JP2003243245A - Ceramic electronic component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a ceramic electronic component having external electrodes on which plated metallic layers are formed to sufficiently cover baked electrodes, and to obtain a method of manufacturing the electronic component. <P>SOLUTION: A laminated ceramic capacitor 10 includes an elemental ceramic body 12 constituted by alternately laminating ceramic dielectric layers 14 and internal electrodes 16 upon another. The external electrodes 18 are formed on both end faces of the ceramic body 12. The external electrodes 18 include the baked electrodes 20 formed by baking electrode paste containing a metallic component and a glass component. On the whole surfaces of the baked electrodes 20, coating layers 22 are formed by using a material containing a metallic component and not containing any glass component. First plated metallic layers 24 are formed on the coating layers 22, and second plated metallic layers 26 are formed on the layers 24. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic electronic component and a method for manufacturing the same, and more particularly to a ceramic electronic component having external electrodes formed on a ceramic body such as a laminated ceramic capacitor and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 2 is an illustrative view showing a monolithic ceramic capacitor as an example of a conventional ceramic electronic component. The monolithic ceramic capacitor 1 has a ceramic body 2
including. The ceramic body 2 is formed by alternately stacking a plurality of dielectric ceramic layers 3 and a plurality of internal electrodes 4. Adjacent ones of the internal electrodes 4 are alternately drawn out to opposite end faces of the ceramic body 2. And
External electrodes 5 are formed on the end faces of the ceramic body 2.
The internal electrode 4 and the external electrode 5 are connected.

The external electrode 5 includes a printing electrode 6. The baking electrode 6 is formed using, for example, an electrode paste containing a metal component such as Cu or Ni and a glass component. The electrode paste is applied to the end surface of the ceramic body 2 and baked, whereby the baked electrode 6 is formed. Here, the glass component is used for bonding the ceramic body 2 and the baking electrode 6.

A first metal plating layer 7 is formed on the baking electrode 6 with Ni or the like. Furthermore, the first
A second metal plating layer 8 is formed on the metal plating layer 7 by using, for example, Sn or the like. These baking electrode 6, first metal plating layer 7 and second metal plating layer 8
Thereby, the external electrode 5 is formed. Here, the first metal plating layer 7 is formed to prevent electrode breakage when the laminated ceramic capacitor 1 is soldered to a circuit board or the like. The second metal plating layer 8 is formed to improve solderability.

[0005]

However, in such a monolithic ceramic capacitor, there is a problem that the glass component floats on the surface when forming the baking electrode. If the glass component floats up on the surface of the baking electrode, the plating property of the portion is deteriorated, which adversely affects the quality of the laminated ceramic capacitor.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 8-97075, it is possible to apply an electrode paste for a baking electrode to the end face of a ceramic element body, and attach a small piece of metal foil onto it to bake it. it was thought. As a result, the metal foil can be attached to the surface of the glass component that has risen, and the deterioration of the plating property can be mitigated. However, in such a method, it is difficult to cover the entire surface of the baking electrode with a small piece of metal foil, and it is difficult to form a metal plating layer on the entire surface of the baking electrode. Further, it is difficult to uniformly attach the metal foil to the surface of the printing electrode, and it is difficult to uniformly form the metal plating layer.

Therefore, a main object of the present invention is to provide a ceramic electronic component having an external electrode having a metal plating layer sufficiently covering the burned electrode and a method for manufacturing the same.

