JPH09260202A - Laminated capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated capacitor which is free from inside structural defect. SOLUTION: An inside electrode piece 22b laminated through a dielectric layer 21 is formed by being shifted alternately by a specified distance in its width direction for each specified number of layers. Since the lamination number of the inside electrode piece 22b and the dielectric layer 21 in vertical layer direction can be made uniform, it is possible to reduce a structural defect caused by inner stress generated during conventional manufacturing and to improve a yield even if a miniaturized laminated capacitor is formed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multilayer capacitor.

[0002]

2. Description of the Related Art FIGS. 2 to 4 show a conventional multilayer capacitor. 2 is an exploded perspective view, FIG. 3 is a plan view, and FIG.
3 is a sectional view taken along line AA of FIG.

[0003] In the drawing, reference numeral 10 denotes a multilayer capacitor in which a dielectric body 13 formed by alternately laminating dielectric layers 11 and internal electrodes 12 and internal electrodes are alternately connected in parallel at both ends of the dielectric body 13. And a pair of external electrodes 14.

The internal electrode 12 is composed of an internal electrode piece 12a provided near the central region of the dielectric layer 11 and an internal electrode lead portion 12b provided along the external electrode 14 and connected to the external electrode 14. The internal electrode piece 12a is connected to the external electrode 14 via the internal electrode lead-out portion 12b.

[0005] The dielectric layer 11 is formed of a ceramic sintered body on a rectangular sheet, and the ceramic sintered body is formed of a dielectric ceramic material containing, for example, barium titanate as a main component. The internal electrode 12 is formed of a metal thin film obtained by sintering a metal paste. As the metal paste, for example, an electrode mainly containing a noble metal material such as Pd or Ag-Pd is used. The external electrode 14 is also formed of the same material as the internal electrode 12, and the surface is plated with solder to improve solder wettability.

[0006]

However, when forming a multilayer capacitor, since the internal electrode layers and the dielectric layers are alternately laminated, the portions where the internal electrodes are formed and the internal electrodes are not formed. Since the number of laminated layers is different from that of the portion, stress is generated at the time of pressurization, and the occurrence rate of structural defects (delamination, cracks, etc.) increases. This appears remarkably when manufacturing a small multilayer capacitor, leading to a decrease in yield.

In view of the above problems, it is an object of the present invention to provide a multilayer capacitor having no internal structural defect.

[0008]

In order to achieve the above object, the present invention provides a rectangular parallelepiped shaped element body in which dielectric layers and internal electrode layers are alternately laminated, and the element body. Is a multilayer capacitor composed of a pair of external electrodes in which the internal electrodes formed on the internal electrode layer are alternately connected in parallel at both ends of the internal electrode, the internal electrodes having side edges parallel to the internal electrode surface. We propose a multilayer capacitor formed by displacing in the direction of the part.

According to the multilayer capacitor, each internal electrode connected to the pair of external electrodes is formed by being displaced in the side edge direction parallel to the internal electrode surface.
The number of stacked layers in the upper and lower layers can be made uniform.

A second aspect of the present invention proposes the multilayer capacitor according to the first aspect, wherein the internal electrodes are formed by alternately displacing each of a predetermined number of continuous layers in a side edge direction. .

According to the multilayer capacitor, the internal electrodes are formed by being displaced alternately in the direction of the side edge portion for each of a predetermined number of continuous layers. Can be realized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is an exploded perspective view showing a multilayer capacitor according to an embodiment of the present invention, FIG. 5 is a plan sectional view, and FIG. 6 is a sectional view taken along line BB in FIG. In the figure, reference numeral 20 denotes a multilayer capacitor, which is a dielectric layer 2
Element body 23 formed by alternately laminating 1 and internal electrodes 22;
It is composed of a pair of external electrodes 24 that alternately connect the internal electrodes 22 in parallel at both ends of the element body 23.

The dielectric layer 21 is made of a rectangular sheet-shaped ceramic sintered body, and the sintered body is made of a dielectric ceramic material formed by firing a green sheet containing barium titanate as a main component, for example.

Each of the pair of internal electrodes 22 adjacent to each other through the dielectric layer 21 has an internal electrode lead-out portion 22a provided along the external electrode 24 and the internal electrode lead-out portion 22a.
And an internal electrode piece 22b to which the base end is connected. The internal electrode piece 22b has a rectangular shape, and the long side of the internal electrode piece 22b is substantially perpendicular to the external electrode 24.

The widths of the internal electrode pieces 22b in the internal electrodes 22 are equal to each other.

On the other hand, the internal electrode pieces 22b are formed alternately every two continuous layers with a predetermined distance offset in the width direction. As a result, as shown in FIG.
The density of the parts is changing in stages.

These internal electrodes 22 are made of a metal thin film obtained by sintering a thin film of a conductive paste, and the conductive paste is mainly composed of palladium powder, for example. The external electrode 24 is also formed of the same material as the internal electrode 22, and its surface is plated with solder to improve solder wettability.

