JPH0883733A - Manufacture of layered ceramic electronic part - Google Patents

Abstract

PURPOSE: To realize a method of manufacturing a layered ceramic electronic part which prevents inner and outer defects such as delamination or cracking from occurring without using a specific conductive paste. CONSTITUTION: An unburned ceramic laminate where an inner electrode is provided is thermally treated (preheat treatment) in a reducing or non-oxidizing (neutral) atmosphere at temperatures above soot and then burned under prescribed conditions. Or, the laminate is thermally treated (preheat treatment) at temperatures of 600 to 800 deg.C.

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 electronic parts, and more particularly to a method for manufacturing monolithic ceramic electronic parts such as a monolithic ceramic capacitor, a monolithic ceramic filter and a ceramic multi-layer substrate.

[0002]

2. Description of the Related Art As an internal electrode constituting a monolithic ceramic electronic component such as a monolithic ceramic capacitor or a monolithic ceramic filter, P
d single system and mixed system containing Pd (eg Ag-Pd
An internal electrode made of a material of a system or Au-Pd system, etc. is generally used.

However, a thin layer product (an electronic component having a thin ceramic layer to be laminated) or a multilayer product (an electronic component having a large number of laminated ceramic layers) having an internal electrode using a mixed material containing Pd. In the case of manufacturing, the internal electrode is peeled off (delamination) due to oxidation and reduction of Pd and the like occurring in the heat treatment step of the laminate (a debinding step usually performed at a temperature of 400 to 500 ° C.), which is accompanied by expansion and contraction. ) And cracks on the surface and inside of the device and the like, and the characteristics are deteriorated.

Therefore, in order to solve these problems, a paste for electrode formation to which needle-shaped or plate-shaped titanium oxide particles are added has been proposed (Japanese Patent Laid-Open No. 4-33480).
No. 6).

However, if an oxide having the above-mentioned shape is to be contained in the electrode forming paste, the dispersibility thereof needs to be remarkably paid, and the manufacturing process becomes complicated and the manufacturing cost of the monolithic ceramic electronic component is reduced. There is a problem of pushing it up.

The present invention solves the above-mentioned problems, and it is possible to suppress the occurrence of internal defects and external defects such as delamination and cracks without requiring a special paste. It is an object to provide a method for manufacturing an electronic component.

[0007]

In order to achieve the above object, a method of manufacturing a monolithic ceramic electronic component according to the present invention is a method of manufacturing a monolithic ceramic electronic component in which internal electrodes are provided in a ceramic. After heat-treating (preliminary heat treatment) an unsintered laminated body in which internal electrodes are arranged in a ceramic in a reducing or non-oxidizing (neutral) atmosphere at a temperature exceeding 500 ° C. The feature is that firing is performed below.

Further, the heat treatment (preliminary heat treatment) of the laminate is 6
It is characterized in that it is performed at a temperature of 00 to 800 ° C.

Further, the internal electrode is characterized by being a Pd single system internal electrode or a mixed system internal electrode containing Pd.

[0010]

A laminated body in which internal electrodes made of a material such as a Pd single system or a Pd-containing mixed system is provided in a ceramic,
Pd forming the internal electrode (internal electrode paste) is once subjected to heat treatment (preheat treatment) at a temperature exceeding 500 ° C. in a reducing or non-oxidizing (neutral) atmosphere.
A metal material such as a single system or a mixture containing Pd (for example, a mixed powder of Ag and Pd, a mixed powder of Au and Pd, etc.) is alloyed without being oxidized, or grain growth is caused along with alloying (from Pd etc. In the case of a single-system metal material, only grain growth occurs without alloying), which suppresses the generation of oxides in the subsequent firing process performed in an oxidizing atmosphere such as air. .

Therefore, it is possible to efficiently prevent the generation of internal and external defects such as delamination and cracks due to expansion and contraction due to oxidation and reduction of the internal electrodes in the firing process.

