JPH09139112A - Thick film conductor composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition in an insulation board including a glass component or an insulation board forming a through hole conductor including the glass component in which dispersion and exudation of a glass component to a conductor film critical face or segregation of the glass component to the conductor film surface is prevented, soldering wettability is better maintained, electrical conductivity with a through hole conductor is good, and any other required characteristic such as strength of adhesive bending or area resistance value is not affected. SOLUTION: In a thick film conductor composition comprising dispersing at least one type of fine powder of silver, palladium, and platinum and minute powder of alloy of these metals and an inorganic bonding material in an organic vehicle, Ni or a Ni compound is contained by 1 to 5wt.% of all amounts of the thick film conductor composition by means of Ni metal conversion.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thick film conductor composition for forming an electric circuit by printing on the surface of an insulating substrate containing a glass component or an insulating substrate having a through hole conductor formed thereon. is there.

[0002]

2. Description of the Related Art Thick film conductor compositions are prepared by kneading at least one of fine powders of noble metals such as silver, palladium, platinum or the like, or fine powders of alloys of these noble metals with a fine inorganic binder together with an organic vehicle. 750, which is a paste-like composition comprising: an insulating substrate or an insulating substrate having a through-hole conductor formed thereon, by a printing means such as screen printing.
It is fired at a temperature of from 950 ° C. to 950 ° C. to form a conductive film on the substrate and is used as a conductor film for joining a semiconductor element or as an electrode of an electric circuit or a resistor.

Conventionally, as an insulating substrate material used for this kind of purpose, a substrate material mainly composed of alumina has been widely used, but in recent years, an inner conductor coating and a surface conductor coating are simultaneously fired in multiple layers. For that purpose, a substrate material containing a glass component whose firing temperature is lower than that of alumina has been attracting attention and is being developed.

Further, in the case of forming a through-hole conductor for obtaining electrical continuity between the inner layer conductor film and the surface conductor film on an insulating substrate containing such a glass component, shrinkage during firing is required. In order to bring the rate close to the shrinkage rate of the substrate material, the development of a through-hole conductor containing a glass component composition similar to or close to the glass component composition contained in the substrate material is underway.

[0005]

However, the thick film conductor composition conventionally used on an insulating substrate containing the above-mentioned glass component or an insulating substrate on which a through-hole conductor containing the same glass component is formed. Print things,
If you try to form a conductor coating by firing,
During the firing process, the glass component in the substrate or in the through-hole conductor diffuses into the conductor coating being formed and reaches its surface, and the formed conductor coating has one of the important required properties, solder wettability. Since there is a problem that the glass component is remarkably deteriorated or the glass component is segregated at the interface with the already formed surface conductor coating film to hinder the electrical conduction with the through-hole conductor, an improvement measure is required.

The present invention has been made to solve the above-mentioned problems, and suppresses the diffusion and leaching of the glass component to the surface of the conductor coating, or the segregation of the glass component at the interface of the conductor coating, and the glass component Does not reach the surface of the conductor coating, so that the solder wettability is kept good, the electrical conductivity with the through-hole conductor is good, and the adhesive strength, area resistance value, and other characteristics such as solder resistance are improved. It is an object of the present invention to provide a thick film conductor composition which does not have a bad influence.

[0007]

To achieve the above object, the present invention provides at least one of fine powder of silver, palladium, platinum or fine powder of alloy of these metals,
In a thick film conductor composition obtained by dispersing an inorganic binder in an organic vehicle, nickel or a nickel compound is further contained in the inorganic binder in an amount of 1 to 5% by weight based on the total amount of the thick film conductor composition in terms of Ni metal. And a thick film conductor composition.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention provides silver,
The inorganic binder in the thick film conductor composition comprising a precious metal such as palladium or platinum or an alloy of these precious metals, an inorganic binder and an organic vehicle further contains nickel or a nickel compound. In the present invention, when using a nickel compound as the nickel component to be contained in the inorganic binder, in addition to nickel oxide,
It is also possible to use organonickel compounds.

In the thick film conductor composition of the present invention, the content of nickel or nickel compound in the inorganic binder is limited to 1 to 5% by weight of the total amount of the thick film conductor composition in terms of Ni metal. If it is less than 1% by weight, the effect of suppressing the diffusion of the glass component from the substrate or through-hole conductor into the conductor coating is not sufficient, and if it exceeds 5% by weight, the sheet resistance value in the conductor coating increases. In addition, it is deposited on the surface of the conductor and causes deterioration of solder wettability.

Further, in general, a thick film conductor composition is made to contain a copper compound, a bismuth compound, a molybdenum compound or the like for the purpose of improving adhesive strength and solder wettability. The nickel or nickel compound used in the composition of the present invention may be used at the same time as the compound used for improving the strength and the solder wettability.

The thick film conductor composition according to the present invention containing such a nickel or nickel compound is printed on an insulating substrate containing a glass component or an insulating substrate on which a through-hole conductor containing a glass component is formed. When applied and dried and then baked in a temperature range of 750 to 950 ° C. according to a conventional method, the suppressing action of nickel or nickel alloy dispersed in the conductor coating suppresses sintering of the noble metal component in the conductor coating, Since the glass components in the substrate and through-hole conductor are captured by the resulting fine grain boundaries, leaching of the diffused glass component to the surface of the conductor coating is prevented, and in addition to the through-hole conductor of the conductor coating, Since segregation of glass components at the interface of the conductor is also suppressed, the solder wettability on the conductor surface does not deteriorate and Electrical conduction can be carried out without hindrance by. As described above, in the present invention, the addition of nickel or nickel alloy does not adversely affect the adhesive strength of the conductor coating to the substrate and the sheet resistance value.

