JP2010114342A - Ceramics electronic component and electronic equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress deterioration in frequency characteristics of a ceramics electronic component. <P>SOLUTION: The ceramics electronic component 8 includes: a dielectric 10 formed by stacking a plurality of dielectric layers 9 made of ceramics; an internal electrode 11 formed among the plurality of dielectric layers 9; an external electrode 12 formed on an outer surface of the dielectric 10; plating 13 formed on an outer surface of the external electrode 12; and resin 14 formed on the interface between the external electrode 12 and the dielectric 10, or on the interface between the internal electrode 11 and the dielectric layer. The resin 14 includes fluorine-based functional groups. The above configuration can suppress penetration of plating liquids into the interface between the external electrode 12 and the dielectric 10 or that between the internal electrode 11 and the dielectric layer 9 in a plating liquid dipping process. More specifically, there can be suppressed the deterioration in the frequency characteristics of the ceramics electronic component 8 caused by the penetration of plating liquids into the interfaces. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ceramic electronic component used in various electronic devices and an electronic device using the same.

  Conventionally, ceramic electronic components are mounted on a high-frequency module for portable communication or near field communication. FIG. 3 shows the configuration of a conventional ceramic electronic component.

  In FIG. 3, a conventional ceramic electronic component 1 includes a dielectric formed by laminating a plurality of dielectric layers 1a made of ceramics, an internal electrode 2 formed between the plurality of dielectric layers 1a, and a dielectric. And an external electrode 3 formed on the outer surface.

As a prior art document related to this application, for example, Patent Document 1 is known.
JP-A-9-205005

  In such a ceramic electronic component 1, a very large gap (not shown) tends to occur between the end of the internal electrode 2 and the interface between the dielectric layers 1 a due to the thickness of the internal electrode 2. Thereby, there was a serious problem that the ceramic electronic component 1 is easily cracked.

  Therefore, an object of the present invention is to improve the productivity of ceramic electronic components.

  In order to achieve the above object, a ceramic electronic component of the present invention includes 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; and a resin formed between the end of the internal electrode and the interface between the plurality of dielectric layers. The elastic modulus is smaller than the elastic modulus of the dielectric layer.

  Thus, by forming a resin having a smaller elastic modulus than the dielectric layer made of ceramics, that is, softer than the dielectric layer, the ceramic electronic component can be prevented from cracking. Thereby, the productivity of ceramic electronic components can be improved.

(Embodiment 1)
Hereinafter, the ceramic electronic component of the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of the ceramic electronic component of the first embodiment.

  In FIG. 1, a 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 a dielectric 10 The external electrode 12 formed on the outer surface of the electrode, the plating 13 formed on the outer surface of the external electrode 12, and the interface between the external electrode 12 and the dielectric 10 or the interface between the internal electrode 11 and the dielectric layer 9 are formed. Resin 14 is provided.

  An electronic device (not shown) on which the ceramic electronic component 8 is mounted is connected to the semiconductor integrated circuit (not shown) connected to the external electrode 12 and having a demodulation function, a decoding function, and the like. And a reproducing unit (not shown) such as a speaker and a liquid crystal screen.

  The dielectric 10 is made of a material that can be sintered at a low temperature up to 1000 ° C., such as glass ceramics, but may be a ceramic material other than glass ceramics. Glass ceramics can be sintered at a low temperature, and has an advantage that a metal having excellent high-frequency characteristics such as Ag and Cu can be used as the internal electrode 11. In addition, functional parts such as a resonator, a capacitor, and an inductor are three-dimensionally formed inside the dielectric 10 by the internal electrodes 11 such as vias and wiring patterns. Further, this functional component is connected to the outside by the external electrode 12. The dielectric 10 generally has a uniform composition, but some layers may have a higher dielectric constant or a higher magnetic permeability than other layers.

  The external electrode 12 is electrically connected to a mother board (not shown) using solder. As a material of the external electrode 12, for example, a low resistance conductor such as Ag or Cu is used. When the external electrode 12 is Ag or Cu, the plating 13 is formed on the surface of the external electrode 12 in order to prevent the external electrode 12 from being eroded by solder (elution of the electrode material into the solder).

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

  The resin 14 is also formed in the gap 16 between the end of the internal electrode 11 and the interface between the plurality of dielectric layers 9. FIG. 2 is a top view of a certain dielectric layer 9 in the ceramic electronic component 8. In FIG. 2, the external electrode 12 and the like are omitted. The resin 14 is mainly composed of, for example, a silicon resin, an epoxy resin, an acrylic resin, a polybutadiene resin, a phenol resin, or an amide resin. The elastic modulus of the resin 14 is the dielectric layer 9 made of ceramics. It is smaller than the elastic modulus.

  As shown in FIGS. 1 and 2, a very large gap 16 is likely to be generated between the end of the internal electrode 11 and the interface between the dielectric layers 9 depending on the thickness of the internal electrode 11. Thereby, there was a serious problem that the ceramic electronic component 8 is easily cracked. Therefore, by forming a resin 14 having a smaller elastic modulus than that of the dielectric layer 9 made of ceramics, that is, softer than the dielectric layer 9, cracks in the ceramic electronic component 8 can be suppressed. Thereby, the productivity of the ceramic electronic component 8 can be improved.

