JPS605087A - Electroconductive paste composition - 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 the Invention The present invention relates primarily to a conductive paste composition used for forming end electrodes of ceramic electronic components such as chip-shaped porcelain capacitors.

Conventional technology In a chip-shaped ceramic capacitor of a laminated type or an internal electrode structure type, when forming an end electrode that is a connection part with the outside, conventionally, 10 to 30% of Pd powder was contained in Ag powder. Using a conductive paste composition, Ag-
It was common for Pd to be baked into an electrode.

The reason why Pd powder is contained in Ag powder is to improve compatibility with internal electrodes whose main component is Pd, and to improve solder heat resistance during soldering and prevent the phenomenon of electrode solder eating. It's for a reason.

The disadvantage of the conventional technology is that the soldering heat resistance of Ag-Pd alloys is generally greatly influenced by the Pd content, so the higher the soldering heat resistance, the more Pd is used, and the cost of forming the end electrodes becomes extremely high. It had the disadvantage of being expensive. Moreover, even if the above-mentioned method is used, the soldering heat resistance is insufficient, and the surface of the Ag-Pd electrode layer has Xl-3n.
It was necessary to take a method such as plating a metal layer such as the like to improve solder heat resistance. In any case, conventionally, in order to improve the soldering heat resistance of the end electrodes, it was necessary to add a large amount of expensive Pd or to perform plating treatment, which resulted in high product costs. It was inevitable.

Furthermore, regarding the plating method, it is true that the solder heat resistance is improved, but because the end electrode of the Ag-Pd alloy that is the plating base has a porous electrode structure, electrolysis is applied inside the bore during the plating process. There was a problem in that the dripping plating solution entered the capacitor and deteriorated the Q and IR characteristics, which are important characteristics for a capacitor.

Purpose of the Invention The present invention eliminates the above-mentioned conventional drawbacks, and provides an inexpensive Ag-Pd alloy end electrode for use as a plating base, which has excellent solder heat resistance and does not cause characteristic deterioration due to penetration of plating solution. It is an object of the present invention to provide a conductive paste composition that can be formed.

Structure of the present invention In order to achieve the above object, a conductive paste composition according to the present invention comprises Ag fine powder, Ag scaly powder, Pd
It is characterized by containing a Pd coating powder whose surface is coated with Pd using particles made of other substances as cores, and an organic vehicle.

That is, as shown in FIG. 1, the conductive paste composition according to the present invention has particles l made of a substance other than palladium (Pd) as cores, and a Pd coating layer 2 on the surface of the core particles l. coated Pd coating powder,
Ag fine powder, Ag phosphorous powder, and Pd powder,
It is dispersed in an organic vehicle together with a glass frit. The amount of Pd coating powder added to the Ag component is suitably in the range of 0.5% by weight to 30% by weight. This is because if the amount added is less than 0.5% by weight, the addition effect cannot be obtained, and if it is more than 30% by weight, the conductivity required for practical use cannot be ensured.

The core particles 1 have the same composition as the dielectric ceramic used as the magnetic capacitor, for example, BaTi0+, TiO2, Alz, which are commonly used in magnetic capacitors.
When obtaining a reduction-reoxidation type semiconductor ceramic capacitor made of metal oxides such as Oa, Zr0z, 5ifi, etc., it is common to construct it with a valence-controlled semiconductor ceramic that is a semimetal oxide. Also, Ni, Cr,
It is also possible to use base metals or semimetals such as Co, AI, Fe, Pb, and Sn, or alloys thereof, carbon, conductive ceramics, nitrides, borides, and the like. In this case, the particle l serving as the core has a particle size of lILm or less, ideally 0.5 to 0.8
It is desirable to classify to about JLm.

Then, the Pd coating layer 2 is coated on the surface of the particles 1 classified into a predetermined particle size as described above, thereby obtaining a Pd coating powder. As a method for coating the core particles 1 with Pd, a metal electroless method, a solution reduction method, a vapor phase deposition method, etc. are suitable.

The particle size of the Ag fine powder and Pd powder is 0. i p,m
It is desirable that the thickness is within a range of 0.3 μm to 0.3 μm. This is because the use of Ag fine powder and Pd powder with a loose particle size improves the dispersibility in the organic vehicle.

Further, the particle size of the Ag scaly powder is 1 gm to 4 gm.
It is desirable that it be within JLIm.

