JPH05175072A - Manufacture of laminated ceramic capacitor - Google Patents

Abstract

PURPOSE:To unite a plurality of internal electrodes and ceramic green sheets per plane by a method wherein, when a laminated body composed of the plurality of internal electrodes and ceramic green sheets is pressurized, the laminated body is pressurized without stretching the laminated body in the manufacturing method of a laminated ceramic capacitor which is used for various electronic apparatuses. CONSTITUTION:When a ceramic laminated body is compression-bonded, its peripheral part 12 where an internal electrode does not exist is pressurized and, after that, its central part 13 where the internal electrode exists is pressurized. In addition, a metal mold used for a pressurization operation is formed as a recessed-face metal mold 16 wherein its peripheral part 16a is high and its central part 16b is a low recessed face.

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 monolithic ceramic capacitor which is a kind of electronic component used in various electronic devices.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become lighter, thinner, shorter and smaller, electronic parts have been made into chips, and the demand for monolithic ceramic capacitors is also increasing.

The structure of a general monolithic ceramic capacitor will be described below. FIG. 4 is a perspective view showing a part of the monolithic ceramic capacitor in section. In FIG. 4, reference numeral 1 is a ceramic dielectric layer, 2 is an internal electrode, and the internal electrode 2 and the ceramic dielectric layer 1 are alternately laminated so that the internal electrodes 2 face each other with the ceramic dielectric layer 1 in between. Has been done. 3 is a terminal electrode, which is the internal electrode 2
Are respectively connected to the terminal electrodes 3.

A conventional method for manufacturing a monolithic ceramic capacitor will be described below. First, a ceramic green sheet having a thickness of 30 to 100 μm is produced by a molding method such as a doctor blade method using a slurry containing an organic binder, a plasticizer, a solvent, and the like as a barium titanate-based mixed raw material.

Next, as shown in FIG. 5, screen-printing or the like is performed on the ceramic green sheet 4 by using an electrode paste containing a noble metal such as palladium or platinum as a main component to form a checkered checkered strip inside. The electrode 2 is formed. Here, in FIG. 5, 5 is a peripheral portion where the internal electrode 2 is not present, and 6 is a central portion where the internal electrode 2 is present.

Next, the ceramic green sheet 4 on which the internal electrodes 2 are formed has the internal electrodes 2 formed on the ceramic dielectric layer 1.
Lamination is repeated up to a desired number of laminations so as to alternately face each other with sandwiching therebetween to form a ceramic laminated body.

Next, as shown in FIG. 6, the mold 7 is provided over the entire ceramic laminated body without distinguishing between the peripheral portion 5 where the internal electrode 2 does not exist and the central portion 6 where the internal electrode 2 exists. With this, pressure is applied at a predetermined pressure in the stacking direction at one time to perform pressure bonding.

Next, the pressure-bonded ceramic laminated body is cut into a predetermined size so as to form individual monolithic ceramic capacitor elements in which the internal electrodes 2 are alternately exposed at opposite end faces.

Finally, individual monolithic ceramic capacitor elements were fired at a temperature of 1200 to 1400 ° C., and terminal electrodes 3 were attached to both ends to produce a monolithic ceramic capacitor.

[0010]

However, in the above-mentioned conventional manufacturing method, when the ceramic laminate is pressed under a predetermined pressure to be pressure-bonded, the entire ceramic laminate is predetermined in the stacking direction at once by the die. Since the pressure is applied with pressure and pressure bonding is applied, the pressure-bonded ceramic laminated body expands in the direction of each end face, and when cut into individual pieces, the dimensional variation of the laminated ceramic capacitor element becomes large. ,
There is a problem in that the cutting position shifts when cutting to a predetermined size.

The present invention solves the above-mentioned problems of the prior art, and provides a monolithic ceramic capacitor which can be pressed and crimped without expansion of the ceramic laminate, has improved cutting yield and is excellent in dimensional accuracy. With the goal.

[0012]

In order to achieve this object, a method for manufacturing a monolithic ceramic capacitor according to the present invention comprises first pressing a peripheral portion where internal electrodes are not present and then applying a central portion where internal electrodes are present. It is something to press.

Further, when pressure-bonding, the die for pressing the ceramic laminated body is a concave die having a concave surface having a high peripheral portion and a low central portion to press the ceramic laminated body.

