JPH06152090A - Ceramic plate board with conductor - Google Patents

Abstract

PURPOSE:To obtain a ceramic plate board with conductor having less reduction in insulation resistance due to diffusion of silver, etc., around silver conductor. CONSTITUTION:Silver conductive powder, glass frit, and organic vehicle are included and further a conductive paste containing antimony oxide for the conductive powder by 0.2-12wt.% in terms of antimony conversion is spread on a ceramic plate board or a non-burn green sheet and then is burn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic substrate with a conductor using a conductive paste.

[0002]

2. Description of the Related Art Silver is a conductive material along with palladium, platinum, gold, copper, nickel, tungsten and their alloys, and this powder is made into a paste by adding an organic binder and various additives as required. Those are generally used as a conductive material for low temperature fired substrates.

A conductor using silver has excellent properties in that it has a low resistance value and can be fired in air. However, during firing or in an electric field, silver may diffuse into the substrate particularly under high humidity, which may cause insulation failure. Conventionally, in order to prevent this diffusion, a method of alloying silver with palladium, platinum, or the like has been adopted, but this increases the resistance value of the conductor, resulting in deterioration of performance.

In particular, when these conductors are used in a low temperature fired multilayer substrate, there is a big problem because the diffusion of silver into the glass is severe.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art, and ceramics using a silver-based conductive paste for a ceramic substrate, which has not been heretofore known. The substrate is newly provided.

[0006]

The present invention has been made to solve the above-mentioned problems, and it contains a silver-based conductive powder, a glass frit, an organic vehicle, and further contains an antimony oxide as the conductive material. Provided is a ceramic substrate with a conductor, characterized in that a conductive paste containing 0.2 to 12% by weight of antimony in terms of antimony is applied onto a ceramic substrate or an unfired green sheet and then fired. It is a thing.

The main component of the conductive powder of the present invention is a silver-based powder, and specifically, a conductive powder composed of silver, a silver-palladium alloy, and a silver-platinum alloy is preferably used. This is because these are advantageous in that the conductor resistance can be suppressed low and the firing can be performed in the air. The alloy mainly composed of silver is preferable, and not only silver-palladium and silver-platinum but also a small amount of the third component may be used.

The size of the electrically conductive powder is approximately 0.
Those in the range of 5 to 10 μm can be used, and those in the range of 1 to 5 μm are particularly preferable. This is because particularly good sinterability and printability in screen printing can be obtained in this range.

The blending ratio of the conductive powder in the conductive paste varies depending on the specific surface area of the main silver powder, but is generally 75 to 99% by weight, preferably 85 to 95% by weight. This is because if it is less than this, sintering becomes insufficient and the resistance value of the conductor increases.

The shape of the conductive powder is not particularly limited in the present invention. For example, powder having various shapes such as spherical shape and flake shape can be used.

The glass frit has a function as an inorganic binder, and its softening point and viscosity at the firing temperature greatly affect the sinterability of the paste. As the glass frit, for example, borosilicate frit and lead borosilicate frit can be preferably used, but the glass frit is not limited thereto.

The compounding ratio of the glass frit is preferably 1 to 15% by weight with respect to the conductive powder, and particularly 2 to
It is preferably 8% by weight. This is because if the glass frit is small, sintering cannot be promoted, and if it is too large, the resistance value of the conductor may increase.

As an organic vehicle, it is used to give the above-mentioned inorganic powder suitable flow characteristics. Specifically, for example, ethyl cellulose in a high boiling point solvent such as butyl carbitol acetate and terpineol,
The viscosity may be adjusted appropriately by dissolving a (meth) acrylic acid-based polymer or the like. The compounding ratio is usually 3 to 30% by weight, preferably 7 to 30% by weight based on the total amount of the conductive paste.
It is 20% by weight.

In the conductive paste of the present invention, the oxide of antimony is converted into the weight of Sb, and the content of the conductive powder is 0.
It is preferable to contain 2 to 12% by weight.

