JP3131004B2 - Manufacturing method of laminated porcelain electronic components - Google Patents

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 laminated ceramic electronic component such as a laminated ceramic capacitor, a laminated actuator, and a laminated varistor.

[0002]

2. Description of the Related Art In recent years, many laminated ceramic electronic components using metal palladium for internal electrodes have been used.

[0003] However, metallic palladium is oxidized in the firing step and its volume expands, which causes internal defects (delamination, cracks, etc.).

[0004] For this reason, it is extremely important to reduce the volume expansion of the internal electrodes in order to improve the production efficiency of the laminated ceramic electronic component. Conventionally, the volume expansion due to the oxidation of metallic palladium is alleviated. As a method, the following method was mainly adopted.

(1) Sintering is performed in a nitrogen atmosphere to suppress oxidation of palladium.

(2) Using palladium powder having a large particle size,
Slows the rate of oxidation of palladium.

(3) Various additives suppress the oxidation of palladium, promote the firing of palladium, and reduce the volume expansion.

(4) The volume expansion is reduced by using palladium powder in which oxidation and calcination proceed simultaneously.

(5) The palladium electrode paste is printed thinly to reduce the absolute volume expansion due to the oxidation of palladium.

[0010]

On the other hand, in the case of a laminated ceramic electronic component, the thickness of the ceramic dielectric layer and the thickness of the internal electrode layer are reduced from the viewpoint of miniaturization, high capacity, and cost reduction. Attempts have been made to increase the number of electrode layers.

For example, taking the case of a laminated ceramic capacitor as an example, in order to increase the capacitance, it is necessary to reduce the thickness of the dielectric layer between the electrode layers and increase the number of internal electrode layers facing each other. Is desirable.

However, if the thickness of the dielectric layer is, for example, 1
In the case of a high-capacity laminated porcelain electronic component having a thickness as small as 0 μm or less and having a large number of internal electrode layers, for example, as many as 50 or more, the above-described conventional method for alleviating volume expansion due to oxidation of metallic palladium does not provide internal defects (delamination). , Cracks, etc.) could not be completely prevented, causing the following problems.

(1) When firing is performed in a nitrogen atmosphere,
Oxidation of palladium can be completely suppressed, but palladium is over-sintered, causing electrode breakage. As a result, the capacitance decreases.

(2) When palladium powder having a large particle size is used, the thickness of the internal electrode layer cannot be reduced, resulting in an increase in cost.

(3) When an additive is added to the internal electrode paste, the coverage of the internal electrode surface decreases,
The dielectric loss, the equivalent series resistance, etc., deteriorate.

(4) When using palladium powder in which oxidation and sintering proceed simultaneously, if the number of electrodes exceeds 50,
Internal defects may occur.

(5) When the palladium electrode paste is printed thinly, the occurrence of internal defects is suppressed, but the electrodes may be cut off due to variations in the electrode thickness, and the capacitance may decrease.

Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a laminated ceramic electronic component capable of efficiently producing a small, high-capacity laminated ceramic electronic component.

[0019]

In order to achieve the above object, the present invention provides a method for manufacturing a laminated porcelain electronic component comprising a step of firing an internal electrode layer made of metal palladium between porcelain layers. The firing step is performed in a chamber
The temperature rise rate in the temperature rise area from temperature to 400 ° C is 300 ° C.
/ H, the rate of temperature rise in the temperature rise region of 400 to 900 ° C. is 600 ° C./h or more ,
The heating rate in the heating area is 300 ° C./h .

[0020]

The operation of the method for manufacturing a laminated ceramic electronic component having such a configuration will be described.

Metal palladium depends on its particle size.
Oxidizes at about 400-800 ° C in air, 800
Above ℃, it returns to metallic palladium. The oxidation rate varies depending on the state of the metal palladium, but is determined by a function of time and temperature in any case. In a temperature range of 800 ° C. or less, the higher the temperature and the longer the time, the more the oxidation reaction proceeds, and a proportional volume expansion occurs. If the temperature can be raised instantaneously from room temperature to a temperature range of 800 ° C. or higher, the reaction time becomes 0 and no oxidation reaction occurs. That is, the higher the rate of temperature rise, the shorter the oxidation reaction time, and the smaller the amount of oxidation and volume expansion of palladium. As a result, it is possible to obtain a laminated ceramic electronic component in which internal defects hardly occur. But like this one
It is impossible to raise the temperature instantaneously, so the temperature gradually increases
And a region of 400 to 900 ° C. where the oxidation reaction is remarkable.
It is said that the temperature rises rapidly and then gradually rises above 900 ° C
Configuration is adopted.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of a laminated ceramic electronic component manufactured by the manufacturing method of the present invention, with a part missing.

The laminated porcelain electronic component 1 is provided with a porcelain dielectric 2 formed by laminating a porcelain dielectric sheet having a small thickness of, for example, 10 μm, and is disposed in the porcelain dielectric 2 in a thickness direction.
A plurality of (in this example, 100 layers) internal electrodes 3 made of metal palladium powder and a pair of external electrodes 4 and 4 are provided. The laminated ceramic electronic component 1 has a small rectangular shape as a whole, and when the direction in which the external electrode 4 faces is L, the direction perpendicular to the direction is W, and the direction perpendicular to the internal electrode 3 is T, the overall Are, for example, L = 3.3 mm and W = 1.6.
5 mm and T = 1.35 mm.

