JP6834167B2 - Multilayer coil parts - Google Patents

Description

The present invention relates to a laminated coil component.

Patent Document 1 discloses electronic components. The electronic component described in Patent Document 1 includes a body, an internal conductor arranged in the body, and an external electrode electrically connected to the internal conductor. In the electronic component described in Patent Document 1, a glass layer is arranged between the element body and the external electrode, and the internal conductor penetrates the glass layer and is connected to the external electrode.

Japanese Unexamined Patent Publication No. 9-007879

In the laminated coil component, the inner conductor is generally formed of a conductive material containing Ag and Pd as metals. However, when the inner conductor is formed of an alloy of Ag and Pd, the manufacturing cost increases because Pd is expensive, and the DC resistance of the coil increases. On the other hand, when the inner conductor does not contain Pd and the inner conductor is formed of Ag, the DC resistance of the coil is lowered, but the connection between the inner conductor connected by the Kirkendall effect and the outer electrode may be insufficient. There is.

One aspect of the present invention is to provide a laminated coil component capable of improving the connectivity between the coil and an external electrode while suppressing an increase in the DC resistance of the coil.

The laminated coil component according to one aspect of the present invention includes an element body in which a plurality of insulator layers are laminated, and a coil formed by electrically connecting a plurality of internal conductors juxtaposed in the element body. An external conductor that is arranged on the outer surface of the body and electrically connected to the coil and has at least a seizure electrode layer, and the inner conductor connected to the outer electrode is a seizure electrode layer and the inner conductor. The connecting conductor has a connecting conductor that electrically connects the two, and the connecting conductor has a protruding portion that protrudes from the outer surface of the element body toward the external electrode side, and the protruding portion is larger than the metal of the main component contained in the baking electrode layer. It contains a metal with a low diffusion coefficient, and the inner conductor has a lower electrical resistance value than the metal contained in the protrusion.

In the laminated coil component according to one aspect of the present invention, the internal conductor has a lower electric resistance value than the metal contained in the protrusion. Therefore, in the laminated coil component of this embodiment, an increase in the DC resistance of the coil can be suppressed. Due to the Kirkendall effect (phenomenon), the baked electrode layer of the external electrode serves as a metal supply source for the connecting conductor to protrude from the end face of the element body toward the baked electrode layer and come into contact with the baked electrode layer. In the laminated coil component of this embodiment, the protruding portion of the connecting conductor contains a metal having a diffusion coefficient smaller than that of the main component metal contained in the external electrode. That is, the main component metal contained in the baking electrode layer has a larger diffusion coefficient than the metal contained in the protruding portion, and is easily diffused. Therefore, in the laminated coil component of this embodiment, a protruding portion is formed by the metal diffusing from the baking electrode layer to the connecting conductor side and the connecting conductor expanding in the manufacturing process. As described above, in the laminated coil component of this embodiment, since the protruding portion for electrically connecting the connecting conductor and the baking electrode layer is formed, the connectivity between the inner conductor and the outer electrode can be sufficiently ensured. As a result, in the laminated coil component of this embodiment, the connectivity between the coil and the external electrode can be improved.

In one embodiment, the main component metal contained in the baking electrode layer is Ag, and the metal contained in the protrusion is Pd. Pd has a smaller diffusion coefficient than Ag. Therefore, in the laminated coil component of one embodiment, the metal is surely diffused from the baking electrode layer to the connecting conductor in the manufacturing process. Therefore, in the laminated coil component of one embodiment, a protruding portion for electrically and reliably connecting the connecting conductor and the seizure electrode layer is formed, so that the connectivity between the inner conductor and the outer electrode can be more sufficiently ensured. As a result, in the laminated coil component of one embodiment, the connectivity between the coil and the external electrode can be improved.

In one embodiment, the outer surface of the element body may be covered with a glass layer, and the protrusion may penetrate the glass layer and be electrically connected to the external electrode. In this configuration, since the outer surface of the element body is covered with a glass layer, for example, when forming the plating layer of the external electrode, it is possible to suppress the plating solution from entering the element body and to plate the outer surface of the element body. It is possible to suppress the precipitation of metal.

According to one aspect of the present invention, it is possible to improve the connectivity between the coil and the external electrode while suppressing an increase in the DC resistance of the coil.

It is a perspective view which shows the laminated coil component which concerns on one Embodiment. It is a figure for demonstrating the cross-sectional structure along the line II-II in FIG. It is a perspective view which shows the coil conductor. It is a figure for demonstrating the manufacturing method of a laminated coil component. It is a figure for demonstrating the manufacturing method of a laminated coil component. It is a figure for demonstrating the manufacturing method of a laminated coil component.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 1, the laminated coil component 1 includes a body 2 and a pair of external electrodes 4 and 5 arranged at both ends of the body 2.

The element body 2 has a rectangular parallelepiped shape. As its outer surface, the element body 2 extends so as to connect between a pair of end faces 2a and 2b facing each other and a pair of end faces 2a and 2b, and a pair of main surfaces 2c and 2d facing each other. And a pair of side surfaces 2e and 2f extending so as to connect between the pair of main surfaces 2c and 2d and facing each other. The main surface 2c or the main surface 2d is defined as a surface facing the other electronic device when, for example, the laminated coil component 1 is mounted on another electronic device (for example, a circuit board or an electronic component) (not shown). ..

The facing directions of the end faces 2a and 2b, the facing directions of the main faces 2c and 2d, and the facing directions of the side surfaces 2e and 2f are substantially orthogonal to each other. The rectangular parallelepiped shape includes a rectangular parallelepiped shape in which the corners and ridges are chamfered, and a rectangular parallelepiped in which the corners and ridges are rounded.

The element body 2 is formed by laminating a plurality of insulator layers 6 (see FIG. 3). The insulator layers 6 are laminated in the opposite directions of the main surfaces 2c and 2d of the element body 2. That is, the stacking direction of each insulator layer 6 coincides with the facing direction of the main surfaces 2c and 2d of the element body 2. Hereinafter, the opposite directions of the main surfaces 2c and 2d are also referred to as “stacking directions”. Each insulator layer 6 has a substantially rectangular shape. In the actual body 2, each insulator layer 6 is integrated so that the boundary between the layers cannot be visually recognized.

Each insulator layer 6 is composed of, for example, a glass made of strontium, calcium, alumina and silicon oxide, and a glass-based ceramic made of alumina. Each insulator layer 6 may be composed of ferrite (Ni-Cu-Zn-based ferrite, Ni-Cu-Zn-Mg-based ferrite, Cu-Zn-based ferrite, Ni-Cu-based ferrite, etc.). The insulator layer 6 of the portion may be made of non-magnetic ferrite.

As shown in FIG. 2, a glass layer 3 is formed on the outer surface (each end surface 2a, 2b, each main surface 2c, 2d, each side surface 2e, 2f) of the element body 2. The thickness of the glass layer 3 is, for example, 0.5 μm to 10 μm. The glass layer 3 preferably has a high softening point, for example, a softening point of 600 ° or more.

The external electrode 4 is arranged on the end surface 2a side of the element body 2. The external electrode 5 is arranged on the end surface 2b side of the element body 2. That is, the external electrodes 4 and 5 are located apart from each other in the opposite directions of the pair of end faces 2a and 2b. Each of the external electrodes 4 and 5 has a substantially rectangular shape in a plan view, and its corners are rounded.

The external electrode 4 has a baking electrode layer 7, a first plating layer 8, and a second plating layer 9. In the external electrode 4, the baking electrode layer 7, the first plating layer 8 and the second plating layer 9 are arranged in this order from the element body 2 side. The baking electrode layer 7 contains a conductive material. The baking electrode layer 7 is configured as a sintered body of a conductive paste containing a conductive metal powder (Ag powder in this embodiment) and a glass frit. The first plating layer 8 is, for example, a Ni plating layer. The second plating layer 9 is, for example, a Sn plating layer.

The external electrodes 4 include an electrode portion 4a located on the end surface 2a, an electrode portion 4b located on the main surface 2d, an electrode portion 4c located on the main surface 2c, and an electrode portion 4d located on the side surface 2e. , And an electrode portion 4e located on the side surface 2f, and five electrode portions are included. The electrode portion 4a covers the entire surface of the end face 2a. The electrode portion 4b covers a part of the main surface 2d. The electrode portion 4c covers a part of the main surface 2c. The electrode portion 4d covers a part of the side surface 2e. The electrode portion 4e covers a part of the side surface 2f. The five electrode portions 4a, 4b, 4c, 4d, and 4e are integrally formed.

The external electrode 5 has a baking electrode layer 10, a first plating layer 11, and a second plating layer 12. In the external electrode 5, the baking electrode layer 10, the first plating layer 11, and the second plating layer 12 are arranged in this order from the element body 2 side. The baking electrode layer 10 contains a conductive material. The baking electrode layer 10 is configured as a sintered body of a conductive paste containing a conductive metal powder (Ag powder in this embodiment) and a glass frit. The first plating layer 11 is, for example, a Ni plating layer. The second plating layer 12 is, for example, a Sn plating layer.

The external electrodes 5 include an electrode portion 5a located on the end surface 2b, an electrode portion 5b located on the main surface 2d, an electrode portion 5c located on the main surface 2c, and an electrode portion 5d located on the side surface 2e. , An electrode portion 5e located on the side surface 2f, and five electrode portions. The electrode portion 5a covers the entire surface of the end face 2b. The electrode portion 5b covers a part of the main surface 2d. The electrode portion 5c covers a part of the main surface 2c. The electrode portion 5d covers a part of the side surface 2e. The electrode portion 5e covers a part of the side surface 2f. The five electrode portions 5a, 5b, 5c, 5d, and 5e are integrally formed.

The laminated coil component 1 includes a coil 15 arranged in the element body 2. As shown in FIG. 3, the coil 15 includes a plurality of coil conductors (internal conductors) 16a, 16b, 16c, 16d, 16e, 16f.

The plurality of coil conductors 16a to 16f are formed of a material having an electric resistance value smaller than that of the metal (Pd) contained in the protrusions 20 and 21 described later. In the present embodiment, the plurality of coil conductors 16a to 16f contain Ag as a conductive material. The plurality of coil conductors 16a to 16f are configured as a sintered body of a conductive paste containing a conductive material which is Ag. The coil conductor 16a has a connecting conductor 17. The connecting conductor 17 is arranged on the end surface 2b side of the element body 2 and electrically connects the coil conductor 16a and the external electrode 5. The coil conductor 16f has a connecting conductor 18. The connecting conductor 18 is arranged on the end surface 2a side of the element body 2 and electrically connects the coil conductor 16f and the external electrode 4. The connecting conductor 17 and the connecting conductor 18 are formed using Ag and Pd as conductive materials. In the present embodiment, the conductor pattern of the coil conductor 16a and the conductor pattern of the connecting conductor 17 are integrally and continuously formed, and the conductor pattern of the coil conductor 16f and the conductor pattern of the connecting conductor 18 are integrally and continuously formed. Will be done.

The coil conductors 16a to 16f are juxtaposed in the element body 2 in the stacking direction of the insulator layer 6. The coil conductors 16a to 16f are arranged in the order of the coil conductor 16a, the coil conductor 16b, the coil conductor 16c, the coil conductor 16d, the coil conductor 16e, and the coil conductor 16f from the side closest to the outermost layer.

The ends of the coil conductors 16a to 16f are connected to each other by through-hole conductors 19a to 19e. As a result, the coil conductors 16a to 16f are electrically connected to each other, and the coil 15 is formed in the element body 2. The through-hole conductors 19a to 19e contain Ag as a conductive material, and are configured as a sintered body of a conductive paste containing the conductive material.

As shown in FIG. 2, the connecting conductor 17 has a protrusion 20. The protruding portion 20 is arranged on the end surface 2a side of the element body 2 in the connecting conductor 17. The protruding portion 20 projects from the end surface 2a of the element body 2 toward the external electrode 5. The protruding portion 20 penetrates the glass layer 3 and is connected to the baking electrode layer 10 of the external electrode 5. The protruding portion 20 contains a metal (Pd) having a diffusion coefficient smaller than that of the main component metal (Ag) contained in the external electrode 5 (baked electrode layer 10). In the present embodiment, the protrusion 20 includes Ag and Pd.

The connecting conductor 18 has a protrusion 21. The protruding portion 21 is arranged on the end surface 2b side of the element body 2 in the connecting conductor 18. The protruding portion 21 projects from the end surface 2b of the element body 2 toward the external electrode 4. The protruding portion 21 penetrates the glass layer 3 and is connected to the baking electrode layer 7 of the external electrode 4. The protruding portion 21 contains a metal (Pd) having a diffusion coefficient smaller than that of the main component metal (Ag) contained in the external electrode 4 (baked electrode layer 7). In the present embodiment, the protrusion 21 includes Ag and Pd. The metal (Pd) contained in the protrusions 20 and 21 has a larger electric resistance value than the plurality of coil conductors 16a to 16f.

Subsequently, the manufacturing method of the laminated coil component 1 will be described with reference to FIGS. 4 and 5.

As shown in FIG. 4A, first, a laminated body 30 including the element body 2 and the coil 15 is formed. Specifically, a ceramic powder, an organic solvent, an organic binder, a plasticizer, and the like are mixed to form a ceramic slurry, which is then molded into a sheet by a doctor blade method to obtain a ceramic green sheet. Subsequently, a conductive paste containing Ag as a metal component is screen-printed on the ceramic green sheet to form a conductor pattern of the coil conductors 16a to 16f.

The connecting conductor 17 of the coil conductor 16a is formed of a conductive paste containing Ag and Pd as metal components. The connecting conductor 18 of the coil conductor 16f is formed of a conductive paste containing Ag and Pd as metal components. The conductor pattern of the connecting conductor 17 and the connecting conductor 18 may be formed on the ceramic green sheet by a conductive paste containing Ag and Pd as a metal component, or a conductor formed by a conductive paste containing Ag as a metal component. It may be formed by superimposing a conductive paste containing Ag and Pd as metal components on the pattern. Then, the ceramic green sheets on which the conductor pattern is formed are laminated, the binder is removed in the atmosphere, and then the firing is performed. As a result, the laminated body 30 is obtained.

Subsequently, as shown in FIG. 4B, the glass layer 3 is formed. Specifically, the glass layer 3 is formed by applying a glass slurry containing glass powder, a binder resin, a solvent, and the like to the entire surface of the element body 2. The glass slurry is applied, for example, by a barrel spray method. The glass layer 3 is formed by simultaneous firing of the glass slurry and the conductive paste described later that forms the baking electrode layers 7 and 10. Therefore, although FIG. 4B shows a state in which the glass layer 3 is formed on the element body 2, the glass layer 3 is actually formed when the baking electrode layers 7 and 10 are fired. Is formed in.

Subsequently, as shown in FIG. 5A, the baking electrode layers 7 and 10 are formed. Specifically, the baking electrode layers 7 and 10 are fired by applying a conductive paste containing Ag powder and glass frit as the conductive metal powder. The softening point of the glass frit is preferably lower than the softening point of the glass powder forming the glass layer 3. When the conductive paste is fired, the connecting conductors 17 and 18 and the baking electrode layers 7 and 10 are electrically connected by the Kirkendall effect (phenomenon).

Specifically, as shown in FIG. 6, when the conductive paste is fired, the glass particles contained in the glass slurry forming the glass layer 3 are dissolved and flowed. Further, due to the Kirkendall effect, Ag particles (Ag ions) contained in the conductive paste having a diffusion coefficient smaller than that of Pd are attracted to the connecting conductors 17 and 18 containing Pd. As a result, the connecting conductors 17 and 18 are stretched toward the baking electrode layers 7 and 10, and the connecting conductors 17 and 18 come into contact with the baking electrode layers 7 and 10. As a result, the connecting conductors 17 and 18 and the baking electrode layers 7 and 10 are electrically connected, and the protruding portions 20 and 21 penetrating the glass layer 3 are formed.

Subsequently, as shown in FIG. 5B, the first plating layers 8 and 11 and the second plating layers 9 and 12 are formed. The first plating layers 8 and 11 are Ni plating layers. The first plating layers 8 and 11 are formed by depositing Ni using a watt-based bath, for example, by a barrel plating method. The second plating layers 9 and 12 are Sn plating layers. The second plating layers 9 and 12 are formed by precipitating Sn using a neutral tin plating bath by a barrel plating method. As described above, the laminated coil component 1 is manufactured.

As described above, in the laminated coil component 1 according to the present embodiment, the coil conductors 16a to 16f have lower electric resistance values than the metals contained in the protrusions 20 and 21. Therefore, in the laminated coil component 1, an increase in the DC resistance of the coil 15 can be suppressed. In the baked electrode layers 7 and 10 of the external electrodes 4 and 5, the connecting conductors 17 and 18 project from the end faces 2a and 2b of the element body 2 toward the baked electrode layers 7 and 10 due to the Kirkendall effect, and the baked electrode layers 7 and 10 It is a source of metal for contact with. In the laminated coil component 1, the protruding portions 20 and 21 of the connecting conductors 17 and 18 include a metal having a diffusion coefficient smaller than that of the main component metal contained in the external electrodes 4 and 5. That is, the main component metal contained in the baking electrode layers 7 and 10 has a larger diffusion coefficient than the metal contained in the protrusions 20 and 21, and is easily diffused. Therefore, in the laminated coil component 1, the metal diffuses from the baking electrode layers 7 and 10 to the connecting conductors 17 and 18 in the manufacturing process, and the connecting conductors 17 and 18 expand to form the protruding portions 20 and 21. There is. As described above, in the laminated coil component 1, the protruding portions 20 and 21 for electrically connecting the connecting conductors 17 and 18 and the baking electrode layers 7 and 10 are formed, so that the coil conductors 16a and 16f and the external electrodes 4 and 4 are formed. Sufficient connectivity with 5 can be ensured. As a result, in the laminated coil component 1, the connectivity between the coil 15 and the external electrodes 4 and 5 can be improved.

