JPH10163061A - Manufacture of layered capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the defective occurrence rate by pressing ceramic green sheets in their thickness direction before pressing a laminate in its laminating direction. SOLUTION: Ceramic green sheets B1 are each formed by screenprinting many first-pole inner electrodes A1 on the surface and ceramic green sheets B2 are each formed by screen-printing many second-pole inner electrodes 3A on the surface. The green sheets B1, B2 are pressed one by one in the thickness direction, using a lower and upper press dies F1, F2, and alternately laminated with a ceramic green sheet B3 laminated on the surface thereof to form a laminate D. The laminate D is pressed in the laminating direction by press dies E1, E2 to integrate the sheets B1, B2, B3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION As shown in FIGS. 1 to 3, in the present invention, a plurality of first ceramic sheets A2 in which one internal electrode A1 is formed and another internal electrode A3 are formed. After laminating a plurality of second ceramic sheets A4 such that the internal electrodes A1 and A3 alternately overlap with each other, they are integrated into one chip body A5, and both left and right end faces A5 ', A5 "of the chip body A5. A terminal electrode A6 electrically connected to each of the internal electrodes A1 in each of the first ceramic sheets A2.
And a terminal electrode A7 electrically connected to each of the internal electrodes A3 of the second ceramic sheet A4 on the other end face A5 ″. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, when manufacturing this type of multilayer capacitor A, for example, it is described in Japanese Patent Application Laid-Open Nos. 61-144811 and 1-312817, and as shown in FIG. , On the surface of the one-sided internal electrode A
A plurality of first ceramic green sheets B1 formed by screen printing a plurality of the first ceramic green sheets B2, and a plurality of second ceramic green sheets B2 formed by screen printing a plurality of the internal electrodes A3 of the other electrode. Are alternately overlapped, and further, a ceramic green sheet B3 for a cover is overlapped on the surface to form a laminate D as shown in FIGS.

Next, the laminate D is pressed in the laminating direction by a lower pressing die E1 and an upper pressing die E2, so that each of the ceramic green sheets B1, B is pressed.
As shown in FIG. 7, each of the internal electrodes A1 and A3 formed on the surface of each of the ceramic green sheets B1, B2, and B3 is embedded in the thickness of each of the ceramic green sheets B1, B2, and B3. Become

The laminate D is cut into a large number of chips A5 along a cutting line D1 in a vertical direction and a cutting line D2 in a horizontal direction. After the firing step, the left and right end faces A
The process is shifted to the step of forming the terminal electrodes A6 and A7 on 5 'and A5 ", respectively, so that the multilayer capacitor A as shown in FIGS. 1 to 3 is completed.

[0005]

As described above, a laminate D in which a plurality of first ceramic green sheets B1, a plurality of second ceramic green sheets B2, and a cover ceramic green sheet B3 are superimposed as described above.
Are pressed in the laminating direction by the two pressing dies E1 and E2 so that the ceramic green sheets B1, B2 and B3 are raised on the surfaces thereof as shown in FIG. Each of the formed internal electrodes A1, A3 is formed of a ceramic green sheet B1, B
In this state, they are integrated so as to be in close contact with each other while being embedded within the thickness of B2 and B3.

[0006] However, the compressive force at the time of pressing in the laminating direction is first of all the ceramic green sheets B1,
B2 and B3 act only on the portion where the internal electrodes A1 and A3 overlap, and each ceramic green sheet B1 and B3
2 and B3, it does not act on the portions where the internal electrodes A1 and A3 do not overlap, so that the portions of the ceramic green sheets B1, B2 and B3 where the internal electrodes A1 and A3 overlap are within the thickness thereof. Internal electrodes A1, A3
As it sinks in, it extends and deforms in the lateral direction so that the thickness at the portion becomes thinner.

The laterally extending deformation is caused by the pressing dies E of the ceramic green sheets B1, B2 and B3.
1 and E2, and those far from both press dies E1 and E2 are considerably different. In other words,
Since the laterally extending deformation is considerably large and irregular in each of the ceramic green sheets B1, B2, and B3, the internal electrodes A overlapping with each other are overlapped with each other.
1, A3 will be relatively displaced from each other.

As a result, the overlapping area of each of the internal electrodes A1 and A3 changes, and each of the internal electrodes A1 and A3 shifts with respect to the predetermined cutting lines D1 and D2. There is a problem that a large number of defective products are generated such as the capacitance is out of a predetermined allowable range or the internal electrodes A1 and A3 are exposed on the left and right side surfaces A8 and the like of the chip body A5. .

It is a technical object of the present invention to solve this problem and to provide a manufacturing method capable of surely reducing the incidence of defective products.

