JPH04177702A - Composition for thick film resistor - Google Patents

Abstract

PURPOSE:To produce the title composition for thick resistor in small fluctuation coefficient of resistance value in high resistance region and small variation coefficient in permanent resistance during short time overload at high voltage by a method wherein specific amount of tin oxide is added to the composition comprising glass powder containing ruthenate and lead. CONSTITUTION:The title composition for thick film resistor is composed of ruthenate represented by a chemical formula of Pb2Ru2Ox wherein x is within the range of 6-7 and particle diameter not exceeding 1000Angstrom as well as lead silicate glass powder in the mean particle diameter not exceeding 10mum containing silicon oxide exceeding 10Wt% and lead oxide also exceeding 10Wt% or ruthenate powder represented by the chemical formula of Pb2Ru2Ox wherein x is within the range of 6-7 and particle diameter not exceeding 1000Angstrom as well as lead silicate glass powder in the mean particle diameter not exceeding 10mum containing silicon oxide exceeding 10Wt% and lead oxide also exceeding 10Wt% and tin oxide powder in the mean particle diameter not exceeding 1mum and organic vehicle while the content ratio of tin oxide in inorganic constituent in this composition is to be 0.2-5Wt%. In such a constitution, the title composition for thick film resistor in small fluctuation coefficient of resistance value and small variation coefficient in permanent resistance during short time overload testing step can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a composition for a thick film resistor containing lead ruthenate used for forming electronic circuits.

[Conventional technology]

In recent years, thick-film resistors using ruthenium oxide-based conductors such as ruthenium oxide and lead ruthenate have been widely used to form circuits in microelectronic components. It has been widely used as an electrical conductor.

If lead ruthenate is used, the resistance value can be increased to 101 ~
It can be set to any value of 106 Ω/hole, the resistance value of the resistor created in 1 is not greatly affected by the concentration of lead ruthenate in the conductive composition, and the rate of variation in resistance value (CV value) is small. It is.

By the way, when creating a resistor using a ruthenium oxide-based conductive material such as lead ruthenate, for example, a powder of a ruthenium oxide-based conductive material and a powder having a softening point of 45.
Lead borosilicate glass powder with a coefficient of thermal expansion of about 0 to 650 C and close to that of alumina is mixed with an organic vehicle, and then kneaded using a three-roll mill or the like to form a paste to obtain a composition for a thick film resistor. This is printed on an insulating substrate such as alumina by screen printing or the like 2, and a circuit pattern is formed, dried, and fired. Then, in order to obtain a desired resistance value, the ratio of the conductive material and the glass is adjusted.

In recent years, for thick film resistors formed in this way, -
It is desired to improve the withstand voltage characteristics of i.

Specifically, the CV value in the high resistance range where the sheet resistance value is about IMQ/D is 10% or less, and the permanent resistance change rate in the short-time overload test (hereinafter referred to as permanent resistance change rate) is 0.2% or less. is required to do so. However, the conventional resistor compositions described above cannot satisfy this requirement. This is because, for example, even if a thick film resistor made using said 5&compound and has a sheet resistance of about 12 KV, which is generally considered to have a small permanent resistance change rate, its permanent resistance change rate is about 15 KV. %
This is because when the sheet resistance value exceeds 100, the dependence of the resistance value on the conductive material concentration becomes large.

Various compositions and methods have been proposed to overcome this drawback, but one of the most effective is the composition disclosed in Japanese Patent Publication No. 55-39883. This is a composition for thick film resistors in which BaTj-0, Ti, and O are added to a composition consisting of a conductive pyrochlore-related oxide and glass. However, the sheet resistance value 1 y, Q/
The permanent resistance change rate of a resistor of about A is 0.3 to 1%, which does not satisfy the above requirements.

[Problem to be solved by the invention]

An object of the present invention is to provide a composition for a thick film resistor, which has a small rate of change in resistance value in a high resistance region and a small rate of change in permanent resistance due to short-term overload of high voltage.

[Means to solve the problem]

The present inventors have discovered that by adding a specific amount of tin oxide to a composition consisting of lead ruthenate and glass powder containing lead, a composition capable of meeting the above requirements can be obtained, leading to the present invention. That is, the composition for a thick film resistor of the present invention is represented by the formula PbRuO, 2 2 silicon oxide and 10% by weight
Lead silicate glass powder with an average particle size of 10 μm or less containing the above lead oxides, or lead ruthenate powder represented by the formula Pb2Ru20x with X in the range of 6 to 7 and a particle size of 1000 A or less, and 10% by weight The composition comprises a lead silicate glass powder having an average particle size of 10 μm or less containing the above silicon oxide and 10% by weight or more of lead oxide, a tin oxide powder having an average particle size of less than 1 μm, and an organic vehicle. The content of tin oxide in the inorganic components is 0.2 to 5% by weight.