  The resin 14 preferably has a fluorine-based functional group. By this fluorine-based functional group, the surface free energy of the resin 14 is lowered, and the water repellency of the resin 14 can be improved. By forming this fluororesin-containing resin 14 at the interface between the external electrode 12 and the dielectric 10, or the interface between the internal electrode 11 and the dielectric layer 9, the external electrode 12 The plating solution is prevented from entering the interface with the dielectric 10 or the interface between the internal electrode 11 and the dielectric layer 9. In other words, in the vicinity of the interface between the dielectric 10 and the external electrode 12 or in the vicinity of the interface between the dielectric layer 9 and the external electrode 12, the dielectric layer 9 and the electrodes 11 and 12 are caused by a difference in firing shrinkage and a difference in thermal expansion coefficient. Since the residual stress is inherent, if there is no resin 14, the interface between the dielectric 10 and the external electrode 12 or the vicinity of the interface between the dielectric layer 9 and the internal electrode 11 is eroded by the plating solution, and the filter pass band is greatly shifted. The filter characteristics cannot be obtained. Therefore, by forming the resin 14 having a fluorine-based functional group at the interface, it is possible to maintain good adhesion at these interfaces, and to prevent deterioration of the filter characteristics caused by the penetration of the plating solution in the plating immersion process. It can be done. That is, it is possible to suppress deterioration of the frequency characteristics of the ceramic electronic component due to the penetration of the plating solution into the interface between the external electrode 12 and the dielectric 10 or the interface between the internal electrode 11 and the dielectric layer 9.

  Hereinafter, a method for manufacturing the ceramic electronic component 8 of the first embodiment will be described.

High purity (99 wt%) BaCO ₃ , Nd ₂ O ₃ , and TiO ₂ are used as a raw material for producing glass ceramics, which is the first component constituting the dielectric layer 9. When the composition of the glass ceramic is represented 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. Here, Nd ₂ O ₃ is used as the rare earth, but other rare earth oxides such as La ₂ O ₃ and Sm ₂ O ₃ 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 at 1200 to 1400 ° C. for 2 hours in an alumina crucible. The calcined powder was crushed and then pulverized and dried with a ball mill to obtain a powder of the first component.

Next, the auxiliary component added to the calcined powder as the second component will be described. By adding and mixing a sintering aid powder of glass and oxide to the calcined powder, a glass ceramic powder that can be sintered in a low temperature range of 1000 ° C. or lower was obtained. Glass powder added _{is, SiO 2 -B 2 O 3 -RO} -La 2 O 3 based glass (R is an alkaline earth metal) is, SiO ₂ is 33-46 _wt%, B 2 _{O 3} is 2-8 It is preferable that the composition is 20% 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. This laminate was cut into pieces and fired at 900 to 940 ° C. to produce a ceramic laminate having dimensions of 2.0 mm in width, 1.25 mm in length, and 0.8 mm in thickness. An Ag paste was applied to both ends using a method such as roller transfer, and further fired at 850 to 920 ° C. to form the external electrode 12 and obtain a ceramic laminated part.

  Next, the ceramic laminated part was put in a vacuum chamber to remove bubbles existing inside the ceramic laminated part, and then immersed in an impregnating material made of silicon-based resin containing octamethylcyclotetrasiloxane. Then, by applying the impregnating agent made of this resin to the ceramic laminated part while applying a pressure of 10 times or more of the atmospheric pressure, the gap between the ceramic laminated parts, in particular, the end portion of the internal electrode 11 and the plurality of dielectric layers 9 are filled. The impregnating agent is filled up to the gap 16 between the interfaces, and after the impregnation, the impregnating material inside the ceramic laminated part is cured at a temperature of 150 to 250 degrees, and then remains on the surface of the ceramic laminated part. The impregnated material was removed by washing and drying, polishing and the like.

  This ceramic laminated part 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 Ni plating is formed on the outer surface of the external electrode 12 by electrolytic plating. Thereafter, it is immersed in a Sn plating bath, and Sn plating is formed on the outer surface of the Ni plating by electrolytic plating. In order to prevent oxidation, an anti-oxidation treatment was performed with sodium triphosphate to obtain a ceramic electronic component 8 shown in FIG.

  The ceramic electronic component according to the present invention has an effect of suppressing deterioration of frequency characteristics, and is useful in an electronic device such as a mobile phone.

Sectional schematic diagram of the ceramic electronic component according to Embodiment 1 of the present invention. Schematic top view of the dielectric layer in the ceramic electronic component Cross-sectional schematic diagram of conventional ceramic electronic components

Explanation of symbols

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

Claims (4)

A dielectric formed by laminating a plurality of dielectric layers made of ceramics;
Internal electrodes 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;
Comprising a resin formed between an end of the internal electrode and an interface between the plurality of dielectric layers;
A ceramic electronic component in which the elastic modulus of the resin is smaller than the elastic modulus of the dielectric layer. 2. The ceramic electronic component according to claim 1, wherein the resin is at least one of a silicon resin, an epoxy resin, an acrylic resin, a polybutadiene resin, a phenol resin, and an amide resin. The ceramic electronic component according to claim 1, wherein the resin has a fluorine-based functional group. The ceramic electronic component according to claim 1;
A semiconductor integrated circuit connected to an external electrode of the ceramic electronic component;
An electronic apparatus comprising a reproducing unit connected to the semiconductor integrated circuit.

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