3201 are provided. The two first resin portions 3201 are part of the first and second resin electrodes 321 and 322, respectively. On the bottom surface 16, the first metal portions 3101 and the first resin portions 3201 are arranged alternately in the W direction. Two of the first metal portions 3101 are provided at both ends of the bottom surface 16 in the W direction.

The fact that the first metal portions 3101 and the first resin portions 3201 are alternately arranged in the W direction can be rephrased as the boundary line BL _B between the first metal portions 3101 and the first resin portions 3201 extending along the L direction. The fact that the boundary line BL _B extends along the L direction means that the acute angle θ between the boundary line BL _B and the L direction is between 0° and 30°. The boundary line BL _B may be a straight line, may include a curved portion, or may meander. When the boundary line between the first metal portion 3101 and the first resin portion 3201 on the bottom surface 16 is curved or meandering, the straight line connecting both ends of the boundary line is defined as the boundary line BL _B. For convenience, the boundary line BL _B on the top surface 17 is shown in FIG. 1 . The boundary line BL _B on the bottom surface 16 is shown in the same manner as the boundary line BL _B on the top surface 17 in FIG. 1 .

The two first resin portions 3201 are arranged symmetrically with respect to a line that passes through the center of the bottom surface 16 and extends in the L direction. This reduces rattle and tilt of the coil component 1 mounted on the bottom surface 16.

In the first external electrode 30A, the total coverage of the first resin portions 3201 is approximately 50%. The coverage of the first resin portions 3201 is not particularly limited and may be set appropriately taking into consideration the balance between the effect of suppressing resistance increase and the effect of reducing deflection stress. The coverage of the first resin portions 3201 may be 30% or more and 70% or less. When the coverage of the first resin portions 3201 is 50% or more, the effect of reducing deflection stress can be particularly improved. The coverage of the first resin portions 3201 is calculated by dividing the total area of the first resin portions 3201 in the first external electrode 30A by the total area of all first resin portions 3201 and all first metal portions 3101.

The maximum width Wb of the first resin portion 3201 in the W direction is wider than the maximum width Wa1 of the first metal portion 3101 adjacent to the first resin portion 3201 in the W direction. This further reduces the above-mentioned deflection stress. In the coil component 1, the ratio of the maximum width Wb of the first resin portion 3201 to the maximum width Wa1 of the first metal portion 3101: Wb/Wa1, is approximately 1.7. The above Wb/Wa1 may be greater than 1 and less than or equal to 5, or may be greater than or equal to 1.2 and less than or equal to 4.5.

The maximum width Wa1 is the longest of the lengths in the W direction of the first metal parts 3101 adjacent to the first resin part 3201 in the projection of the bottom surface 16. If there are two first metal parts 3101 adjacent to the first resin part 3201, the maximum width Wa of each first metal part 3101 is calculated, and the larger of these is taken as Wa1.

The maximum width Wb is the maximum length of the first resin part 3201 in the W direction in a projection of the bottom surface 16.

The maximum width Wa2 of the first metal portion 3101 sandwiched between two adjacent first resin portions 3201 is approximately 110 μm. This makes it easy to adjust the coverage of the first resin portion 3201. The maximum width Wa2 may be 10 μm or more and 160 μm or less, or 10 μm or more and 120 μm or less.

The maximum width Wa2 is the longest of the lengths in the W direction of the first metal portion 3101 sandwiched between two adjacent first resin portions 3201 in a projection of the bottom surface 16. If there are two first metal portions 3101 sandwiched between two adjacent first resin portions 3201, the maximum width Wa of each first metal portion 3101 is calculated, and the larger of these is designated as Wa2. The maximum widths Wa1 and Wa2 may be the same.

(Second Metal Portion and Second Resin Portion)
Next, the second metal portion 3102 and the second resin portion 3202 will be described.
Three second metal portions 3102 are provided. The three second metal portions 3102 are part of the first, second, and third exposed portions 311, 312, and 313, respectively. Two second resin portions 3202 are provided. The two second resin portions 3202 are part of the first and second resin electrodes 321 and 322, respectively. On the first end surface 15A, the second metal portions 3102 and the second resin portions 3202 are arranged alternately in the W direction. Two of the second metal portions 3102 are provided at each end of the first end surface 15A in the W direction.

The second metal portion 3102 and the second resin portion 3202 being arranged alternately in the W direction can be said to have a boundary line _BLt between the second metal portion 3102 and the second resin portion 3202 extending along the T direction. The boundary line _BLt extending along the T direction means that the acute angle θ formed by the boundary line _BLt and the T direction is between 0° and 30°. The boundary line _BLt may be a straight line, may include a curved portion, or may be serpentine. When the boundary line between the first metal portion 3101 and the first resin portion 3201 on the first end surface 15A is curved or serpentine, the straight line connecting both ends of the boundary line is defined as the boundary line _BLt .

The two second resin portions 3202 are each provided across from the bottom surface 16 side of the first end face 15A to the top surface 17 side. Each of the second resin portions 3202 may be provided in an area extending from the bottom surface 16 side of the first end face 15A to 1/2 of the height of the element body 10. Each of the second resin portions 3202 may be provided in an area extending from the bottom surface 16 side of the first end face 15A to 1/3 of the height of the element body 10. Each of the second resin portions 3202 may be provided in an area extending from the bottom surface 16 side of the first end face 15A to 1/6 of the height of the element body 10.

In the first external electrode 30A, the total coverage of the second resin portion 3202 is approximately 50%. The coverage of the second resin portion 3202 is not particularly limited and may be set appropriately taking into consideration the balance between the effect of suppressing resistance increase and the effect of reducing deflection stress. The coverage of the second resin portion 3202 may be 30% or more and 70% or less. If the coverage of the second resin portion 3202 is 50% or more, the effect of reducing deflection stress can be particularly improved. The coverage of the second resin portion 3202 is calculated in the same way as the first resin portion 3201.

The maximum width Wb of the second resin portion 3202 in the W direction is wider than the maximum width Wa1 of the second metal portion 3102 adjacent to the second resin portion 3202 in the W direction. This further reduces the above-mentioned deflection stress. In the coil component 1, the ratio of the maximum width Wb of the second metal portion 3102 to the maximum width Wa1 of the second metal portion 3102: Wb/Wa1, is approximately 1.7. The above Wb/Wa1 may be greater than 1 and less than or equal to 5, or may be greater than or equal to 1.2 and less than or equal to 4.5. The maximum width Wa1 of the second metal portion 3102 is calculated in the same way as for the first metal portion 3101. The maximum width Wb of the second resin portion 3202 is calculated in the same way as for the first resin portion 3201.

The maximum width Wa2 of the second metal portion 3102 sandwiched between two adjacent second resin portions 3202 is approximately 110 μm. The maximum width Wa2 may be 10 μm or more and 160 μm or less, or 10 μm or more and 120 μm or less. The maximum width Wa2 of the second metal portion 3102 is calculated in the same manner as the first metal portion 3101. The maximum widths Wa1, Wa2, and Wb at the first end surface 15A are shown in the same manner as the maximum widths Wa1, Wa2, and Wb at the bottom surface 16 in Figure 2B.

The two second resin portions 3202 are arranged symmetrically with respect to a line that passes through the center of the first end surface 15A and extends in the T direction. The arrangement of the two second resin portions 3202 is also point-symmetric with respect to the center of the first end surface 15A.

