The present disclosure relates to a coil component and, more particularly, to a two-terminal type coil component in which a single coil conductor is incorporated in an element body.
As a two-terminal type coil component in which a single coil conductor is incorporated in an element body, a coil component described in JP 01-167023A is known. As described in JP 01-167023A, coil components of such a type generally employ a so-called five-surface electrode structure, in which a pair of external terminals each cover five surfaces of an element body.
However, the five-surface electrode is generally made of conductive resin or the like, so that when a coil component of such a type is mounted on a circuit board using a solder or the like, it disadvantageously has an increased connection resistance with respect to the circuit board.
It is therefore an object of the present disclosure to reduce a connection resistance in a two-terminal type coil component in which a single coil conductor is incorporated in an element body.
A coil component according to the present disclosure includes: an element body having a mounting surface, first and second side surfaces which are perpendicular to the mounting surface and parallel to each other, and third and fourth side surfaces which are perpendicular to the mounting surface and the first surface and parallel to each other; a coil conductor embedded in the element body; a first bump conductor which is connected to one end of the coil conductor and exposed to the mounting surface, the first side surface, and the third side surface; a second bump conductor which is connected to the other end of the coil conductor and exposed to the mounting surface, the second side surface, and one of the third and fourth side surfaces; a first dummy bump conductor which is exposed to the mounting surface, the first side surface and the fourth side surface; a second dummy bump conductor which is exposed to the mounting surface, the second side surface, and the other one of the third and fourth side surfaces; a first conductive resin layer which is formed on the mounting surface and connects the first bump conductor and first dummy bump conductor; and a second conductive resin layer which is formed on the mounting surface and connects the second bump conductor and the second dummy bump conductor. First side surface parts of the first bump conductor and first dummy bump conductor that are exposed to the first, third, and fourth side surfaces are each not covered at least partly with the first conductive resin layer, and second side surface parts of the second bump conductor and second dummy bump conductor that are exposed to the second, third, and fourth side surfaces are each not covered at least partly with the second conductive resin layer.
The above features and advantages of the present disclosure will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:
Preferred embodiments of the present disclosure will be explained below in detail with reference to the accompanying drawings.
As illustrated in
Bump conductors 131, 132, and dummy bump conductors 141, 142 are exposed to the surfaces of the element body 110. The bump conductor 131 is connected to one end of the coil conductor embedded in the element body 110, and the bump conductor 132 is connected to the other end of the coil conductor embedded in the element body 110. The dummy bump conductors 141 and 142 are not directly connected to the coil conductor but connected respectively to the bump conductors 131 and 132 through the respective conductive resin layers 121 and 122. The bump conductor 131 is exposed to three surfaces of the mounting surface S0 and side surfaces S1 and S3, and the bump conductor 132 is exposed to three surfaces of the mounting surface S0 and side surfaces S2 and S3. The dummy bump conductor 141 is exposed to three surfaces of the mounting surface S0 and side surfaces S1 and S4, and the dummy bump conductor 142 is exposed to three surfaces of the mounting surface S0 and side surfaces S2 and S4.
The conductive resin layers 121 and 122 are made of a conductive material, such as silver paste, containing metal power and a resin binder and are formed at least on the mounting surface S0 of the element body 110. The conductive resin layer 121 connects the bump conductor 131 and the dummy bump conductor 141, and the conductive resin layer 122 connects the bump conductor 132 and the dummy bump conductor 142. In the example illustrated in
In the example illustrated in
Alternatively, a part of each of the bump conductor 131 and dummy bump conductor 141 that is exposed to the side surface S1 may be partly covered with the conductive resin layer 121, and a part of each of the bump conductor 132 and dummy bump conductor 142 that is exposed to the side surface S2 may partly be covered with the conductive resin layer 122. In this case, a part of the conductive resin layer 121 that covers the bump conductor 131 and the dummy bump conductor 141 that are exposed respectively to the side surfaces S3 and S4 may be larger in thickness than a part of the conductive resin layer 121 that covers the bump conductor 131 and dummy bump conductor 141 that are exposed to the side surface S1. Similarly, a part of the conductive resin layer 122 that covers the bump conductor 132 and the dummy bump conductor 142 that are exposed respectively to the side surfaces S3 and S4 may be larger in thickness than a part of the conductive resin layer 122 that covers the bump conductor 132 and dummy bump conductor 142 that are exposed to the side surface S2. This makes rotational displacement of mounting position (to be described later) unlikely to occur.
