JP2008166666A - Ceramic electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic electronic component in which adhesion between a metal electrode layer and an electrically conductive resin electrode layer is improved. <P>SOLUTION: A laminated capacitor C1 comprises a ceramic material body 10, and outer electrodes 30 arranged on the outer surface of the ceramic material body 10. Each outer electrode 30 includes a first metal electrode layer 32 containing a metal as a main component and an electrically conductive resin electrode layer 34 containing a metal powder and contacting the first metal electrode layer 32, wherein the metal contained in the first metal electrode layer 32 and the metal powder contained in the electrically conductive resin layer 34 form an alloy. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ceramic electronic component.

  As this type of ceramic electronic component, an external electrode having a metal electrode layer containing metal as a main component and a conductive resin electrode layer in contact with the metal electrode layer and containing metal powder is known. (For example, refer to Patent Document 1).

Such a ceramic electronic component is generally mounted on a substrate by soldering external electrodes to the substrate. When the substrate on which the ceramic electronic component is mounted is subjected to a thermal shock due to a rapid temperature change, the ceramic electronic component and the substrate expand and contract according to their respective thermal expansion coefficients. At that time, the amount of expansion / contraction differs depending on the difference in thermal expansion coefficient between the ceramic electronic component and the substrate, resulting in bending. This bending may cause the ceramic electronic component to crack and fail to function. Therefore, in the ceramic electronic component described in Patent Document 1, bending is absorbed by the conductive resin electrode layer to prevent generation of cracks due to thermal shock.
JP-A-10-284343

  This invention makes it a subject to provide the ceramic electronic component which can improve the adhesiveness of a metal electrode layer and a conductive resin electrode layer.

  The inventors of the present invention have also intensively studied ceramic electronic components that can improve the adhesion between the metal electrode layer and the conductive resin electrode layer. As a result, when the present inventors alloy the metal contained in the metal electrode layer and the metal powder contained in the conductive resin electrode layer, the adhesion between the metal electrode layer and the conductive resin electrode layer is improved. I came up with a new fact.

  Based on such research results, the ceramic electronic component according to the present invention includes a ceramic body and an external electrode disposed on the outer surface of the ceramic body, and the external electrode contains a metal as a main component. And a conductive resin electrode layer containing metal powder and in contact with the metal electrode layer, the metal contained in the metal electrode layer and the metal powder contained in the conductive resin electrode layer It is alloyed.

  In the ceramic electronic component according to the present invention, the metal contained in the metal electrode layer and the metal powder contained in the conductive resin electrode layer are alloyed. For this reason, the coupling | bonding between a metal electrode layer and a conductive resin electrode layer becomes strong, and the adhesiveness of a metal electrode layer and a conductive resin electrode layer can be improved.

  Moreover, when the present inventors make the metal contained in the metal electrode layer and the metal powder contained in the conductive resin electrode layer the same metal component, the metal contained in the metal electrode layer and the conductive resin electrode layer contain it. It came to discover the new fact that the adhesiveness of a metal electrode layer and a conductive resin electrode layer improves because a metal powder couple | bonds and the couple | bonded metal functions as a wedge.

  Based on such research results, the ceramic electronic component according to the present invention includes a ceramic body and an external electrode disposed on the outer surface of the ceramic body, and the external electrode contains a metal as a main component. And a conductive resin electrode layer containing a metal powder made of the same metal component as the metal contained in the metal electrode layer and in contact with the metal electrode layer, and the metal contained in the metal electrode layer, The metal powder contained in the conductive resin electrode layer is bonded.

  In the ceramic electronic component according to the present invention, the metal contained in the metal electrode layer is bonded to the metal powder contained in the conductive resin electrode layer. For this reason, the coupling | bonding between a metal electrode layer and a conductive resin electrode layer becomes strong, and the adhesiveness of a metal electrode layer and a conductive resin electrode layer can be improved.

  Preferably, the metal electrode layer is formed by applying and baking a conductive paste containing metal powder contained as a main component in the metal electrode layer on the outer surface of the ceramic body.

  Preferably, the conductive resin electrode layer is formed by applying and heating a conductive paste containing metal powder and thermosetting resin contained in the conductive resin electrode layer on the outer surface of the metal electrode layer. . By heat treatment for curing the thermosetting resin, the metal contained in the metal electrode layer and the metal powder contained in the conductive resin electrode layer are alloyed or combined, and the alloy or the combined metal is the metal electrode layer and the conductive resin electrode. It exists at the interface with the layer and in the vicinity of the interface and functions like a wedge. For this reason, the bond between the metal electrode layer and the conductive resin electrode layer can be further strengthened.