(Third metal portion and third resin portion)
Next, the third metal portion 3103 and the third resin portion 3203 will be described.
Three third metal portions 3103 are provided. The three third metal portions 3103 are part of the first, second, and third exposed portions 311, 312, and 313, respectively. Two third resin portions 3203 are provided. The two third resin portions 3203 are part of the first and second resin electrodes 321 and 322, respectively. On the top surface 17, the third metal portions 3103 and the third resin portions 3203 are arranged alternately in the W direction. Two of the third metal portions 3103 are provided at each end of the top surface 17 in the W direction.

The shape, arrangement, coverage, size, etc. of the third resin part 3203 on the top surface 17 are the same as those of the first resin part 3201 on the bottom surface 16.

5 shows a modified example of the coil component, which is cut along a plane corresponding to the YY cross section in FIG.
5, the first and second resin electrodes 321, 322 protrude outward in the T direction from the surface of the metal electrode 31 on which they are provided. It is desirable that the first and second resin electrodes 321, 322 form unevenness, particularly on the bottom surface 16. This allows solder to penetrate during mounting so as to reduce the step between the first and second resin electrodes 321, 322 and the metal electrode 31, thereby improving the connection strength between the circuit board and the coil component 1. In addition, the plating layer 40 covering the first external electrode 30A is less likely to peel off.

Another modified example is shown in Fig. 6. Fig. 6 is a cross-sectional view of a coil component according to another modified example, taken along a plane corresponding to the YY cross section in Fig. 1.
When the first and second resin electrodes 321, 322 protrude outward in the T direction beyond the surface of the metal electrode 31 on which the resin electrodes are provided, a metal film 41 may be provided so as to cover the first, second, and third exposed portions 311, 312, and 313, as shown in Fig. 6. The metal film 41 is made of a metal material such as Ag. This makes it possible to reduce the DC resistance increased by the resin electrodes 32 without changing the size of the coil component 1.

The metal film 41 does not contain organic matter and is conductive. It is not directly connected to the coil 20. It is electrically connected to the coil 20 via the first, second, and third exposed portions 311, 312, and 313, and serves as an electrode. Hereinafter, the metal electrode 31, resin electrode 32, and metal film 41 may be collectively referred to as the first external electrode 30A. The metal film 41 is typically formed from the same material as the coil wiring 22, first and second lead conductors 23A and 23B, and metal electrode 31. The metal film 41 is typically formed by a method different from that of the plating layer 40 (for example, a method similar to that for the metal electrodes or a dry plating method).

The metal film 41 may further cover the first and second resin electrodes 321, 322. In this case, the metal film 41 can be electrically connected to the first external electrode 30A via the first and second resin electrodes 321, 322.

The metal film 41 may be arranged to fill the gaps between the first and second resin electrodes 321, 322 and the first, second, and third exposed portions 311, 312, and 313, so that the surfaces of the first and second resin electrodes 321, 322 and the metal film 41 are flush with each other at least on the bottom surface 16. This reduces wobbling and tilting of the coil component 1 during mounting.

Whether the surfaces of the first and second resin electrodes 321, 322 on the bottom surface 16 are flush with the surface of the metal film 41 can be confirmed by taking enlarged photographs of multiple different TW cross sections (e.g., 3 to 8 locations) obtained by polishing the coil component 1. Multiple TW cross sections can be obtained by polishing the coil component 1 in the L direction. In the enlarged photographs, the maximum difference between the distance from the surface of the bottom surface 16 to the surfaces of the first and second resin electrodes 321, 322 and the distance from the surface of the bottom surface 16 to the surface of the metal film 41 is calculated. The maximum value is calculated for each enlarged photograph, and their average value is calculated. If this average value is 5 μm or less, it can be said that the surfaces of the first and second resin electrodes 321, 322 on the bottom surface 16 and the surface of the metal film 41 are flush with each other. The magnification of the enlarged photographs is, for example, between 50x and 300x.

By forming the metal electrode 31 in an uneven shape and providing the first and second resin electrodes 321, 322 in the recesses of this metal electrode 31, the surfaces of the first, second and third exposed portions 311, 312, 313 can be made flush with the surfaces of the first and second resin electrodes 321, 322.

The plating layer 40 may be thickened in some areas to fill in the steps between the first and second resin electrodes 321, 322 and the first, second, and third exposed portions 311, 312, and 313, thereby smoothing the surface of the plating layer 40.

7 shows yet another modified example of the coil component, taken along a plane corresponding to the YY cross section in FIG.
7 , in the T-W cross section, the length (width) in the W direction of the first surface X of the first and second resin electrodes 321, 322 on the metal electrode 31 side may be narrower than the width of the second surface Y of the resin electrode on the opposite side from the first surface X. In other words, the widths of the first and second resin electrodes 321, 322 in the T-W cross section may narrow stepwise or linearly toward the metal electrode 31. This suppresses peeling of the plating layer 40 from the contact portion between the metal electrode 31 and the first and second resin electrodes 321, 322. In particular, when the first and second resin electrodes 321, 322 have the above-described cross-sectional shape on the bottom surface 16, an anchor effect is produced, improving the solder joint strength between the circuit board and the coil component 1.

In the T-W cross section, the acute angle (hereinafter referred to as the taper angle θ) formed between at least one side surface of the first and second resin electrodes 321, 322 and the metal electrode 31 is, for example, greater than or equal to 60° and less than 90°. The taper angle θ can also be measured using an SEM image of the T-W cross section, as described above.

≪Manufacturing method≫
The coil component 1 is manufactured by a method including the steps of preparing an element body 10 having a first end face 15A, a second end face 15B opposing the first end face 15A, and a bottom face 16 perpendicular to the first end face 15A and the second end face 15B, forming a metal electrode 31 on at least a portion of the bottom face 16, and forming a resin electrode 32 that covers a portion of the portion of the metal electrode 31 provided on the bottom face 16. In the step of forming the resin electrode, first, second, and third exposed portions 311, 312, and 313 of the metal electrode 31 that are exposed from the resin electrode 32 are formed on the bottom face 16.

<Preparing the body>
In this embodiment, an element body 10 and a coil 20 provided inside the element body 10 are prepared.
First, multiple magnetic layers 21 each having coil wiring 22 formed thereon are laminated so as to be sandwiched between two or more magnetic layers 21 each having no coil wiring 22 formed thereon. A magnetic layer 21 having a first lead conductor 23A or a second lead conductor 23B is disposed on the outermost of each of the multiple magnetic layers 21 each having coil wiring 22 formed thereon. Next, this laminate is fired. In this manner, the element body 10 and the coil 20 disposed inside the element body 10 are obtained. The firing temperature is not particularly limited and may be set appropriately taking into consideration the type of material used, etc. The configuration of the coil 20 and element body 10 is as shown in FIG. 2A .

The magnetic layer 21 is obtained by forming a paste containing a magnetic material into a sheet. Examples of magnetic materials include Ni-Cu-Zn ferrite materials. Ni-Cu-Zn ferrite materials contain, for example, 40 mol% to 49.5 _mol % of Fe calculated as _Fe2O3 , 2 mol% to 35 mol% of Zn calculated as ZnO, 6 mol% to 13 mol% of Cu calculated as CuO, and 10 mol% to 45 mol% of Ni calculated as NiO _. The magnetic _material may contain additives and unavoidable impurities as needed. Examples of additives include _Mn3O4 , _Co3O4 , _SnO2 , _{Bi2O3 ,} and _SiO2 .

Specifically, the magnetic layer 21 is produced as follows. First, Fe ₂ O ₃ , ZnO, CuO, and NiO are weighed out to achieve a predetermined composition. These are then placed in a ball mill with pure water, along with PSZ (partially stabilized zirconia) media, and wet-mixed and pulverized for 4 to 8 hours. The water is then evaporated to dryness, and the mixture is calcined at a temperature of 700°C to 800°C for 2 to 5 hours. This produces a Ni-Cu-Zn ferrite material (magnetic material).

