JPH0917605A - Thick film resistor paste composition - Google Patents

Abstract

PURPOSE: To form a thick film resistor of low resistance which is excellent in geometry effect, by using ruthenium oxide to which admixture is added in the form of oxide coating, as conducting component, and printing and forming the conducting component on an Ag rich thick film conductor electrode. CONSTITUTION: In thick film resistor paste composition wherein conducting powder whose main component is ruthenium oxide, glass powder, titnium oxide, and manganese oxide are dispersed in organic vehicle, the surface of the ruthenium oxide powder is previously coated with titanium oxide and manganese oxide. In another thick film resistor paste composition, the following is used as conducting powder; ruthenium oxide powder on which surface titanium oxide coating and manganese oxide coating are formed by heat treatment after ruthenium oxide powder is dispersed in an aqueous solution which is a mixture of the colloidal solution of titanium oxide and the aqueous solution of manganese oxide precursor, and water content is evaporated. Thereby a resistor wherein geometry effect is small can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick film resistor paste composition used for forming a printed resistor of an electronic circuit component such as a hybrid IC, a network resistor and a chip resistor, and more particularly to an electrode made of an Ag-rich conductor. The present invention relates to a thick film resistance paste composition which is useful for forming a printed resistor having a low resistance value range which exhibits good characteristics when combined with.

[0002]

2. Description of the Related Art A thick film resistance paste composition used for forming a printed resistor is generally prepared by measuring and mixing conductive powder, glass powder, organic vehicle and additives mainly containing ruthenium oxide or lead ruthenate. Then, it is manufactured by kneading using a three-roll mill or the like. The resistor paste thus manufactured forms a resistor by printing on an insulating ceramic substrate on which electrodes are formed in advance and firing it. As electrodes, Ag, Au, AgPd, AgPt
The one formed by printing and firing a thick film conductor paste containing any of the above as a main component is usually used.

[0003]

The printed resistor may have a difference in sheet resistance, temperature coefficient of resistance (TCR), ESD characteristics, etc. depending on its pattern shape and pattern size. This phenomenon is referred to as a geometric effect. In other words, it is generally known that the degree of influence of this geometry effect greatly varies depending on the electrode material combined with the resistor. When an AgPd conductor with a high Pd content, that is, a Pd-rich conductor or an Au conductor was used as an electrode material, no remarkable geometric effect was observed, but the Ag content, which has become popular recently, is overwhelming. When a very high so-called Ag-rich conductor is used as the electrode material, it is very susceptible to the geometry effect, and the resistance value and TCR change greatly depending on the pattern. In addition, the pattern size of the resistor tends to become finer due to the miniaturization of electronic circuits and parts, and the distance between the electrodes tends to decrease, so that the effect of the geometry effect cannot be ignored.

An object of the present invention is to solve the above problems,
It is an object of the present invention to provide a thick film resistor paste composition capable of forming a resistor having a small geometric effect even when combined with an Ag-rich thick film conductor.

[0005]

The present invention provides a thick film resistance paste composition comprising a conductive powder containing ruthenium oxide as a main component, a glass powder, titanium oxide and manganese oxide dispersed in an organic vehicle. It is characterized in that the surface of ruthenium oxide powder is previously coated with titanium and manganese oxide.

In order to exert the effects of the present invention more effectively, ruthenium oxide powder is dispersed in an aqueous solution of titanium oxide and manganese oxide, water is evaporated, and then heat treatment is performed to coat the surface with titanium oxide and manganese oxide. It is desirable to use the ruthenium oxide powder having the above-mentioned structure as the conductive powder. Further, it is desirable that the temperature of the heat treatment be 500 ° C.

In the present invention, as the ruthenium oxide powder, a hydrate of ruthenium oxide can be used, and in particular, a specific surface area of 50 m ² / g or more, more preferably 100 m ²
/ G or more ultrafine powdery ruthenium oxide hydrate is preferably used. Such ruthenium oxide hydrate fine powder can be obtained, for example, by neutralizing and reducing an aqueous ruthenium chloride solution with an alkali or alcohol.

