JPS60254608A - Laminated ceramic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multilayer ceramic capacitor, and more particularly to the structure of a multilayer ceramic capacitor comprising a non-reducible dielectric ceramic and a base metal internal electrode.

Conventional technology Traditionally, the internal electrodes of multilayer ceramic capacitors include
Negative metals such as palladium and platinum are used. This is due to the following reason. In other words, a multilayer ceramic capacitor is made by stacking ceramic green sheets with internal electrodes printed on them, bonding them together under heat, and heating them in the air at a temperature of 1,200 to 14
Since it is manufactured by providing external electrodes on both ends after firing at 00°C, the internal electrode material has a
This is because metals that do not react with dielectric ceramic materials and do not oxidize even when fired in air at 111i temperature of 1400°C are required, and the metals that meet this requirement are limited to noble metals such as palladium and platinum. .

However, these internal electrode materials such as palladium and platinum account for as much as 30 to 50% of the product price, which has been a major obstacle to reducing the price of multilayer ceramic capacitors.

As a solution to this problem, the Special Publication No. 57-3900
The non-reducible dielectric ceramic composition disclosed in No. 1 etc. is used as the dielectric ceramic material, and cheap base metals such as nickel, iron, cobalt, etc. are used as the internal electrode material, and these are fired in a reducing atmosphere. What has been done is known. According to this method, since the firing is performed in a reducing atmosphere, it has the advantage that inexpensive base metals such as nickel, iron, and cobalt can be used as the internal electrodes. Moreover, the above-mentioned non-reducible dielectric ceramic composition does not undergo reduction even when fired in a reducing atmosphere and exhibits excellent electrical properties.

However, even with this method, since base metals such as nickel, iron, and cobalt are ferromagnetic and have high magnetic permeability, internal electrodes made of these metals are greatly affected by the skin effect in the high frequency range, and the equivalent There was a problem that the series resistance became large. Table 1 shows a comparison of the skin effects of palladium and nickel.

Table 1 Purpose of the Invention This invention was made to solve the above problems, and its purpose is to use a non-reducible dielectric ceramic material and a base metal such as nickel as the internal electrode material. An object of the present invention is to provide an internal electrode structure with low equivalent series resistance in a multilayer ceramic capacitor.

SUMMARY OF THE INVENTION To summarize the invention, a non-reducible dielectric ceramic material is used, and each internal electrode is connected to a multilayer electrode via the dielectric ceramic.
This is a multilayer ceramic capacitor that has an L structure, is connected to the same external electrode, and is made of base metals such as nickel, iron, and cobalt.

Description of examples Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of a ceramic green sheet used in an embodiment of the present invention, and FIG. 2 shows an embodiment of a multilayer ceramic capacitor according to the present invention.

First, referring to FIG. 1, ceramic green sheets 1a and 1b made of a non-reducible dielectric ceramic composition are prepared.

1c, 1d, 1e, if, 1o, 1h, l
i is prepared. Ceramic green sheet Ib, I
d, 1f, 1h are ceramic green sheets 1a,
It is thinner than 1c, 1e, 1g, and 1i. These ceramic green sheets 1a, 1b
, 1c, 1d, 1e, 1f, 1g, and Ih, electrode layers 2a and 2 made of a base metal, such as nickel.
b, 2c, 2d.

2e, 2f, 2g, and 2h are provided by screen printing or the like. Since the ceramic green sheet 11 is a protective layer, no electrode layer is provided. The ceramic green sheets 18 to 11 are stacked in the order shown in the figure, thermocompressed, and then fired at 1360° C. in a reducing atmosphere to form a capacitor element.

Next, referring to FIG. 2, 3 is a ceramic capacitor body formed by the method described above. 4 is electrode layer 2a and 2b
5 is an internal electrode group composed of electrode layers 2C and 2d, and 6 is an internal electrode group composed of electrode layers 2C and 2d.
An internal electrode group is composed of e and 2f, and 7 is an internal electrode group composed of electrode layers 2g and 2h. 8.
Reference numeral 9 represents an external electrode, for example, a silver paste is applied to both ends of the capacitor element body 3, and the electrode is heated to 800 to 900 nm in a reducing atmosphere.
It is applied by baking at 0°C. External electrode 8 is electrically connected to internal electrode groups 5 and 7, and external electrode 9 is electrically connected to internal electrode groups 4 and 6, respectively.

The multilayer ceramic capacitor of the present invention formed in this way uses a non-reducing dielectric ceramic material, so it exhibits excellent electrical characteristics even though it is fired in a reducing atmosphere. . Furthermore, since base metals such as nickel are used for the internal electrodes and fired in a reducing atmosphere, no oxidation of the internal electrodes is observed.

Furthermore, instead of conventionally consisting of internal electrodes of 1 m, each internal electrode group is composed of two layers of 4.5° and 6.7°, which essentially increases the thickness of the internal electrodes. It has the same effect, but the equivalent series resistance is smaller.

Table 2 shows a comparison of the equivalent series resistances of a conventional multilayer ceramic capacitor using palladium and nickel as internal electrodes and a multilayer ceramic capacitor of the present invention using nickel as internal electrodes.

As can be seen from Table 2, the multilayer ceramic capacitor of the present invention using a base metal such as nickel for the internal electrodes has the following characteristics:
The equivalent series resistance is as low as that of conventional multilayer ceramic capacitors that use noble metals such as palladium for internal electrodes.

The above is an embodiment of the present invention, and it goes without saying that design changes can be made within a scope that does not impair the spirit of the invention.

For example, although nickel is used for the internal electrodes in this embodiment, other base metals such as iron or cobalt may also be used.

Furthermore, the multilayer ceramic capacitor of this example is composed of four internal electrode groups, and each internal electrode group has two
Although it is composed of internal electrodes of layers, the number of each internal electrode group and the number of electrode layers constituting each internal electrode group are arbitrary and are not limited to these in any way.

Effects of the Invention As is clear from the above explanation, the multilayer ceramic capacitor of the present invention has a multilayer structure in which each internal electrode is interposed with a dielectric ceramic. Even when used in a high frequency range, the equivalent series resistance does not become large.

Therefore, according to the present invention, a multilayer ceramic capacitor having electrical characteristics with low series resistance can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a ceramic green sheet used in an embodiment of the present invention, and FIG. 2 is a side sectional view showing an embodiment of a multilayer ceramic capacitor according to the present invention. la, 1b, Ic, 1d, 1e, 1f, 1
g, 1h, 11・---- Ceramic Green Seah, 2a, 2b, 2c, 2d, 2e,
2f. Patent applicant: Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] Mutual l! A plurality of internal electrodes for forming capacitance arranged in a laminated state through electric ceramic, and a pair of external electrodes for taking out capacitance connected to a predetermined one of the internal electrodes. In the multilayer ceramic capacitor, the dielectric ceramic is a non-reducible dielectric ceramic, and each of the plurality of internal electrodes is formed of a multilayer electrode layer with a dielectric ceramic interposed therebetween, and is connected to the same external electrode. , and is made of a base metal.