The resulting magnetic material, an organic binder such as polyvinyl butyral, an organic solvent such as ethanol or toluene, and a plasticizer are placed in a ball mill along with PSZ media and further mixed. The resulting mixture is then formed into a sheet with a thickness of 5 μm or more and 30 μm or less using a doctor blade method or similar. The sheet is then punched into a predetermined shape (typically rectangular) to obtain the magnetic layer 21.

Via holes are formed in predetermined locations in the fabricated magnetic layer 21, for example by laser irradiation.

A conductive paste containing a conductive material (typically Ag powder) as its main component is prepared separately. In addition to the conductive material, the conductive paste may also contain solvents, resins, dispersants, etc. This conductive paste is applied to the magnetic layer 21 in which the via holes have been formed, for example by screen printing. This fills the via holes with the conductive paste, and forms the coil wiring 22 and the first and second lead conductors 23A and 23B on the magnetic layer 21.

Then, the multiple magnetic layers 21 thus produced are stacked in a predetermined order and thermocompressed to form a laminated block. The laminated block is then cut into individual pieces using a dicer or similar. These individual pieces are sintered in a sintering furnace at 900°C to 920°C for 2 to 4 hours. The resulting sintered body is placed in a rotary barrel machine along with media and rotated to polish the edges and corners of the sintered body. This yields the element body 10 and coil 20.

<Formation of First and Second External Electrodes>
Next, a first external electrode 30A is provided on the first end face 15A side of the element body 10, and a second external electrode 30B is provided on the second end face 15B side. The process of providing the first external electrode 30A includes the steps of forming a metal electrode 31 on at least a portion of the bottom face 16 on the first end face 15A side, and forming a resin electrode 32 that covers a portion of the portion of the metal electrode 31 provided on the bottom face 16. In the process of forming the resin electrode 32, first, second, and third exposed portions 311, 312, and 313 of the metal electrode 31 that are exposed from the resin electrode 32 are formed. The second external electrode 30B is provided in the same manner as the first external electrode 30A.

<Formation of metal electrodes>
The metal electrodes 31 are formed in two locations on the first end face 15A side and the second end face 15B side of the element body 10. The metal electrode 31 on the first end face 15A side is provided on the entire surface of the first end face 15A and on each end of the bottom face 16, top face 17, first side face 18A, and second side face 18B on the first end face 15A side. The metal electrode 31 on the second end face 15B side is provided on the entire surface of the second end face 15B and on each end of the bottom face 16, top face 17, first side face 18A, and second side face 18B on the second end face 15B side. Each metal electrode 31 is directly connected to the coil 20.

The metal electrode 31 is formed, for example, by applying a conductive paste containing conductive particles such as Ag powder and glass to a predetermined location on the element body 10 and firing it at 750°C to 850°C. The application method is not particularly limited and may be, for example, a dipping method or a screen printing method. The conductive particles are sintered by firing, forming a metal layer. The firing temperature is not particularly limited and may be set appropriately taking into account the type of material used, etc.

<Formation of resin electrodes>
Next, a resin electrode 32 is formed to cover a portion of the metal electrode 31. The resin electrode 32 is formed, for example, by the steps of applying a conductive composition containing a photosensitive resin to at least a portion of the metal electrode 31 formed on the bottom surface 16, irradiating a portion of the applied resin composition with laser light, and removing the portion or the remainder of the resin composition after the irradiation step. As a result, first, second, and third exposed portions 311, 312, and 313 of the metal electrode 31 that are exposed from the resin electrode 32 are formed on the bottom surface 16, and the first and second external electrodes 30A and 30B according to this embodiment are obtained.

The photosensitive resin may be a positive type that is decomposed by laser light, or a negative type that is polymerized or crosslinked by laser light. When a positive type photosensitive resin is used, the portion exposed to the laser light is removed in the removal process. When a negative type photosensitive resin is used, the portion not exposed to the laser light is removed in the removal process. A mask may be used when irradiating the laser light. The mask partially blocks the laser light.

By employing photolithography using laser light, resin electrodes 32 can be formed with the desired shape and thickness with higher precision than with screen printing. For example, the maximum width Wa of the second exposed portion 312 sandwiched between the first resin electrode 321 and the second resin electrode 322 can be set to 10 μm or more and 160 μm or less. Alternatively, the maximum width Wb of the first resin electrode 321 and the second resin electrode 322 can be set to 10 μm or more and 160 μm or less. Furthermore, the thickness of the resin electrode 32 can be made uniform. With screen printing, it is generally difficult to achieve a maximum width Wa or Wb of 80 μm or less due to the influence of the elongation of the screen plate and the viscosity of the resin composition.

Photolithography using laser light allows for arbitrary control of the degree of polymerization or cross-linking of the photosensitive resin. Therefore, as shown in FIG. 7 , in the T-W cross section, the width of the first surface X of the first and second resin electrodes 321, 322 on the metal electrode 31 side can be made narrower than the width of the second surface Y on the opposite side of the resin electrode from the first surface X. For example, when using a negative-type photosensitive resin, the width of the first and second resin electrodes 321, 322 in the T-W cross section can be narrowed in a stepwise or linear manner toward the metal electrode 31 by reducing the intensity of the laser light irradiation or the number of irradiations to reduce the degree of polymerization or cross-linking of the photosensitive resin.

The conductive resin composition further contains conductive particles. Examples of conductive particles include Ag powder. The conductive resin composition may further contain a solvent and a dispersant.

Specifically, the resin composition contains 60% to 85% by weight of Ag powder, 2% to 20% by weight of an epoxy resin (e.g., bisphenol A-type epoxy resin), and 10% to 20% by weight of an organic solvent (e.g., diethylene glycol monobutyl ether). The resin composition may further contain 1% by weight or less of a thermosetting resin (e.g., phenolic resin), a silane coupling agent (e.g., 3-glycidoxypropyltrimethoxysilane), and a curing agent (e.g., an imidazole compound). For application, a paste obtained by mixing 100% by weight of the resin composition with 10% by weight of a photosensitive varnish may be used.

When a negative epoxy resin is used as the photosensitive resin, the area where the resin electrode 32 is to be formed is irradiated with laser light. The area coated with the resin composition is then immersed in a developer. The epoxy resin that is not irradiated with the laser light dissolves in the developer and is removed. On the other hand, the exposed epoxy resin hardens and remains. Finally, the resin electrode 32 is formed by heat treatment at 230°C for approximately 1 hour.

<Metal film formation>
After the metal electrode 31 is formed, a step of forming the metal film 41 may be carried out before or after the resin electrode 32 is formed.

The metal film 41 can be formed, for example, using the same method and material as the metal electrode 31, before forming the resin electrode 32. Specifically, the metal film 41 is formed by applying a conductive paste containing a conductive material (typically Ag powder) as a main component to at least the portions corresponding to the first, second, and third exposed portions 311, 312, and 313 of the metal electrode 31, and firing the paste at 750°C to 850°C. The firing to form the metal electrode 31 and the firing to form the metal film 41 may be performed simultaneously.

The metal film 41 can be formed, for example, by sputtering after forming the resin electrode 32. Specifically, the metal film 41 is formed by sputtering at least the first, second, and third exposed portions 311, 312, and 313 of the metal electrode 31 using Ag as a target.

<Formation of plating layer>
After the step of forming the resin electrode 32 and, optionally, the step of forming the metal film 41, a step of forming a plating layer 40 covering at least a portion of the first and second external electrodes 30A, 30B may be performed. The plating layer 40 is typically formed by a wet plating method. There are no particular limitations on the wet plating method, and it may be an electrolytic plating method or an electroless plating method. The step of forming the plating layer 40 may be performed multiple times as necessary. The plating layer is formed, for example, by an electrolytic plating method, in the order of a Ni plating layer and a Sn plating layer.

