JP2010123647A - Ceramics electronic component, and electronic apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize electrical connection between an external electrode and an internal electrode of a ceramics electronic component. <P>SOLUTION: This ceramics electronic component 8 includes a metal layer 14 formed between a side face of the internal electrode 11 having an end and the external electrode 12, and the external electrode 12 contains a resin and metal particles. The average particle diameter of the metal constituting the metal layer 14 is smaller than that of the metal constituting the external electrode 12, and the electrical connection between the external electrode 12 and the internal electrode 11 can be stabilized. Since the external electrode 12 containing the resin and the metal particles can be formed by being hardened at low temperature of 150-300°C, damage to the ceramics electronic component due to high temperature can be reduced while improving an electric characteristic between the internal electrode 11 and the external electrode 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ceramic electronic component for high frequency and an electronic device using the same.

  In recent years, with the development of communication technology using electromagnetic waves in the microwave region used in mobile phones and wireless LANs, ceramic electronic components are mounted on high-frequency modules as, for example, noise removal filters. FIG. 3 shows a schematic cross-sectional view of a conventional ceramic electronic component 1.

  In FIG. 3, a conventional ceramic electronic component 1 includes a dielectric 3 formed by laminating a plurality of dielectric layers 2 made of ceramics, an internal electrode 4 formed between the plurality of dielectric layers 2, An internal plating layer 7 covering the surface of the internal electrode 4 exposed in layers, an external electrode 5 formed on the side surface having the end of the internal electrode 4, and an external plating layer 6 formed on the surface of the external electrode 5 With. Further, the external electrode 5 uses a resin-based conductive paste prepared by mixing and dispersing metal particles in an epoxy-based resin or a polyimide-based resin, and this conductive paste is applied to the outer surface of the dielectric 3. Cured at a temperature of 150 ° C. or higher and 300 ° C. or lower.

  As described above, the conventional ceramic electronic component 1 has the external electrode 5 and the internal electrode 4 formed by forming the internal plating layer 7 on the exposed surface of the internal electrode 4 exposed on the side surface of the ceramic electronic component 1 by electroless plating. The electrical connection of was aimed at stabilization.

As a prior art document related to this application, for example, the following Patent Document 1 is known.
JP 2000-306763 A

  However, in the conventional ceramic electronic component 1, in order to improve the electrical connection between the internal electrode 4 and the external electrode 5, the internal electrode 4 exposed in layers is formed by electroless plating that can be formed at a low temperature. An internal plating layer 7 was formed on the exposed surface. As a result, there is a problem that the plating solution enters the interface between the dielectric layers 2 or the interface between the internal electrode 4 and the dielectric layer 2 to deteriorate the electrical characteristics.

  Accordingly, an object of the present invention is to improve the electrical characteristics of ceramic electronic components.

  In order to achieve the above object, a ceramic electronic component of the present invention includes a metal layer formed between a side surface having an end portion of an internal electrode and an external electrode, and an average particle of metal particles constituting the metal layer The diameter is smaller than the average particle diameter of the metal particles constituting the external electrode.

  Since the average particle size of the metal layer is smaller than the average particle size of the external electrode, the reaction surface area of the side surface of the metal layer and the dielectric layer and the reaction surface area of the metal layer and the end surface of the internal electrode are increased. As a result, the ceramic electronic component can be fired at a low temperature, and the reliability of electrical connection between the external electrode and the internal electrode can be increased.

  Therefore, in the prior art, when an internal plating layer is provided on the surface of the internal electrode exposed on the side surface of the ceramic electronic component, the plating solution penetrates into the interface between the internal electrode and the dielectric layer, etc. The problem of deteriorating characteristics can be solved.

(Embodiment 1)
Hereinafter, the ceramic electronic component 8 according to the first embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of a ceramic electronic component 8 according to the first embodiment. The ceramic electronic component 8 includes a dielectric 10 formed by laminating a plurality of dielectric layers 9 made of ceramics, an internal electrode 11 formed between the plurality of dielectric layers 9, and an electrical connection to the internal electrode 11. The external electrode 12 formed on the outer surface of the dielectric 10, the plating layer 13 formed on the outer surface of the external electrode 12, and the interface between the side surface having the end of the internal electrode 11 and the external electrode 12 And a metal layer 14 formed on the substrate. The external electrode 12 includes a resin and metal particles, and the average particle diameter of the metal particles constituting the metal layer 14 is smaller than the average particle diameter of the metal particles constituting the external electrode 12.

  The electronic device on which the ceramic electronic component 8 is mounted includes a semiconductor integrated circuit (not shown) connected to the external electrode 12 and having a demodulation function, a decoding function, etc., and a speaker or a liquid crystal connected to the semiconductor integrated circuit. A playback unit (not shown) such as a screen is provided.

