JPH07335476A - Manufacture of layered ceramic electronic component - Google Patents

Abstract

PURPOSE:To provide a method, which can inhibit delamination and along with that, makes it possible to obtain a layered ceramic electronic component having superior environment-proof characteristics. CONSTITUTION:In the case where layered materials 13 formed of a plurality of raw ceramic layers via an internal electrode are fired in a batch type furnace 14, the pressure in the furnace 14 is made higher than the atmospheric pressure to conduct a firing of the layered material 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a ceramic laminated electronic component, and more particularly to a method for producing a ceramic laminated electronic component having an improved firing process.

INDUSTRIAL APPLICABILITY The present invention can be generally used in a method for manufacturing a ceramic multilayer piezoelectric resonance component, a ceramic multilayer electronic component such as a ceramic multilayer substrate, as well as a multilayer capacitor.

[0003]

2. Description of the Related Art An example of a conventional method for manufacturing a ceramic multilayer electronic component will be described by taking a multilayer capacitor as an example. When manufacturing a multilayer capacitor, first, a ceramic green sheet is formed using a ceramic slurry containing a dielectric ceramic as a main component. Then, an internal electrode paste containing a conductive powder such as Pd is screen-printed on the ceramic green sheet to form internal electrodes.
Thereafter, the ceramic green sheets having the internal electrodes formed thereon are laminated so as to form a laminated capacitor, and an appropriate number of ceramic green sheets on which the internal electrode paste is not printed are laminated on the upper and lower sides to obtain a laminated body. A molded body is obtained by pressing this laminated body in the thickness direction. Further, the molded body obtained as described above is fired, the internal electrodes are fired, and the ceramics are fired to obtain an integrally fired sintered body. Finally, external electrodes are formed on the outer surface of the obtained sintered body to obtain a multilayer capacitor.

By the way, in the above firing, a tunnel furnace is generally used in order to improve productivity. That is, the molded body before firing is arranged on a conveyor such as a belt conveyor, and while passing a large number of molded bodies on the belt conveyor, it is passed through a tunnel furnace, and the molded body is preliminarily specified while passing through the tunnel furnace. It was baked according to the temperature profile of.

[0005]

However, in the firing method using the conventional tunnel furnace, the delamination phenomenon called delamination sometimes occurs in the sintered body. When such delamination occurs, even if an external electrode is formed and a multilayer capacitor is obtained, moisture or the like easily enters from the portion where delamination occurs, and thus stable characteristics can be exhibited. Could not be provided.

An object of the present invention is to provide a manufacturing method capable of providing a ceramic laminated electronic component which is less likely to cause delamination during firing and therefore has excellent environmental resistance.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a ceramic laminated electron using an integrally fired sintered body obtained by firing a molded body in which a plurality of ceramic layers are laminated via internal electrodes. In the method of manufacturing a component, the firing is performed in a batch furnace, and the formed body is fired by increasing the internal pressure of the batch furnace at the highest temperature during the firing above atmospheric pressure. The ceramic laminated electronic component to which the present invention is applied includes a wide variety of ceramic laminated electronic components such as a ceramic multilayer substrate and a laminated ceramic piezoelectric resonance component in addition to a laminated capacitor.

The molded body used for firing in the present invention is used for the above-mentioned ceramic laminated electronic component and has a structure in which a plurality of raw ceramic layers are laminated via internal electrodes. . In this case, the structure in which a plurality of ceramic layers are laminated via the internal electrodes widely includes a structure in which a raw ceramic layer is laminated in the thickness direction via one or more internal electrodes, and the same height A plurality of internal electrodes may be arranged at the position.

In the present invention, firing is carried out in a batch furnace.
The firing is carried out in a batch furnace in order to increase the internal pressure of the batch furnace at the highest temperature during firing above atmospheric pressure, that is, to increase the pressure applied to the molded body,
This is to suppress the occurrence of delamination.

As the batch furnace, a batch furnace of an appropriate type conventionally used for firing ceramic electronic parts can be used, and is not particularly limited. Regarding the relationship between the internal pressure of the batch furnace and the atmospheric pressure, the internal pressure of the batch furnace at the maximum temperature during firing may be higher than the atmospheric pressure, and the higher the internal pressure of the batch furnace is, the higher the atmospheric pressure. The occurrence of delamination can be effectively suppressed. However, in order to suppress the occurrence of delamination, the higher the internal pressure of the batch furnace, the more preferable, but in consideration of other problems such as the size increase of the batch furnace, the internal pressure of the batch furnace at the maximum temperature is higher than the atmospheric pressure. It is also preferable that the pressure becomes higher in the range of 20 kg / cm ² or less, and more preferably the internal pressure of the batch furnace is set to about 5 to 10 kg / cm ^{2 as} compared with the atmospheric pressure.

As a method of adjusting the internal pressure of the batch furnace,
It can be performed by supplying an appropriate gas having a pressure higher than atmospheric pressure into the batch furnace. In this case, if a gas suitable for adjusting the firing atmosphere is used as the gas to be supplied, both the atmosphere adjustment and the pressure adjustment in the batch furnace in the present invention can be achieved by the supply of the gas.

