JP4463046B2 - Ceramic electronic components and capacitors - Google Patents

Description

  The present invention relates to a ceramic electronic component and a capacitor.

  A typical ceramic electronic component will be described using a ceramic capacitor.

  FIG. 4 is a cross-sectional view showing a conventional ceramic capacitor.

  In the figure, a ceramic capacitor 30 includes internal electrodes (wiring conductors) 33 and 34 interposed between adjacent dielectric layers 32 in a laminated body 31 in which a plurality of dielectric layers (ceramic layers) 32 are laminated. The external electrodes 35 and 36 electrically connected to the end portions of the internal electrodes 33 and 34 are formed on the side surfaces of the multilayer body 31, and one ends of the external electrodes 35 and 36 are extended to the four main surfaces of the multilayer body 31. I am letting.

According to the ceramic capacitor 10, the external electrodes 35 and 36 contain a metal component and a glass component. At the time of baking, the glass components gather at the interfaces between the metal components of the external electrodes 35 and 36 and the side surfaces and the four main surfaces of the multilayer body 31, thereby connecting the external electrodes 35 and 36 and the multilayer body 31 ( For example, see Patent Document 1).
JP 2002-270457 A

  However, according to the ceramic capacitor 30, the portion formed on the side surface of the multilayer body 31 among the external electrodes 35 and 36 is firmly connected to the internal electrodes 33 and 34 by a metal-metal bond. The portions formed on the four main surfaces of the body 31 have a problem that peeling 37 is likely to occur due to an external impact as shown in FIG. 5 because the connection strength with the laminated body 31 is weak.

  The present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to provide a ceramic electronic component and a capacitor that can effectively prevent peeling of external electrodes by a simple and inexpensive method. is there.

  In the present invention, a wiring conductor is disposed on the surface and / or inside a laminated body in which a plurality of ceramic layers are laminated, and an external electrode electrically connected to the wiring conductor is formed on the main surface of the laminated body. In this ceramic electronic component, a dummy wiring is disposed inside the multilayer body with a ceramic layer separated from the external electrode, and in the ceramic layer between the dummy wiring and the external electrode. A metal which is connected to the metal component in the dummy wiring by sintering, and a plurality of metal particles partially exposed to the external electrode side are embedded, and deposited from the exposed portion of the metal particles The external electrode is formed of a metal plating film in which materials are connected to each other.

  The average particle size A of the metal particles present in the ceramic layer is set to 100% to 200% with respect to the thickness B of the ceramic layer located between the dummy wiring and the external electrode. It is a feature.

  Further, an internal electrode is interposed between adjacent dielectric layers in a multilayer body in which a plurality of dielectric layers are stacked, and an external part electrically connected to an end portion of the internal electrode on the side surface of the multilayer body In a capacitor in which an electrode is formed and one end of the external electrode extends to the main surface of the multilayer body, a dummy wiring is provided inside the multilayer body with a dielectric layer separated from the external electrode by one layer. In the dielectric layer between the dummy wiring and the external electrode, a plurality of metal components in the dummy wiring are connected by sintering and a part thereof is exposed to the external electrode side. The external electrode is formed by a metal plating film in which metal particles are embedded and metal materials deposited from the exposed portions of the metal particles are interconnected.

  The average particle diameter A of the metal particles existing in the dielectric layer is set to 100% to 200% with respect to the thickness B of the dielectric layer located between the dummy wiring and the external electrode. It is characterized by.

  According to the present invention, the dummy wiring is disposed inside the laminated body with the ceramic layer being separated from the external electrode, and the metal in the dummy wiring is disposed in the ceramic layer between the dummy wiring and the external electrode. Metal plating that embeds a plurality of metal particles that are connected to the components by sintering and that are partially exposed to the external electrode side, and that interconnects metal materials deposited from the exposed portions of these metal particles An external electrode is formed by a film.

  That is, since the external electrode is joined to the exposed portion of the metal particles partially embedded in the laminate by a strong metal-metal bond on the main surface of the laminate, the connection strength between the external electrode and the laminate main surface is Can be increased, and peeling of the external electrode can be prevented.

  In addition, since the metal particles and the metal components in the dummy wiring are connected by sintering, the external electrodes can be prevented from being peeled off without changing the normal production line, and the metal particles and the dummy wiring are integrated. This also effectively prevents the external electrode from peeling off.

