JP2002064029A - Method for manufacturing laminated ceramic electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminated ceramic electronic part using an electrode made of Ni or made mainly of Ni, by which a highly realiable and stable product can be provided in a high reproducibility. SOLUTION: When a laminated ceramic green chip using an electrode made of Ni or made mainly of Ni is subjected to binder removal and baking, it is heated in an atmosphere gas whose oxygen partial pressure is lower than the oxidization reduction equilibrium oxygen partial pressure of Ni and higher than that having a small value by one digit, in the binder removing process of 500 to 1000 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 a multilayer ceramic electronic component represented by a multilayer ceramic capacitor, and more particularly to a method for removing a binder and firing a multilayer ceramic green chip using a base metal such as Ni as an electrode. Things.

[0002]

2. Description of the Related Art Conventionally, a method of debinding and firing a multilayer ceramic electronic component using Ni or a metal containing Ni as a main component as an electrode is performed in an atmosphere gas having an oxygen partial pressure lower than the redox equilibrium oxygen partial pressure of Ni. A method of performing a heat treatment is generally used.

[0003]

However, in order to meet the conflicting market demands of higher performance and lower cost, recent multilayer ceramic electronic components have been required to reduce the thickness of ceramic layers of multilayer ceramic electronic components, increase the number of layers, and increase the number of layers. Base metalization of the internal electrode material is proceeding at a rapid pace. Under such circumstances, the method for removing the binder and firing the multilayer ceramic electronic component has the following problems.

A base metal such as Ni or Ni is used as an internal electrode.
In a multilayer ceramic electronic component using a metal whose main component is Ni, it is necessary to remove the binder and fire it under a low oxygen partial pressure in order to prevent oxidation of Ni. For this reason, the binder removal tends to be insufficient, and the binder component remains in the sintered body as residual carbon, which may deteriorate the product characteristics, and it is difficult to ensure high reliability.

When the oxygen partial pressure is high and a part of Ni is oxidized, the oxidized Ni diffuses into the ceramic layer in the sintering process even if the amount is small, and the electric characteristics after sintering are reduced. It has the property of changing. In particular, the rate of change of the capacitance with respect to temperature (temperature characteristic of the capacitance) deteriorates, and it becomes difficult to supply a reliable multilayer ceramic electronic component having stable characteristics.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component with high reproducibility and with high reproducibility. Things.

[0007]

Means for Solving the Problems To solve the above problems, the present invention has the following arrangement.

[0008] The invention described in claim 1 of the present invention is, in particular,
When debinding and firing a laminated ceramic green chip using Ni or a metal containing Ni as a main component as an electrode, in the temperature range of 500 ° C. to 1000 ° C. in the debinding process, the oxidation-reduction equilibrium oxygen partial pressure of Ni is lower than that of Ni. In addition, the heat treatment is performed in an atmosphere gas having an oxygen partial pressure higher than one digit below the oxidation-reduction equilibrium oxygen partial pressure. In order to heat-treat the ceramic green chip,
It defines the oxygen partial pressure value and the temperature range in the debinding process in which the organic binder can be sufficiently removed by combustion decomposition and carbon can be prevented from remaining inside the sintered body.

[0009] The invention described in claim 2 of the present invention is, in particular,
When debinding and firing a multilayer ceramic green chip using Ni or a metal containing Ni as a main component as an electrode, in the temperature range of 1000 ° C. or more in the sintering process, one digit below the oxidation-reduction equilibrium oxygen partial pressure of Ni. The heat treatment is performed in an atmosphere gas having a lower oxygen partial pressure. This makes it possible to minimize the oxidation of Ni in the multilayer ceramic green chip, and the Ni oxide diffuses into the ceramic layer. It specifies the oxygen partial pressure and the temperature range in the firing process that can provide stable and reliable multilayer ceramic electronic components with a small rate of change in capacitance with respect to temperature (temperature characteristics of capacitance). is there.