In constructing the composition of the present invention, lead ruthenate powder is prepared by mixing ruthenium oxide and lead oxide in a predetermined ratio, melting the mixture, cooling it, and pulverizing the mixture to a particle size of 1000R or less, and a lead ruthenate powder having an average particle size of 1000R or less. It is made by kneading lead silicate glass powder of 10 μm or less, tin oxide powder with an average particle size of less than 1 μm, and an organic vehicle, or it is made by mixing and melting ruthenium oxide, lead oxide, silica, alumina, etc. , cooled and crushed to an average particle size of 10 μm or less
It may be made by kneading glass powder containing fine crystals of lead ruthenate of R or less, tin oxide powder having an average particle size of less than 1 μm, and an organic vehicle.

Tin oxide powder having an average particle size of less than 1 μm is usually obtained by crushing and classifying coarse tin oxide using a crusher such as a ball mill, but it is preferable to use tin oxide as fine as possible. As fine tin oxide, tin oxide sol (manufactured by Tasui Kagaku, average particle size 80χ) or tin chloride solution is hydrolyzed to form tin hydroxide, which is dehydrated to obtain an average particle size of about 0.2 μm. There is tin oxide.

As the organic vehicle used in the present invention, those commonly used as pastes for resistors can be used, and the composition thereof is not particularly limited. Further, the amount used is preferably 20 to 40% by weight of the entire composition so that a suitable resistor pattern can be formed by screen printing as in the past.

[Effect]

The lead ruthenate used in the present invention is a pyrochlore-type conductive oxide, and its structure is made of a combination of two octants consisting of a cubic OaF structure, and the oxygen atoms are arranged in a tetrahedron inside the cube of the GaF2 structure. position. Of the oxygen in lead ruthenate, the oxygen at the diagonal position of the pb atom tends to be missing, and as a result, the stoichiometric amount of oxygen varies from 6 to 7, and when expressed by the formula Pb Ru, O. 2 2X, the range of X is 6 to 7.

The most preferable lead ruthenate to be used is particle size 1.
ooo R or less, preferably 100 to 500χ Pb2
Ru2O6,5theal. This is because when the particle size exceeds 100 OR, the CV value of a resistor made using the resulting composition becomes significantly large.

The lead silicate glass powder to be used is intended to contain 10 M% or more, preferably 15 to 35% by weight of silicon oxide, and 10% by weight or more of lead oxide, preferably 50 to 80% by weight. In addition to these components, AIO and BO are suitable for creating a resistor.

There is no problem in containing one or more of MgO, Cao, Bad, Tie□, ZrO2, etc. If the particle size of the lead silicate glass used is too large, it will not be possible to mix the lead ruthenate powder and glass powder uniformly.
Furthermore, the characteristics of the resistor made using the composition deteriorate, making it impossible to achieve the object of the present invention. For this reason, it is necessary that the average particle size of lead silicate glass is 10 μm or less.

In the present invention, tin oxide such as Sno, Sn, and O reacts with lead oxide, which is a glass component, to form lead stannate (pbsno).
), which is thought to play a role in disrupting the conductive network of lead ruthenate and increasing its resistance, but in order to fully demonstrate this function, it is necessary to adjust the amount of tin oxide added and the particle size. There is.

For example, the thickness of a resistor that is usually formed is at most 15 μm.
Therefore, if too large particles are present, the Cv value and withstand voltage characteristics will naturally deteriorate, as shown in Comparative Example 2 below. Therefore, the average particle size of tin oxide used in the present invention needs to be smaller than 1 μm.

Furthermore, even if the average particle size of tin oxide is smaller than 1 μm, or if the content is less than 0.2% by weight or more than 5% by weight, the aV value and withstand voltage characteristics are poor, as shown in Comparative Example 1 below. Therefore, the content of tin oxide is set in the range of 0.2 to 5% by weight.

〔Example〕

Example 1 Ru06.7 g, Pb○68.1 g, SiO
23.8g, AI O2, 7g, MgO1,,2
g were mixed and heated at 1000 C for 3 hours to melt. This was poured into water, rapidly cooled, and ground in a ball mill to obtain a powder with an average particle size of 7.3 μm.