[0014]

According to the method of manufacturing a laminated ceramic capacitor of the present invention, the peripheral portion of the laminated body of the internal electrode and the ceramic green sheet where the internal electrode does not exist is first pressed, so that the portion is pressure-bonded and fixed. When the central portion where the internal electrode is present is pressed, the peripheral portion acts as a frame for suppressing the lateral extension, so that the central portion can be pressure-bonded without the lateral extension. Become.

Further, by using a concave mold having a concave surface having a high peripheral portion and a low central portion, the mold for pressurizing and integrating the laminated body of the internal electrodes and the ceramic green sheet is used. The peripheral portion of the laminated body of the internal electrode and the ceramic green sheet presses the peripheral portion where the internal electrode does not exist, and the central portion adds the central portion of the laminated body of the internal electrode and the ceramic green sheet where the internal electrode exists. Since the pressure is applied, the peripheral portion where the internal electrode is not present is more firmly pressure-bonded and fixed than the central portion where the internal electrode is present, and the peripheral portion acts as a frame for suppressing the lateral extension of the central portion. Further, since the central portion is prevented from extending in the lateral direction even by the mold, it is possible to perform pressure bonding without causing lateral extension in the central portion.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 (a) and 1 (b) are manufacturing process diagrams for press-bonding a ceramic laminate in a manufacturing method according to a first embodiment of the present invention. Figure 1
In (a) and (b), 11 is a ceramic laminate formed by sequentially laminating ceramic green sheets having internal electrodes so that the internal electrodes are alternately opposed to each other with a ceramic dielectric layer interposed therebetween, and 12 is an internal electrode. Is a peripheral portion where 13 is not present, 13 is a central portion where internal electrodes are present, and 14 and 15 are a peripheral die and a central die for pressing the peripheral portion 12 and the central portion 13 of the ceramic laminate 11, respectively.

The method of manufacturing the monolithic ceramic capacitor according to the present invention will be described below with reference to FIG. Here, detailed description of steps similar to those of the conventional technique will be omitted.

First, a barium titanate-based mixed raw material is added.
Using a slurry consisting of an organic binder, plasticizer, solvent, etc., a thickness of 50μ can be obtained by a molding method such as a doctor blade method.
A ceramic green sheet of m is produced, and one side is 200
Cut into mm squares.

Next, as shown in FIG. 5, an internal electrode 2 is formed on the central portion 6 of the ceramic green sheet 4 by screen printing or the like using an electrode paste containing a noble metal such as palladium or platinum as a main component. At this time, the ceramic green sheet 4 is provided with a peripheral portion 5 having a width of 10 mm from the end and having no internal electrode 2.

Next, the ceramic green sheets having the internal electrodes are sequentially laminated so that the internal electrodes are alternately opposed to each other with the ceramic dielectric layer sandwiched therebetween, and the ceramic laminated body 11 is formed.
To form.

Next, as shown in FIG. 1A, the peripheral portion 12 of the ceramic laminate 11 where the internal electrodes are not present is
Pressure is applied by the peripheral mold 14 from the stacking direction. afterwards,
As shown in FIG. 1B, the central portion 13 where the internal electrodes are present is pressed by the central die 15.

After the ceramic laminated body 11 is pressed and pressure-bonded in this manner, it is cut into individual elements and terminal electrodes are formed in the same manner as in the prior art to form a laminated ceramic capacitor.

(Embodiment 2) FIGS. 2 (a) and 2 (b) show a second embodiment of the present invention. In FIG. 2, the same parts as those shown in FIG. However, the description of the same steps in the manufacturing method is omitted.

In the manufacturing method of this embodiment, first, the peripheral portion 12 where the internal electrodes are not present is pressed by the peripheral die 14, and then the central portion 13 where the internal electrodes are present is applied to the central die 15.
2B, while pressing the peripheral portion 12 where the internal electrode does not exist by the peripheral die 14, the central portion 13 where the internal electrode exists is pressed by the central die 15 as shown in FIG. 2B. It is to pressurize.

Here, as shown in FIG. 6, a conventional one and a conventional one in which the whole ceramic laminated body is pressed and pressure-bonded at a predetermined pressure in the laminating direction at a time by the mold 7,
Regarding the product of the present invention according to (1), the elongation width of the ceramic laminate and the pressurizing condition are shown in comparison with (Table 1). In this (Table 1), the elongation width of the ceramic laminate was measured by measuring the dimensions of a, b, c, d, e, and f shown in FIG.
The difference is shown. In addition, Sample 1 is prepared by the conventional example, and Samples 2 and 5 are prepared by Examples 1 and 2, respectively. In addition, Samples 3 and 4 are the same as in Example 1 except that the pressure applied is changed, and Samples 6 and 7 are similar to those in Example 2 where the pressure applied is different.

