JP2009170752A - Electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component having a stack of an insulating layer and an internal electrode, the component in which cracking is suppressed at the boundary between a lead-out electrode and a magnetic material layer. <P>SOLUTION: The stack 12 is formed by stacking magnetic material layers 4 and 5. The internal electrode 8 is stacked together with the magnetic material layer 4. An external electrode is formed on a surface of the stack 12. The lead-out electrode 9 electrically connects the internal electrode 8 and external electrode to each other. A dummy electrode 16 is formed overlapping with the lead-out electrode 9 in plane view from a stacking direction in the magnetic material layer 4 disposed between a surface of the stack 12 close to the lead-out electrode 9 in the stacking direction, and the lead-out electrode 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic component, and more particularly, to an electronic component including a laminate in which insulating layers are laminated.

  In the field of electronic components, there is an electronic component in which a coil is built in a laminated body by laminating a magnetic layer and an internal electrode. FIG. 6 is a sectional structural view of the laminate 112 of the electronic component. The laminated body 112 shown in FIG. 6 includes magnetic layers 104a to 104e, internal electrodes 108a to 108d, and extraction electrodes 109a and 109d.

  The internal electrodes 108a to 108d are formed on the magnetic layers 104b to 104e, respectively. Furthermore, via conductors (not shown) are formed in the magnetic layers 104b to 104d, so that the internal electrodes 108a to 108d are electrically connected to form a coil. The lead electrodes 109a and 109d serve to electrically connect a coil and an external electrode (not shown), respectively, and are formed on the magnetic layers 104b and 104e.

  In the laminated body 112 shown in FIG. 6, cracks 110a and 110d as shown in FIG. 6 are generated when the magnetic layers 104a to 104e are laminated and pressure bonded. More specifically, in the region where the internal electrodes 108a to 108d are formed, the thickness of the stacked body 112 is increased by the thickness of the internal electrodes 108a to 108d. Therefore, the magnetic layers 104a and 104e arranged in the uppermost layer and the lowermost layer are greatly curved as shown in FIG. When the magnetic layers 104a and 104e are greatly curved in this way, the magnetic layers 104a and 104e extend in the left-right direction in FIG. 6 and try to shrink in the left-right direction in FIG.

  Here, since the magnetic layers 104a and 104e and the extraction electrodes 109a and 109d are formed of different materials, adhesion is poor compared to layers formed of the same material. For this reason, when the magnetic layers 104a and 104e are contracted, cracks 110a and 110d are generated between the magnetic layers 104a and 104e and the extraction electrodes 109a and 109d as shown in FIG.

Patent Document 1 describes a multilayer chip component that improves connectivity between an external electrode and an internal electrode. More specifically, in the multilayer chip component, a dummy electrode is formed on the magnetic layer on which the internal electrode is formed. Thereby, since the silver concentration in the atmosphere at the time of baking of a laminated body becomes high, it is suppressed that the internal electrode consisting of silver evaporates. As a result, in the multilayer chip component described in Patent Document 1, the internal electrode is prevented from being degenerated, and the connectivity between the internal electrode and the external electrode is improved. However, Patent Document 1 does not include a description of the unevenness generated on the upper surface and the lower surface of the laminate as shown in FIG.
JP 2001-93745 A

  Therefore, an object of the present invention is to suppress the occurrence of cracks at the boundary between the extraction electrode and the magnetic layer in an electronic component including a laminate in which an insulating layer and an internal electrode are laminated.

  The present invention provides an electronic component in which an insulating layer is laminated, an internal electrode laminated with the insulating layer, an external electrode formed on a surface of the laminated body, the internal electrode, When the lead electrode electrically connected to the external electrode and the insulating layer located between the lead electrode and the surface of the multilayer body that is closer to the lead electrode in the stacking direction when viewed in plan from the stack direction And a dummy layer formed so as to overlap with the extraction electrode.

  According to the present invention, the dummy layer is formed so as to overlap the extraction electrode. Thereby, in this invention, the difference of the thickness of the part in which the extraction electrode is formed, and the part in which the internal electrode is formed can be made small compared with the laminated body in which the dummy layer is not provided. That is, since the unevenness of the upper surface and the lower surface of the stacked body can be reduced, the force for shrinking the insulating layers on the upper surface and the lower surface of the stacked body can be reduced. As a result, generation of cracks between the extraction electrode and the insulating layer can be suppressed.