The dielectric layer _{9, Li 2 O, B 2 O} 3, and Si- alkaline earth or the like is added ZnO metal -La-O-based xBaO-yNd ₂ in glass components of O ₃ -zTiO ₂ -wBiO ₃ etc. It is comprised from the glass ceramics which included the filler of this. This glass ceramic is a material that can be sintered at a low temperature up to 1000 ° C.

  The internal electrode 11 is a metal having excellent high frequency characteristics such as Ag and Cu, and constitutes functional parts such as a capacity and an inductance.

  For example, the external electrode 12 is cured by dispersing at least one kind of metal particles among Ni, Cu, Pd, Ag, Pt, and Au having an average particle diameter of 1 mm or more and 20 mm or less in a synthetic resin such as epoxy resin or polyimide resin. It is comprised by the made resin.

  The plating layer 13 includes, for example, an Ni layer formed on the outer surface of the external electrode 12 to prevent solder erosion, and an Au layer or Sn layer formed on the outer surface of the Ni layer to improve solder wettability. Consists of Moreover, the plating layer 13 may have a Pd layer formed in order to improve adhesion at the interface between the Ni layer and the Au layer.

  Next, the metal layer 14 will be described in detail with reference to FIG. FIG. 2 is an enlarged view of a region 15 surrounded by a broken line in FIG. The metal layer 14 is formed of metal particles that are at least one of Ni, Cu, Pd, Ag, Pt, and Au having an average particle diameter of 4 nm to 20 nm. In addition, the same effect can be acquired even if the average particle diameter of the metal particles is 4 nm or more and 100 nm or less. Since the average particle diameter of the metal layer 14 is smaller than the average particle diameter of the external electrode 12, the reaction surface area of the side surface of the metal layer 14 and the dielectric layer 9 and the reaction between the end surface of the metal layer 14 and the internal electrode 11. Increases surface area. As a result, the ceramic electronic component 8 can be fired at a low temperature, and the reliability of electrical connection between the external electrode 12 and the internal electrode 11 can be increased.

  Therefore, in the prior art, when the internal plating layer 7 is provided on the surface of the internal electrode 4 exposed on the side surface of the ceramic electronic component 1, the plating solution enters the interface between the internal electrode 4 and the dielectric layer 2, and the like. The problem of deteriorating the electrical characteristics of the ceramic electronic component 1 can be solved.

  Hereinafter, the manufacturing process of the ceramic electronic component 8 of the first embodiment will be described.

As the first component, high-purity (99 wt%) BaCO ₃ , Nd ₂ O ₃ and TiO ₂ are used as raw materials for producing the glass ceramics constituting the dielectric layer 9. When the composition of the glass ceramic is expressed by xBaO-yNd ₂ O ₃ -zTiO ₂ (x + y + z = 100, x, y, and z are molar ratios), 13 ≦ x ≦ 17, 13 ≦ y ≦ 17, 68 ≦ z A composition range of ≦ 72 is preferred. Although Nd ₂ O ₃ is used as the rare earth here, other rare earth oxides such as La ₂ O ₃ and Sm ₂ O ₃ which are oxides other than Nd may be used. It is also possible to substitute a part of Nd with another rare earth element. The powder and pure water were mixed in a ball mill for 18 hours, and then the slurry was dried and calcined in an alumina crucible at 1200 ° C. to 1400 ° C. for 2 hours. The calcined powder was crushed and then pulverized and dried with a ball mill to obtain a powder of the first component.

Next, the second component is composed of at least one of SiO ₂ , H ₃ BO ₃ , Al (OH) ₃ , MgO, BaCO ₃ , CaCO ₃ , SrCO ₃ , La ₂ O ₃ , Li ₂ CO ₃ , and ZnO. The raw material was used. After correcting the purity of the raw material, it was named so as to have a predetermined composition. These powders were mixed by a V blender, put in a platinum or platinum rhodium crucible, melted at a temperature of 1400 ° C. or higher and 1600 ° C. or lower, and rapidly cooled by a twin roller to prepare a glass cullet. The obtained glass cullet was pulverized with a ball mill for 8 hours, dried, and used as the second component powder. A glass ceramic powder that can be sintered in a low temperature range of 1000 ° C. or lower is obtained by adding and mixing the second component glass powder and the oxide sintering aid powder to the first component calcined powder. Can do. The added glass powder is SiO ₂ —B ₂ O ₃ —RO—La ₂ O ₃ glass (R is an alkaline earth metal), SiO ₂ is 33 wt% or more and 46 wt% or less, and B ₂ O ₃ is It is preferable that the composition is 2 to 8% by weight, RO (particularly BaO) is 20 to 40% by weight, and La ₂ O ₃ is 8 to 12% by weight. In addition to the above, Al ₂ O ₃ , ZnO, alkali metal oxides and the like may be contained. In addition, although the said glass composition type | system | group was shown here as an example, even if it is a glass powder of a composition type | system | group other than this, if a similar effect is acquired, it can be used.