[0027]

[Table 1]

As is clear from this (Table 1), in Samples 2, 3, 5 and 6 according to the present invention, the extension width before and after the pressing of the laminated body of the internal electrodes and the ceramic green sheet was very small. There is.

The peripheral mold 14 and the central mold 1
The pressurizing pressure of 5 depends on the desired characteristics of the monolithic ceramic capacitor.

(Embodiment 3) FIG. 3 shows a third embodiment of the present invention. In FIG. 3, the same parts as those shown in FIG. The description of the step is omitted.

In this embodiment, as shown in FIG. 3, by using a concave metal mold 16 having a concave surface having a high peripheral portion 16a and a low central portion 16b, the peripheral portion 12 where the internal electrode does not exist and the internal electrode exist. The center portion 13 to be pressed is not distinguished, and is pressed and pressed by a predetermined pressure in the stacking direction.

Here, the extension width before and after the pressing and the height difference between the peripheral portion and the central portion of the die were examined for the ceramic laminate pressed by the conventional die and the concave die 16 of this embodiment. .. The results are shown in (Table 2).

[0033]

[Table 2]

As is clear from this (Table 2), the use of the concave mold 16 which provides a height difference between the peripheral portion and the central portion of the mold makes it possible to obtain a monolithic ceramic having a small expansion width when the ceramic laminate is pressure-bonded. Capacitor can be provided. Also,
The height difference between the peripheral portion 16a and the central portion 16b of the concave mold 16 is ½ of the thickness of the laminated body, so that a monolithic ceramic capacitor having a smaller stretch width can be provided.

[0035]

As described above, according to the method of manufacturing a monolithic ceramic capacitor of the present invention, when the ceramic laminate is pressure-bonded, the peripheral portions where the internal electrodes are not present are pressurized, and then the internal electrodes are present. By pressing the central part and pressing the ceramic laminated body using a concave mold with a high peripheral part and a low central part, the laminated structure of the internal electrodes and the ceramic green sheet can be pressed without stretching. -It can be crimped, which improves the cutting yield and realizes a monolithic ceramic capacitor with excellent dimensional accuracy.

[Brief description of drawings]

1A and 1B are cross-sectional views showing a pressure bonding step of a ceramic laminated body in a method for manufacturing a laminated ceramic capacitor according to a first embodiment of the present invention.

2 (a) and 2 (b) are cross-sectional views showing a pressure-bonding step of a ceramic laminate in the second embodiment of the present invention.

FIG. 3 is a sectional view showing a pressure-bonding process of a ceramic laminate in a third embodiment of the present invention.

FIG. 4 is a perspective view showing a part of a general monolithic ceramic capacitor in section.

FIG. 5 is a schematic view showing a ceramic green sheet on which internal electrodes are printed in the same capacitor.

FIG. 6 is a sectional view showing a pressure-bonding process of a ceramic laminate according to a conventional example.

[Explanation of symbols]

 11 Ceramic Laminated Body 12 Peripheral Part 13 Central Part 14 Peripheral Part Mold 15 Central Part Mold

Claims (5)

[Claims] 1. When pressure-bonding a ceramic laminated body in which ceramic green sheets and internal electrodes are alternately laminated, first, a peripheral portion where internal electrodes do not exist is pressed, and then a central portion where internal electrodes exist is pressed. A method for manufacturing a monolithic ceramic capacitor, which comprises crimping. 2. When pressure-bonding a ceramic laminated body in which ceramic green sheets and internal electrodes are alternately laminated, first, a peripheral portion where no internal electrode is present is pressed, and then the peripheral portion is pressed, while A method for manufacturing a monolithic ceramic capacitor, characterized in that the existing central portion is pressed and pressure-bonded. 3. The method for producing a monolithic ceramic capacitor according to claim 1, wherein the peripheral portion where the internal electrode does not exist is pressed at a pressure higher than the pressure for pressing the central portion where the internal electrode exists. 4. When pressure bonding a ceramic laminate in which ceramic green sheets and internal electrodes are alternately laminated, the ceramic laminate is pressed and pressure-bonded by a concave mold having a concave surface having a high peripheral portion and a low central portion. A method for manufacturing a monolithic ceramic capacitor, comprising: 5. The method for producing a monolithic ceramic capacitor according to claim 4, wherein in the concave die, the height difference between the peripheral portion and the central portion of the die is 1/2 or less of the thickness of the ceramic laminated body.