Furthermore, the organic vehicle may include rosin as a main component and 1
, a lacquer-like mixture of this and a solvent is suitable. The organic vehicle containing rosin as a main component has an excellent effect in further improving the dispersibility of Ag fine powder, Ag scaly powder, and Pd coating powder, and forming a dense electrode without bores. It is.

The conductive paste composition according to the present invention having the above-mentioned composition can be applied to porcelain or the like by a dip method, a roll coater method, or a brush painting method and baked, in the same way as conventional conductive paste compositions. An end electrode is formed.

In this case, since the conductive paste composition according to the present invention contains Pd coating powder in which the Pd coating layer 2 is coated on the surface of the core particle 1 made of a dielectric material etc., electrode baking can be prevented by the treatment. Formed Ag
- Mutual diffusion between the Pd alloy and the solder is inhibited by the core particles 1, improving solder heat resistance and preventing solder eating. Furthermore, since the amount of expensive metal particles such as Pd used can be extremely reduced, it is possible to form an end electrode with excellent soldering heat resistance while significantly reducing the number of connections.

Furthermore, since it contains Ag starchy powder, the dispersibility is improved, resulting in a dense electrode structure without bores. Therefore, even when the surface is plated, a chip-shaped ceramic electronic component can be obtained without the penetration of coating fluid and without deterioration of characteristics.

EXAMPLE A dielectric ceramic was used as the core particle l, and Pd was coated on the surface thereof in a ratio of Pd:porcelain particles=80:20 (weight ratio) to obtain a Pd-coated powder. A solution reduction method was used for Pd coating. In a conventional conductive paste composition having a composition of Ag:Pd=75:25 (wt%), Pd was 0.0%.
A conductive paste composition was prepared by replacing 5-30% by weight with the Pd coating powder and dispersing it in an organic vehicle together with a glass frit. The conductive paste composition thus prepared was applied to both ends of a chip-shaped ceramic capacitor and baked to form end electrodes.

FIG. 2 shows the soldering heat resistance of the chip-shaped porcelain capacitor obtained in the above example, Ag: Pd = '75: 2
FIG. 5 is a diagram showing a comparison of the solder heat resistance of a conventional chip-shaped ceramic capacitor whose end electrodes were formed using a conductive paste composition of 5 (weight ratio).

When a conventional type using an Ag-Pd based conductive paste composition was immersed in a solder bath at 270°C for 3 seconds, the electrode solder was eaten away by about 50% (shown as point B in Figure 2). ,,) Shita. On the other hand, in the present invention, the second
As shown by curve A in the figure, the solder eating rate decreases rapidly when the Pd coating powder exceeds 0.5% by weight, and even if immersed in a solder bath at 270°C for 5 seconds, no solder eating occurs. The phenomenon could hardly be confirmed.

As mentioned above, the main use of the conductive paste composition according to the present invention is as a conductive paste composition for forming the end electrode of a ceramic capacitor, but there are various other uses as well. Needless to say.

Effects of the present invention As described above, the conductive paste composition according to the present invention has a core made of particles made of Ag fine powder, Ag scalloped powder, and a substance other than Pd, and the surface thereof is coated with Pd. An A3-Pd alloy end electrode for use as a plating base, which is characterized by containing Pd coating powder and an organic vehicle, has excellent solder heat resistance and does not cause characteristic deterioration due to penetration of plating solution. A conductive paste composition that can be formed at low cost can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view modeling the structure of the conductive paste composition according to the present invention, and FIG. 2 is a diagram showing the soldering heat resistance of the conductive paste composition according to the present invention in comparison with a conventional one. It is. 1- Particles that form the core of a fist 2...- To the Pd coating layer

Claims (6)

[Claims] (1) A conductive material characterized by containing Ag fine powder, Ag phosphorous powder, Pd coating powder whose surface is coated with Pd using particles other than Pd as cores, and an organic vehicle. Paste composition. (2) The conductive paste composition according to claim 1, wherein the amount of the Pd coating powder added to the Ag component is 0.5% to 30% by weight. (3) The particles made of a substance other than Pd are made of at least one of a metal oxide, a metalloid oxide, a nitride, or a boride. The conductive paste composition described in . (4) Particles made of substances other than Pd. The conductive paste composition according to claim 1 or 2, which has conductivity. (5) The particles made of a substance other than Pd include Ni
, Cr, Go, A1. 5. The conductive paste composition according to claim 4, comprising at least one of a base metal such as Fe, a metalloid, or an alloy thereof. (6) The conductive paste M1 composition according to claim 4, wherein the particles made of a substance other than Pd are made of at least one of carbon and conductive ceramic.