JP3057991B2 - Manufacturing method of ceramic electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic electronic component, and more particularly to a method for firing a ceramic body having a structure in which internal electrodes are embedded in a ceramic, and then reoxidizing the ceramic body. And a method for manufacturing a ceramic electronic component manufactured by the method described above.

[0002]

2. Description of the Related Art A multilayer ceramic capacitor is one of the typical ceramic electronic components. This multilayer ceramic capacitor is usually formed by arranging a predetermined pattern of internal electrodes in a ceramic so as to have a structure in which ceramic layers and internal electrodes are alternately stacked.

In this multilayer ceramic capacitor, noble metal materials such as Au, Pt, Pd, and Ag have been used as internal electrodes so as not to be oxidized when the ceramic body is fired. In order to reduce the use of non-reducing material as ceramic,
A multilayer ceramic capacitor using a base metal material such as Ni or Cu as an internal electrode has been manufactured.

When a multilayer ceramic capacitor using a base metal such as Ni or Cu as an internal electrode is manufactured, the internal electrode provided in the ceramic should not be oxidized in the step of firing the ceramic body. To
The firing is performed in a reducing atmosphere or a neutral atmosphere.

[0005] Therefore, a re-oxidation step of oxidizing the ceramic body in an oxidizing atmosphere after firing the ceramic body is required so that the ceramic has predetermined characteristics. Unless re-oxidation is performed, there is a problem that the insulation resistance of the ceramic becomes insufficient, or the capacity formed when a DC bias is applied becomes small, so that desired characteristics cannot be obtained. .

Therefore, re-oxidation is performed after firing. As a method of re-oxidation, conventionally, the oxygen concentration in the atmosphere is increased when the temperature is lowered in the firing step in which the ceramic body is mounted on the fired sheath and firing is performed. A method and a method of performing an oxidation treatment in an oxidizing atmosphere in a batch furnace or the like after firing are used.

[0007]

However, in the above-mentioned conventional reoxidation method, the ceramic body may not always be sufficiently oxidized, and there is a problem that the characteristics of the product vary. In particular, in the case of large chip-type ceramic electronic components, the lower surface side of the ceramic body that is in contact with the bottom surface of the fired sheath at the time of re-oxidation may not be sufficiently in contact with the oxidizing atmosphere and may not be easily oxidized. It tends to be difficult to do.

The present invention has been made to solve the above-mentioned problems, and it is possible to reliably reoxidize a fired ceramic body, and to obtain desired characteristics with respect to insulation resistance and the size of a formed capacitor. It is an object of the present invention to provide a method for manufacturing a ceramic electronic component capable of manufacturing a ceramic electronic component having the same.

[0009]

In order to achieve the above object, a method for manufacturing a ceramic electronic component according to the present invention comprises: firing a ceramic body having a structure in which internal electrodes are embedded in ceramic; the method of manufacturing a ceramic electronic component comprising the step of re-oxidation, Serra after firing
Mick body, put in a rotatable container for re-oxidation,
Rotate the container and do not roll the ceramic body inside.
Meanwhile, reoxidation of the ceramic body in an oxidizing atmosphere at a processing temperature of 600 to 900 ° C. and a processing time of 30 minutes or more.
Is performed .

The processing temperature is preferably in the range of 600 to 900 ° C., but if it is lower than 600 ° C., the effect of reoxidation is reduced, and if it exceeds 900 ° C., oxidation of the internal electrode occurs, which is not preferable. It depends.

If the processing time is 30 minutes or more, necessary reoxidation can be performed, and if the processing time is less than 30 minutes, the effect of reoxidation is reduced. Therefore, a processing time of 30 minutes or more is secured. Is preferred.

There is no particular limitation on the rotation speed of the container, but it is preferable that the rotation speed be such that the ceramic element does not chip or crack.

[0013]

In the method of manufacturing a ceramic electronic component according to the present invention, the fired ceramic body is placed in a rotatable container, and reoxidized in an oxidizing atmosphere while rolling in the rotating container. Therefore, the ceramic body is reliably brought into contact with the oxidizing atmosphere, and sufficient reoxidation is performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing one embodiment of an apparatus used in a reoxidation step of the method for manufacturing a ceramic electronic component of the present invention, wherein (a) is a perspective view, (b) is a side view,
FIG. 2 is a front sectional view of the same.

In this embodiment, a cylindrical container made of nickel is used as a container (rotating container) 1 for holding a ceramic body to be reoxidized. Further, holes 2 for communicating the inside of the container 1 with an external atmosphere (oxidizing atmosphere) are formed on both end surfaces of the container 1. In this embodiment, as the ceramic body to be subjected to the reoxidation treatment, a capacitor body in which a plurality of layers of nickel internal electrodes are buried and the internal electrodes are alternately led to the opposite end of the body, What is fired at a predetermined firing temperature in a reducing atmosphere is used.