Next, a method for manufacturing the laminated ceramic electronic component of the present invention will be described.

In the present manufacturing method, an electrode paste made of metal palladium powder is laminated in a thickness direction so as to face each other via a raw ceramic dielectric sheet, and then a binder is removed.
Through a firing step, a pair of external electrodes 4 and 4 are formed by deposition,
This is to obtain the laminated ceramic electronic component 1 shown in FIG.

In the baking step, the temperature is raised from room temperature to 400 ° C. at a slow rate of 300 ° C./h.
After the temperature rising region of 00 ° C. was set to a high temperature rising speed of 600 ° C./h or more, and the temperature rising region of 900 to 1360 ° C. was set to a slow temperature rising speed of 300 ° C./h, the temperature was raised to 1360 ° C. The temperature is maintained at 1360 ° C. for 2 hours, and the temperature is reduced from 1360 ° C. to room temperature at a slow rate of 300 ° C./h.

The effects of the manufacturing method of the above-described embodiment will be described with reference to Table 1 and FIGS.

Table 1 shows that the temperature rise range from 400 to 900 ° C. is 150 ° C./h, 300 ° C./h, 600 ° C./h, 1200
It shows the rate of occurrence of internal defects (delamination, cracks, etc.) when the temperature was changed to 2400 ° C / h and 2400 ° C / h.

[0030]

[Table 1]

According to the table, the higher the rate of temperature rise, the smaller the defect occurrence rate, and the rate of occurrence was 0 at 600 ° C./h or more. As a result, it is possible to obtain the laminated ceramic electronic component 1 in which internal defects are less likely to occur.

This can be said from the results shown in FIGS.

FIG. 2 shows that the heating rate is 150 ° C./h, 600 ° C.
It is a graph which shows the volume change rate (volume expansion rate) of the laminated porcelain electronic component in the heating process when it changes into 2400 degreeC / h and 2400 degreeC / h. According to FIG.
It can be seen that in the temperature rise region, the higher the rate of temperature rise, the lower the expansion rate of the laminated ceramic electronic component, and particularly at around 800 ° C., it becomes remarkable. In addition, this 800
The volume expansion in the vicinity is caused by expansion of the palladium used for the internal electrode 3 due to oxidation.

FIG. 3 shows that the heating rate was 150 ° C./h,
It is a graph which shows the weight change rate of the internal electrode 3 in the heating process at the time of changing at 600 degreeC / h and 2400 degreeC / h. According to the figure, in the temperature rise region of 400 to 900 ° C., the rate of weight change due to oxidation of metal palladium decreases as the temperature rise rate increases. In addition, 20
In the temperature range of 0 to 350 ° C., the weight rapidly decreases, but this is due to the decomposition or combustion of organic substances such as solvents and resins in the internal electrodes 3. The slow increase in weight around 600 ° C. is due to the weight increase due to the oxidation of metal palladium, and the rapid decrease near 800 ° C. is the weight decrease due to reduction of the metal palladium.

The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the scope of the invention.
For example, the present invention can be similarly applied to a laminated actuator in which a porcelain layer is made of piezoelectric porcelain, or a laminated thermistor or varistor in which a porcelain layer is made of ZnO or SrTiO ₃ .

[0036]

As described in detail above, according to the present invention, since the heating rate in the heating range of 400 to 900 ° C. in the firing step is set to 600 ° C./h or more, the metal used for the internal electrode Since the oxidation reaction of palladium is suppressed and the volume expansion is reduced, internal defects are less likely to occur. For this reason, the thickness of the ceramic dielectric layer is reduced and the number of internal electrode layers is increased to produce a small and high-capacity laminated ceramic electronic component stably at low cost without deteriorating electrical characteristics. In addition, by increasing the heating rate, the firing time can be shortened, and the production efficiency can be increased. And above 4
In the region before and after the temperature range of 00 to 900 ° C, the normal rise
Since the heating rate is used, there is no difficulty in the firing step. Therefore, it is possible to provide a method of manufacturing a laminated ceramic electronic component capable of efficiently producing a small, high-capacity laminated ceramic electronic component.

[Brief description of the drawings]

FIG. 1 is a perspective view of a laminated ceramic electronic component manufactured by a manufacturing method of the present invention, with a part missing.

FIG. 2 is a graph showing a volume change rate of the laminated ceramic electronic component to show the effect of the method for manufacturing the laminated ceramic electronic component according to the present invention.

FIG. 3 is a graph showing a weight change rate of an internal electrode to show the effect of the method for manufacturing a laminated ceramic electronic component according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 laminated porcelain electronic component 2 porcelain dielectric 3 internal electrode

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Sasaki 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-59-69909 (JP, A) JP-A-3 -142808 (JP, A) JP-A-4-280613 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 4/00-4/40 H01G 13/00-13/06

Claims (1)

(57) [Claims] 1. A method for manufacturing a laminated ceramic electronic component, comprising a step of firing an internal electrode layer made of metallic palladium between porcelain layers, wherein the firing step is performed in a temperature rising region from room temperature to 400 ° C. You
400-900 ° C at a heating rate of 300 ° C / h
The heating rate in the heating area of 600 ° C./h or more ,
The heating rate in the heating range of 900 to 1360 ° C is 3
A method for producing a laminated ceramic electronic component, wherein the temperature is set to 00 ° C./h .