FIG. 1 shows that Ag and Pd are alloyed to a certain degree and grain-grown by once heat-treating (preheat-treating) at 600 ° C. in a reducing or non-oxidizing (neutral) atmosphere. Heat treated at 300 ° C with internal electrodes,
FIG. 3 is a diagram showing a relationship between temperature and weight when an internal electrode in which Ag and Pd are not alloyed and grain growth is not performed is fired in air. As shown in FIG. 1, the internal electrode heat-treated (alloyed and grain-grown) at 600 ° C. was 300 ° C.
It can be seen that the weight increase / decrease during the temperature rise process is smaller than that of the internal electrode that has been heat-treated (no alloying and grain growth) (that is, the ratio of oxidation and reduction is small). .

In the method for manufacturing a monolithic ceramic electronic component of the present invention, the laminated body is once subjected to a heat treatment (preliminary heat treatment) at a temperature exceeding 500 ° C. in a reducing or non-oxidizing (neutral) atmosphere. As a result, the effect of improving properties such as alloying and grain growth can be recognized, but the more preferable range of heat treatment temperature is 600 to 800 ° C.

This is because the heat treatment (preliminary heat treatment) temperature is 60.
This is because by setting the temperature to 0 ° C. or higher, alloying, grain growth and the like are more appropriately promoted, and when the temperature exceeds 800 ° C., sintering tends to proceed too much, and the function as the internal electrode tends to be difficult to obtain.

[0015]

EXAMPLES Examples of the present invention will be shown below to explain the features thereof in more detail.

In this embodiment, first, Ag: Pd
A dielectric sheet was formed by screen-printing an internal electrode paste containing a mixed powder of 3: 7 (weight ratio) as a conductive powder on a green sheet having a thickness of 20 μm. Then, 80 sheets of this dielectric sheet were stacked, dummy sheets were further stacked on both upper and lower sides thereof, and then pressure bonding was performed to form a multilayer body (pressure bonding block) for a multilayer ceramic capacitor.

Next, this laminated body is subjected to 600 nm in a nitrogen atmosphere.
400 ℃ after heat treatment (preheat treatment) of heating up to 600 ℃ at a rate of 1.0 ℃ / min and holding at 600 ℃ for 2 hours
Cooled down. Then, switch the atmosphere to air, 5
The temperature was raised to 1300 ° C. at a rate of ° C./min, held for 2 hours, and then cooled (Example 1).

For comparison, the laminate was heat-treated (preliminary heat treatment) under the following conditions and then fired under the same conditions as in the above-mentioned examples. Hold at 400 ° C. for 2 hours in nitrogen atmosphere (Comparative Example 1) Hold in air for 2 hours (Comparative Example 2)

Then, the above-mentioned Example 1 and Comparative Examples 1 and 2 were used.
The occurrence rate of delamination (internal defects) and surface cracks (external defects) was examined for the laminate fired by the method described in 1. The results are shown in Table 1. However, the number of samples is 10,000 (n = 10000).

[0020]

[Table 1]

As shown in Table 1, in Example 1,
Generation of delamination (internal defect) and crack (external defect) was not observed at all, but in the case of Comparative Example 1, delamination (internal defect) was generated in 5% and crack (external defect) was generated in 10%. did. Further, in the case of Comparative Example 2, 60% delamination (internal defect), 90%
A crack (external defect) occurred in%.

The state of the internal electrodes of each sample was analyzed by the X-ray diffraction method. In the case of Example 1, Ag and Pd were completely alloyed with Ag: Pd = 3: 7 (weight ratio). Was confirmed. On the other hand, in the case of Comparative Example 1, the alloy of Ag: Pd = 4: 6 (weight ratio) and PdO were mixed, and in the case of Comparative Example 2, Ag: Pd = 4: 6 (weight ratio).
It was in a state where the alloy of Pd = 5: 5 (weight ratio) and PdO were mixed.

According to the above example, the laminated body is heated to 600 ° C. in a nitrogen atmosphere and subjected to a heat treatment (preheat treatment) in which the temperature is kept at 600 ° C. for 2 hours (Example 1), whereby delamination (internal defects) is performed. It was confirmed that the occurrence of cracks and cracks (external defects) can be suppressed and prevented, but the conditions of the preliminary heat treatment are not limited to the conditions of the above-mentioned examples, and
By carrying out the preliminary heat treatment at a temperature of more than 00 ° C., preferably 600 to 800 ° C., the same effect as in the above embodiment can be obtained.