  In the present invention, the dummy layer may be formed of a material different from that of the insulating layer.

  In the present invention, the dummy layer may be formed of the same conductive material as the extraction electrode.

  In the present invention, the extraction electrode and the dummy layer may be exposed on a side surface of the multilayer body.

  In the present invention, the dummy layer may be electrically connected only to the external electrode.

  In the present invention, the dummy layer may have the same shape as the extraction electrode.

  In the present invention, the internal electrode may form a coil.

  According to the present invention, since the dummy layer is formed so as to overlap the extraction electrode, it is possible to suppress the occurrence of cracks between the extraction electrode and the insulating layer.

  Hereinafter, an electronic component according to an embodiment of the present invention will be described. FIG. 1 is an external perspective view of the electronic component 10. FIG. 2 is an exploded view of the laminate 12. Hereinafter, the direction in which the ceramic green sheets are laminated when the electronic component 10 is formed is defined as the lamination direction. The stacking direction is the z-axis direction, the longitudinal direction of the electronic component 10 is the x-axis direction, and the direction orthogonal to the x-axis and the z-axis is the y-axis direction. The x axis, the y axis, and the z axis are parallel to the sides constituting the electronic component 10.

(About the configuration of electronic components)
As shown in FIG. 1, the electronic component 10 includes a rectangular parallelepiped laminated body 12 including a coil therein, and external electrodes 14 a and 14 b formed on the surface of the laminated body 12. The laminated body 12 has a rectangular parallelepiped shape. In FIG. 1, the surface of the laminated body 12 located at both ends in the z-axis direction is referred to as an upper surface S1 and a lower surface S2. Moreover, the surface of the laminated body 12 located at both ends in the y-axis direction is referred to as a side surface Sa and a side surface Sb. Furthermore, the surface of the laminated body 12 located at both ends in the x-axis direction is referred to as a side surface Sd and a side surface Se. The external electrodes 14a and 14b are formed so as to cover the side surfaces Sd and Se, respectively.

  The laminated body 12 is configured by laminating a plurality of internal electrodes and a plurality of magnetic layers together. Specifically, it is as follows. As shown in FIG. 2, the laminated body 12 is formed by laminating a plurality of magnetic layers 4a to 4g and 5a to 5f made of ferrite having high magnetic permeability (for example, Ni-Zn-Cu ferrite or Ni-Zn ferrite). It is constituted by. The plurality of magnetic layers 4a to 4g and 5a to 5f are rectangular insulating layers each having substantially the same area and shape.

  Internal electrodes 8a to 8e are formed on the main surfaces of the magnetic layers 4b to 4f, respectively. In addition, lead electrodes 9a and 9e are formed on the main surfaces of the magnetic layers 4b and 4f. Further, dummy electrodes 16a and 16g are formed on the main surfaces of the magnetic layers 4a and 4g, respectively. Furthermore, via conductors Ba to Bd are formed in the magnetic layers 4b to 4e, respectively. In the following, when the individual magnetic layers 4a to 4g, the internal electrodes 8a to 8e, the lead electrodes 9a and 9e, the dummy electrodes 16a and 16g, and the via conductors Ba to Bd are shown, an alphabet is added after the reference symbol. When the magnetic layers 4a to 4g, the internal electrodes 8a to 8e, the lead electrodes 9a and 9e, the dummy electrodes 16a and 16g, and the via conductors Ba to Bd are collectively referred to, the alphabet after the reference sign is omitted. .

  As shown in FIG. 2, each internal electrode 8 is made of a conductive material made of Ag and has a “U” shape. However, the internal electrodes 8a and 8e arranged on the uppermost side and the lower side in the z-axis direction have an “L” shape. Thereby, one internal electrode 8 constitutes a part of the coil L corresponding to 3/4 turns. The internal electrode 8 may be made of a conductive material such as a noble metal containing Pd, Au, Pt or the like as a main component or an alloy thereof.

  As shown in FIG. 2, the via conductor B is made of a conductive material made of Ag, and is formed at one end of the internal electrode 8 so as to penetrate the magnetic layer 4 in the z-axis direction. Thereby, the via conductor B electrically connects the internal electrodes 8 adjacent in the z-axis direction. Thereby, the plurality of internal electrodes 8 constitute a spiral coil L.

