JP3336776B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to laminating green sheets.
, Degreasing and baking processes
The present invention relates to a method for manufacturing electronic components .

[0002]

2. Description of the Related Art
When manufacturing a ceramic sintered body such as a structural ceramic or a ceramic electronic component, a ceramic raw material formed by molding a ceramic raw material containing an organic substance such as a binder is heat-treated under predetermined conditions to remove the organic substance such as a binder. After decomposing, burning and removing (degreasing), main firing is performed to sinter the ceramic raw material molded body, thereby producing the same.

However, in the above-mentioned conventional method for producing a ceramic sintered body, a decomposed gas generated in a degreasing step of heat-treating a ceramic raw material under predetermined conditions to decompose, burn and remove organic substances such as a binder. In some cases, internal defects (delamination, etc.) and external defects (cracks, peeling, cracks, voids, etc.) occur in the ceramic raw material molded article due to gas or combustion gas, resulting in deterioration of product characteristics. .

Therefore, conventionally, the ceramic material, binder type, product size, electrode material type, atmosphere and temperature profile at the time of firing are appropriately selected to prevent internal defects and external defects from occurring in the product. ing.

[0005] The occurrence of internal defects and external defects in the ceramic sintered body is closely related to the temperature profile of the degreasing step and the subsequent firing step. In particular, the rate of temperature rise in the degreasing process is closely related to the rate of evaporation, decomposition, or combustion of organic substances such as binders, which are the main causes of internal defects and external defects (hereinafter, also simply referred to as "decomposition rate"). However, as the heating rate increases, the decomposition rate increases, the amount of heat generated and absorbed per unit time increases, and the defect generation rate increases.

[0006] As described above, although the heating rate in the degreasing step is closely related to the occurrence of internal and external defects, the determination thereof still largely depends on experience and trial and error. The fact is that it takes a lot of time to determine the speed. Therefore, there is a problem that an internal defect or an external defect is likely to occur until a proper condition is set, and the yield is reduced.
If the heating rate is determined to be small in consideration of safety, there is a problem that the time required for degreasing becomes long and the production efficiency decreases.

[0007] The present invention is intended to solve the above problems, and internal defects such as delamination, cracking, peeling, cracking, no external defects, such as voids, efficient and reliable multilayer ceramic electronic component An object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component that can be manufactured.

[0008]

In order to achieve the above object, a method for manufacturing a multilayer ceramic electronic component according to the present invention is provided .
Manufactured through the process of laminating, degreased and firing lean sheets
The method of manufacturing a multilayer ceramic electronic component, data on heating and heat absorption temperature profile and the ceramic material compacts in the degreasing step beforehand obtained by differential thermal analysis, on the basis of the data, the amount of heat generated per unit time It is characterized in that degreasing is performed according to a temperature profile set so that the variation range of the heat absorption amount is within a predetermined range.

[0009]

It is formed by laminating green sheets.
The organic material of the ceramic material compacts in like laminate that
When removing (degreasing), the oxidative decomposition (combustion) of an organic substance usually involves heat generation, and the volatilization or depolymerization decomposition of a solvent usually involves endotherm. Therefore, by obtaining in advance the temperature profile in the degreasing process and the data on the heat generation and endotherm of the ceramic raw material by differential thermal analysis, the oxidative decomposition (combustion) of the organic substance in the ceramic raw material and the volatilization of the solvent are performed. Thus, the behavior of depolymerization and decomposition can be grasped reliably. From the data of the heat generation and heat absorption, the fluctuation range of the heat generation and heat absorption of the ceramic raw material is within a predetermined range so that the oxidative decomposition of the organic substance, the volatilization of the solvent, and the depolymerization decomposition do not proceed rapidly. By setting a temperature profile (to maintain the temperature) and performing degreasing in accordance with the temperature profile, it is possible to suppress rapid generation of decomposition gas, combustion gas, and the like. Therefore, it is possible to perform degreasing efficiently while preventing the occurrence of internal defects such as delamination, and external defects such as cracks, peeling, cracks, and voids, and to achieve high reliability without internal defects or external defects. Ceramic sintered bodies can be formed with good yield.
You. As a result, highly reliable multilayer ceramic electronic components
It can be manufactured efficiently .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described, and features thereof will be described in more detail. In this embodiment, a case where a multilayer ceramic capacitor is manufactured using a barium titanate-based ceramic raw material will be described as an example.