<Evaluation>
The coil component 1 according to this embodiment was evaluated by simulation. The size, number, and arrangement of the resin electrodes 32 of the coil component 1 are as shown in FIG. 1 . The coil component 1 used in the simulation further includes a metal film 41 covering the first, second, and third exposed portions 311, 312, and 313. The coil component 1 measures a length (L) of 1.6 mm, a width (W) of 0.8 mm, and a height (T) of 0.8 mm. As shown in FIG. 4 , the coil component 1 was assumed to be mounted on a bottom surface 16 of the coil component 1, with first and second end surfaces 15A and 15B of the bottom surface 16 soldered to pads 6 located near the center of a substrate (thickness 1.6 mm) (not shown). Femtet (registered trademark) manufactured by Murata Software Co., Ltd. was used for the simulation.

<Flexural stress>
For the evaluation of deflection stress, the composition and physical properties of each component were set as shown in Table 1. The deflection test was performed as follows: The substrate was supported from below at two points (support distance 90 mm) so that the surface on which the coil component 1 was mounted faced downward. A load was applied from above to below the approximate center of the substrate using a pressure tool at a speed of 0.08 mm/sec. The stress acting on the coil component 1 when the substrate deflected 5 mm was obtained as the deflection stress.

<Resistance value>
In evaluating the resistance value, the composition and physical properties of each member were set as shown in Table 2. The DC resistance value between the first and second end faces 15A and 15B of the coil component 1 and the surface of the pad 6 was obtained.

Coil component 2A and coil component 2B were prepared for comparison. Comparative coil component 2A has the same base body and metal electrodes as coil component 1, except that it does not have a resin electrode 32 and has a metal film 41 covering the entire surface of the metal electrode 31. Comparative coil component 2B has the same base body and metal electrodes as coil component 1, except that it has a metal film 41 covering the entire surface of the metal electrode 31 and a resin electrode 32 covering the entire surface of the metal film 41. Figure 8 is a perspective view showing comparative coil component 2A. Figure 9 is a perspective view showing comparative coil component 2B.

Comparative coil component 2B has a resin electrode 32 that covers the entire surface of the metal film 41, so its bending stress is reduced by 73.6% compared to comparative coil component 2A. Meanwhile, the resistance value of comparative coil component 2B is increased by 66.6%.

In contrast, the coil component 1 according to this embodiment has first, second, and third exposed portions 311, 312, and 313 on at least the bottom surface 16, so the resistance increase rate is limited to 21.4%. Meanwhile, the first and second strip-shaped resin electrodes 321 and 322 reduce the deflection stress by as much as 53.5%. In this way, the coil component according to this embodiment can effectively reduce the deflection stress while suppressing an increase in resistance.

Second Embodiment
FIG. 10 is a perspective view showing a second embodiment of a coil component, corresponding to FIG. 1 of the first embodiment. The second embodiment differs from the first embodiment in the size, number, and arrangement of the resin electrodes. This different configuration will be described below. The configuration of the second embodiment is the same as that of the first embodiment except for the size, number, and arrangement of the resin electrodes, so a description thereof will be omitted. In the second embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, so a description thereof will be omitted. In the second embodiment, the manufacturing method is the same as that in the first embodiment, so a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1A of the second embodiment will be described below. The second external electrode 30B has a similar configuration.
The resin electrode 32 is a single strip-like electrode that extends continuously in the L direction on the bottom surface 16, in the T direction on the first end surface 15A, and in the L direction on the top surface 17, in this order.

The metal electrode 31 has first and second exposed portions 311, 312 exposed from the resin electrode 32. The first exposed portion 311 is located at the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second exposed portion 312 is located at the end of the second side surface 18B facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and the second side surface 18B, the end of the top surface 17 facing the first end surface 15A and the second side surface 18B, and the end of the first end surface 15A facing the second side surface 18B.

The first exposed portion 311, resin electrode 32, and second exposed portion 312 are arranged in this order in the W direction from the first side surface 18A side. The first and second exposed portions 311, 312 are provided on the first and second side surfaces 18A, 18B sides of the element body 10, respectively.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 40%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is greater than 1. Specifically, the ratio Wb/Wa1 is approximately 1.4.

<Evaluation>
Coil component 1A was evaluated by simulation in the same manner as in Embodiment 1. Coil component 1A has an element body and metal electrodes with the same configuration as coil component 1, except that one strip-shaped resin electrode 32 is provided approximately at the center of first external electrode 30A in the W direction, and coil component 1A has metal film 41 covering first and second exposed portions 311, 312.

The coil component 1A according to this embodiment has first and second exposed portions 311, 312 at least on the bottom surface 16, so its resistance increase rate is only 15.6% compared to the comparative coil component 2A. Meanwhile, the band-shaped resin electrode 32 reduces the bending stress of the coil component 1A by 34.6%.

[Third embodiment]
FIG. 11 is a perspective view showing a coil component according to a third embodiment, corresponding to FIG. 1 of the first embodiment. The third embodiment differs from the first embodiment in the size, number, and arrangement of the resin electrodes. This difference in configuration will be described below. The configuration of the third embodiment is the same as that of the first embodiment except for the size, number, and arrangement of the resin electrodes, and therefore a description thereof will be omitted. In the third embodiment, the same reference numerals as those in the first embodiment represent the same configuration as that in the first embodiment, and therefore a description thereof will be omitted. In the third embodiment, the manufacturing method is the same as that in the first embodiment, and therefore a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1B of the third embodiment will be described below. The second external electrode 30B has a similar configuration.
The resin electrode 32 is a single strip-like electrode that extends continuously in the L direction on the bottom surface 16, in the T direction on the first end surface 15A, and in the L direction on the top surface 17, in this order.

The metal electrode 31 has first and second exposed portions 311, 312 exposed from the resin electrode 32. The first exposed portion 311 is located at the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second exposed portion 312 is located at the end of the second side surface 18B facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and the second side surface 18B, the end of the top surface 17 facing the first end surface 15A and the second side surface 18B, and the end of the first end surface 15A facing the second side surface 18B.

The first exposed portion 311, resin electrode 32, and second exposed portion 312 are arranged in this order in the W direction from the first side surface 18A side. The first and second exposed portions 311, 312 are provided on the first and second side surfaces 18A, 18B sides of the element body 10, respectively.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 67%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is greater than 1. Specifically, the ratio Wb/Wa1 is approximately 4.3.

<Evaluation>
Coil component 1B was evaluated by simulation in the same manner as in Embodiment 1. Coil component 1B has an element body and metal electrodes with the same configuration as coil component 1, except that one wide, strip-shaped resin electrode 32 is provided approximately at the center of first external electrode 30A in the W direction, and that coil component 1B has metal film 41 covering first and second exposed portions 311, 312.

Since the coil component 1B according to this embodiment has first and second exposed portions 311, 312 at least on the bottom surface 16, its resistance increase rate is only 30.0% compared to the comparative coil component 2A. On the other hand, the wide, strip-shaped resin electrode 32 reduces the bending stress of the coil component 1B by 65.7%.