  The lead electrodes 9a and 9e have one end connected to the internal electrodes 8a and 8e and the other end exposed at the side surfaces Sd and Se of the stacked body 12 located at both ends in the x-axis direction. , 4f. The lead electrodes 9a and 9e are electrically connected to the external electrodes 14a and 14b through portions exposed from the side surfaces Sd and Se of the multilayer body 12, respectively. Thereby, the extraction electrodes 9a and 9e electrically connect the internal electrodes 8a and 8e and the external electrodes 14a and 14b.

  The dummy electrode 16a is viewed in plan view from the stacking direction on the magnetic layer 4a located between the surface (upper surface S1) of the stacked body 12 closer to the extraction electrode 9a in the z-axis direction and the extraction electrode 9a. Sometimes it is formed to overlap with the extraction electrode 9a. Similarly, the dummy electrode 16g is planarly viewed from the stacking direction in the magnetic layer 4g located between the surface (upper surface S2) of the multilayer body 12 closer to the extraction electrode 9e in the z-axis direction and the extraction electrode 9e. Then, it is formed so as to overlap with the extraction electrode 9e. The dummy electrodes 16a and 16g are electrically connected only to the external electrodes 14a and 14b, respectively. Further, as shown in FIG. 2, the dummy electrodes 16a and 16g have the same rectangular shape as that of the extraction electrodes 9a and 9e, and are formed of the same conductive material as that of the extraction electrodes 9a and 9e.

  The laminated body 12 is formed by overlapping the magnetic layers 5a to 5c, 4a to 4g, and 5d to 5f in the exploded perspective view shown in FIG. 2 in this order from the upper side in the z-axis direction. Furthermore, when the external electrodes 14a and 14b are formed on the surface of the laminate 12, the electronic component 10 is obtained.

(About electronic component manufacturing methods)
Hereinafter, a method for manufacturing the electronic component 10 will be described with reference to FIGS. 1 and 2.

First, the ceramic green sheets to be the magnetic layers 4 and 5 are produced as follows. Ferrous oxide (Fe ₂ O ₃ ), zinc oxide (ZnO), nickel oxide (NiO), and copper oxide (CuO) were weighed at a predetermined ratio and each material was put into a ball mill as a raw material. I do. The obtained mixture is dried and pulverized, and the obtained powder is calcined at 800 ° C. for 1 hour. The obtained calcined powder is wet pulverized by a ball mill, dried and crushed to obtain a ferrite ceramic powder having a particle size of 2 μm.

  A binder (vinyl acetate, water-soluble acrylic, etc.), a plasticizer, a wetting material, and a dispersing agent are added to the ferrite ceramic powder, followed by mixing with a ball mill, and then defoaming is performed under reduced pressure. The obtained ceramic slurry is formed into a sheet by the doctor blade method and dried to produce a ceramic green sheet having a desired film thickness (for example, 50 μm).

  Next, via conductors Ba to Bd are formed in the ceramic green sheets to be the magnetic layers 4b to 4e, respectively. Specifically, a via hole is formed by irradiating a ceramic green sheet to be the magnetic layers 4b to 4e with a laser beam. Next, the via hole is filled with a conductive paste such as Ag, Pd, Cu, Au or an alloy thereof by a method such as printing.

  Next, on the ceramic green sheets to be the magnetic layers 4a to 4g, a conductive paste mainly composed of Ag, Pd, Cu, Au, or an alloy thereof is applied by a method such as a screen printing method or a photolithography method. The internal electrode 8, the extraction electrode 9, and the dummy electrode 16 are formed by applying the above. Note that the via conductors Ba to Bd may be formed simultaneously with the formation of the internal electrode 8, the extraction electrode 9, and the dummy electrode 16.

  Next, each ceramic green sheet is laminated. Specifically, a ceramic green sheet to be the magnetic layer 5f is disposed. Next, the ceramic green sheet to be the magnetic layer 5e is placed and temporarily pressed onto the ceramic green sheet to be the magnetic layer 5f. Thereafter, the ceramic green sheets to be the magnetic layers 5d, 4g, 4f, 4e, 4d, 4c, 4b, 4a, 5c, 5b, and 5a are similarly laminated and temporarily pressed in this order. Thereby, a mother laminated body is formed. The mother laminate is subjected to main pressure bonding by a hydrostatic pressure press or the like.