[0010]

In order to achieve this technical object, the present invention relates to a process for superposing a plurality of ceramic green sheets having a plurality of internal electrodes formed on a surface thereof, And pressing them in the stacking direction to integrate them, cutting the integrated laminate into a large number of chip bodies and firing them, and forming terminal electrodes on both right and left end surfaces of each of the chip bodies. And a step of pressing each of the ceramic green sheets in the thickness direction thereof in advance before pressing the ceramic green sheets in the stacking direction of the multilayer body. It is.

[0011]

As described above, by pressing each ceramic green sheet in its thickness direction, each of the internal electrodes formed so as to swell on the surface of each ceramic green sheet can be entirely or completely removed. Most of the ceramic green sheets can be immersed in the thickness of the ceramic green sheets, and at the same time, the laterally extending deformation occurring at this time can be made substantially constant for each of the ceramic green sheets. By pressing in the stacking direction a laminated body in which a plurality of ceramic green sheets each of which has been pressed are stacked in the laminating direction, the gap generated between the internal electrodes of each ceramic green sheet when integrated is greatly reduced. It can be reduced or almost eliminated.

That is, according to the present invention, when manufacturing a multilayer capacitor, a defective capacitor whose capacitance is out of a predetermined allowable range or whose internal electrodes are exposed on the left and right sides of the chip body, and the like. Is generated, that is, the generation rate of defective products can be significantly reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG. 8 and FIG. 9, a plurality of first ceramic green sheets B1 in which a large number of unipolar internal electrodes A1 are formed by screen printing on the surface, and similarly, the other electrode A plurality of second ceramic green sheets B2 in which a large number of the internal electrodes A3 are formed by screen printing are formed into a lower press mold F1;
The upper press die F2 is pressed one by one in the thickness direction.

By this pressing, all or most of the internal electrodes A1 and A3 formed so as to swell on the surface of each of the ceramic green sheets B1 and B2 are set within the thickness of each of the ceramic green sheets B1 and B2. Can be inserted. This pressing may be performed by feeding each of the ceramic green sheets B1 and B2 one by one between a pair of press rollers.

When the pressing of each of the ceramic green sheets B1 and B2 is completed in this manner, as shown in FIG. 10, a plurality of the first ceramic green sheets B1 and the second ceramic A plurality of green sheets B2 are alternately overlapped, and furthermore,
On its surface, ceramic green sheet B3 for cover
Are laminated to form a laminate D.

Then, this laminate D is, as in the prior art,
The ceramic green sheets B1, B2, and B3 are integrated by pressing the lower press die E1 and the upper press die E2 in the stacking direction. At the time of pressing the laminate D, each of the ceramic green sheets B1 and B2 constituting the laminate D is pressed in advance, thereby causing the ceramic green sheets B1 and B2 to expand and deform in the lateral direction. It can be stopped slightly.

As a result, when the laminated body D is pressed and integrated in the laminating direction, the internal electrodes A1, A3 in each of the ceramic green sheets B1, B2 are integrated.
However, the overlapping area shifts to increase or decrease,
In addition, deviation from the predetermined cutting lines D1 and D2 can be reliably reduced. After that,
As in the prior art, the laminate D is cut into a large number of chips A5 along the cutting lines D1 and D2, fired at a high temperature in a firing furnace, and then left and right end surfaces A5 ', A
By forming terminal electrodes A6 and A7 on each of the 5 ″, a multilayer capacitor A as shown in FIGS. 1 to 3 is completed.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional front view of a multilayer capacitor.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 is a perspective view showing a ceramic green sheet.

FIG. 5 is a perspective view showing a state in which a laminate of ceramic green sheets is being pressed.

FIG. 6 is an enlarged sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is an enlarged sectional view showing a state where the laminate is pressed in a conventional method.

FIG. 8 is a perspective view showing a state where a ceramic green sheet is being pressed in the method of the present invention.

FIG. 9 is an enlarged cross-sectional view taken along the line IX-IX of FIG.

FIG. 10 is an enlarged sectional view showing a state in which a laminate is pressed in the method of the present invention.

[Explanation of symbols]

A Multilayer capacitor A1, A3 Internal electrode A2, A4 Ceramic sheet A5 Chip body A5 ', A5 ″ End face of chip body A6, A7 Terminal electrode B1, B2, B3 Ceramic green sheet D Laminate D1, D2 Cutting line E1, E2 Press mold for laminated body F1, F2 Press mold for ceramic green sheet

Claims (1)

[Claims] A step of laminating a plurality of ceramic green sheets having a large number of internal electrodes formed on the surface thereof; a step of pressing the laminated body in a laminating direction to integrate the laminated body; A method for manufacturing a multilayer capacitor, comprising: a step of cutting the formed multilayer body into a large number of chip bodies, followed by firing; and a step of forming terminal electrodes on both right and left end surfaces of each of the chip bodies. A method for manufacturing a multilayer capacitor, comprising: pressing each of the ceramic green sheets in the thickness direction thereof before pressing in the direction.