  Further, since some of the metal particles are bonded to the dummy wiring, the metal particles themselves are securely fixed in the laminated body, and this can also effectively prevent the external electrodes from peeling off. Furthermore, it is possible to prevent peeling between the dielectric layer disposed between the external electrode and the dummy wiring and the dummy wiring.

  Furthermore, since the external electrode is formed of a metal plating film in which metal materials deposited from the exposed portions of a plurality of metal particles are connected to each other, the thickness accuracy of the external electrode is improved and the laminate is not required. The external electrode can be formed by a simple and inexpensive method in which the electrode is immersed in a plating solution for electrolytic plating for a predetermined time.

  Furthermore, it is desirable that the average particle diameter A of the metal particles present in the ceramic layer is set to 100% to 200% with respect to the thickness B of the ceramic layer located between the dummy wiring and the external electrode. That is, since the average particle diameter A of the metal particles is 100% or more with respect to the thickness B of the ceramic layer, the metal particles penetrate the ceramic layer, and the dummy wiring and the external electrode can be reliably bonded. On the other hand, since the average particle diameter A of the metal particles is 200% or less with respect to the thickness B of the ceramic layer, the dummy wiring can be formed with high precision by screen printing or the like at the time of manufacture, and the ceramic that becomes the laminate When pressurizing and heating the layers and the wiring conductor, there is no problem that the adhesion between the ceramic layers is lowered.

  For the reasons described above, the present invention interposes an internal electrode between adjacent dielectric layers in a laminated body in which a plurality of dielectric layers are laminated, and electrically connects the end of the internal electrode to the side surface of the laminated body. It is particularly suitable for a capacitor in which external electrodes to be connected are formed, and one end of the external electrode is extended to the main surface of the laminate.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  1A and 1B are diagrams showing a ceramic capacitor according to an embodiment of the present invention, in which FIG. 1A is an external perspective view, and FIG. 1B is a cross-sectional view. FIG. 2 is a cross-sectional view showing a method for manufacturing the ceramic capacitor of FIG.

  In the figure, a ceramic capacitor 10 includes internal electrodes (wiring conductors) 3 and 4 interposed between adjacent dielectric layers 2 in a laminated body 1 in which a plurality of dielectric layers (ceramic layers) 2 are laminated. The external electrodes 5 and 6 electrically connected to the end portions of the internal electrodes 3 and 4 are formed on the side surfaces of the multilayer body 1, and one ends of the external electrodes 5 and 6 are extended to the four main surfaces of the multilayer body 1. I am letting.

The dielectric layer 2 is formed to a thickness of 0.5 μm to 2 μm per layer by a dielectric material mainly composed of, for example, BaTiO ₃ , CaTiO ₃ , SrTiO _{3, and the} like. The stacked body 1 is formed by stacking, for example, 20 to 2000 layers in a direction perpendicular to the mounting surface of the capacitor 10.

  The internal electrodes 3a and 4a are formed to a thickness of, for example, 0.5 μm to 2.0 μm by using a conductive material whose main component is a metal such as Ni, Cu, Cu—Ni, or Ag—Pd.

  What is important in the present invention is that the dummy wirings 3b and 4b (wiring conductors) are disposed inside the multilayer body 1 with the dielectric layer 2 being separated from the external electrodes 5 and 6, and the dummy wirings. In the dielectric layer 2 between 3b and 4b and the external electrodes 5 and 6, a plurality of metal components in the dummy wirings 3b and 4b are connected by sintering and a part is exposed to the external electrodes 5 and 6 side. This is a point in which individual metal particles M are embedded. In the figure, the internal electrodes 3a, 4a and the dummy electrodes 3b, 4b are combined to form the wiring conductors 3, 4. The dummy electrodes 3b and 4b may be the same conductive material as the internal electrodes 3a and 4a, or may be different conductive materials. The metal particles M may be the same metal as other small metal particles (metal fine particles) m in the dummy electrodes 3b and 4b, or may be different metals. Further, in the drawing, two layers of the dummy electrodes 3b and 4b are arranged on one main surface side of the laminate 1, but any number of layers may be used as long as it is one or more layers. As the number of dummy electrodes 3b and 4b increases, the connection strength between the external electrodes 5 and 6 and the main surface of the multilayer body 1 can be increased, and peeling of the external electrodes 5 and 6 can be prevented. Further, in the drawing, a plurality of metal particles M are embedded so as to straddle between adjacent dummy electrodes (3b-3b, 4b-4b). However, such metal particles M may not be embedded.