The obtained powder contains 200~soo x fine PbRu
It was a glass powder containing O crystals. Next, SnO is ground in a ball mill using Zircoir balls, classified to obtain SnO powder with a predetermined particle size, and this and the above-mentioned Pb
Glass powder containing RuO crystals was mixed at a predetermined ratio of 226.6 mm, and 130 parts by weight of ethyl cellulose dissolved in terpineol was added to 70 parts by weight of this mixture and kneaded in a three-roll mill to obtain a composition for a thick film resistor. Ta.

This composition was printed on an alumina substrate provided with Ag/PD electrodes using a pattern with a length of 1 trrrn, a width of 1 m, and tn, dried at 120 C for 20 minutes, and heated to a peak temperature of 850 r using a belt firing furnace. Firing was performed for a peak time of 10 minutes. The length obtained in this way is 1 line and the width is 1 line.
The sheet resistance value, aV value, and permanent resistance change rate of a resistor with a thickness of 15 μm were measured. The voltage intensity applied when measuring the permanent resistance change rate was determined by the following formula in accordance with TTS O5202.

Applied voltage (V) = (overload condition x rated power x sheet resistance value) 1/2, overload condition is 10 times, rated power is calculated as 1/4W, and applied after rounding to the nearest whole 1oO. I found the voltage. In addition, when the sheet resistance value was 1 y, Q/x or more, the applied voltage L1 was set to 1600 V-9.

The applied voltage determined in this way was applied for 5 seconds, then the sheet resistance value was determined, and the permanent resistance change rate was determined from the difference between the sheet resistance values before and after the application.

Table 1 shows the composition of the composition for thick film resistors, the applied voltage, and the measurement results obtained.

Table 1 shows that if the composition for thick film resistors of the present invention is used, a high resistance value, a small Cv value, and a permanent resistance change rate of 0.2 can be obtained.
It can be seen that a resistor with excellent characteristics of less than % can be obtained.

Table 1 Example 2 Glass 22 containing Pb Ru O crystal used in Example 1
6.5 The powder was mixed with a commercially available tin oxide sol (manufactured by Tasui Kagaku, average particle size 80
12 after mixing with x (tin oxide sol solution) at a prescribed ratio
Using the powder dried at 0C, a resistor was made in the same manner as in Example 1, and its CV value and permanent resistance change rate were measured. The results are shown in Table 2.

From Table 2, it can be seen that even when tin oxide sol was used, a resistor with excellent characteristics such as high resistance, small ay value, and permanent resistance change rate of less than 0.2% was obtained.

Table 2 The amount of SnO added was calculated from the amount of tin oxide sol.

Comparative Example 1 The amount of SnO powder with an average particle size of 0.2 μm was 0°0.1
, 5.4% by weight, and the CV value and permanent resistance change rate were measured in the same manner as in Example 1, and the results are shown in Table 3.

From Table 1, it can be seen that only those with a large Cv value and a large permanent resistance change rate were obtained.

Table 3 Comparative Example 2 Measurements were made in the same manner as in Example 1, with the amount of SnO powder with an average particle size of 1.3 μm added at 0.2°2.7.4.4.5.2% by weight, and the results were It is shown in Table 4.

It can be seen from Table 1 that only those with a large CV value and a large permanent resistance change rate were obtained.

Table 4 [Effects of the Invention] By using the conductive composition for a thick film resistor of the present invention, it becomes possible to manufacture a thick film resistor having a small Cv value and a small rate of change in permanent resistance due to a short-time overload test.

Applicant: Sumitomo Metal Mining Co., Ltd.

Claims (1)

[Claims] 1) Represented by the formula Pb_2Ru_2O_x, where x ranges from 6 to
7 with a particle size of 1000 Å or less and 10
Lead silicate glass powder containing at least 10% by weight of silicon oxide and 10% by weight or more of lead oxide and having an average particle size of 10 μm or less, or a powder represented by the formula Pb_2Ru_2O_x where x is in the range of 6 to 7 and the particle size is 1000 Å or less lead ruthenate powder, 10
A lead silicate glass powder with an average particle size of 10 μm or less containing at least 10% by weight of silicon oxide and 10% by weight or more of lead oxide, a tin oxide powder with an average particle size of less than 1 μm, and an organic vehicle, and the composition A composition for a thick film resistor, characterized in that the content of tin oxide in the inorganic components is 0.2 to 5% by weight.