  ADVANTAGE OF THE INVENTION According to this invention, the ceramic electronic component which can improve the adhesiveness of a metal electrode layer and a conductive resin electrode layer can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  FIG. 1 is a cross-sectional view of the multilayer capacitor C1 according to the embodiment. As shown in FIG. 1, the multilayer capacitor C <b> 1 includes a ceramic body 10 and two external electrodes 30.

  In the ceramic body 10, the internal electrode 20 is laminated via a dielectric layer 22. Each dielectric layer 22 is made of a sintered body of a ceramic green sheet containing a dielectric ceramic, for example. The actual multilayer capacitor C1 is integrated so that the boundary between the dielectric layers 22 is not visible.

  The internal electrodes 20 arranged in the ceramic body 10 are alternately drawn out to two opposing side surfaces of the ceramic body 10 parallel to the stacking direction of the internal electrodes 20. The internal electrode 20 is made of a conductive material that is usually used as an internal electrode of a laminated electric element. In this embodiment, the internal electrode 20 contains Ni, which is a base metal, as a conductive material.

  The external electrode 30 is disposed on the outer surface of the ceramic body 10. The external electrode 30 has a first metal electrode layer 32, a conductive resin electrode layer 34, a second metal electrode layer 36, and a third metal electrode layer 38.

  The first metal electrode layer 32 contains Cu, which is a base metal, as a main component. The first metal electrode layer 32 is formed on the outer surface of the ceramic body 10, that is, on two opposing end faces of the ceramic body 10 parallel to the stacking direction of the internal electrodes 20. Electrically connected. The first metal electrode layer 32 is formed by applying and baking a conductive paste containing Cu powder on the outer surface of the ceramic body 10. The thickness of the first metal electrode layer 32 is, for example, 10 to 30 μm. The particle size of the Cu powder is about 0.1 to 10 μm.

  The conductive resin electrode layer 34 includes metal powder as a conductive material. The conductive resin electrode layer 34 is formed on the first metal electrode layer 32 so as to cover the first metal electrode layer 32, and the first metal powder and the second metal having a predetermined average particle diameter. It is a layer formed by curing the resin layer forming composition of the metal powder and the thermosetting resin. The thickness of the conductive resin electrode layer 34 is, for example, 20 to 100 μm.

  In this embodiment, Ag which is a noble metal is used as the material of the first metal powder. The conductivity in the conductive resin electrode layer 34 is ensured mainly by the first metal powder, that is, Ag powder. The particle size of the first metal powder is about 0.1 to 10 μm.

  In this embodiment, base metal Ni is used as the second metal powder. The shape of the second metal powder may be any shape such as a sphere or a scale, but is preferably a sphere. The second metal powder has an average particle size of about 10 to 50 nm and is extremely fine. Here, the average particle diameter is measured by a dynamic light scattering method.

Although it does not restrict | limit especially as a thermosetting resin, For example, a phenol resin, an acrylic resin,
Silicon resin, epoxy resin, polyimide, or the like can be used.

  The total metal powder content in the resin layer forming composition is preferably 60 to 95% by mass based on the total solid content of the resin layer forming composition. When the content is less than 60% by mass, the conductivity inside the conductive resin electrode layer 34 tends to be insufficient as compared with the case where the content is in the above range. When the content exceeds 95% by mass, the amount of the thermosetting resin is insufficient as compared with the case where the content is within the above range, and therefore the first metal electrode layer 32 and the conductive resin electrode layer 34 There is a tendency for the adhesion of the material to decrease.

  The composition for resin layer formation further contains a solvent as needed. As the solvent, any known solvent can be used without particular limitation as long as it can dissolve or disperse the thermosetting resin. Specific examples of the solvent include methyl carbitol, ethyl carbitol, butyl carbitol, butyl carbitol acetate, cellosolve, butyl cellosolve, butyl cellosolve acetate, and terpineol.

  The conductive resin electrode layer 34 is formed by applying the resin layer forming composition on the first metal electrode layer 32 and performing drying and thermosetting. Here, the temperature at the time of thermosetting is appropriately adjusted according to the curable resin to be used.

  By the way, the second metal powder existing at the interface with the first metal electrode layer 32 and in the vicinity of the interface, as described above, partially melts the metal and alloy contained in the first metal electrode layer 32. The first metal electrode layer 32 is an alloy (in this embodiment, Cu—Ni alloy) of the metal contained in the first metal electrode layer 32 and the second metal powder contained in the conductive resin electrode layer 34. And the conductive resin electrode layer 34 are present at and near the interface. Since this alloy functions like a wedge, the bond between the first metal electrode layer 32 and the conductive resin electrode layer 34 is strengthened.