  Further, the external electrodes 5 and 6 are formed of a metal plating film in which metal materials deposited from the exposed portions of the metal particles M are connected to each other.

  The particle size A of the metal particles M existing in the dielectric layer 2 is 100% of the thickness B of the dielectric layer 2 located between the dummy wirings 3b and 4b and the extended portions of the external electrodes 5 and 6. It is set to ~ 200%. Here, the particle size A of the metal particles M can be confirmed with a metal microscope after the fracture surface of the fired laminate 1 is chemically etched.

  At this time, one or two metal particles M exist in the dielectric layer 2 between the dummy wirings 3b and 4b and the external electrodes 5 and 6 or in the dielectric layer 2 between the dummy wirings 3b and 4b. It becomes. As a result, the entire metal particle has an indefinite shape and does not fall off the dielectric layer 2 due to external impact or the like.

  Hereinafter, a method for manufacturing the above-described ceramic capacitor 10 will be described. In addition, each code | symbol in a figure shall not distinguish before and after baking.

First, an appropriate organic solvent, glass frit, organic binder, and the like are added to and mixed with a dielectric material powder mainly composed of BaTiO ₃ , CaTiO ₃ , SrTiO _3, etc. to produce a slurry ceramic slurry. A ceramic green sheet 2 to be a dielectric layer having a predetermined shape and a predetermined thickness is formed from the ceramic slurry thus obtained by a conventionally known doctor blade method or the like.

  Next, a conductive paste obtained by adding and mixing an appropriate organic solvent, an organic binder, etc. to a powder of a metal material such as Ni, Cu, Cu—Ni, Ag—Pd, etc. on the ceramic green sheet 2 is conventionally known. A predetermined pattern is applied by screen printing or the like to form conductor patterns 3 and 4 to be wiring conductors. At this time, as shown in FIG. 2A, metal particles M having a large particle diameter are mixed in the conductor pastes 3b and 4b serving as dummy electrodes. Specifically, when the thickness of the ceramic green sheet 2 is 0.5 μm to 1 μm, the average particle size of the metal particles M is 0.5 μm to 2 μm, and the average particle size of the other metal particles m is 0.1 μm to 0 μm. Desirably, it is in the range of 3 μm. On the other hand, when the thickness of the ceramic green sheet 2 is 1 μm to 2 μm, the average particle size of the metal particles M is in the range of 1 to 4 μm, and the average particle size of the other metal fine particles m is in the range of 0.3 μm to 0.5 μm. Is desirable. Further, when the thickness of the ceramic green sheet 2 is 2 μm to 3 μm, it is desirable that the average particle diameter of the metal particles M is 2 to 6 μm and the average particle diameter of the metal fine particles m is in the range of 0.4 μm to 0.6 μm. . When the thickness of the ceramic green sheet 2 is 3 μm to 4 μm, the average particle size of the metal particles M is preferably 3 μm to 8 μm, and the average particle size of the metal fine particles m is preferably in the range of 0.5 μm to 0.1 μm. .

  Next, as shown in FIG. 2B, a predetermined number of ceramic green sheets 2 on which conductor patterns 3 and 4 are formed are stacked.

  Next, the large laminated body 11 is obtained by pressurizing and heating the laminated conductor patterns 3 and 4 and the ceramic green sheet 2. At this time, as shown in FIG. 2 (c), since the metal particles M serving as metal particles are contained in the conductor patterns 3b and 4b serving as dummy wirings, the metal particles M break through the ceramic green sheet 2, It is exposed on the surface of the large laminate 11. Moreover, it is desirable that the ceramic green sheet 2 pierced by the metal particles M is softer than the other ceramic green sheets 2.

  Next, as shown in FIG. 2B, a predetermined number of ceramic green sheets 2 on which conductor patterns 3 and 4 are formed are stacked.

  Next, the large laminated body 11 is obtained by pressurizing and heating the laminated conductor patterns 3 and 4 and the ceramic green sheet 2. At this time, as shown in FIG. 2 (c), since the metal particles M having a large particle diameter are contained in the conductor patterns 3b and 4b serving as dummy electrodes, the metal particles M break through the ceramic green sheet 2, It is exposed on the surface of the large laminate 11 or straddles a conductor pattern (3b-3b, 4b-4b) that becomes an adjacent dummy electrode. In addition, the ceramic green sheet 2 to be pierced by the metal particles M is desirably easier to be pressure-deformed and softer than the other ceramic green sheets 2 or is a thermoplastic ceramic green sheet 2.