For example, five conductor layers L1 to L5 are embedded inside the element body 110 to constitute a coil conductor. The conductor layers L1 to L5 are each made of a material lower in resistance than at least the conductive resin layers 121 and 122. For example, the conductor layers L1 to L5 are made of copper (Cu).
As illustrated in
As illustrated in
As illustrated in
As illustrated in
As illustrated in
With the above configuration, one and the other ends of the coil conductor composed of the coil patterns 10, 20, 30, and 40 are connected respectively to the bump conductors 131 and 132. As illustrated in
As illustrated in
Further, in the present embodiment, the conductive resin layers 121 and 122 partly go around to the side surfaces S3 and S4 of the element body 110, and thus the side surface parts of the bump conductors 131 and 132 and dummy bump conductors 141 and 142 are partly covered with the conductive resin layers 121 and 122. Such a structure further enhances stress relaxation characteristics. Even in this case, a height H1 in the z-direction of a part of the side surface part that is covered with each of the conductive resin layers 121 and 122 is preferably smaller than a height H2 in the z-direction of a part of the side surface part that is not covered with each of the conductive resin layers 121 and 122. With this configuration, the contact areas between the surface treatment layer 150 and the bump conductors 131 and 132 and between the surface treatment layer 150 and the dummy bump conductors 141 and 142 are sufficiently ensured. However, in the present disclosure, it is not essential that the conductive resin layers 121 and 122 partly go around to the side surfaces S3 and S4 of the element body 110, and the conductive resin layers 121 and 122 may be provided only on the mounting surface S0 of the element body 110, as illustrated in the YZ cross-sectional view of
In the circuit board 200 illustrated in
When the coil component 100 according to the present embodiment is mounted on the circuit board 200 having such a structure, the land pattern 201 and the bump conductor 131 are connected to each other through a solder 220 as illustrated in a partial cross-sectional view of
Further, since four terminal electrodes constituted by the bump conductors 131 and 132 and dummy bump conductors 141 and 142 are exposed to the side surfaces S1 to S4 of the element body 110, the fillet of the solder 220 is formed at four corners denoted by thick lines in
Although the connection patterns 11 to 14, 21 to 24, 31 to 34, and 41 to 44 are also exposed to the side surfaces S1 to S4 of the element body 110, the fillet of the solder 220 is unlikely to be formed on the connection patterns 11 to 14, 21 to 24, 31 to 34, and 41 to 44 since they are separated from one another through interlayer insulating films on the side surfaces S1 to S4 of the element body 110. This prevents the height of the fillet of the solder 220 from being increased more than necessary, so that high-density mounting is not hindered. However, the fillet of the solder 220 may be formed on the connection patterns 11 to 14, 21 to 24, 31 to 34, and 41 to 44 due to deformation of a connection pattern occurring during singulation or the presence of the via conductors exposed to the side surfaces S1 to S4 of the element body 110.
As described above, according to the coil component 100 of the present embodiment, it is possible to enhance both electrical connection characteristics and stress relaxation characteristics and further to prevent displacement of the mounting position in the planar and rotational directions upon mounting.
While the preferred embodiment of the present disclosure has been described, the present disclosure is not limited to the above embodiment, and various modifications may be made within the scope of the present disclosure, and all such modifications are included in the present disclosure.
For example, although the bump conductors 131 and 132 are both exposed to the side surface S3 of the element body 110 in the above embodiment, the bump conductors 131 and 132 and dummy bump conductors 141 and 142 are not particularly limited in position. Therefore, the bump conductors 131 and 132 may be disposed at diagonal positions by interchanging the positions of the bump conductor 132 and dummy bump conductor 142.
The technology according to the present disclosure includes the following configuration examples but not limited thereto.