[Configuration of Temperature Control System] FIG. 1 shows a schematic configuration of a temperature control system for controlling temperature conditions in a degreasing step. This temperature control system
In carrying out the method for producing a multilayer ceramic electronic component of the present invention, the temperature of the degreasing furnace 6 such as the temperature rising rate is controlled so that the fluctuation range of the heat generation and heat absorption of the ceramic raw material compact can be kept within a predetermined range. It is a system for controlling conditions, comprising a computer 3 having data input means 1 and arithmetic processing means 2, a D / A converter 4, and a heater control circuit 5 for controlling the heating state of the degreasing furnace 6. It is provided with.

In this temperature control system, the data input means 1 is means for reading data from a magnetic disk (floppy disk) or the like in which a temperature profile in the degreasing step and data on heat generation and heat absorption of the ceramic raw material compact are stored. The data is differentiated and integrated by the arithmetic processing means 2 to calculate and output a heating rate at which the amount of heat generated per unit time becomes constant. Then, the output signal is converted into an analog signal by the D / A converter 4,
It is sent to the heater control circuit 5 of the degreasing furnace 6. And D /
The temperature of the degreasing furnace 6 is increased at a desired rate by the signal sent from the A converter 4.

EXAMPLE Next, a multilayer ceramic electronic component (multilayer ceramic electronic component ) of the present invention will be described.
Examples of the method for manufacturing the capacitor element will be described. First, 6% by weight of polyvinyl butyral as a binder and an appropriate amount of a plasticizer were added to a dielectric material containing barium titanate as a main component, and mixed and stirred in an organic solvent to prepare a slurry. Then, this slurry was formed into a green sheet having a thickness of 12 μm after firing using a forming machine, and Ag was formed by a printing coating method.
After forming an electrode by printing and applying a conductive paste of / Pd = 3/7 (weight ratio), tens of layers are laminated, and the dimensions after firing are 3.2 mm in length × 2.5 mm in width × A sample (ceramic raw material molded body) having a thickness of 1.0 mm was obtained.

The sample was subjected to differential thermal analysis in an air atmosphere at a heating rate of 5 ° C./min, and the behavior of heat generation and heat absorption in the degreasing step (heating step) was examined. The result (data) is shown in FIG.

FIG. 2 shows that there are two large exothermic peaks during the degreasing step.

The data is analyzed by the temperature control system shown in FIG. 1 so that the oxidative decomposition of the organic substance, the volatilization of the solvent, and the depolymerization decomposition do not proceed rapidly (that is, the heat generation of the formed ceramic raw material). And a heating rate (temperature profile) so that the fluctuation range of the heat absorption is kept within a predetermined range. The result is shown in FIG. In this example, a temperature rising rate (temperature profile) was determined such that the fluctuation range of heat generation was kept within a predetermined range in a temperature region (heat generation region) having two heat generation peaks shown in FIG.

Then, by outputting a predetermined control signal to the heater control circuit 5 of the degreasing furnace 6, the temperature was raised in accordance with the temperature profile of FIG. 3, and the ceramic raw material compact was degreased.

Then, by sintering at 1,300 ° C. for 2 hours in the atmosphere, a ceramic sintered body (multilayer ceramic capacitor element) was obtained.

For comparison, a ceramic raw material compact was degreased by a conventional method, that is, a temperature profile as shown in FIG. 2, and then main-baked under the same conditions as in the above embodiment. (Multilayer ceramic capacitor
Child) .