  Next, the large-sized laminated body 11 is cut | disconnected by a predetermined dimension, and the laminated body 1 of an unbaking state is obtained.

  Next, the laminated body 1 is obtained by firing the obtained unfired laminated body 1 at a temperature of 1100 ° C. to 1400 ° C., for example. At this time, a part of the plurality of metal particles M embedded in the laminate 1 can be exposed on the surface of the laminate 1 by barrel polishing the laminate 1 after firing.

  Next, external electrodes 5 and 6 are formed on the pair of end faces of the laminate 1 by electroless plating. Specifically, as shown in FIG. 2D, the exposed portions of the internal electrodes 3a, 4a on the end face of the multilayer body 1 and the exposed portions of the metal particles M on the main surface of the multilayer body 1, Cu, The metal plating films 5 and 6 such as Ni, Ag, and Au are deposited, and these precipitates are connected to each other to be integrally formed. In this case, the thickness accuracy of the external electrodes 5 and 6 is improved, and the external electrodes 5 and 6 are formed into a desired pattern by simple processing by simply immersing the laminate 1 in a plating solution for electroless plating for a predetermined time. Therefore, it is possible to improve the productivity of the ceramic capacitor 10. At this time, a heat treatment (annealing) is performed on the laminate 1 on which the metal plating films 5 and 6 are deposited by the electroless plating method, thereby forming an alloy layer at the boundary between the metal particles M and the metal plating films 5 and 6. The bonding strength between the metal particles M and the metal plating films 5 and 6 may be further improved. Specifically, when the metal particles M are Ni and the metal plating films 5 and 6 are Cu, it is desirable to perform heat treatment at about 600 ° C. If necessary, a Ni plating film, a Sn plating film, or the like (not shown) may be formed on the surface of a metal plating film such as Cu, Ni, Ag, or Au by an electrolytic plating method. At this time, it is necessary to perform the heat treatment before forming these Ni plating film, Sn plating film and the like.

  In this way, a ceramic capacitor 10 as shown in FIG. 1 is obtained.

  Thus, according to the present invention, the dummy wirings 3b and 4b are disposed inside the multilayer body 1 with the dielectric layer 2 being separated from the external electrodes 5 and 6, and the dummy wirings 3b and 4b. In the dielectric layer 2 between the external electrodes 5 and 6, a plurality of metal particles are connected to the metal components in the dummy wirings 3a and 4a by sintering, and a part thereof is exposed to the external electrodes 5 and 6 side. Since the external electrodes 5 and 6 are formed by metal plating films in which M is embedded and the metal materials deposited from the exposed portions of the metal particles M are connected to each other, the external electrodes 5 and 6 are laminated bodies. 1 is partially bonded to the exposed portion of the metal particles M embedded in the laminate 1 by a strong metal-metal bond, so that the space between the external electrodes 5 and 6 and the laminate 1 main surface is The connection strength of the external electrodes 5 and 6 can be increased and the peeling 37 of the external electrodes 5 and 6 can be prevented. .

  Further, since the metal particles M and the metal components in the dummy wirings 3b and 4b are connected by sintering, the separation 37 of the external electrodes 5 and 6 can be prevented without changing the normal production line. The metal particles M and the dummy wirings 3b and 4b are integrated, and this also effectively prevents the separation 37 of the external electrodes 5 and 6.

  In addition, since a part of the metal particles M are bonded to the dummy wirings 3b and 4b, the metal particles M themselves are securely fixed in the laminated body 1, and this also effectively removes the external electrodes 5 and 6. Can be prevented. Further, the separation between the dielectric layers 2 disposed between the external electrodes 5 and 6 and the dummy wirings 3b and 4b and the dummy wirings 3b and 4b can be effectively prevented.

  The average particle size A of the metal particles M present in the dielectric layer 2 is 100% to 200% with respect to the thickness B of the dielectric layer 2 located between the dummy wirings 3b and 4b and the external electrodes 5 and 6. % Is desirable. That is, since the average particle diameter A of the metal particles M is 100% or more with respect to the thickness B of the dielectric layer 2, the metal particles M penetrate the dielectric layer 2, and the dummy wirings 3b and 4b and the external electrode 5 , 6 can be reliably joined. On the other hand, since the average particle diameter A of the metal particles M is 200% or less with respect to the thickness B of the dielectric layer 2, the conductor patterns 3b and 4b serving as dummy wirings are accurately formed by screen printing or the like at the time of manufacture. In addition, it is possible to effectively prevent the adhesion between the ceramic green sheets 2 from being lowered when the ceramic green sheet 2 and the conductor patterns 3 and 4 to be the large laminate 11 are pressed and heated. .