[0012]

Next, an embodiment of the present invention will be described. It goes without saying that the present invention is not limited to this embodiment.

0.5% by weight of alumina powder as a binder is added to noble metal powder having a ratio of Ag and Pd of 81:19.
A thick film of the present invention comprising an organic bihilur and a mixed powder in which nickel oxide powder is added to the composition in an amount corresponding to a range of 1 wt% to 5 wt% of the total amount of the composition in terms of Ni metal Conductor composition samples 1, 2 and 3 were prepared.
As a comparative sample, a composition comparative sample 1 in which the nickel oxide content in each of the above thick conductor film compositions was zero
And a composition comparative sample 2 having a nickel content of 6% by weight were prepared.

These thick film conductor compositions were formed on a glass-ceramic substrate having an alumina: glass component = 50: 50 weight ratio to form a through-hole conductor containing 100% by weight of the same glass component as described above with a diameter of 100 μm. 2 mm x 2 mm is applied by screen printing on an insulating substrate, a pattern with a line width of 600 µm x 60 mm is applied, dried, and then baked in the atmosphere at a temperature of 850 ° C for 10 minutes twice, and a conductor film is formed. Was formed. The reason why the firing is performed twice is that, in a normal circuit design process, after the conductor is fired, the conductor coating is subjected to the heating and firing twice in total because the resistors are printed and fired. is there. The thickness of the conductor coating formed by this is 10μ
m.

The surface of the sample was observed by using a stereoscopic microscope, and the presence or absence of granular glass showing that the glass component in the substrate reached the surface of the conductor film was examined. Further, the solder wettability was evaluated by visually observing the substrate on which the conductor coating was formed, after immersing the substrate in molten solder at 235 ° C. for 5 seconds.

The adhesion strength was evaluated by soldering a tin-plated copper wire having a diameter of 0.65 mm on a conductor coating of 2 mm × 2 mm and measuring the tensile strength in the direction perpendicular to the substrate. Furthermore, the evaluation of the sheet resistance value is 6
It was performed by measuring a pattern resistance value of 00 μm × 60 mm.

The electrical continuity between the through-hole conductor and the surface conductor coating is evaluated by observing the presence or absence of a glass layer at the interface between the through-hole conductor and the surface conductor coating by observing a cross section using a scanning electron microscope. went. Table 1 shows the results of the characteristic evaluation of each conductor film by the above evaluation method.

[0018]

[Table 1] Sample Ni oxide amount Surface grain Solder wetting Interface rattle Adhesive strength Area resistance (metal conversion) Glass property observation * Value of glass layer (% by weight) No observation (Visual) No observation (kg) (mΩ / sq) Invention 1 1.0 None ○ None 4.5 22.4 Invention 2 3.0 None ○ None 4.6 23.2 Invention 3 5.0 None ○ None 4.3 24.5 Comparative Example 1 0.0 Yes x Yes 4.6 21.9 Comparative Example 2 6.0 No x No None 4.4 36.8 * ○ means good, and × means bad.

From the results shown in Table 1, the conductor compositions of the present inventions 1, 2 and 3 are clearly improved in solder wettability as compared with Comparative Example 1, that is, the conductor composition containing no nickel oxide. Moreover, since no glass layer is observed at the interface of the through-hole conductor, the diffusion of the glass diffusion component from the substrate or the through-hole conductor to the conductor surface and the segregation of the glass component from the through-hole conductor to the conductor coating interface are suppressed simultaneously. Therefore, electrical conduction is not hindered, and other characteristic values such as adhesive strength and sheet resistance are not adversely affected, and nickel oxide is contained as in Comparative Example 2. When the amount exceeds the amount of the present invention, it has the effect of suppressing the diffusion of the glass component, but the solder wettability decreases and the sheet resistance value also increases. That.

[0020]

As described above, the thick film conductor composition according to the present invention captures the glass component diffused from the substrate or the through-hole conductor in which the glass component is used in the conductor film, and thus the conductor film surface is obtained. Since it is possible to prevent the glass component from reaching the through hole conductor and at the same time to suppress the segregation of the glass component at the interface of the through-hole conductor, it is possible to maintain good electrical continuity between the obtained conductor film and the through-hole conductor. In addition, it has good solder wettability and does not adversely affect other properties such as adhesive strength and sheet resistance. Use as a conductor film forming composition for connecting semiconductor elements or a conductor composition for forming circuit electrodes on a substrate on which a through-hole conductor using the same glass component is formed. It can be said that is a great invention of useful and industrial effect.

Claims (1)

[Claims] 1. At least one of fine powder of silver, palladium, platinum or fine powder of an alloy of these metals,
In a thick film conductor composition in which an inorganic binder is dispersed in an organic vehicle, nickel or a nickel compound is further contained in the inorganic binder in an amount of 1 to 5% by weight based on the total amount of the thick film conductor composition in terms of Ni metal. A thick film conductor composition comprising: