JPS6054105A - Conductive paste - 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 Field of Industrial Application The present invention relates to a conductive paste used as an internal electrode in a multilayer ceramic capacitor.

Conventional configurations and their problems Recently, as electronic components have become smaller and thinner, electronic devices equipped with these electronic components have also become smaller and thinner, whether for industrial use or general consumer use. This trend is moving in the direction of J [next], and this trend is also demanding further miniaturization and greater integration of electronic components. In capacitor parts, which are an important element in electronic components, ceramic capacitors with relatively small capacitance have shifted from conventional disk-type capacitors to chip capacitors, which can increase capacitance and be smaller by stacking them. Demand is rapidly expanding. However, even the above chip capacitor is a single discrete component, and when configured as one electronic component with other electronic components, there is a limit to the integration density of the electronic components. Therefore, recently, capacitor blocks that are a single capacitor chip but each have a plurality of different capacitance values have become a hot topic. However, in this case, it is necessary to configure one circuit part in a certain electric circuit as one block, so the capacitance values that should be included in one capacitor block are diverse, and the shape of the internal electrode is therefore different. becomes extremely complex. On the other hand, one of the main causes of defective products in the manufacturing process of the above-mentioned ceramic multilayer capacitor chips (hereinafter simply referred to as capacitor chips) is a delamination phenomenon called delamination that occurs in the internal electrode layers of capacitor chips. The cause of the delamination described above has not yet been fully elucidated, but from a mechanical perspective, it is mainly the dielectric material that makes up the conde chip, and the organic binder material that is required to form a slurry when forming the green sheet. There is also an internal electrode, and from the viewpoint of manufacturing conditions, factors such as the temperature and pressure when stacking the green sheets and the temperature profile during firing are considered to be factors. Furthermore, research has recently revealed that the cause of the delamination is that its tendency varies greatly depending not only on the materials and manufacturing conditions mentioned above, but also on the shape of the internal electrodes.

Shidaka - This is due to delamination, which did not occur or occurred less frequently when manufacturing capacitor chips with internal electrodes of conventional simple shapes using materials commonly used in the past. This results in frequent failures in capacitor chips having so-called complex electrode shapes having a plurality of capacitance values each having different values.

Purpose of the Invention The present invention requires a complicated internal electrode shape in order to include a plurality of capacitors with different capacitance values as described above in one ceramic chip, and therefore, delamination failure occurs. An object of the present invention is to provide a conductive paste for internal electrodes that is intended to solve the problems of capacitor chips that are prone to this problem from a material standpoint.

Structure of the Invention In order to achieve this object, the conductive paste of the present invention contains 3 parts by weight of metal palladium powder, 3 parts by weight of ethyl cellulose, 1 part by weight of terpineol, 20-60 parts by weight, 30-70 parts by weight of kerosene. It is characterized in that 35 to 70 parts by weight of an organic vehicle consisting of 2 to 5 parts by weight of sorbitan triolate and 2 to 8 parts by weight of oxbutylbenzyl phthalate are added.

Description of examples The present invention will be explained below based on examples.

Generally, a conductive paste is composed of a metal powder, which is a conductive material, and an organic vehicle for forming the paste. First, as an organic glue material, the viscosity is 10 cpu −1
000 ps of ethyl cellulose 40I9 to kerosene 20
0,9. Add 220 g of terpineol to the mixed solvent and stir well to dissolve. Add to this 20g of sorbitan triolate as a dispersant to disperse the metal powder well in the organic vehicle, and 2og of butylbenzyl phthalate as a plasticizer.
and further mix to obtain an organic vehicle. Next, 120 g of the above organic vehicle is added to 180 g of metal palladium powder having an average particle size o of 05 to 2.0 μm, and the mixture is thoroughly mixed.

This pasty mixture was then kneaded on a three-roll mill until it was sufficiently homogeneous. - When manufacturing a multilayer ceramic capacitor using the conductive paste prepared as described above, first, dielectric powder and organic binder are mixed and pulverized and mixed using a ball mill or the like for about 3 to 7 days to form a slurry. This slurry is formed into a green sheet having a thickness of 20 to 40 mm using a doctor blade, and then cut out to a predetermined size and printed in a predetermined shape by screen printing using the conductive paste. After drying at 90° C. for about 5 minutes, the required number of sheets are laminated, pressure molded, cut into chips, and fired at a maximum temperature of 1000 to 1400° C. for about 1 hour in an electric furnace according to a predetermined heating program. At the beginning of the above firing process, the organic binder in the green sheet and the organic vehicle in the internal electrode conductive paste decompose.

It gasifies and dissipates, but if the materials used or the process conditions are inappropriate, delamination defects will occur.

In the configuration of this example, if the metal palladium powder is broken down by 3 degrees, a homogeneous electrode film cannot be obtained after firing, resulting in extremely high resistance values or disconnection. If it exceeds 66%, the electrode film becomes too thick, causing delamination and increasing costs. If the content of ethyl cellulose is less than 4%, appropriate printability cannot be obtained, and if the content is more than 16%, the viscosity is extremely high and cannot be made into a paste. If terpineol is less than 20%, it will not dissolve ethylcellulose, and 60%
% or more, the green sheet will dissolve when printing the internal electrodes. If the kerosene content is less than 30, the solvent in the conductive paste evaporates quickly and the viscosity becomes high during printing, making printing impossible. When the ratio exceeds 70, the solubility in ethyl cellulose deteriorates. When the amount of sorbitan triolate is less than 2, the dispersibility of metal palladium is poor and the powder particles tend to aggregate together.

If the number is 8 or higher, printability will be adversely affected. If the content of butylbenzyl phthalate is less than 2%, cracks will occur on the electrode surface after printing, and if it is more than 8%, the drying time will be long and high temperatures will be required. Organic vehicle is 36
When printing is performed in relation to the amount of metal palladium added, the electrode film thickness becomes thicker and causes delamination.

If it exceeds 70%, the electrode thickness will become thinner, resulting in a significant increase in resistance value or wire breakage.

Effects of the Invention As described in detail, by applying the conductive paste according to the present invention as internal electrodes to a capacitor block in which a plurality of capacitor groups each having different capacitance values are included in one chip, the conductive paste can be used as an internal electrode. A capacitor chip without lamination defects can be obtained, which is extremely advantageous in practical terms.

Claims (1)

[Claims] 30-65% by weight of metallic palladium powder, 4-164% by weight of ethyl cellulose, 20-6% by weight of terpineol, 30-70% by weight of kerosene, 2-8% by weight of sorbitan triolate, and 2-8% by weight of butylbenzyl phthalate.
A conductive paste prepared by adding 36 to 70 parts by weight of an organic vehicle consisting of 8 parts by weight.