[0010] The invention described in claim 3 of the present invention is, in particular,
When debinding and firing a laminated ceramic green chip using Ni or a metal containing Ni as a main component as an electrode, in the temperature range of 500 ° C. to 1000 ° C. in the debinding process, the oxidation-reduction equilibrium oxygen partial pressure of Ni is lower than that of Ni. In an atmosphere gas having an oxygen partial pressure higher than one digit below the oxidation-reduction equilibrium oxygen partial pressure, and in a temperature range of 1000 ° C. or more in the sintering process, lower than one digit below the Ni oxidation-reduction equilibrium oxygen partial pressure. The heat treatment is performed in an oxygen partial pressure atmosphere gas.In the temperature range of the debinding process, the oxidation of Ni is suppressed, and the oxygen partial pressure as high as necessary for the decomposition and combustion of the binder is used. Heat treatment is performed to smooth the decomposition and removal of the organic binder, to prevent carbon from remaining inside the sintered body, and to keep the oxygen partial pressure lower within the temperature range of the sintering process. Stipulates the oxygen partial pressure and the temperature range of the binder removal process and the firing process, which can suppress the oxidation of Ni as much as possible and can prevent the Ni oxide from diffusing into the ceramic layer to provide a stable and reliable multilayer ceramic electronic component. It is.

[0011] The invention according to claims 4 to 6 of the present invention is characterized in that the atmosphere gas when debinding and firing a multilayer ceramic green chip using Ni or a metal mainly composed of Ni as an electrode is a nitrogen gas. , Hydrogen gas, carbon dioxide gas,
The heat treatment is performed by using a mixed gas of at least two or more selected from steam. By mixing these gases at a predetermined ratio, the oxygen partial pressure can be easily adjusted in a lower range. It defines the types of gas that can be well controlled.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to a first embodiment, taking a multilayer ceramic capacitor as a representative example of a multilayer ceramic electronic component. .

First, a polyvinyl butyral resin as an organic binder, dibutyl phthalate as a plasticizer, and n-butyl acetate as an organic solvent are added to a dielectric material powder containing barium titanate as a main component, and mixed using a ball mill to prepare a slurry. did.

Next, the slurry was applied on a carrier film by a reverse roll coater method to a thickness of 13 μm, and an electrode paste containing nickel as a main component was applied to a dried green sheet by screen printing.

Next, the green sheets coated with the electrodes are peeled off from the carrier film, and the green sheets are alternately shifted by a predetermined size and stacked on 80 sheets. Then, 10 green sheets on which no electrode paste is applied are stacked on both upper and lower surfaces. Thus, a laminated green block was produced.

Thereafter, the laminated green block is
The resultant was cut into a size of mm × 1.6 mm × 1.6 mm to produce a multilayer ceramic green chip. One end of the internal electrode is disposed on both end faces of the cut multilayer ceramic green chip with a ceramic green sheet interposed therebetween, and is exposed to different end faces which are alternately opposed to each other.

Next, the laminated ceramic green chips were put into a batch type atmosphere furnace, heated to 500 ° C. while flowing nitrogen gas at 100 liters per minute, and then heat-treated at 500 ° C. for 5 hours.

Next, the heat-treated multilayer ceramic green chip is charged into a batch type atmosphere furnace similar to that used for the heat treatment, and while flowing nitrogen gas at 50 liters per minute and hydrogen gas at 0.2 to 2 liters per minute, 500 ° C ~ 1000
Heat treatment is performed in an atmosphere gas having an oxygen partial pressure shown in Table 1 in a temperature range of 1 ° C., and an oxygen partial pressure one digit lower than the oxidation-reduction equilibrium oxygen partial pressure of Ni in a temperature range of 1000 ° C. or more. Heat treatment was carried out in an atmosphere gas, and firing was carried out at a temperature of 1300 ° C. for 2 hours.

Thereafter, Ag paste was applied to both end portions of the sintered body where the internal electrodes were exposed, and baked to form terminal electrodes, thereby producing a multilayer ceramic capacitor.

A life test of insulation resistance was performed on each of the obtained multilayer ceramic capacitors by continuously applying DC 32 V for 250 hours in a thermostat at 125 ° C. The results are shown in Table 1 below.

[0021]

[Table 1]

Table 1 shows that the initial value of the insulation resistance is 1 × 1.
The numbers indicate that 50 or more samples of ⁰⁹ or more deteriorated to 1 × 10 ⁷ or less after the life test. The samples marked with a triangle are out of the scope of the present invention and are comparative examples.

As shown in (Table 1), the multilayer ceramic capacitor manufactured by the method of the present invention has only a small deterioration of the insulation resistance, whereas the comparative example suffers a large deterioration of the insulation resistance and has a regular insulation resistance. It can be seen that no characteristics were obtained. From these results, it is clear that the manufacturing method of the present invention is an effective means for improving yield and product characteristics. It should be noted that residual carbon was detected from a sample in which insulation was not deteriorated and a sample in which insulation was deteriorated, which was obtained by analyzing a sample having deteriorated insulation.