It is known that the diffusion process of the silver conductor into the substrate is because silver undergoes an ion exchange reaction with cations in the substrate to become monovalent cations, which penetrate into the substrate. At this time, the ions may turn into colloids, which may cause coloration or yellowing. According to the conductive paste of the present invention, it is possible to obtain a ceramics substrate with a conductor in which the above diffusion phenomenon is suppressed.

Regarding the addition of antimony oxide, a sufficient effect can be obtained only by adding a commercially available powder to the paste composition. In order to disperse it in the paste densely, the particle size of the powder should be small, preferably 5μ.
m or less, and particularly preferably 2.5 μm or less.

The amount of antimony oxide added is preferably 12% or less in terms of Sb weight. If it is too large, the conductivity and the solder wettability may decrease. Also,
If it is less than 0.2%, the effect of suppressing diffusion will not be significant.

[0018]

EXAMPLE A silver powder having an average particle diameter of 2.5 μm, a borosilicate glass frit at 2.0% by weight based on the silver powder, and an antimony trioxide having a particle diameter of 2 μm relative to the silver powder. In addition to various proportions as shown in Table 1, as an organic binder, a vehicle in which ethyl cellulose was dissolved in α-tarpiol was added to the paste in an amount of 15%.
% By weight, mixed all together in an automatic mortar, and further mixed with three rolls to form a paste.

52 parts by weight of alumina particles having an average particle size of 2.0 μm, 50 parts by weight of lead borosilicate glass having an average particle size of 2.5 μm, polyvinyl butyral as a binder,
Methyl ethyl ketone, toluene and butanol were used as a solvent to form a slurry, which was formed into a ceramic green sheet by the doctor blade method.

A conductor having a width of 100 μm is screen-printed on the ceramic green sheet at intervals of 100 μm with the above-mentioned paste and fired to produce a ceramic substrate. The resistance value of the conductor, the insulation resistance value between the conductor patterns, and the conductor Table 1 shows the observed and measured appearance of yellowing around the periphery. No. In Nos. 3 to 5, both the conductor resistance value of the conductor portion and the insulation resistance value between the conductor patterns showed good values, and no yellowing occurred. No. In No. 6, the insulation resistance between conductor patterns did not decrease, but the resistance of the conductor portion increased. In addition, No. In Nos. 1 and 2, a decrease in insulation resistance was observed and yellowing around the conductor was observed.

The indications relating to yellowing in Table 1 are as follows. ○: No yellowing ×: Yellowing

[0022]

[Table 1]

[0023]

According to the present invention, by using a predetermined silver-based conductive paste, the insulation resistance is prevented from lowering and yellowing due to the diffusion of silver or the like around the silver-based conductor is prevented, the resistance value of the conductor is low, and the appearance is good. Ceramic substrates with high commercial value can be obtained. Furthermore, since the present invention can obtain the effect without changing the conventional paste manufacturing method at all, it is excellent in mass productivity, and its industrial value is great. Moreover, it is cheaper than the method using a noble metal such as palladium, and has an effect that the resistance value can be suppressed low.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keiichi Kawakami Inventor Keiichi Kawakami 1160 Matsubara, Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa GG Technology Co., Ltd. (72) Eiji Ichikura Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa 1150, Central Research Laboratory, Asahi Glass Co., Ltd. (72) Inventor Masatoshi Suehiro 50-8 Kawashima Awata-cho, Nishikyo-ku, Kyoto-shi, Kyoto (72) Inventor Katsuo Sugano 37 Ushikasegawaraguchi-cho, Nishi-kyo-ku, Kyoto-shi, Kyoto

Claims (1)

[Claims] 1. A conductive paste containing silver-based conductive powder, glass frit, an organic vehicle, and further containing antimony oxide in an amount of 0.2 to 12% by weight in terms of antimony based on the conductive powder. Is applied onto a ceramic substrate or a green sheet that has not been fired and then fired, and a ceramic substrate with a conductor.