JPS58165312A - Method of producing laminated 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 for manufacturing a laminated ceramic capacitor, and more particularly, to a method for manufacturing a pressed ceramic unfired laminated body. .

Conventionally, the method for manufacturing a green pressed laminated body for a laminated ceramic capacitor is to place a dummy layer of ceramic green sheets on top of a gold plate with approximately the same dimensions as the punched ceramic green sheets.

), the required number of ceramic clean sheets with an internal electrode pattern in the middle are laminated on the squares that serve as opposing electrodes, and after applying pressure, the laminated body made of gold inside is machined through upper and lower movable bunches. It is common to apply pressure to form a laminated press-bonded body, and in many cases heat is applied at the same time as pressurization to improve the pressability. Next, the pressed laminated body is cut into a predetermined shape, and subjected to firing and external electrode baking to obtain a laminated ceric condenser.

Ceramic green sheets are usually made of ceramic powder bound with a fat component, and contain several weight particles.
Contains a binder, and the ceramic clean sheet itself has no air permeability. Therefore, gold! When setting up the inward Z-tsuku green sheets, there is air between each laminated sheet)k! When laminated in the IN state, air may remain in the sheet gap inside the crimped body even during the next internal processing of the laminate crimped body 11&C by heating and pressurizing. Such residual air may cause partial crimping failure (delamination) inside the laminated crimped body, and cracks will appear after firing, eventually causing damage to the laminated ceramic capacitor. This had the disadvantage that it resulted in defective products during the inspection process, lowering manufacturing yield and reliability.

Furthermore, the increase in the number of laminated layers due to the increase in the inner diameter of green sheets and molds due to the reduction in manufacturing costs, as well as the demand for large capacity quick capacitors on lamination, has resulted in the gap between green sheets being increased in the above-mentioned lamination process. It is inevitable that the probability that air remaining in the laminate will remain inside the laminate is increased, resulting in a reduction in manufacturing yield and reliability due to delamination fields.

The present invention provides a method for manufacturing a multilayer ceramic capacitor with good manufacturing yield and reliability by eliminating delamination caused by residual air inside the laminated crimped body.

In the present invention, first, a required number of ceramic green sheets and ceramic green sheets having internal electrode patterns are layered in a mold, and then the entire mold is placed in a vacuum container and kept in a reduced pressure state for a certain period of time. . Here, the reduced pressure state is a high vacuum, so it is effective in removing residual air.
101 intestine H# or less O vacuum degree is poor. Further, since the longer the retention time is, the more effective it is, it is desirable to set it to sO minutes or more. Next, in a reduced pressure atmosphere, mechanical pressure is applied to the laminate through the vertically movable punch of the mold to produce a laminate crimped body. 450 (− range means good crimpability,
Also, when heating 2Ill to the same w# as pressurizing, it is 69.8 as it is affected by the type and amount of organic substances in the green sheet.
A temperature of about 0°C to 120°C is effective for pressure bonding properties. In addition, if air is prevented from entering the gap between the stacked green sheets by passing through a machine that returns from a reduced pressure atmosphere to a normal pressure atmosphere, even if mechanical pressure is applied after returning to a normal pressure atmosphere, it will be the same as in a reduced pressure atmosphere. The effect of this can be obtained.

Hereinafter, the actual results will be explained using examples.

Fb (Fe-(1) (Pb
Fang Nbchi) Egg! The essence having the composition of
A ceramic green sheet with a thickness of SOIkxm was prepared.

The slurry and green sheet compositions are shown in Table IIII.

1st-! R Next, several internal electrode patterns were formed by screen-imprinting an electrode paste containing 15% palladium and the rest silver as metal components on a green sheet punched to a size of 120mm x 150mm. did. The stacking inside the mold consisted of 10 upper and lower ceramic green sheets and 51 ceramic green sheets having an internal electrode pattern in the middle. FIG. 1 schematically shows a reduced pressure atmosphere and mechanical pressurization device according to the present invention. - The equipment can be broadly divided into vacuum systems and mechanical pressure systems, and commercially available products are available for each.

In Fig. 1, a gold layer die f laminated with ceramic green sheets is placed in a vacuum valley device a installed on a support stand.
7 tons and exhaust through the pulp above the volume Da.
After holding the SO for a minute at a vacuum level of ×10″-Ht, the entire mold was heated to 120°C for 2IEI using a heater below the gold layer, and a mechanical pressure of 2504/csl per unit area was applied to the pressure support stand dK. The ram of the press towards the upper punch @c
K'4i lower bunch
In addition, by holding for 50 minutes], a laminated and pressed body was obtained.

Next, in the cutting process, one set of laminated crimped bodies was divided into 40 parts, and the unfired laminated bodies were cut into 5 pieces (as condensers) and placed in the atmosphere.
C. for 5 hours, and the external electrodes were baked to form a laminated ceramic condenser. The 1m area of this inner mold is 14 x &4am, and the number of layers is 50.)The calculated design evaluation value is #J70μF.

According to the original @ - In comparison with Doubunki, Tsumugi 11vII 2111 manufactured by the conventional method is shown. Manufacturing quantity varies at each level.

10 sets of laminated crimped bodies, laminated ceramic condenser
The number is 400.

#I2 It is clear from Table 1 that according to the aluminum/dispensing method of the present invention, there is no occurrence of defects due to redelamining errors or cracks in the cutting process or firing process), and the number of characteristic defects in the end-of-life process mK. It also decreased. This clearly indicates that the defects that occur due to the removal of air to the outside of the laminate due to the reduced pressure atmosphere are thought to be caused by minute defects inside the ceramic green sheets. The rate is.

It is equivalent to the conventional method.

As described above, according to the manufacturing method according to the present invention, delamination and cracks caused by residual air inside the laminated crimped body can be eliminated, and the manufacturing yield and reliability are improved. It has the effect of providing the following benefits.

[Brief explanation of the drawing]

Figure 1 schematically shows the reduced pressure atmosphere and mechanical pressurization device used in the manufacturing method according to the present invention. 1'・a is the vacuum container, y is the entire support base, and C is 1! I: The ram of the machine, d: pressure support, e: punch above the mold, f: die, g: punch below the mold, h: laminate.

Claims (1)

[Claims] (υ Ceramic green sheets and a laminate of ceramic green sheets having internal electrode patterns are placed in a reduced pressure atmosphere for a certain period of time, and then the laminate is placed in a reduced pressure atmosphere or at normal pressure.
1. A method for manufacturing a laminated ceramic capacitor, which comprises mechanically pressurizing a laminated body in air.