[Fourth embodiment]
FIG. 12 is a perspective view showing a fourth embodiment of a coil component, corresponding to FIG. 1 of the first embodiment. The fourth embodiment differs from the first embodiment in the size of the resin electrodes. This different configuration will be described below. The configuration of the fourth embodiment is the same as that of the first embodiment except for the size of the resin electrodes, so a description thereof will be omitted. In the fourth embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, so a description thereof will be omitted. In the fourth embodiment, the manufacturing method is the same as that in the first embodiment, so a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1C of the fourth embodiment will be described below. The second external electrode 30B has a similar configuration.
The resin electrode 32 has two strip-shaped first and second resin electrodes 321 and 322. The first and second resin electrodes 321 and 322 extend continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The first resin electrode 321 and the second resin electrode 322 are arranged side by side in the W direction with a gap between them.

The metal electrode 31 has first, second, and third exposed portions 311, 312, and 313 exposed from the resin electrode 32. The first exposed portion 311 is located at the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and facing the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second exposed portion 312 is located between the first resin electrode 321 and the second resin electrode 322 and is a strip-like portion that extends continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The third exposed portion 313 is located at the end of the second side surface 18B on the first end surface 15A side, the end of the bottom surface 16 on the first end surface 15A side and the second side surface 18B side, the end of the top surface 17 on the first end surface 15A side and the second side surface 18B side, and the end of the first end surface 15A on the second side surface 18B side.

The first exposed portion 311, the first resin electrode 321, the second exposed portion 312, the second resin electrode 322 and the third exposed portion 313 are arranged in the W direction in this order from the first side surface 18A side.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 26%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is 1 or less. Specifically, the ratio Wb/Wa1 is approximately 0.45. When the ratio Wb/Wa1 is 1 or less, the effect of suppressing an increase in resistance is particularly likely to be improved. The maximum width Wa2 of the second exposed portion 312 sandwiched between two adjacent first and second resin electrodes 321, 322 is approximately 104 μm.

<Evaluation>
Coil device 1C was evaluated by simulation in the same manner as in the first embodiment. Coil device 1C has an element body and metal electrodes with the same configuration as coil device 1, except that band-shaped resin electrodes 32 are narrower and coil device 1C has metal films 41 that cover first, second, and third exposed portions 311, 312, and 313.

Since the coil component 1C according to this embodiment has the first, second, and third exposed portions 311, 312, and 313 on at least the bottom surface 16, its resistance increase rate is only 8.9% compared to the comparative coil component 2A. Meanwhile, the first and second resin electrodes 321 and 322 reduce the bending stress of the coil component 1C by 23.1%.

Fifth Embodiment
FIG. 13 is a perspective view showing a coil component according to a fifth embodiment, corresponding to FIG. 1 of the first embodiment. The fifth embodiment differs from the first embodiment in the size, number, and arrangement of the resin electrodes. This difference in configuration will be described below. The configuration of the fifth embodiment is the same as that of the first embodiment except for the size, number, and arrangement of the resin electrodes, and therefore a description thereof will be omitted. In the fifth embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, and therefore a description thereof will be omitted. In the fifth embodiment, the manufacturing method is the same as that of the first embodiment, and therefore a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1D of the fifth embodiment will be described below. The second external electrode 30B has a similar configuration.
The metal electrode 31 has, in order from the first side surface 18A side, first and second strip-shaped exposed portions 311 and 312 exposed from the resin electrode 32. The two strip-shaped first and second exposed portions 311 and 312 each extend continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The first exposed portion 311 and the second exposed portion 312 are arranged side by side in the W direction with a gap between them.

The resin electrode 32 has first, second, and third resin electrodes 321, 322, and 323. The first resin electrode 321 is provided on the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and facing the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second resin electrode 322 is located between the first exposed portion 311 and the second exposed portion 312 and is a strip-like electrode that extends continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The third resin electrode 323 is provided at the end portion of the second side surface 18B on the first end surface 15A side, the end portion of the bottom surface 16 on the first end surface 15A side and the second side surface 18B side, the end portion of the top surface 17 on the first end surface 15A side and the second side surface 18B side, and the end portion of the first end surface 15A on the second side surface 18B side.

The first resin electrode 321, the first exposed portion 311, the second resin electrode 322, the second exposed portion 312, and the third resin electrode 323 are arranged in this order in the W direction from the first side surface 18A side. The first and third resin electrodes 321, 323 are provided on the first and second side surfaces 18A, 18B sides of the element body 10, respectively.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 70%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is greater than 1. Specifically, the ratio Wb/Wa1 is approximately 2.0. The maximum width Wa2 of the first exposed portion 311 sandwiched between two adjacent first and second resin electrodes 321, 322, and the second exposed portion 312 sandwiched between two adjacent second and third resin electrodes 322, 323, are both approximately 104 μm.

<Evaluation>
Coil component 1D was evaluated by simulation in the same manner as in Embodiment 1. Coil component 1D has an element body and metal electrodes with the same configuration as coil component 1, except that a strip-shaped second resin electrode 322 is provided substantially in the center of the first external electrode 30A in the W direction, first and third resin electrodes 321, 323 are provided at both ends of the first external electrode 30A in the W direction, and a metal film 41 is provided to cover the first and second exposed portions 311, 312.

Since the coil component 1D according to this embodiment has first and second exposed portions 311, 312 at least on the bottom surface 16, its resistance increase rate is only 41.1% compared to the comparative coil component 2A. Meanwhile, the first, second, and third resin electrodes 321, 322, and 323 reduce the bending stress of the coil component 1D by 48.4%.

Sixth Embodiment
FIG. 14 is a perspective view showing a sixth embodiment of a coil component, corresponding to FIG. 1 of the first embodiment. The sixth embodiment differs from the first embodiment in the size, number, and arrangement of the resin electrodes. FIGS. 15A and 15B are perspective views showing a modified example of the sixth embodiment. The modified example shown in FIGS. 15A and 15B differs from the sixth embodiment in the arrangement of the resin electrodes on each end face. These different configurations will be described below. The configuration of the sixth embodiment is the same as that of the first embodiment except for the size, number, and arrangement of the resin electrodes, and therefore a description thereof will be omitted. In the sixth embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, and therefore a description thereof will be omitted. In the sixth embodiment, the manufacturing method is the same as that of the first embodiment, and therefore a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1E of the sixth embodiment will be described below. The second external electrode 30B has a similar configuration.
The metal electrode 31 has, in order from the first side surface 18A side, first, second, and third strip-shaped exposed portions 311, 312, and 313 exposed from the resin electrode 32. The three strip-shaped first, second, and third exposed portions 311, 312, and 313 each extend continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in this order. The first exposed portion 311, the second exposed portion 312, and the third exposed portion 313 are arranged side by side in the W direction at intervals from one another.

The resin electrode 32 has first, second, third, and fourth resin electrodes 321, 322, 323, and 324. The first resin electrode 321 is provided on the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and facing the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second resin electrode 322 is located between the first exposed portion 311 and the second exposed portion 312 and is a strip-like electrode that extends continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The third resin electrode 323 is located between the second exposed portion 312 and the third exposed portion 313, and has a strip shape that extends continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The fourth resin electrode 324 is provided on an end of the second side surface 18B on the first end surface 15A side, an end of the bottom surface 16 on the first end surface 15A side and the second side surface 18B side, an end of the top surface 17 on the first end surface 15A side and the second side surface 18B side, and an end of the first end surface 15A on the second side surface 18B side.

The first resin electrode 321, the first exposed portion 311, the second resin electrode 322, the second exposed portion 312, the third resin electrode 323, the third exposed portion 313, and the fourth resin electrode 324 are arranged in this order in the W direction from the first side surface 18A side. The first and fourth resin electrodes 321, 324 are provided on the first and second side surfaces 18A, 18B sides of the element body 10, respectively.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 55%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is 1 or less. Specifically, the ratio Wb/Wa1 is approximately 1.0. The maximum width Wa2 of the first exposed portion 311 sandwiched between two adjacent first and second resin electrodes 321, 322, the second exposed portion 312 sandwiched between two adjacent second and third resin electrodes 322, 323, and the second exposed portion 312 sandwiched between two adjacent third and fourth resin electrodes 323, 324 is all approximately 110 μm.