The titanium oxide aqueous solution used in the present invention is preferably titanium oxide colloid (TiO ₂ sol), and the manganese oxide precursor is a water-soluble substance that produces manganese oxide. Well, for example KMnO ₄ is suitable.

As an organic vehicle for dispersing the oxide-coated ruthenium oxide powder thus obtained and the glass powder, ethyl cellulose is used as carbitol acetate,
Those dissolved in an organic solvent such as terpineol are preferably used.

[0010]

[Function] Titanium oxide and manganese oxide are uniformly dispersed in the resistance film obtained by firing the resistance paste containing the oxide-coated ruthenium oxide powder as a conductive component so as to surround the conductive component ruthenium oxide. It is thought that this contributes better to the suppression of the geometrical effect because the appearance of the state occurs. Moreover, in the heat treatment during powdering and the firing after forming into a paste, the oxide around the ruthenium oxide powder serves as a barrier to prevent nonuniform grain growth of ruthenium oxide, and as a result, coarsening of ruthenium oxide is suppressed. It is considered that there is a large contribution to improving the characteristics of the resistor.

[0011]

EXAMPLE 100 parts by weight of ruthenium oxide (RuO ₂ ) powder was dispersed in pure water, and a KMnO ₄ aqueous solution (equivalent to containing 4.5 parts by weight of manganese oxide MnO ₂ ) and TiO ₂ sol (TiO ₂ ) were dispersed therein. Of 1.7 parts by weight) and well stirred and dispersed, and then dried at 120 ° C. to 800 ° C.
Was heat-treated in order to prepare RuO ₂ powder (specific surface area 20 m ² / g) coated with MnO ₂ and TiO ₂ . SiO ₂ : 28.3
%, B ₂ O ₃ 8.0%, PbO 55.2%, Al ₂ O ₃ 4.
55 parts by weight of glass powder having a composition of 7% and 3.8% of CuO and 107.2 parts by weight of RuO ₂ powder coated with MnO ₂ and TiO ₂ were added to an organic vehicle in which 3 parts by weight of ethyl cellulose was dissolved in 25 parts by weight of terpineol. , And was well dispersed by a three-roll mill to prepare a thick film resistance paste. This thick film resistance paste was used as an A with an AgPd ratio of 99.5: 0.5.
A thick film resistor was obtained by screen-printing on an alumina substrate on which an electrode made of a gPd conductor was formed, drying at 120 ° C. for 10 minutes, and baking at 850 ° C. The pattern size of the resistor at this time was 1.0 mm wide and 1.0 mm long and 0.5 mm wide and 0.5 mm long. Table 1 shows the evaluation results.

[0012]

[Table 1]

As a conventional example, R obtained by heat treating RuO ₂ powder at 400 ° C. and adjusting the specific surface area to 20 m ² / g
100 parts by weight of uO ₂ powder, 55 parts by weight of glass powder having the above composition, 4.5 parts by weight of MnO ₂ and 1.7 parts by weight of TiO ₂ were added to 28 parts by weight of the above organic vehicle and dispersed by a three-roll mill to form a thick film. A resistance paste was created. The sample preparation method and evaluation were performed in the same manner as in the example. The results are also shown in Table 1.

[0014]

As described above, since the thick film resistance paste of the present invention uses ruthenium oxide to which an additive is added in the form of an oxide coating as a conductive component, it is printed on an Ag-rich thick film conductor electrode. By forming it, it becomes possible to form a low resistance thick film resistor having an extremely excellent geometry effect.

Claims (2)

[Claims] 1. A thick film resistance paste composition comprising a conductive powder containing ruthenium oxide as a main component, a glass powder, titanium oxide and manganese oxide dispersed in an organic vehicle, wherein the titanium oxide and manganese oxide are preliminarily ruthenium oxide. A thick film resistor paste composition, characterized in that the powder surface is coated. 2. A ruthenium oxide powder is dispersed in an aqueous solution obtained by mixing a colloidal solution of titanium oxide and an aqueous solution of a manganese oxide precursor, the water content is evaporated, and then heat treatment is performed to coat the surface with titanium oxide and manganese oxide. The thick film resistance paste composition according to claim 1, wherein the ruthenium oxide powder formed with is used as a conductive powder.