[0008]

The present invention includes a ceramic element body, a baking electrode formed on an end surface of the ceramic element body by baking an electrode paste containing a metal component and a glass component, and a metal component. It is a ceramic electronic component including a coat layer formed so as to cover a baked electrode using a material containing no glass component, and a metal plating layer formed so as to cover the coat layer. In such a ceramic electronic component, the thickness of the coat layer is
It is preferably in the range of 0.05 μm to 500 μm. Here, it is preferable to use, as the metal component for forming the coat layer, a metal component having an ionization tendency close to that of the metal component contained in the metal plating layer. Further, Ni can be used as a metal component for forming the coat layer and the metal plating layer formed thereon. Also,
This invention provides a step of preparing a ceramic body, a step of forming a baked electrode by baking an electrode paste containing a metal component and a glass component on the ceramic body, and a material containing a metal component but not a glass component. A method of manufacturing a ceramic electronic component, comprising: a step of forming a coat layer on a baked electrode using the method; and a step of forming a metal plating layer on the coat layer. In such a method for manufacturing a ceramic electronic component, the coat layer can be formed by applying a conductive paste containing a metal component for forming the coat layer onto the baking electrode and baking the conductive paste.

This ceramic electronic component includes a coating layer for coating the baking electrode on the end face of the ceramic body. Since this coat layer is formed of a material containing a metal component and not a glass component, it has a good plating property. Therefore, the metal plating layer is formed on substantially the entire surface of the coating layer, and the external electrode is one in which the glass component contained in the baking electrode is not exposed, and a ceramic electronic component having good quality can be obtained. In addition, when the thickness of the coat layer is in the range of 0.05 μm to 500 μm, it is possible to obtain a coat layer having good plating property. Further, as a metal component for forming the coat layer,
By using a metal component having an ionization tendency close to that of the metal component contained in the metal plating layer, the metal plating layer is easily formed on the coat layer. In particular, Ni is often used as the metal plating layer formed on the coat layer, which causes less metal shaving during soldering, and in that case, Ni is also used as the metal component of the coat layer. A coat layer formed of a metal material is formed on the entire surface of the baking electrode by forming a coat layer on the baking electrode using a material containing a metal component but not a glass component. In this way, since the coating layer formed of the metal material is formed on the entire surface of the printing electrode, the coating property of the coating layer becomes good. In order to form such a coat layer, a conductive paste may be applied and baked on the baking electrode.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the invention with reference to the drawings.

[0011]

FIG. 1 is an illustrative view showing a monolithic ceramic capacitor as an example of a ceramic electronic component of the present invention. The monolithic ceramic capacitor 10 includes a ceramic body 12. The ceramic body 12 is formed by alternately stacking a plurality of dielectric ceramic layers 14 and a plurality of internal electrodes 16. Adjacent ones of the internal electrodes 16 are formed so as to be alternately exposed on the opposing end faces of the ceramic body 12.

Ceramic body 1 with internal electrodes 16 exposed
An external electrode 18 is formed on the end face of 2. External electrode 1
8 includes a printing electrode 20. The baking electrode 20 is formed by applying an electrode paste containing a metal component and a glass component to the end surface of the ceramic body 12 and baking the electrode paste. Examples of the metal contained in the electrode paste include C
u, Ni, a Cu-Ni alloy, etc. are used, and also a solvent, an inorganic oxide, etc. are contained.

A coat layer 22 is formed on the printing electrode 20. The coat layer 22 is formed, for example, by applying a conductive paste containing a metal component such as Ni and not containing a glass component and baking it. It should be noted that Ni contained in the conductive paste is selected according to the first metal plating layer because Ni is often used as the first metal plating layer formed on the coat layer 22. When Ni is used as the first metal plating layer, if Ni metal or a compound thereof is contained as the metal material contained in the conductive paste for forming the coat layer 22, tin, solder, gold or the like is used. A metal or alloy may be contained.

Further, a first metal plating layer 24 is formed on the coat layer 22. First metal plating layer 24
Is formed of, for example, Ni. Here, the first metal plating layer 24 is the monolithic ceramic capacitor 1
It is formed in order to prevent metal breakage of the external electrode 18 when 0 is soldered to a circuit board or the like. Then, Ni or the like is used as a material suitable for preventing such metal cracks.