(Modification)
15A shows a coil component 1Ea according to a modified example of the present embodiment. In the coil component 1Ea, the first, second, third, and fourth resin electrodes 321, 322, 323, and 324 are all provided in a region extending from the bottom surface 16 side of each end face 15A and 15B to ⅙ of the height T of the element body 10. The first exposed portion 311 is a continuous region of the metal electrode 31 other than the first, second, third, and fourth resin electrodes 321, 322, 323, and 324.

Figure 15B shows a coil component 1Eb, a modified example of this embodiment. In coil component 1Eb, the first, second, third, and fourth resin electrodes 321, 322, 323, and 324 are all provided in a region extending from the bottom surface 16 side of each end face 15A, 15B to 1/3 of the height T of the base body 10. The first exposed portion 311 is a single continuous region of the metal electrode 31 other than the first, second, third, and fourth resin electrodes 321, 322, 323, and 324.

These modified examples also achieve the above-mentioned effect of reducing deflection stress.

<Evaluation>
Coil components 1E, 1Ea, and 1Eb were evaluated by simulation in the same manner as in the first embodiment. Coil component 1E has an element body and metal electrodes with the same configuration as coil component 1, except that band-shaped second and third resin electrodes 322 and 323 are provided near the center of first external electrode 30A in the W direction, first and fourth resin electrodes 321 and 324 are provided at both ends of first external electrode 30A in the W direction, and coil component 1E has metal film 41 covering first, second, and third exposed portions 311, 312, and 313.

Coil component 1Ea has an element body and metal electrodes of the same configuration as coil component 1, except that the first, second, third, and fourth resin electrodes 321, 322, 323, and 324 are all provided in an area extending from the bottom surface 16 of each end face 15A and 15B to 1/6 of the height T of the element body 10, and that it has a metal film 41 covering the first exposed portion 311.

Coil component 1Eb has an element body and metal electrodes of the same configuration as coil component 1, except that the first, second, third, and fourth resin electrodes 321, 322, 323, and 324 are all provided in an area extending from the bottom surface 16 of each end face 15A and 15B to 1/3 of the height T of the element body 10, and that it has a metal film 41 covering the first exposed portion 311.

Since the coil component 1E according to this embodiment has the first, second, and third exposed portions 311, 312, and 313 at least on the bottom surface 16, its resistance increase rate is only 31.0% compared to the comparative coil component 2A. Meanwhile, the first, second, third, and fourth resin electrodes 321, 322, 323, and 324 reduce the deflection stress by 30.8%. Since the coil component 1Ea according to this embodiment also has the first exposed portion 311 at least on the bottom surface 16, its resistance increase rate is only 23.7%. Meanwhile, the first, second, third, and fourth resin electrodes 321, 322, 323, and 324 reduce the deflection stress by 32.6%. Since the coil component 1Eb according to this embodiment also has the first exposed portion 311 at least on the bottom surface 16, its resistance increase rate is only 30.1%. On the other hand, the first, second, third and fourth resin electrodes 321, 322, 323 and 324 reduce the deflection stress by as much as 31.3%.

Seventh Embodiment
FIG. 16 is a perspective view showing a seventh embodiment of a coil component, corresponding to FIG. 1 of the first embodiment. The seventh embodiment differs from the first embodiment in the size, number, and arrangement of the resin electrodes. This different configuration will be described below. The configuration of the seventh embodiment is the same as that of the first embodiment except for the size, number, and arrangement of the resin electrodes, so a description thereof will be omitted. In the seventh embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, so a description thereof will be omitted. In the seventh embodiment, the manufacturing method is the same as that of the first embodiment, so a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1F of the seventh embodiment will be described below. The second external electrode 30B has a similar configuration.
The metal electrode 31 has, in order from the first side surface 18A side, first and second strip-shaped exposed portions 311 and 312 exposed from the resin electrode 32. The two strip-shaped first and second exposed portions 311 and 312 each extend continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The first exposed portion 311 and the second exposed portion 312 are arranged side by side in the W direction with a gap between them.

The resin electrode 32 has first, second, and third resin electrodes 321, 322, and 323. The first resin electrode 321 is provided on the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and facing the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second resin electrode 322 is located between the first exposed portion 311 and the second exposed portion 312 and is a strip-like electrode that extends continuously in the L direction on the bottom surface 16, the T direction on the first end surface 15A, and the L direction on the top surface 17, in that order. The third resin electrode 323 is provided at the end portion of the second side surface 18B on the first end surface 15A side, the end portion of the bottom surface 16 on the first end surface 15A side and the second side surface 18B side, the end portion of the top surface 17 on the first end surface 15A side and the second side surface 18B side, and the end portion of the first end surface 15A on the second side surface 18B side.

The first resin electrode 321, the first exposed portion 311, the second resin electrode 322, the second exposed portion 312, and the third resin electrode 323 are arranged in this order in the W direction from the first side surface 18A side. The first and third resin electrodes 321, 323 are provided on the first and second side surfaces 18A, 18B sides of the element body 10, respectively.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 45%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is 1 or less. Specifically, the ratio Wb/Wa1 is approximately 0.6. The maximum width Wa2 of the first exposed portion 311 sandwiched between two adjacent first and second resin electrodes 321, 322 and the second exposed portion 312 sandwiched between two adjacent second and third resin electrodes 322, 323 are both approximately 210 μm. This embodiment, in which the coverage is less than 50% and the ratio Wb/Wa is 1 or less, is particularly effective in suppressing an increase in resistance.

<Evaluation>
Coil component 1F was evaluated by simulation in the same manner as in Embodiment 1. Coil component 1F has an element body and metal electrodes with the same configuration as coil component 1, except that a strip-shaped second resin electrode 322 is provided substantially in the center of first external electrode 30A in the W direction, first and third resin electrodes 321, 323 are provided at both ends of first external electrode 30A in the W direction, and a metal film 41 is provided covering first and second exposed portions 311, 312.

Since the coil component 1F of this embodiment has first and second exposed portions 311, 312 at least on the bottom surface 16, the resistance value increases by only 24.3% compared to the comparative coil component 2A described above.

Eighth Embodiment
FIG. 17 is a perspective view showing an eighth embodiment of a coil component, corresponding to FIG. 1 of the first embodiment. The eighth embodiment differs from the first embodiment in the size and arrangement of the resin electrodes. This different configuration will be described below. The configuration of the eighth embodiment is the same as that of the first embodiment except for the size and arrangement of the resin electrodes, so a description thereof will be omitted. In the eighth embodiment, the same reference numerals as those in the first embodiment represent the same configuration as in the first embodiment, so a description thereof will be omitted. In the eighth embodiment, the manufacturing method is the same as that of the first embodiment, so a description thereof will be omitted.

The configuration of the first external electrode 30A of the coil component 1G of the eighth embodiment will be described below. The second external electrode 30B has a similar configuration.
The metal electrode has one strip-shaped first exposed portion 311. The first exposed portion 311 extends continuously in the L direction on the bottom surface 16, in the T direction on the first end surface 15A, and in the L direction on the top surface 17, in this order.