A coil component according to the present disclosure includes: an element body having a mounting surface, first and second side surfaces which are perpendicular to the mounting surface and parallel to each other, and third and fourth side surfaces which are perpendicular to the mounting surface and the first surface and parallel to each other; a coil conductor embedded in the element body; a first bump conductor which is connected to one end of the coil conductor and exposed to the mounting surface, the first side surface, and the third side surface; a second bump conductor which is connected to the other end of the coil conductor and exposed to the mounting surface, the second side surface, and one of the third and fourth side surfaces; a first dummy bump conductor which is exposed to the mounting surface, the first side surface and the fourth side surface; a second dummy bump conductor which is exposed to the mounting surface, the second side surface, and the other one of the third and fourth side surfaces; a first conductive resin layer which is formed on the mounting surface and connects the first bump conductor and first dummy bump conductor; and a second conductive resin layer which is formed on the mounting surface and connects the second bump conductor and the second dummy bump conductor. First side surface parts of the first bump conductor and first dummy bump conductor that are exposed to the first, third, and fourth side surfaces are each not covered at least partly with the first conductive resin layer, and second side surface parts of the second bump conductor and second dummy bump conductor that are exposed to the second, third, and fourth side surfaces are each not covered at least partly with the second conductive resin layer.
According to the present disclosure, the first and second side surface parts are not covered at least partly with the first and second conductive resin layers, so that a connection resistance can be reduced there. In addition, mounting characteristics comparable with those of a four-terminal type coil component can be achieved due to the presence of the first and second dummy bump conductors.
In the present disclosure, the first side surface part may be partly covered with the first conductive resin layer, and the second side surface part may be partly covered with the second conductive resin layer. This enhances stress relaxation characteristics in a state where the coil component is mounted on the circuit board. In this case, the height of a part of the first side surface part that is covered with the first conductive resin layer may be smaller than the height of another part of the first side surface part that is not covered with the first conductive resin layer, and the height of a part of the second side surface part that is covered with the second conductive resin layer may be smaller than the height of another part of the second side surface part that is not covered with the second conductive resin layer. This makes it possible to suppress an increase in a connection resistance due to the presence of the conductive resin layer.
In the present disclosure, the first conductive resin layer may cover a part of the first side surface part that is exposed to the third and fourth side surfaces without covering another part of the first side surface part that is exposed to the first side surface to constitute an L-shaped electrode on each of the first bump conductor and first dummy bump conductor, and the second conductive resin layer may cover a part of the second side surface part that is exposed to the third and fourth side surfaces without covering another part of the second side surface part that is exposed to the second side surface to constitute an L-shaped electrode on each of the second bump conductor and second dummy bump conductor. This makes it possible to sufficiently ensure the area of a part of each of the first and second side surface parts that is exposed without being covered with the first or second conductive resin layer.
In the present disclosure, a part of the first conductive resin layer that covers a part of the first side surface part that is exposed to the third and fourth side surfaces may be larger in thickness than another part of the first side surface part that is exposed to the first side surface, and a part of the second conductive resin layer that covers a part of the second side surface part that is exposed to the third and fourth side surfaces may be larger in thickness than another part of the second side surface part that is exposed to the second side surface. This makes rotational displacement of mounting position unlikely to occur.
In the present disclosure, the width of a part of the first side surface part that is exposed to the first side surface and the width of another part of the first side surface part that is exposed to the third and fourth side surfaces may be equal to each other, and the width of a part of the second side surface part that is exposed to the second side surface and the width of another part of the second side surface part that is exposed to the third and fourth side surfaces may be equal to each other. This makes rotational displacement of mounting position unlikely to occur.
The coil component according to the present disclosure may further include a surface treatment layer that covers the first and second conductive resin layers and the first and second side surface parts. This makes it possible to enhance wettability to a solder. The surface treatment layer may be a laminated film containing Ni and Si.
As described above, according to the present disclosure, it is possible to reduce a connection resistance in a two-terminal type coil component in which a single coil conductor is incorporated in an element body.
Number | Date | Country | Kind |
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2022-130393 | Aug 2022 | JP | national |