In the first embodiment, nitrogen gas is used up to 500 ° C., and a mixed gas of nitrogen gas and hydrogen gas is used from 500 ° C. to 1000 ° C., but nitrogen gas and hydrogen gas are used up to 500 ° C. A mixture of two or more gases selected from nitrogen gas, hydrogen gas, carbon dioxide gas and water vapor at a predetermined ratio in the range of 500 ° C. to 1000 ° C. in any atmosphere of carbon dioxide, water vapor A similar result was obtained when using.

The reason why a mixed gas of nitrogen gas, hydrogen gas, carbon dioxide gas and water vapor is used is that the oxygen partial pressure can be easily controlled with high accuracy. Furthermore, the multilayer ceramic capacitor has been described as an example, but the present invention is not limited to this, and other electronic components such as a multilayer actuator,
The same effect can be obtained by applying to a laminated varistor or the like.

(Embodiment 2) Hereinafter, the second embodiment of the present invention will be described by using the second embodiment as a representative of the same multilayer ceramic electronic component as that of the first embodiment. A description will be given taking a ceramic capacitor as an example.

First, using the same batch type atmosphere furnace as that used for the heat treatment, the heat-treated multilayer ceramic green chip produced in the first embodiment was charged, and 50 liters of nitrogen gas per minute and hydrogen gas were supplied. While flowing at 0.2 to 2 liters per minute, 100
In a temperature range of 0 ° C. to 1300 ° C., heat treatment is performed in an atmosphere gas having an oxygen partial pressure shown in (Table 2).
The temperature was maintained at a temperature of 2 ° C. for 2 hours for firing.

Next, a silver paste was applied to both end surfaces of the sintered body where the internal electrodes were exposed and baked to form terminal electrodes, thereby producing a multilayer ceramic capacitor.

A life test was performed on each of the obtained multilayer ceramic capacitors under the same conditions as in the first embodiment, and the temperature characteristics of the capacitance and the results of the deterioration of the insulation resistance are shown together (Table 2).

[0030]

[Table 2]

Table 2 shows that the initial insulation resistance is 1 × 1
50 or more samples of ⁰⁹ or more deteriorated to 1 × 10 ⁷ or less after the life test, and the temperature characteristic of capacitance shows the rate of change of capacitance at 85 ° C. based on 20 ° C. . In addition, ♯
Samples marked with are outside the scope of the present invention and are comparative examples.

As shown in Table 2, the multilayer ceramic capacitor according to the manufacturing method of the present invention has a small change rate of the capacitance with respect to the temperature, whereas the comparative example has a large change rate of the capacitance with respect to the temperature. You can see that. In particular, in the temperature range of 500 ° C. to 1000 ° C. of the present invention, the laminated ceramic green chip is subjected to an atmosphere gas having an oxygen partial pressure lower than the oxidation-reduction equilibrium oxygen partial pressure of Ni and higher than one digit below the oxidation-reduction equilibrium oxygen partial pressure. When heat treatment is performed in an atmosphere gas having an oxygen partial pressure lower than 1 digit below the oxidation-reduction equilibrium oxygen partial pressure of Ni in a temperature range of 1000 ° C. or more, there is almost no deterioration in insulation resistance, and The rate of change of the capacity with respect to temperature was also small, which was the best. From these results, it is clear that the manufacturing method of the present invention is an effective means for improving yield and product characteristics.

(Embodiment 3) Hereinafter, the third embodiment of the present invention will be described by using the third embodiment as a representative of the multilayer ceramic electronic component, similarly to the first embodiment. A description will be given taking a ceramic capacitor as an example.

First, the heat-treated multilayer ceramic green chip produced in the first embodiment was heated at 500 ° C. in the same batch-type atmosphere furnace as that used for the heat treatment while flowing the atmosphere gas shown in Table 3 below. ~ 1000 ° C and 100
In the temperature range of 0 ° C. to 1300 ° C., heat treatment was performed by controlling the oxygen partial pressure by adjusting the mixing ratio of the gas, and firing was performed at a temperature of 1300 ° C. for 2 hours.