The resin electrode 32 has first and second resin electrodes 321 and 322. The first resin electrode 321 is provided on the end of the first side surface 18A facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the first side surface 18A, the end of the top surface 17 facing the first end surface 15A and facing the first side surface 18A, and the end of the first end surface 15A facing the first side surface 18A. The second resin electrode 322 is provided on the end of the second side surface 18B facing the first end surface 15A, the end of the bottom surface 16 facing the first end surface 15A and facing the second side surface 18B, the end of the top surface 17 facing the first end surface 15A and facing the second side surface 18B, and the end of the first end surface 15A facing the second side surface 18B.

The first resin electrode 321, the first exposed portion 311, and the second resin electrode 322 are arranged in this order in the W direction from the first side surface 18A side. The first and second resin electrodes 322 are provided on the first and second side surfaces 18A and 18B sides of the element body 10, respectively.

The coverage of the resin electrode 32 on the bottom surface 16, top surface 17, and first end surface 15A is approximately 30%. On each of the above surfaces, the ratio of maximum width Wb to maximum width Wa1 (Wb/Wa1) is 1 or less. Specifically, the ratio Wb/Wa1 is approximately 0.2. The maximum width Wa2 of the first exposed portion 311 sandwiched between two adjacent first and second resin electrodes 321, 322 is approximately 540 μm. This embodiment is also particularly effective in suppressing an increase in resistance.

<Evaluation>
Coil component 1G was evaluated by simulation in the same manner as in the first embodiment. Coil component 1G has an element body and metal electrodes with the same configuration as coil component 1, except that first and second resin electrodes 321, 322 are provided at both ends of first external electrode 30A in the W direction, and coil component 1G has metal film 41 covering first exposed portion 311.

Since the coil component 1G of this embodiment has a first exposed portion 311 at least on the bottom surface 16, its resistance increase rate is limited to 18.3%.

The present disclosure is not limited to the above-described embodiments, and design modifications are possible within the scope of the present disclosure. For example, various combinations of the features of the first to eighth embodiments may be used. The number, arrangement, and size of the resin electrodes may be modified.

In the first to eighth embodiments, a coil component has been described as an example of an electronic component, but the electronic component according to the present disclosure is not limited to a coil component.
The electronic component according to the present disclosure may be an active component or a passive component other than a coil component. An active component is a component that amplifies, rectifies, or converts supplied power. Examples of active components include transistors and various sensors. A passive component is a component that consumes, stores, or releases supplied power, but does not perform active operations such as amplification or rectification. In addition to coil components, examples of passive components include resistors, capacitors, and thermistors.

The arrangement of the metal electrodes 31 is not limited to the above embodiment.
The metal electrode 31 may be provided only on the bottom surface 16 , or may be L-shaped and extend from the first end surface 15</b>A or the second end surface 15</b>B to the bottom surface 16 .

The arrangement of the resin electrodes 32 is not limited to the above embodiment.
The resin electrode 32 may be provided only on the bottom surface 16 , or may be L-shaped and extend from the first end surface 15</b>A or the second end surface 15</b>B to the bottom surface 16 .

The resin electrode 32 may cover the entire surface of the metal electrode 31 provided on the first and second end faces 15A and 15B. The resin electrode 32 may cover the entire surface of the metal electrode 31 provided on the top surface 17.

The shape, arrangement, coverage, size, etc. of the resin electrode 32 on the top surface 17 may be the same as or different from the resin electrode 32 on the bottom surface 16.

The number of resin electrodes 32 is not limited to that in the above embodiment.
It is sufficient that at least one resin electrode 32 is provided on the bottom surface 16 .

The thickness of the resin electrode 32 is not limited to that in the above embodiment.
The thickness of the resin electrode 32 may be uniform or may be non-uniform.
The thickness of the resin electrode 32 on each surface may be the same or different. The thicknesses of the multiple resin electrodes 32 provided on the same surface may be the same or different.

The shape, number, arrangement, coverage, size, etc. of the resin electrodes 32 provided on the first end surface 15A side of the bottom surface 16 may be the same as or different from the resin electrodes 32 provided on the second end surface 15B side of the bottom surface 16.

The shape, number, arrangement, coverage, size, etc. of the resin electrodes 32 provided on the first end surface 15A may be the same as or different from those of the resin electrodes 32 provided on the second end surface 15B.

The shape, number, arrangement, coverage, size, etc. of the resin electrodes 32 provided on the first end surface 15A side of the top surface 17 may be the same as or different from the resin electrodes 32 provided on the second end surface 15B side of the top surface 17.

The shape of the element body 10 is not limited to the above-described embodiment.
The bottom surface 16 does not have to be continuous with both the first end surface 15A and the second end surface 15B. For example, the bottom surface 16 may be divided into a first bottom surface that is continuous only with the first end surface 15A and a second bottom surface that is continuous only with the second end surface 15B.

The arrangement of the exposed portion and the resin electrode 32 is not limited to the above embodiment.
In at least a part of the region where the metal electrode 31 is provided on the bottom surface 16, the exposed portion and the resin electrode 32 may be arranged side by side in the W direction. For example, in a part of the region where the metal electrode 31 is provided on the bottom surface 16, only the exposed portion may be provided from one end to the other end in the W direction of the bottom surface 16. In a part of the region where the metal electrode 31 is provided on the bottom surface 16, only the resin electrode 32 may be provided from one end to the other end in the W direction of the bottom surface 16.

This application claims priority based on Japanese Patent Application No. 2022-051695, filed on March 28, 2022, the entire contents of which are incorporated herein by reference.
<1>
The base body and
an external electrode provided on the element body,
The element body is
A first end surface;
a second end surface facing the first end surface;
a bottom surface perpendicular to the first end surface and the second end surface,
The external electrode is
a first external electrode provided on the first end surface side;
a second external electrode provided on the second end surface side,
The first external electrode is
a metal electrode provided on at least a portion of the bottom surface;
a resin electrode that covers a part of the portion of the metal electrode that is provided on the bottom surface,
The electronic component has, on the bottom surface, an exposed portion of the metal electrode that is exposed from the resin electrode.
<2>
The electronic component according to <1>, further comprising a plating layer on the bottom surface that covers at least a portion of the first external electrode.
<3>
The direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
On the bottom surface,
The electronic component according to <1> or <2>, wherein the exposed portion and the resin electrode are arranged side by side in the W direction.
＜4＞
The direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
The electronic component according to any one of <1> to <3>, wherein the exposed portions are provided on both ends of the bottom surface in the W direction.
<5>
The direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
On the bottom surface,
The electronic component according to any one of <1> to <4>, wherein the resin electrodes are provided so as to sandwich the exposed portion from both sides in the W direction.
<6>
On the bottom surface,
The electronic component according to any one of <3> to <5>, wherein the maximum width of the resin electrode in the W direction is wider than the maximum width of the exposed portion adjacent to the resin electrode in the W direction.
＜７＞
On the bottom surface,
The electronic component according to any one of <3> to <6>, wherein the maximum width of the exposed portion sandwiched between the two resin electrodes is 10 μm or more and 160 μm or less.
＜8＞
In the first external electrode,
the metal electrode is further provided on a portion of at least one of the first end surface and the second end surface,
The electronic component according to any one of <1> to <7>, wherein the resin electrode further covers a part of a portion of the metal electrode provided on at least one of the first end surface and the second end surface.
＜９＞
The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
In the first external electrode,
The electronic component described in <8>, wherein the resin electrode provided on a portion of at least one of the first end face and the second end face is provided in a region of the end face on which the resin electrode is provided, from the bottom side to 1/2 of the height of the element body in the T direction.
<10>
The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
<1> to <9>, wherein the resin electrode provided on the bottom surface protrudes outward in the T direction from a surface of the metal electrode provided on the bottom surface.
<11>
The electronic component according to any one of <1> to <10>, further comprising a metal film that covers at least a portion of the metal electrode that is exposed from the resin electrode.
<12>
The electronic component according to <11>, wherein at least on the bottom surface, the surface of the resin electrode and the surface of the metal film are flush with each other.
<13>
<13> The electronic component according to any one of <1> to <12>, wherein the resin electrode provided on the bottom surface is symmetrical with respect to a line that passes through the center of the bottom surface and extends in an L direction in which the first end surface and the second end surface face each other.
<14>
The electronic component according to any one of <1> to <13>, wherein the resin electrode provided on the bottom surface has a uniform thickness.
＜15＞
The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
In a cross section of the resin electrode, the cross section is parallel to a T-W plane formed by a line extending in the W direction and a line extending in the T direction,
<15> The electronic component according to any one of <1> to <14>, wherein a width of a first surface of the resin electrode provided on the bottom surface on the metal electrode side is narrower than a width of a second surface of the resin electrode on the opposite side to the first surface.
<16>
Further, the magnetron includes a coil provided inside the element body,
The electronic component according to any one of <1> to <15>, wherein the coil is electrically connected to the first external electrode and the second external electrode, respectively.
＜17＞
preparing an element body having a first end surface, a second end surface opposite to the first end surface, and a bottom surface perpendicular to the first end surface and the second end surface;
providing a first external electrode on the first end surface side;
and providing a second external electrode on the second end surface side.
The step of providing the first external electrode includes:
forming a metal electrode on at least a portion of the bottom surface on the first end surface side;
forming a resin electrode that covers a portion of the portion of the metal electrode that is provided on the bottom surface;
In the step of forming the resin electrode, an exposed portion of the metal electrode is formed, the exposed portion being exposed from the resin electrode.
＜18＞
The step of forming the resin electrode includes:
applying a conductive resin composition containing a photosensitive resin to at least a portion of the portion of the metal electrode provided on the bottom surface;
irradiating a portion of the applied resin composition with laser light;
The method for producing an electronic component according to <17>, further comprising: a step of removing the part or remainder of the resin composition after the irradiating step.
＜19＞
After the step of forming the resin electrode,
The method for manufacturing an electronic component according to <17> or <18>, further comprising a step of forming a metal film that covers at least the exposed portion of the metal electrode.

