JPS6089913A - Method of producing ceramic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a ceramic capacitor.

As shown in Figure 1, a single-plate ceramic capacitor has a structure in which electrodes 2 are provided on both sides of a dielectric 1 made of ceramic, and lead wires 3 and 4 are connected to both electrodes 2. Since there is a trend toward miniaturization in the various electronic devices used, the current situation is that ceramic capacitors that are small in size and have a large capacity are required.

Conventional method for manufacturing single-plate ceramic capacitors 1- In Toshiba, ceramic powder is pressed and sintered to form a dielectric, and then an electrode film is formed on the outer surface of the dielectric by electroless plating. After that, a part of the electrode film is removed,
Methods that have been adopted include forming a counter electrode with a ceramic dielectric in between, and printing and applying metal paint on both sides of a sintered ceramic dielectric produced in the same manner as above, followed by firing. .

By the way, in any of the above conventional manufacturing methods, ceramic powder is press-molded and then sintered to form a ceramic dielectric, so if you try to make the dielectric thinner and increase the capacitance, There is a problem in that damage such as cracking and chipping is likely to occur during the molding process.

For this reason, even though the voltage resistance and other characteristics are excessive compared to the desired characteristics, it is necessary to use an excessively thick dielectric material, which cannot meet the demand for miniaturization. be.

In addition, both methods require the ceramic powder to be individually pressure-molded and the electrodes provided on the dielectric to be heat-treated or separately fired, resulting in a large number of manufacturing steps and high production costs. be. Furthermore, when electrodes are formed by printing or coating, if the dielectric is thin, cracks will occur during coating, so there is a limit to how thin the dielectric can be made beyond a certain thickness.

This invention was made to solve the above-mentioned problems. It eliminates the occurrence of cracks and chips during the molding process of ceramic dielectrics, makes the dielectric thinner, increases capacitance, and makes it easier to mass produce. The purpose of the present invention is to provide a method of manufacturing a ceramic capacitor that enables the following.

The structure of this invention is to create a green ceramic sheet using a slurry of powdered ceramic mixed with a binder, provide electrodes on both sides of this sheet, and then sinter the sheet and fire the electrodes at the same time to form a ceramic dielectric. This allows the thickness to be reduced.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 7 of the accompanying drawings.
This will be explained based on the diagram.

In the method of the present invention, a ceramic raw sheath 11 of a desired shape is created using a slurry formed by mixing powdered ceramic with organic powder, etc., and electrodes 12 are placed at corresponding positions on both sides of the raw ceramic sheath 1-11. After providing the electrodes 12 and 13, the sintering of the green sheets 1 to 11 and the firing of the electrodes 12 and 13 are performed simultaneously.

The green ceramic sheet 11 using the slurry can be easily formed by a doctor blade method, a pulling method, an extrusion method, a printing method, etc., and since the obtained ceramic green sheet 11 is highly flexible, it can be used as an electrode 12.13. It is possible to almost completely eliminate the occurrence of damage such as cracking or chipping during handling during the application process.

Further, since the raw ceramic sheet 11 is highly flexible and has excellent strength, its thickness can be reduced. For example, the thickness during molding can be freely selected from 25 to 300μ,
The thickness of the green sheet 11 becomes 15 to 200 μm in the ceramic dielectric body 14 after sintering.

Further, the electrodes 12 and 13 provided on both sides of the raw ceramic sheet 11 can be formed, for example, by screen printing or spraying.

Sintering of the ceramic green sheets 1 to 11 and electrodes 12.13
In order to perform the firing of the electrodes 12 and 13 at the same time, the metal used for the electrodes 12 and 13 needs to be one with a high point or a metal with poor reactivity depending on the sintering temperature of the raw ceramic sheet 11.

For example, since the sintering temperature of the raw ceramic sheet 11 is high, a metal material for the electrode corresponding to this is Pt.
, Au, 'Pd and their alloys, ~-Pd
An alloy with a ratio of ~30% or less, or nickel, etc. must be used, and the film thickness of the electrodes 12 and 13 is 0.
8 to 3.0μ is appropriate. □The example shown in the figure shows the case where a large number of capacitors are manufactured simultaneously using one wide and long raw ceramic sheet.The first example shown in Figures 2 to 4 is a circular ceramic sheet. A ceramic capacitor is shown, and the second example in FIGS. 5 to 7 shows a rectangular ceramic capacitor.

In order to manufacture a large number of capacitors from one raw ceramic sheet 11, a large number of electrodes 12 are formed on both sides of the raw ceramic sheet 11.
and 13 are formed so as to correspond to each other on both sides with a predetermined spacing.

The electrodes 12.13 are formed in a circular pattern in the first example and in a rectangular pattern in the second example, and the electrodes 12.13 are formed on both sides.
13 so that there is no problem even if there is a misalignment when forming -
The electrode 13 on the other side is formed slightly larger than the electrode 12 on the side.

Ceramic raw sheet 1 with electrodes 12 and 13 formed on both sides
1 is then punched out into a circular or square shape for each electrode 12, 13 by a punching or cutting method to form a single-plate capacitor material as shown in FIGS. 4 and 7.

By heating the punched single plate capacitor material in an atmosphere and temperature depending on the ceramic raw material composition and the electrode composition, if the raw ceramic sheet 11 and the electrodes 12 and 13 are simultaneously sintered, both sides of the shellac dielectric material are heated. A capacitor element having electrodes is obtained.

This capacitor element already has the performance as a capacitor, so by soldering lead wires to the electrodes 12 and 13 on both sides and applying no insulation coating, a single-plate ceramic capacitor with lead wires can be created. Ru.

As described above, according to the present invention, since the configuration is as described above, there are the following effects.

(1) Since the dielectric of the ceramic capacitor is formed from ceramic raw sheets 1 to 1, the raw sheets are highly flexible and have excellent strength, and even with a thin wall thickness, there are fewer cracks or chips during handling, improving yields. do.

(2) By using green sheets, the thickness of the dielectric material can be reduced, making it possible to manufacture small ceramic capacitors with large capacitance.

(3) By using raw sheets, the shape of the capacitor can be freely selected.

(71) Since sintering of the ceramic dielectric and firing of the electrode are performed at the same time, manufacturing efficiency is improved by reducing the number of steps.

(5) Since a large number of capacitors can be manufactured simultaneously from a single raw seal, mass production is possible and product costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the basic structure of a ceramic capacitor, Fig. 2 is a plan view of a raw seam 1~ showing the first example of the present invention, Fig. 3 is a back view of the same, and Fig. 4 is a top view of the same. A perspective view of a capacitor element that has been punched out, FIG. 5 is a plan view of the raw sheet 1 without showing the second example, FIG. 6 is a back view of the same, and FIG. 7 is a perspective view of a capacitor element punched out from the same above. It is a diagram. 11...Ceramic green sheet 12.13...Electrode 14...Dielectric patent applicant Mura January Manufacturing Co., Ltd. Agent Patent attorney Kazu 1) 1986 UN'' 1 Figure 5 Figure 6

Claims (1)

[Claims] A ceramic characterized in that a raw sheet is prepared from a slurry made of powdered ceramic mixed with a binder, electrodes are provided at corresponding positions on both sides of the raw sheet, and then sintering into the raw sheet 1 and firing of the electrodes are performed simultaneously. Method of manufacturing capacitors.