  Next, the mother laminate is cut into a laminate 12 having a size of 2.0 mm × 1.25 mm by guillotine cutting. Thereby, the unfired laminated body 12 is obtained. The unfired laminate 12 is subjected to binder removal processing and firing. The binder removal treatment is performed, for example, in a low oxygen atmosphere at 500 ° C. for 2 hours. Firing is performed, for example, at 890 ° C. for 2.5 hours. Thereby, the baked laminated body 12 is obtained. External electrodes 14a and 14b are formed on the surface of the laminate 12 by applying and baking an electrode paste whose main component is silver by a method such as dipping. The external electrodes 14a and 14b are dried at 120 ° C. for 10 minutes, and the external electrodes 14a and 14b are baked at 800 ° C. for 60 minutes. The external electrodes 14a and 14b are formed on the side surfaces Sd and Se, respectively, as shown in FIG.

  Finally, Ni plating / Sn plating is performed on the surfaces of the external electrodes 14a and 14b. Through the above steps, the electronic component 10 as shown in FIG. 1 is completed.

(effect)
According to the electronic component 10, the dummy electrodes 16a and 16g are formed so as to overlap with the extraction electrodes 9a and 9e. Thereby, in the laminated body 12, compared with the laminated body in which the dummy electrodes 16a and 16g are not provided, the z-axis direction between the portion where the extraction electrodes 9a and 9e are formed and the portion where the internal electrode 8 is formed The difference in thickness can be reduced. That is, since the curvature of the magnetic layer 5 can be reduced, the force with which the magnetic layer 5 tries to shrink can be reduced. As a result, it is possible to suppress the occurrence of cracks between the extraction electrodes 9a and 9e and the magnetic layers 4a and 4e.

  Further, according to the electronic component 10, as will be described below, even if a crack is generated in the multilayer body 12, a crack is generated between the extraction electrodes 9a and 9e and the magnetic layers 4a and 4e. Hateful. Hereinafter, a phenomenon that occurs between the extraction electrode 9a and the magnetic layer 4a will be described as an example.

  When the magnetic layers 5a, 5b, and 5c are curved, the magnetic layers 5a, 5b, and 5c are contracted, so that the magnetic layers 4a and 4b are pulled upward in the z-axis direction. When the dummy electrode 16a is not provided, there is a possibility that a crack may be generated between the magnetic layer 4a and the extraction electrode 9a whose adhesion is inferior to that of other layers.

  Therefore, in the electronic component 10, the dummy electrode 16a is provided so as to overlap the extraction electrode 9a. Since the dummy electrode 16a is formed of the same conductive material as the extraction electrode 9a, the adhesion between the magnetic layer 5c and the dummy electrode 16a is the adhesion between the magnetic layer 4a and the extraction electrode 9a. Is almost the same. Furthermore, the dummy electrode 16a is provided on the upper surface S1 side with respect to the extraction electrode 9a. Therefore, when the magnetic layers 5a, 5b, and 5c are contracted, first, cracks are generated between the magnetic layer 5c and the dummy electrode 16a. When this crack is generated, the force from the magnetic layers 5a, 5b, 5c is not transmitted to the magnetic layers 4a, 4b. As a result, the occurrence of cracks between the magnetic layer 4a and the extraction electrode 9a is suppressed. The same phenomenon occurs between the extraction electrode 9e and the magnetic layer 4e.

  In the electronic component 10, the dummy electrodes 16 a and 16 g are formed so as to be exposed on the side surface of the multilayer body 12. Therefore, in the electronic component 10, the adhesion between the dummy electrodes 16 a and 16 g and the magnetic layers 5 c and 4 f can be reduced as compared with the case where the dummy electrodes 16 a and 16 g are not exposed on the side surface of the multilayer body 12. . Therefore, in the electronic component 10, when the magnetic layers 5a, 5b, and 5c are contracted, the magnetic layers 5c and 4f are not generated between the magnetic layers 4a and 4e and the extraction electrodes 9a and 9e. And the dummy electrodes 16a and 16g are likely to be cracked.

  In the electronic component 10, the dummy electrodes 16a and 16g have the same shape as the extraction electrodes 9a and 9e. Thereby, when the dummy electrodes 16a and 16g do not exist, the cracks having the same shape as the cracks generated between the magnetic layers 4a and 4e and the lead electrodes 9a and 9e are removed from the magnetic layers 5c and 4f and the dummy electrodes 16a. , 16g. When a crack is generated between the magnetic layers 5c and 4f and the dummy electrodes 16a and 16g, the force that generates the crack is not transmitted to the magnetic layers 4a and 4e. As a result, it is possible to effectively suppress the occurrence of cracks between the magnetic layers 4a and 4e and the extraction electrodes 9a and 9e.

(Modification)
The electronic component according to the present invention is not limited to the electronic component 10 according to the embodiment. Therefore, the design of the electronic component 10 may be changed as appropriate. Hereinafter, an electronic component according to a modification will be described with reference to the drawings. FIG. 3 is an exploded view of an electronic component laminate 12a according to a first modification. FIG. 4 is an exploded view of an electronic component laminate 12b according to a second modification. FIG. 5 is an exploded view of an electronic component laminate 12c according to a third modification. 3, 4, and 5, the same reference numerals are assigned to the same configurations as those of the laminate 12 in FIG. 2.

  As in the stacked body 12a illustrated in FIG. 3, the dummy electrodes 16a and 16g may not be exposed on the side surface of the stacked body 12a. Moreover, like the laminated body 12b shown in FIG. 4, the dummy electrodes 16a and 16g may be divided | segmented into plurality.

  Further, like the laminated body 12c shown in FIG. 5, dummy electrodes 16a and 16g having the same shape as the extraction electrodes 9a and 9e and the internal electrodes 8a and 8e may be formed. In this case, the same magnetic layer as the magnetic layers 4b and 4f is arranged on the upper side or the lower side of the magnetic layers 4b and 4f. Thereby, the magnetic layers 4b and 4f can be reused for the magnetic layers 4a and 4g on which the dummy electrodes 16a and 16g are formed.

  The dummy layer that functions as the dummy electrode 16 may be made of the same material as the magnetic layers 4 and 5. Even if the dummy electrode 16 and the magnetic layers 4 and 5 are made of the same material, the unevenness generated on the upper surface S1 and the lower surface S2 of the multilayer body 12 can be suppressed, so that the magnetic layers 4a and 4e and the extraction electrodes 9a and 9e can be suppressed. It can suppress that a crack generate | occur | produces between. However, the dummy electrode 16 is preferably made of a material different from that of the magnetic layers 4 and 5. Since the dummy electrode 16 and the magnetic layers 4 and 5 are formed of different materials, the adhesion between the dummy electrode 16 and the magnetic layers 4 and 5 can be made lower than the adhesion between the magnetic layers 4 and 5. It is.

1 is an external perspective view of an electronic component according to the present invention. It is an exploded view of the laminated body of the said electronic component. It is an exploded view of the laminated body of the electronic component which concerns on a 1st modification. It is an exploded view of the laminated body of the electronic component which concerns on a 2nd modification. It is an exploded view of the laminated body of the electronic component which concerns on a 3rd modification. It is sectional structure drawing of the laminated body of the conventional electronic component.

Explanation of symbols

4a, 4b, 4c, 4d, 4e, 4f, 4g, 5a, 5b, 5c, 5d, 5e, 5f Magnetic layer 8a, 8b, 8c, 8d, 8e Internal electrode 9a, 9e Lead electrode 10 Electronic component 12, 12a , 12b, 12c Laminated body 14a, 14b External electrode 16a, 16g Dummy electrode

Claims (7)

A laminated body in which insulating layers are laminated;
An internal electrode laminated with the insulating layer;
An external electrode formed on the surface of the laminate;
An extraction electrode that electrically connects the internal electrode and the external electrode;
A dummy formed in the insulating layer located between the surface of the multilayer body closer to the extraction electrode in the stacking direction and the extraction electrode so as to overlap the extraction electrode when viewed in plan from the stacking direction Layers,
Providing
Electronic parts characterized by The dummy layer is formed of a material different from that of the insulating layer;
The electronic component according to claim 1. The dummy layer is formed of the same conductive material as the extraction electrode;
The electronic component according to claim 2. The extraction electrode and the dummy layer are exposed on a side surface of the laminate;
The electronic component according to any one of claims 1 to 3, wherein: The dummy layer is electrically connected only to the external electrode;
The electronic component according to claim 4. The dummy layer has the same shape as the extraction electrode;
The electronic component according to claim 1, wherein: The internal electrode forms a coil;
The electronic component according to claim 1, wherein:

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