1, 1A to 1G, 1Ea, 1Eb Coil component 10 Body 15A First end face 15B Second end face 16 Bottom face 17 Top face 18A First side face 18B Second side face 20 Coil 21 Magnetic layer 22 Coil wiring 23A First lead conductor 23B Second lead conductor 24 Via wiring 30A First external electrode 30B Second external electrode 31 Metal electrode 311 First exposed portion 312 Second exposed portion 313 Third exposed portion 3101 First metal portion 3102 Second metal portion 3103 Third metal portion 32 Resin electrode 321 First resin electrode 322 Second resin electrode 323 Third resin electrode 324 Fourth resin electrode 3201 First resin portion 3202 Second resin portion 3203 Third resin portion 40: plating layer 41: metal film 2A, 2B: comparative coil component 5: solder 6: pad

Claims (18)

The base body and
an external electrode provided on the element body,
The element body is
A first end surface;
a second end surface facing the first end surface;
a bottom surface perpendicular to the first end surface and the second end surface,
The external electrode is
a first external electrode provided on the first end surface side;
a second external electrode provided on the second end surface side,
The first external electrode is
a metal electrode provided on at least a portion of the bottom surface;
a resin electrode that covers a part of the portion of the metal electrode that is provided on the bottom surface,
the metal electrode has an exposed portion on the bottom surface that is exposed from the resin electrode;
The resin electrode is formed from a conductive resin composition containing a photosensitive resin , and the electronic component includes a cured product of the resin composition . The electronic component according to claim 1, further comprising a plating layer on the bottom surface that covers at least a portion of the first external electrode. The direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
On the bottom surface,
The electronic component according to claim 1 , wherein the exposed portion and the resin electrode are arranged side by side in the W direction. The direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
The electronic component according to claim 1 , wherein the exposed portions are provided at both ends of the bottom surface in the W direction. The direction in which the first end surface and the second end surface face each other is referred to as an L direction, and
The direction perpendicular to the L direction on the bottom surface is defined as a W direction,
On the bottom surface,
The electronic component according to claim 1 , wherein the resin electrodes are provided so as to sandwich the exposed portion from both sides in the W direction. On the bottom surface,
6. The electronic component according to claim 3, wherein the maximum width of the resin electrode in the W direction is greater than the maximum width of the exposed portion adjacent to the resin electrode in the W direction. On the bottom surface,
6. The electronic component according to claim 3, wherein the maximum width of the exposed portion sandwiched between the two resin electrodes is 10 μm or more and 160 μm or less. In the first external electrode,
the metal electrode is further provided on a portion of at least one of the first end surface and the second end surface,
The electronic component according to claim 1 , wherein the resin electrode further covers a part of a portion of the metal electrode provided on at least one of the first end face and the second end face. The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
In the first external electrode,
9. The electronic component according to claim 8, wherein the resin electrode provided on a portion of at least one of the first end face and the second end face is provided in a region of the end face on which the resin electrode is provided, from the bottom side to 1/2 of the height of the element body in the T direction. The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
3. The electronic component according to claim 1, wherein the resin electrode provided on the bottom surface protrudes outward in the T direction beyond a surface of the metal electrode provided on the bottom surface. The electronic component according to claim 1 or 2, further comprising a metal film covering at least the exposed portion of the metal electrode that is exposed from the resin electrode. The electronic component according to claim 11, wherein the surface of the resin electrode and the surface of the metal film are flush with each other at least on the bottom surface. The electronic component described in claim 1 or 2, wherein the resin electrode provided on the bottom surface is symmetrical with respect to a line that passes through the center of the bottom surface and extends in the L direction, in which the first end surface and the second end surface face each other. An electronic component as described in claim 1 or 2, wherein the resin electrode provided on the bottom surface has a uniform thickness. The direction in which the first end surface and the second end surface face each other is called the L direction.
The direction perpendicular to the L direction on the bottom surface is the W direction, and
A direction perpendicular to both the L direction and the W direction is defined as a T direction,
In a cross section of the resin electrode, the cross section is parallel to a T-W plane formed by a line extending in the W direction and a line extending in the T direction,
3 . The electronic component according to claim 1 , wherein a width of a first surface of the resin electrode provided on the bottom surface on the side of the metal electrode is narrower than a width of a second surface of the resin electrode on the opposite side to the first surface. Further, the magnetron includes a coil provided inside the element body,
The electronic component according to claim 1 , wherein the coil is electrically connected to the first external electrode and the second external electrode, respectively. preparing an element body having a first end surface, a second end surface opposite to the first end surface, and a bottom surface perpendicular to the first end surface and the second end surface;
providing a first external electrode on the first end surface side;
and providing a second external electrode on the second end surface side, wherein the step of providing the first external electrode includes:
forming a metal electrode on at least a portion of the bottom surface on the first end surface side;
forming a resin electrode that covers a portion of the portion of the metal electrode that is provided on the bottom surface;
The step of forming the resin electrode includes:
applying a conductive resin composition containing a photosensitive resin to at least a portion of the portion of the metal electrode provided on the bottom surface;
irradiating a portion of the applied resin composition with laser light;
and removing the part or remainder of the resin composition after the irradiating step,
In the step of forming the resin electrode, an exposed portion of the metal electrode is formed, the exposed portion being exposed from the resin electrode ;
The resin electrode includes a cured product of the resin composition . After the step of forming the resin electrode,
The method for manufacturing an electronic component according to claim 17 , further comprising the step of forming a metal film that covers at least the exposed portion of the metal electrode.