This multilayer capacitor was manufactured as follows. First, an organic binder was added to the dielectric raw material powder.
% By weight, and further 50% by weight of water, and these were put into a ball mill and mixed well to prepare a slurry of a dielectric ceramic raw material.

Next, after putting this slurry in a vacuum defoamer to defoam it, put it in a reverse roll coater to form a thin film of this slurry on a polyester film,
This thin film is dried by heating to 100 ° C. on a polyester film, punched out, and 10 cm square, about 2 mm thick.
A green sheet of 0 μm was obtained.

On the other hand, 10 g of palladium powder having an average particle size of 1.5 μm and 0.9 g of ethyl cellulose dissolved in 9.1 g of butyl carbitol were placed in a stirrer.
By stirring for 10 hours, a conductive paste for an internal electrode was obtained.

After that, the above-mentioned internal electrode pattern
Using each of the screens having zero, a pattern of the internal electrode made of the conductive paste was printed on one surface of the green sheet, and dried.

Next, a plurality of green sheets were laminated with the printing surface facing upward, and further, unprinted green sheets were laminated on the upper and lower surfaces of this laminate. Then
This laminate was pressed at a temperature of about 50 ° C. by applying a pressure of about 40 tons in the thickness direction. Thereafter, the laminate was cut into a lattice to obtain about 50 laminated chips.

Next, this laminated chip is placed in a furnace capable of firing in an atmosphere, heated to 600 ° C. in the atmosphere to fire the organic binder, and then the atmosphere of the oven is set to the atmosphere in the atmosphere to heat the laminated chip. The temperature was maintained at 600 ° C. to 1150 ° C. (maximum temperature), which is the firing temperature, for 3 hours. After this, 1
The temperature was lowered to 600 ° C. at a rate of 00 ° C./hr and cooled to room temperature to obtain a sintered body chip.

Next, a conductive paste consisting of silver, glass frit and vehicle is applied to the side surface of the sintered body chip where the internal electrodes are exposed and dried, and this is dried in air at 800 ° C.
Baking at a temperature of 15 minutes to form a silver electrode layer, further depositing copper thereon by electroless plating, and providing a Pb-Sn solder layer thereon by electroplating to form a pair of external electrodes did. As a result, a multilayer capacitor was obtained.

According to the multilayer capacitor having the above-mentioned structure, each of the internal electrode pieces 22b connected to the pair of external electrodes 24 is alternately arranged in the width direction in parallel with the internal electrode surface every two layers. Since it is formed, it is possible to maintain the balance in the width direction and make the number of stacked layers in the upper and lower layers uniform, thereby reducing the occurrence of internal stress. Also, the adhesion is improved. As a result, it is possible to reduce structural defects due to internal stress that have occurred during conventional manufacturing, and it is possible to improve the yield even when a small multilayer capacitor is formed.

These embodiments are merely examples, and the present invention is not limited to these. For example, as shown in FIG. 7, the internal electrodes 22 are gradually shifted in the width direction for each layer,
Almost the same effect can be obtained by repeating this process for each predetermined number of layers.

Further, it is not necessary to set the area of the internal electrode pieces 22b equal over all the layers, and the same effect can be obtained even if they are different.

[0028]

As described above, according to claim 1 of the present invention, each internal electrode connected to the pair of external electrodes is formed by being displaced in the side edge direction parallel to the internal electrode surface. Therefore, the number of stacked layers in the upper and lower layers can be made uniform, and the generation of internal stress can be reduced. Therefore, it is possible to reduce the structural defects due to the internal stress that have occurred during conventional manufacturing. In addition, the yield can be improved even when a small multilayer capacitor is formed.

According to the second aspect, in addition to the above effect, since the internal electrodes are alternately displaced in the direction of the side edge portion for every predetermined number of continuous layers, the direction of the side edge portion is formed. The number of laminated layers can be made uniform while maintaining the above balance, the occurrence of internal stress strain can be reduced, and the occurrence of structural defects such as cracks and delamination can be prevented.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a multilayer capacitor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a conventional multilayer capacitor.

FIG. 3 is a cross-sectional plan view showing a conventional multilayer capacitor.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a plan sectional view showing a multilayer capacitor according to an embodiment of the present invention.

6 is a sectional view taken along the line BB in FIG.

FIG. 7 is a sectional view showing a multilayer capacitor of another embodiment of the present invention.

[Explanation of symbols]

20 ... Multilayer capacitor, 21 ... Dielectric layer, 22 ... Internal electrode, 22a ... Internal electrode lead-out part, 22b ... Internal electrode piece, 2
3 ... Element body, 24 ... External electrodes.

Claims (2)

[Claims] 1. A rectangular parallelepiped element body in which dielectric layers and internal electrode layers are alternately laminated, and internal electrodes formed on the internal electrode layers at both ends of the element body are alternately connected in parallel. A multilayer capacitor comprising a pair of external electrodes, wherein the internal electrode is formed by being displaced in a side edge direction parallel to the internal electrode surface. 2. The multilayer capacitor according to claim 1, wherein the internal electrodes are formed by alternately displacing each of a predetermined number of continuous layers in a side edge direction.