Next, the step of reoxidizing the ceramic body performed using the container 1 will be described.

First, a large number of fired ceramic bodies 3 are housed in a container 1. At this time, the ceramic element 3 is accommodated in the container 1 in such an amount that the ceramic element 3 sufficiently rolls in the container 1 as the container 1 rotates.

Then, the rotation speed, temperature, atmosphere, and processing time of the container were respectively set as follows: rotation speed of the container: 0.3 rpm, temperature: 780 ° C. atmosphere (oxidizing atmosphere): air atmosphere, and processing time: 60 minutes. The container 1 filled with the ceramic body 3 was rotated and positioned in the furnace to perform a reoxidation treatment.
Then, an external electrode is applied to the opposite end of the obtained ceramic body, and conductively connected to the embedded internal electrode,
This was a multilayer ceramic capacitor.

For comparison, the ceramic bodies were placed on a baked sheath of ZrO ₂ so as not to overlap each other, treated under the same conditions as in the above embodiment, and reoxidized to form external electrodes. did.

Then, for the samples obtained by the methods of the above Examples and Comparative Examples, the insulation resistance at 25 ° C., 85 ° C., and 150 ° C., and the rate of decrease in the capacitance formed when a voltage of 1 kV / mm was applied were measured. did. Table 1 shows the results.

[0021]

[Table 1]

As shown in Table 1, the insulation resistance is
The sample of the comparative example is 1.4 × 10 ⁹ Ω at 25 ° C. and 150 ° C.
In contrast is the a 5.0 × 10 ⁷ Ω, it can be seen that 2 × 10 ⁹ Ω at 25 ° C. in a sample embodiment, is 1.2 × 10 ⁸ Ω and a high insulation resistance at 0.99 ° C. is obtained .

The rate of decrease in capacity is -58% in the sample of the comparative example, whereas it is -45% in the sample of the example. It can be seen that the rate of decrease in capacity has decreased.

In the above embodiment, the case where a cylindrical container is used as the container has been described. However, the shape of the container is such that the ceramic body filled therein is rolled by rotating the container to oxidize the container. Various shapes that can be fired while being sufficiently in contact with the atmosphere, for example, it is also possible to configure a shape such as a square tube or hexagonal tube,
It is also possible to use a container provided with projections (buffers) or the like inside to promote the rolling of the ceramic body. Further, there is no particular restriction on the shape and arrangement position of the hole for communicating the inside of the container with the atmosphere (oxidizing atmosphere), and it is possible to arbitrarily modify the shape within the scope of the invention. Further, in the above embodiment, the case where a nickel container was used was described. However, there is no particular limitation on the material of the container, and other metal materials, alumina, ceramics such as zirconia, or a mesh-like metal made of metal. It is also possible to configure the container using a material (wire mesh) or the like.

In the above embodiment, the method of manufacturing a multilayer ceramic capacitor has been described by way of example. However, the present invention is not limited to the method of manufacturing a multilayer ceramic capacitor. It is also possible to apply to the manufacturing method of various ceramic electronic components having a structure in which the electrodes are embedded,
In that case, the same effect can be obtained. In particular, the present invention is effective when applied to an internal electrode using a base metal such as nickel or copper.

[0026]

As described above, according to the method for manufacturing a ceramic electronic component of the present invention, the fired ceramic body is
Placed in a rotatable vessel for reoxidation, rotating the container
Te, while rolling the interior of the ceramic body, in an oxidizing atmosphere, treatment temperature 600 to 900 ° C., under the conditions of further processing time of 30 minutes, to perform the re-oxidation of the ceramic body
And which, in the ceramic body is oxidizing atmosphere, for re-oxidation process is performed while rolling the container to be rotated, it can be surely contacted with an oxidizing atmosphere between the ceramic element
Now, it made a sufficient re-oxidation to be able to line Ukoto.

Therefore, by applying the present invention,
In particular, it is possible to obtain a ceramic electronic component having a high insulation resistance particularly at a high temperature and a small rate of decrease in capacitance when a DC bias is applied, which can contribute to improvement in product quality.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of an apparatus used in a reoxidation step of the method for manufacturing a ceramic electronic component of the present invention, wherein (a) is a perspective view and (b) is a side view.

FIG. 2 is a front sectional view of the apparatus of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container (rotary container) 2 Holes 3 Ceramic body

Claims (1)

(57) [Claims] 1. A method for manufacturing a ceramic electronic component comprising the steps of firing a ceramic body having a structure in which an internal electrode is embedded in a ceramic and then reoxidizing the fired ceramic body. Rotatable for re-oxidation
Put in a container and rotate the container to roll the ceramic body inside.
In an oxidizing atmosphere at a processing temperature of 600 to 900
℃, the treatment time is 30 minutes or more , the ceramic body
A method for manufacturing a ceramic electronic component, comprising performing re-oxidation .