The ceramic sintered bodies (multilayer ceramic capacitor elements) of the above Examples and Comparative Examples were
The occurrence rates of external defects such as cracks, peeling, cracks and voids, and internal defects such as delamination (the ratio of the number of samples in which the occurrence of defects was recognized to the total number of samples (100 in this example)) were examined. Table 1 shows the results.

[0021]

[Table 1]

As shown in Table 1, in the comparative example, the external defect occurrence rate is 15% and the internal defect occurrence rate is 10%, whereas in the embodiment, the external defect occurrence rate and the internal defect occurrence rate are All were 0%.

According to the above embodiment, according to the manufacturing method of the present invention, the temperature profile in the degreasing step capable of preventing the occurrence of external defects and internal defects can be set efficiently and in a short time. It was confirmed that a multilayer ceramic electronic component having no defect can be efficiently manufactured.

In the above embodiment, the case of degreasing in an air atmosphere, that is, an oxidizing atmosphere has been described as an example. However, the atmosphere in the degreasing step is not limited to this, and a neutral atmosphere or a reducing atmosphere may be used. The present invention can be applied to degreasing in the inside.

Further, according to the present invention, since it is possible to set an optimum temperature profile in the degreasing step by performing a differential thermal analysis in advance, the molecular weight and the degree of polymerization of the varnish in the binder and the conductive paste due to lot fluctuations. This is extremely significant from the viewpoint of preventing the occurrence of sudden failures caused by changes in the data.

In the above embodiment, the case where polyvinyl butyral was used as the binder was described. However, in the present invention, there is no particular restriction on the type and amount of the binder.

Furthermore, in the above embodiment, the case of manufacturing a multilayer ceramic capacitor as a multilayer ceramic electronic component has been described as an example, the present invention, the binder material
After molding by adding organic matter such as
Various laminated cells that can be used to obtain a finished product by sintering
The present invention can be applied to a method for manufacturing a lamic electronic component .

The present invention is not limited to the above-described embodiment in other respects. The present invention relates to the type and composition ratio of the ceramic raw material, the specific structure of the formed ceramic raw material, and the like. It is possible to add various applications and modifications in.

[0029]

As described above, the laminated ceramic of the present invention
In the method of manufacturing an electronic component, a temperature profile in a degreasing step and data relating to heat generation and heat absorption of a ceramic raw material molded body are obtained in advance by differential thermal analysis, and based on the data, fluctuations in heat generation and heat absorption per unit time are obtained. Since the degreasing is performed according to the temperature profile set so that the width is within the predetermined range, the temperature profile of the degreasing process can be set efficiently without using a method such as experience or trial and error as in the past. It becomes possible to do.

Further, it is possible to reliably suppress the occurrence of unexpected failures due to lot fluctuations of materials and the like.

Therefore, according to the present invention, a highly reliable laminated ceramic free from internal defects such as delamination and external defects such as cracks, peeling, cracks and voids.
Electronic components can be efficiently and reliably manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a temperature control system for controlling a temperature condition in a degreasing step used in an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a temperature profile in a degreasing step and heat generation and heat absorption of a ceramic raw material molded body according to one embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a temperature profile in a degreasing step and heat generation and heat absorption of a ceramic raw material compact set in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Data input means 2 Arithmetic processing means 3 Computer 4 D / A converter 5 Heater control circuit 6 Degreasing furnace

Claims (1)

(57) [Claims] (1)Laminate green sheets, degrease and bake
How to manufacture multilayer ceramic electronic components manufactured through the process
In the law,  Temperature profile and ceramic raw material formation in degreasing process
Preliminary data on heat generation and heat absorption of the form
Obtained by analysis and based on the data, unit time
The fluctuation range of the calorific value and heat absorption per hit is within the specified range
Degrease according to the set temperature profile
Characterized byMultilayer ceramic electronic componentsHow to make
Law.