Next, a silver paste was applied to both end portions of the sintered body where the internal electrodes were exposed and baked to form terminal electrodes, thereby producing a multilayer ceramic capacitor.

A life test was performed on each of the obtained multilayer ceramic capacitors under the same conditions as in the first embodiment, and the temperature characteristics of the capacitance and the results of deterioration of the insulation resistance are shown together (Table 3).

[0037]

[Table 3]

As shown in Table 3, since the mixed gas used in the present invention can easily control the oxygen partial pressure accurately and accurately, the obtained multilayer ceramic capacitor has a capacitance change rate with respect to temperature. Is small, while the rate of change of the capacitance with respect to temperature is large in the comparative example. In particular, the laminated ceramic green chip
In a temperature range of 1000 ° C., in an atmosphere gas having an oxygen partial pressure lower than the oxidation-reduction equilibrium oxygen partial pressure of Ni and higher than one digit below the oxidation-reduction equilibrium oxygen partial pressure, and in a temperature range of 1000 ° C. or higher, Ni When heat treatment was performed in an atmosphere gas having an oxygen partial pressure lower than one digit below the oxidation-reduction equilibrium oxygen partial pressure, the insulation resistance was hardly degraded, and the rate of change of the capacitance with respect to temperature was small. . From these results, it is clear that the manufacturing method of the present invention is an effective means for improving yield and product characteristics.

[0039]

As is apparent from the above embodiment, according to the method for manufacturing a multilayer ceramic electronic component of the present invention, the multilayer ceramic green chip is subjected to a redox equilibrium oxygen partial pressure of Ni in a temperature range of 500 ° C. to 1000 ° C. By performing heat treatment in an atmosphere gas having an oxygen partial pressure that is lower and higher than one digit below the oxidation-reduction equilibrium oxygen partial pressure, a multilayer ceramic green chip can be formed in an oxygen partial pressure as high as possible while suppressing oxidation of Ni. Can be heat-treated, and the organic binder can be sufficiently decomposed and removed to prevent carbon from remaining inside the sintered body. Therefore, the multilayer ceramic electronic component obtained by this manufacturing method has N
Even when a base metal such as i is used as an electrode material,
It can be seen that there is an effect that the production can be performed with high reliability and stable performance with good reproducibility, and the effect is industrially large.

Claims (6)

[Claims] 1. When debinding and firing a multilayer ceramic green chip having Ni or a metal containing Ni as a main component as an electrode, a temperature of 500 ° C. to 10 ° C.
A method for producing a multilayer ceramic electronic component, wherein heat treatment is performed in an atmosphere gas having an oxygen partial pressure lower than the oxidation-reduction equilibrium oxygen partial pressure of Ni and higher than one digit below the oxidation-reduction equilibrium oxygen partial pressure in the temperature range of 00 ° C. 2. When debinding and firing a laminated ceramic green chip using Ni or a metal containing Ni as a main component as an electrode, the oxidation-reduction equilibrium oxygen partial pressure of Ni in the temperature range of 1000 ° C. or more in the firing process. A method for producing a multilayer ceramic electronic component, wherein heat treatment is performed in an atmosphere gas having an oxygen partial pressure lower than one digit. 3. When debinding and firing a laminated ceramic green chip using Ni or a metal containing Ni as a main component as an electrode, a temperature of 500.degree.
In the temperature range of 00 ° C., in an atmosphere gas having an oxygen partial pressure lower than the redox equilibrium oxygen partial pressure of Ni and higher than one digit below the redox equilibrium oxygen partial pressure, and at 1000 ° C. in the sintering process.
A method for manufacturing a multilayer ceramic electronic component, wherein heat treatment is performed in an atmosphere gas at an oxygen partial pressure lower than one digit below the oxidation-reduction equilibrium oxygen partial pressure of Ni in the above temperature range. 4. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the atmosphere gas is a mixed gas of at least two or more selected from nitrogen gas, hydrogen gas, carbon dioxide gas, and water vapor. 5. The method for manufacturing a multilayer ceramic electronic component according to claim 2, wherein the atmospheric gas is a mixed gas of at least two selected from nitrogen gas, hydrogen gas, carbon dioxide gas, and water vapor. 6. The method for producing a multilayer ceramic electronic component according to claim 3, wherein the atmosphere gas is a mixed gas of at least two selected from nitrogen gas, hydrogen gas, carbon dioxide gas, and water vapor.