  The second metal electrode layer 36 contains Ni as a main component. The second metal electrode layer 36 is formed on the conductive resin electrode layer 34 so as to cover the conductive resin electrode layer 34. The second metal electrode layer 36 is formed by plating the surface of the conductive resin electrode layer 34 with Ni. The thickness of the second metal electrode layer 36 is, for example, 1 to 5 μm.

  The third metal electrode layer 38 contains Sn or Sn alloy as a main component. The third metal electrode layer 38 is formed on the second metal electrode layer 36 so as to cover the second metal electrode layer 36. The third metal electrode layer 38 is formed by plating the surface of the second metal electrode layer 36 with Sn or an Sn alloy. The thickness of the third metal electrode layer 38 is, for example, 1 to 5 μm.

  As described above, in the present embodiment, the metal contained in the first metal electrode layer 32 and the second metal powder contained in the conductive resin electrode layer 34 are alloyed. For this reason, the bond between the first metal electrode layer 32 and the conductive resin electrode layer 34 becomes strong, and the adhesion between the first metal electrode layer 32 and the conductive resin electrode layer 34 can be improved. .

  As a modification of the present embodiment, the metal powder contained in the conductive resin electrode layer 34 may be the same metal component as the metal contained in the first metal electrode layer 32. That is, in this embodiment, the conductive resin electrode layer 34 contains Cu powder as a conductive material. The average particle diameter of the Cu powder is about 10 to 50 nm as described above.

  Since the Cu powder is extremely fine like the Ni powder described above, the surface thereof is partially melted by the heat treatment at the time of thermosetting. Therefore, when the Cu powder existing at the interface with the first metal electrode layer 32 and in the vicinity of the interface partially melts, the Cu contained in the first metal electrode layer 32 is bonded, and the bonded Cu is wedged. Will function as. As a result, the bond between the first metal electrode layer 32 and the conductive resin electrode layer 34 is strengthened, and the adhesion between the first metal electrode layer 32 and the conductive resin electrode layer 34 can be improved. .

  The preferred embodiments of the present invention have been described above. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, in this embodiment, the first metal electrode layer 32 contains Cu as the main component metal, and the conductive resin electrode layer 34 contains Ni powder as the second metal powder. The material is not limited to these. Any material may be used as long as the metal contained in the first metal electrode layer 32 as a main component and the metal powder (second metal powder) contained in the conductive resin electrode layer 34 are alloyed. Even when the metal contained in the first metal electrode layer 32 as a main component and the metal powder contained in the conductive resin electrode layer 34 are the same metal component, this metal component is limited to the above-described Cu. Absent.

  In this embodiment, an example in which the present invention is applied to a capacitor is shown, but the present invention is not limited to this. The present invention can be applied to, for example, a piezoelectric element (piezoelectric actuator), an inductor, a varistor, a thermistor, and the like.

1 is a cross-sectional view of a multilayer capacitor according to an embodiment.

Explanation of symbols

  C1 ... multilayer capacitor, 10 ... ceramic body, 20 ... internal electrode, 22 ... dielectric layer, 30 ... external electrode, 32 ... first metal electrode layer, 34 ... conductive resin electrode layer, 36 ... second metal Electrode layer, 38... Third metal electrode layer.

Claims (4)

A ceramic body,
An external electrode disposed on the outer surface of the ceramic body,
The external electrode is
A metal electrode layer containing a metal as a main component;
A conductive resin electrode layer containing metal powder and in contact with the metal electrode layer;
A ceramic electronic component, wherein a metal contained in the metal electrode layer and a metal powder contained in the conductive resin electrode layer are alloyed. A ceramic body,
An external electrode disposed on the outer surface of the ceramic body,
The external electrode is
A metal electrode layer containing a metal as a main component;
A conductive resin electrode layer that is in contact with the metal electrode layer and contains a metal powder composed of the same metal component as the metal contained in the metal electrode layer;
A ceramic electronic component comprising a metal contained in the metal electrode layer and a metal powder contained in the conductive resin electrode layer bonded together.   The metal electrode layer is formed by applying and baking a conductive paste containing a metal powder contained as a main component in the metal electrode layer on an outer surface of the ceramic body. Item 3. The ceramic electronic component according to Item 1 or 2.   The conductive resin electrode layer is formed by applying and heating a resin layer forming composition containing a metal powder and a thermosetting resin contained in the conductive resin electrode layer on the outer surface of the metal electrode layer. The ceramic electronic component according to any one of claims 1 to 3, wherein the ceramic electronic component is provided.

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