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in the above embodiment, the ceramic capacitor is used as the ceramic electronic component. However, the present invention can be used for any ceramic electronic component such as a laminated piezoelectric component, a circuit board, and a semiconductor component.

  FIG. 3 is a cross-sectional view showing a ceramic electronic component according to another embodiment of the present invention. As shown in the figure, the ceramic electronic component 10 of the present invention can also be applied to a circuit board 10. Further, the external electrode 5 may be separated from the side surface of the multilayer body 1. Further, the dummy wiring 4b having a size larger than that of the external electrode 5 and the dummy wiring 3b is embedded, and the dummy wiring 3b and the dummy wiring 4b are connected via the metal particles M existing in the ceramic layer 2 therebetween. May be. Thereby, the connection intensity | strength between the external electrode 5 and the main surface of the laminated body 1 can further be increased, and peeling of the external electrode 5 can be prevented further effectively. At this time, if the metal paste M is contained in the conductor paste that becomes the dummy wiring 4b, the metal particles M protrude outside the dummy wiring 3b. Therefore, the dummy wiring 3b and the dummy wiring 4b are conductors that become the dummy wiring 3b. The metal particles M contained in the paste are connected. In the figure, 3a is an internal wiring conductor, 7 is a via-hole conductor, and 8 is another electronic component.

  Furthermore, the dummy wirings 3b and 4b may contain ceramic particles substantially the same as those of the dielectric layer 2. That is, since the ceramic particles serve as a bridge between the dielectric layers 2 sandwiching the dummy wirings 3b and 4b, it is possible to prevent peeling between the dielectric layer 2 and the dummy wirings 3b and 4b.

It is a figure which shows the ceramic capacitor which concerns on one Embodiment of this invention, (a) is an external appearance perspective view, (b) is a cross-sectional view. It is sectional drawing for demonstrating the manufacturing method of the ceramic capacitor of FIG. It is a cross-sectional view showing a ceramic electronic component according to another embodiment of the present invention. It is a cross-sectional view showing a conventional ceramic capacitor.

Explanation of symbols

10 ... Ceramic electronic components (capacitors)
DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Dielectric layer (ceramic layer)
3, 4 ... wiring conductor 3a, 4a ... internal electrode 3b, 4b ... dummy wiring (dummy electrode)
5, 6 ... External electrode (external terminal electrode)
M ... Metal particles

Claims (4)

A ceramic in which a wiring conductor is disposed on the surface and / or inside of a laminate in which a plurality of ceramic layers are laminated, and an external electrode electrically connected to the wiring conductor is formed on the main surface of the laminate. In electronic components,
Inside the laminate, a dummy wiring is disposed with a ceramic layer separated from the external electrode, and a metal component in the dummy wiring is formed in the ceramic layer between the dummy wiring and the external electrode. A metal plating in which a plurality of metal particles, which are connected by sintering and are partially exposed to the external electrode side, are embedded, and metal materials deposited from the exposed portions of the metal particles are interconnected. A ceramic electronic component, wherein the external electrode is formed of a film. The average particle diameter A of the metal particles existing in the ceramic layer is set to 100% to 200% with respect to the thickness B of the ceramic layer located between the dummy wiring and the external electrode. The ceramic electronic component according to claim 1. An internal electrode is interposed between adjacent dielectric layers in a multilayer body in which a plurality of dielectric layers are stacked, and an external electrode electrically connected to an end portion of the internal electrode is provided on a side surface of the multilayer body. In a capacitor formed and extending one end of the external electrode to the main surface of the laminate,
A dummy wiring is disposed inside the stacked body with a dielectric layer separated from the external electrode by a single dielectric layer, and in the dielectric layer between the dummy wiring and the external electrode, A plurality of metal particles that are connected to the metal component by sintering and that are partly exposed to the external electrode side are embedded, and the metal materials deposited from the exposed portions of the metal particles are interconnected. A capacitor characterized in that the external electrode is formed of a metal plating film. The average particle diameter A of the metal particles existing in the dielectric layer is set to 100% to 200% with respect to the thickness B of the dielectric layer located between the dummy wiring and the external electrode. The capacitor according to claim 3.

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