In the above embodiment, the internal electrode is Ag:
The case where the internal electrode is a mixed system of Pd = 3: 7 (weight ratio) has been described, but in the present invention, there is no particular restriction on the composition ratio of Ag and Pd. That is, according to the present invention, it is possible to suppress or prevent the generation of oxides by alloying Ag and Pd having an arbitrary composition ratio or simultaneously growing grains. The present invention also provides Ag and P
Not only the mixed system of d, but also a mixed system of Pd and another metal (for example, Au-Pd system), and a monolithic ceramic electron having a Pd single system or a single system or mixed system internal electrode made of another material. It can also be applied when manufacturing parts. Further, in the present invention, when a mixed metal material is used, it is necessary to perform a predetermined alloying by heat treatment, but grain growth is not necessarily required. On the other hand, when a single metal material is used, it is necessary to grow the grains by heat treatment.

In the above embodiments, the case of manufacturing a monolithic ceramic capacitor has been described as an example, but the present invention is not limited to a monolithic ceramic capacitor, and various monolithic ceramic filters, ceramic multi-layer substrates and the like can be used. It can be applied to a monolithic ceramic electronic component.

The present invention is not limited to the above-mentioned embodiments in other points as well, and relates to a specific structure of the laminate, a pattern of the internal electrodes and the like, and various applications within the scope of the gist of the invention. Modifications can be added.

[0027]

As described above, according to the method for producing a laminated ceramic electronic component of the present invention, the laminated body in which the internal electrodes are arranged in the ceramic is placed in a reducing or non-oxidizing (neutral) atmosphere. After the heat treatment (preliminary heat treatment) at a temperature higher than 500 ° C., the firing is performed under predetermined conditions, so that it is possible to suppress the generation of oxides such as PdO in the subsequent firing step.

Therefore, it is possible to suppress and prevent the occurrence of structural defects such as delamination and cracks, which are difficult to screen, though the product quality is fatally affected, and to improve the product yield. it can.

Further, according to the method for manufacturing a monolithic ceramic electronic component of the present invention, the manufacturing cost can be reduced as compared with the case of using a conductive paste in which an alloy powder alloyed beforehand is used as a conductive material.

Further, in the method for manufacturing a monolithic ceramic electronic component of the present invention, the laminated body is once subjected to heat treatment (preheat treatment) at 600 to 800 ° C. in a reducing or non-oxidizing (neutral) atmosphere. As a result, it is possible to effectively promote alloying and grain growth of the internal electrodes, and it is possible to reliably manufacture a multilayer ceramic electronic component without structural defects by subsequent firing.

[Brief description of drawings]

FIG. 1 is a result of heat treatment (preliminary heat treatment) at 600 ° C. and Ag.
And Pd are alloyed to a certain degree and grain-grown, and the relationship between temperature and weight when the internal electrode heat-treated at 300 ° C. and the internal electrode not alloyed with Ag and Pd are fired in air FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunobu Yoneda 2 26-10 Tenjin Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. A method for manufacturing a monolithic ceramic electronic component in which internal electrodes are arranged in a ceramic, wherein a non-sintered laminated body in which internal electrodes are arranged in a ceramic is reduced or non-oxidized. 5 in neutral (neutral) atmosphere
A method for manufacturing a laminated ceramic electronic component, comprising performing heat treatment (preliminary heat treatment) at a temperature higher than 00 ° C., and then performing firing under predetermined conditions. 2. Heat treatment (preliminary heat treatment) of the laminate is 600.
The method for producing a monolithic ceramic electronic component according to claim 1, wherein the method is performed at a temperature of ˜800 ° C. 3. The method for producing a monolithic ceramic electronic component according to claim 1, wherein the internal electrode is a Pd single system or a mixed system internal electrode containing Pd.