The above example will be specifically described. For example, when firing a laminated ceramic electronic component using a lead composite perovskite-based dielectric ceramic, it is necessary to fire a molded body in which a plurality of raw ceramic layers are laminated via internal electrodes in a predetermined atmosphere. . Therefore, by increasing the pressure of the atmosphere gas, firing can be performed according to the method of the present invention, and the atmosphere at the time of firing and the pressure in the batch furnace can be adjusted at the same time by supplying the gas.

The method for producing a ceramic laminated electronic component of the present invention is characterized in that it is fired in a batch furnace as described above, and the pressure conditions during firing are set as described above. The step of is not particularly limited. Therefore, the step of preparing the molded body, the step of forming the external electrode after firing, and the like can be appropriately performed according to a conventionally known method for manufacturing a ceramic laminated electronic component.

[0014]

In the method for producing a ceramic laminated electronic component of the present invention, the molded body is fired in the batch furnace, and the internal pressure of the batch furnace at the highest temperature is set higher than the atmospheric pressure during the firing. . Therefore, even if the delamination phenomenon occurs in the firing step, since the ambient pressure is higher than the atmospheric pressure, the delamination is suppressed. As a result, it is possible to stably obtain an integrally fired ceramic sintered body in which delamination does not occur, and it is possible to enhance the environmental resistance characteristics of the ceramic laminated electronic component.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be clarified by describing embodiments with reference to the drawings.

First, as shown in FIG. 1A, an internal electrode paste 12 containing Pd as a conductive powder was printed on a rectangular ceramic green sheet 11. Next, a plurality of the ceramic green sheets 11 on which the internal electrode paste 12 is printed are alternately laminated so as to have the orientation shown in FIG. 1A and the orientation shown in FIG. An appropriate number of ceramic green sheets on which the internal electrode paste 12 was not printed were laminated to obtain a laminated body. The obtained laminated body was pressed in the thickness direction to obtain a molded body shown in FIG. In the molded body 13, the internal electrode paste 12 is laminated via a green ceramic layer.

Next, the plurality of molded bodies 13 prepared as described above were put into the batch furnace 14 shown in FIG. 3 and fired. At the time of firing, gas (oxygen, air, etc.) was introduced into the batch furnace 14 from the gas introduction pipe 14a to perform firing. In addition, 14b shows a gas discharge pipe. Also,
The pressure in the batch furnace 14 due to the introduction of the gas is shown in Table 1 below.
Various changes (in Example 1, the pressure difference between the inside and outside was 2 kg / cm ² , and in Example 2 the pressure difference was 5 kg / cm 2).
⁽² , 10 kg / cm ^{2 in} Example 3) For comparison, the pressure difference between the inside and outside was set to 0, and firing was performed in the same manner.

External electrodes were provided on the outer surfaces of the sintered bodies of Examples 1 to 3 and Comparative Example obtained as described above, and multilayer capacitors were produced. With respect to the obtained multilayer capacitor, the rate of delamination was evaluated by cutting the multilayer capacitor and observing it with a microscope. The results are shown in Table 1 below. Further, a high temperature load test was conducted in the following manner to evaluate the high temperature load initial failure rate. The results are shown in Table 1 below.

High-temperature load test: Multilayer capacitors at 85 ° C
It was placed in an atmosphere of No. 3, and a voltage four times the rated voltage was applied to evaluate whether or not an initial failure occurred.

[0020]

[Table 1]

As is clear from Table 1, in the comparative example in which the pressure difference between the inside and the outside was 0, the high temperature initial failure rate of the obtained multilayer capacitor was as high as 500 ppm, and the occurrence rate of delamination was as high as 1200 ppm. On the other hand, in Examples 1 to 3, the internal pressure of the batch furnace was increased by ² to 10 Kg / cm ² as compared with the atmospheric pressure. Therefore, the high temperature load initial failure rate was low, and delamination occurred. It can be seen that the rate is also very low compared to the comparative example. From this, in the present invention, the pressure difference between the inside and outside of the furnace is 2 kg / c.
5kg / cm ² is more effective than m ²
It can be seen that a higher effect can be obtained with 0 kg / cm ² .

[Brief description of drawings]

1A and 1B are plan views showing a printed shape of a ceramic green sheet prepared in an example and an internal electrode paste formed thereon.

FIG. 2 is a cross-sectional view of a molded body prepared in an example.

FIG. 3 is a schematic configuration diagram for explaining a step of firing a molded body in a batch furnace.

[Explanation of reference numerals] 11 ... Ceramic green sheet 12 ... Internal electrode paste 13 ... Molded body 14 ... Batch furnace

Claims (1)

[Claims] 1. A method for producing a ceramic laminated electronic component using an integrally fired sintered body obtained by firing a molded body in which a plurality of ceramic layers are laminated via internal electrodes, wherein the firing is performed. A method for manufacturing a ceramic laminated electronic component, comprising: firing a molded body in a batch furnace at a maximum temperature during firing at an internal pressure of the batch furnace higher than atmospheric pressure.