A second metal plating layer 26 is formed on the first metal plating layer 24. Second metal plating layer 26
Is formed of a material having good solderability, such as Sn or Sn-Pb. Such a second metal plating layer 2
Forming 6 facilitates soldering when mounting the monolithic ceramic capacitor 10 on a circuit board or the like.

Such a monolithic ceramic capacitor 10
Then, when the baking electrode 20 is formed on the end surface of the ceramic body 12, the glass component floats out on the electrode surface. However, since the entire surface of the baking electrode 20 is covered with the coating layer 22, the plating property is improved, and the first metal plating layer 24 is formed on the entire surface of the coating layer 22. Therefore, the second metal plating layer 26 can also be formed on the entire end face of the ceramic body 12, and the reliability of the monolithic ceramic capacitor 10 can be increased.

Thus, the coating layer 2 is formed on the baking electrode 20.
By forming 2, the first metal plating layer 24 can be formed uniformly. Although the Ni plating layer for preventing metal cracks is formed as the first metal plating layer 24, when another metal material is used, the first metal plating layer 24 and the first metal plating layer 24 are used as the material of the coat layer 22. The same material or a material having a close ionization tendency is used. By selecting such a material, the first metal plating layer 24 can be easily formed on the coat layer 22, and the adhesion between the coat layer 22 and the first metal plating layer 24 can be improved. be able to.

It should be noted that such a manufacturing method is applicable not only to the monolithic ceramic capacitor but also to other ceramic electronic parts such as resistors, inductors and LC parts. Also in these ceramic electronic components, the metal plating layers 24 and 26 can be formed on the entire surface of the baking electrode 20,
It is possible to obtain a highly reliable ceramic electronic component.

[0019]

Example (Example 1) 3.2 × with internal electrodes formed
Cu on the end face of the 1.6 × 1.6 mm ceramic body,
By coating and baking an electrode paste containing a glass component, a solvent, an inorganic oxide, etc., the thickness of the end face is 100 μm.
m printing electrode was formed. On this baked electrode, a conductive paste containing Ni and not containing a glass component is applied,
A 3 μm-thick coat layer was formed by baking.
Ni plating was applied on the coat layer to form a 3 μm first metal plating layer. Further, a 5 μm second metal plating layer of Sn was formed on the first metal plating layer to form a monolithic ceramic capacitor. As a comparative example, the first layer was formed on the baking electrode without forming the coat layer.
A metal plating layer was formed, and a second metal plating layer was further formed to form a monolithic ceramic capacitor.

With respect to these laminated ceramic capacitors, the plating property was examined. As a result, the number of samples in the multilayer ceramic capacitor with the coat layer is 100
Among the individual pieces, no poor plating property was observed. On the other hand, in the monolithic ceramic capacitor in which the coat layer was not formed, 35 out of 100 samples had defective plating property. Regarding the plating property, a product in which 90% or more of the surface of the baking electrode is covered with the first metal plating layer and the second metal plating layer is a good product, and less than 90% of the surface of the baking electrode is Those not covered with the first metal plating layer and the second metal plating layer were regarded as defective products.

With respect to the laminated ceramic capacitor having the coat layer formed thereon, the relationship between the thickness of the coat layer and the plating property was examined, and the results are shown in Table 1. In Table 1, the number of samples for each thickness of the coat layer was 100. Then, among these samples, the number of defective plating properties was shown.

[0022]

[Table 1]

As can be seen from Table 1, in the case where the thickness of the coat layer was in the range of 0.5 μm to 500 μm, no poor plating property was observed. The thickness of the coat layer was 0.
If the thickness is 1 μm or less, the conductive paste for forming the coat layer cannot be sufficiently applied.
It is considered that the entire surface of the printing electrode could not be covered with the coating layer.

(Example 2) A baked electrode was formed by applying an electrode paste containing a metal component, a glass component, a solvent, an inorganic oxide, etc., to the end surface of the ceramic element body on which the internal electrode was formed and firing it. . On this baked electrode, a conductive paste containing Ni and containing no glass component is applied,
A coat layer was formed by baking. Further, the baked electrode was covered with Ni foil and baked to form a coat layer.