In the laminated coil component 1 according to the present embodiment, the main component metal contained in the baked electrode layers 7 and 10 of the external electrodes 4 and 5 is Ag, and the protruding portions 20 and 21 include Pd as a metal. Pd has a smaller diffusion coefficient than Ag. As a result, in the manufacturing process of the laminated coil component 1, when the glass slurry forming the glass layer 3 and the conductive paste forming the baking electrode layers 7 and 10 are simultaneously fired, the conductive paste is formed by the Kirkendall effect (phenomenon). The contained Ag is attracted to Pd. As a result, the ends of the connecting conductors 17 and 18 expand, and the connecting conductors 17 and 18 come into contact with the baking electrode layers 7 and 10. Therefore, the protrusions 20 and 21 are formed to electrically and reliably connect the connecting conductors 17 and 18 and the baking electrode layers 7 and 10. As a result, in the laminated coil component 1, the connectivity between the coil 15 and the external electrodes 4 and 5 can be improved.

In the laminated coil component 1 according to the present embodiment, a glass layer 3 is formed on the surface of the element body 2. As a result, in the process of forming the first plating layers 8 and 11 and the second plating layers 9 and 12, it is possible to prevent the plating solution from invading the element body 2, and the plating metal is formed on the outer surface of the element body 2. Precipitation can be suppressed.

Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

In the above embodiment, a mode in which the external electrodes 4 and 5 have electrode portions 4a and 4b, electrode portions 4c, 5c, 4d and 5d, and electrode portions 4d, 5d, 4e and 5e has been described as an example. However, the shape of the external electrode is not limited to this. For example, the external electrode may be formed only on the end face, or may be formed on the end face and at least one of the main face and the side surface.

In the above embodiment, a mode in which the external electrodes 4 and 5 have the first plating layers 8 and 11 and the second plating layers 9 and 12 has been described as an example. However, the plating layer may be one layer or three or more layers.

1 ... Laminated coil component, 2 ... Elementary body, 3 ... Glass layer, 4, 5 ... External electrode, 6 ... Insulator layer, 7, 10 ... Baking electrode layer, 15 ... Coil, 16a to 16b ... Coil conductor (internal conductor) ), 17, 18 ... Connecting conductors, 20, 21 ... Projections.

Claims (3)

An element body in which multiple insulator layers are laminated, and
A coil formed by electrically connecting a plurality of internal conductors juxtaposed in the body,
An external electrode that is disposed on the outer surface of the element body and is electrically connected to the coil and has at least a seizure electrode layer.
The inner conductor connected to the outer electrode has a connecting conductor that electrically connects the baked electrode layer and the inner conductor.
The connecting conductor has a protruding portion protruding from the outer surface of the element body toward the outer electrode side.
The protrusion contains a metal having a diffusion coefficient smaller than that of the main component metal contained in the baking electrode layer.
The inner conductor, the electric resistance value than the metal contained in the protruding portion is rather low,
The outer surface of the element body is covered with a glass layer,
The baking electrode layer is formed including a glass frit having a lower softening point than the glass layer.
The protruding portion is a laminated coil component that penetrates the glass layer and is electrically connected to the baking electrode layer. The main component of the metal contained in the baking electrode layer is Ag.
The laminated coil component according to claim 1, wherein the metal contained in the protruding portion is Pd. An element body in which multiple insulator layers are laminated, and
A coil formed by electrically connecting a plurality of internal conductors juxtaposed in the body,
An external electrode arranged on the outer surface of the element body and electrically connected to the coil and having at least a seizure electrode layer is provided.
The inner conductor connected to the outer electrode has a connecting conductor that electrically connects the baked electrode layer and the inner conductor.
The outer surface of the element body is covered with a glass layer,
The connecting conductor is a method for manufacturing a laminated coil component having a protruding portion protruding from the outer surface of the element body toward the outer electrode side.
The diffusion coefficient of the metal contained in the conductive paste forming the connecting conductor is the main component contained in the conductive paste containing the glass frit which is the conductive paste forming the baking electrode layer and has a lower softening point than the glass layer. By firing the conductive paste that forms the connecting conductor and the conductive paste that forms the baking electrode layer, the metal is spread from the baking electrode layer side to the connecting conductor side. By diffusing, the connecting conductor is expanded to form the protruding portion that penetrates the glass layer and is electrically connected to the baking electrode layer.
A method for manufacturing a laminated coil component, wherein the electric resistance value of the inner conductor is made smaller than the electric resistance value of the metal contained in the conductive paste forming the protruding portion.

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