  Add a binder such as polyvinyl butyral or acrylic resin, a plasticizer such as dibutyl phthalate, and an organic solvent to the mixed pulverized powder composed of the first component and the second component, and mix and disperse to obtain a slurry. A ceramic green sheet to be the dielectric layer 9 was produced by applying the slurry onto a base film such as a PET film by a coating method or the like. On the ceramic green sheet, Ag paste is screen-printed to form a desired electrode pattern, and a desired number of these layers are laminated and thermocompression bonded to form a green sheet laminate having an electrode pattern that becomes the inner electrode 11 on the inner layer or surface layer. Obtained. The laminated body was cut into individual pieces and fired at 900 ° C. or higher and 940 ° C. or lower to produce a dielectric 10 having dimensions of 2.0 mm in width, 1.25 mm in length, and 0.8 mm in thickness.

  In the dielectric 10, the metal layer 14 is formed on the entire side surface having the end of the internal electrode 11. The manufacturing process prepares an Ag paste in which Ag metal particles of 4 nm or more and 20 nm or less are dispersed in a binder, and uses the roller transfer technique to apply the Ag paste to the side surface of the dielectric 10 having the end of the internal electrode 11. Apply to the whole. Thereafter, firing is performed at 150 ° C. or more and 300 ° C. or less, and the metal layer 14 made of metal particles is formed. Thereby, the reaction surface area of the side surface of the metal layer 14 and the dielectric layer 9 and the reaction surface area of the metal layer 14 and the end surface of the internal electrode 11 are increased. As a result, the ceramic electronic component 8 can be fired at a low temperature, and the reliability of electrical connection between the external electrode 12 and the internal electrode 11 can be increased. Here, Ag is used as the metal particles of the metal layer 14, but metal particles such as refractory metals Ni, Cu, Pd, Pt, or Au other than Ag having an average particle diameter of 4 nm to 20 nm may be used. .

  The external electrode 12 is a resin-based conductive paste made by mixing and dispersing metal particles such as Ag or Cu having an average particle diameter of 1 mm or more and 20 mm or less in an epoxy resin or a polyimide resin at 150 ° C. in air. By baking at 300 ° C. or lower, the metal layer 14 is formed on the outer surface so as to cover it. Therefore, since the external electrode 12 can be fired at a low temperature of 150 ° C. or more and 300 ° C. or less, the metal of the internal electrode 11 generated when firing at a high temperature diffuses into the dielectric layer 9 and deteriorates the electrical characteristics of the ceramic electronic component 8. Can solve the problem.

  The product obtained in the above process was put in a barrel plating tank together with a dummy ball and subjected to a predetermined pretreatment to perform degreasing and acid activity. Then, this is immersed in a Ni plating bath, and an Ni plating layer is formed on the outer surface of the external electrode 12 by electrolytic plating. Thereafter, it is immersed in an Sn plating bath, and an Sn plating layer is formed on the outer surface of the Ni plating layer by electrolytic plating. Further, in order to prevent the oxidation of Sn, an anti-oxidation treatment was performed with sodium triphosphate to obtain a ceramic electronic component 8 shown in FIG.

  The ceramic electronic component of the present invention has an effect of improving the stability of electrical connection between the external electrode and the internal electrode, and is useful in electronic devices such as mobile phones.

1 is a schematic cross-sectional view of a ceramic electronic component according to an embodiment of the present invention. The enlarged schematic diagram of the metal layer vicinity of the ceramic electronic component in one Embodiment of this invention Cross-sectional schematic diagram of ceramic electronic component in one embodiment of the preceding example

Explanation of symbols

8 Ceramic Electronic Components 9 Dielectric Layer 10 Dielectric 11 Internal Electrode 12 External Electrode 13 Plating Layer 14 Metal Layer

Claims (6)

A dielectric formed by laminating a plurality of dielectric layers made of ceramics;
An internal electrode formed between the plurality of dielectric layers;
An external electrode electrically connected to the internal electrode and formed on the outer surface of the dielectric;
A plating layer formed on the outer surface of the external electrode;
A metal layer formed between a side surface having an end of the internal electrode and the external electrode;
The external electrode includes a resin and metal particles,
A ceramic electronic component in which an average particle diameter of metal particles constituting the metal layer is smaller than an average particle diameter of metal particles constituting the external electrode. The ceramic electronic component according to claim 1, wherein the metal layer is formed on the entire side surface. The ceramic electronic component according to claim 1, wherein the metal layer is at least one of Ni, Cu, Pd, Ag, Pt, and Au. The ceramic electronic component according to claim 1, wherein the resin is at least one of an epoxy resin and a polyimide resin. The ceramic electronic component according to claim 1, wherein the metal particles are at least one of Ni, Cu, Pd, Ag, Pt, and Au. The ceramic electronic component according to claim 1;
An electronic apparatus comprising: a semiconductor integrated circuit connected to an external electrode of the ceramic electronic component; and a reproducing unit connected to the semiconductor integrated circuit.

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