Ni plating was applied on the coat layer to form a first metal plating layer. Further, a second metal plating layer of Sn was formed on the first metal plating layer. Then, the relationship between the thickness of the coat layer and the plating property was investigated, and the results are shown in Table 2. The determination of the plating property was performed in the same manner as in Example 1. In addition, the number of samples in each thickness of the coat layer was 100, and the number of defective plating properties was shown.

[0026]

[Table 2]

From Table 2, when the first metal plating layer and the second metal plating layer are formed after the coat layer is formed, the plating property is obtained when the thickness of the coat layer is in the range of 0.05 μm to 500 μm. Turns out to be good.
Since it is difficult to thin the Ni paste when manufacturing the coat layer, the thickness of the coat layer was set to 0.1 μm to 500 μm. Also,
When the Ni thin film is too thick, it becomes difficult to coat the surface of the baking electrode, and when it is too thin, it becomes difficult to cover the entire surface of the baking electrode, so that the thickness of the coating layer is 0.05 μm to 10 μm. And the range.

[0028]

According to the present invention, by forming the coating layer so as to cover the baking electrode on the ceramic body, it is possible to form the metal layer on the surface of the glass component that is raised at the time of forming the baking electrode. Therefore, the plating adherence of the first metal plating layer and the second metal plating layer can be improved. Therefore, the ceramic electronic component of the present invention has the external electrode having a good structure, and it is possible to reduce defective products and enhance reliability.

[Brief description of drawings]

FIG. 1 is an illustrative view showing a monolithic ceramic capacitor as an example of a ceramic electronic component of the present invention.

FIG. 2 is an illustrative view showing a monolithic ceramic capacitor as an example of a conventional ceramic electronic component.

[Explanation of symbols]

10 Multilayer ceramic capacitors 12 Ceramic body 14 Dielectric ceramic layer 16 internal electrodes 18 External electrode 20 Burning electrode 22 Coat layer 24 First metal plating layer 26 Second metal plating layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takaaki Kawai             2-10-10 Tenjin, Nagaokakyo, Kyoto Stock             Murata Manufacturing Co., Ltd. F-term (reference) 5E001 AB03 AC04 AF00 AF06 AH01                       AH07 AH09 AJ03                 5E082 AA01 AB03 BC38 FG26 GG10                       GG11 GG26 GG28 JJ03 JJ12                       JJ23 MM24 PP09

Claims (6)

[Claims] 1. A ceramic body, a baking electrode formed on an end surface of the ceramic body by baking an electrode paste containing a metal component and a glass component, and a material containing a metal component and not containing a glass component. A ceramic electronic component comprising: a coat layer formed to cover the baked electrode; and a metal plating layer formed to cover the coat layer. 2. The thickness of the coat layer is from 0.05 μm to
The ceramic electronic component according to claim 1, wherein the ceramic electronic component is in a range of 500 μm. 3. The ceramic electronic component according to claim 1, wherein a metal component having an ionization tendency close to that of the metal component contained in the metal plating layer is used as the metal component for forming the coat layer. . 4. The ceramic according to claim 1, wherein a metal component for forming the coating layer and the metal plating layer formed thereon is Ni. Electronic components. 5. A step of preparing a ceramic body, a step of forming a baked electrode by baking an electrode paste containing a metal component and a glass component on the ceramic body, a material containing a metal component and not containing a glass component A method of manufacturing a ceramic electronic component, comprising: forming a coat layer on the baked electrode using the method; and forming a metal plating layer on the coat layer. 6. The ceramic electronic component according to claim 5, wherein the coat layer is formed by applying a conductive paste containing a metal component for forming the coat layer onto the baking electrode and baking the conductive paste. Manufacturing method.