JPH02210801A - Conductive composite powder and resistance composition using same - Google Patents

Abstract

PURPOSE:To easily manufacture with excellent reproducibility a resistor having stable and superior resistance characteristics wherein process sensitivity is small in a wide range of resistance value by previously heat-treating tantalum powder and glass powder and making them composite to be used. CONSTITUTION:Mixture of tantalum metal powder and glass powder is heat treated in an inert gas atmosphere at a temperature higher than or equal to the softening temperature of glass and then ground. The average grain diameter of tantalum metal powder is 5mum or less. There is no restriction for glass powder, if it can be ordinarily used as resistor composite. For example, borosilicate alkali earth metal glass, borosilicate alkali earth metal aluminum glass, etc. are typical. The one whose average grain diameter is 10mum or less is used. Thereby, a stable resistor can be manufactured with excellent reproducibility, whose resistance characteristics are hardly affected by the change of baking conditions.

Description

[Detailed description of the invention] The present invention can be fired in an inert atmosphere such as a nitrogen atmosphere,
Especially resistance value reproducibility, noise, ESD (electrostatic discharge)
The present invention relates to a tantalum-based thick film resistor composition with excellent resistance properties and materials used therein.

Servant! 11■ Thick film resistors are made by dispersing a conductive powder made of a metal or a metal compound such as a metal oxide and glass powder in an organic vehicle to form a paint or paste composition, and spreading it on a predetermined insulating substrate. After printing the pattern, it is fired and, if necessary, trimmed to obtain a predetermined resistance value.

Conventionally, ruthenium oxide-based resistors have been the mainstream, but in recent years, tin oxide-based and tantalum-based resistors have been put into practical use as thick film resistors that can be fired in an inert atmosphere and are compatible with base metal thick film conductors. Among these, tantalum-based metal tantalum,
Products containing tantalum nitride, tantalum boride, etc. as conductive components are known. For example, in JP-A-55-108702, tantalum particles, glass frit, and optionally titanium, boron, zirconium oxide, tantalum oxide, titanium oxide, etc. are known. A resistance composition is disclosed in which additives such as barium oxide, tungsten oxide, tantalum nitride, titanium nitride, molybdenum silicide, and magnesium silicate are blended up to 50% by weight of tantalum particles. This kind of tantalum resistance is 10
It is expected to be used for low to medium resistance in the range of Ω/min to 10 Ω/min.

However, the resistor obtained by firing a resistive composition consisting of tantalum metal powder and glass frit has a resistance of more than 100 Ω/hole, and is easily influenced by the firing conditions, i.e., the firing atmosphere, temperature, and time. There is a problem that the characteristics tend to fluctuate due to strong exposure, and the reproducibility of the resistance value is poor. Furthermore, as the resistance value increases, the variation in resistance value becomes significantly larger, and current noise and ESD
The characteristics will deteriorate and the temperature coefficient of resistance will become negative, so 1
If it exceeds Ω/min, it is not practical at all, and the range of usable resistance values is narrow.

Therefore, an object of the present invention is to provide a resistor composition that can produce a stable resistor with good reproducibility, which has a wide resistance value range, has low process sensitivity, and whose resistance characteristics are not easily affected by changes in firing conditions. It is in.

-゛The present invention is to heat-treat a mixture of tantalum metal powder and glass powder, or a mixture of tantalum metal powder, glass powder, and additive powder in an inert atmosphere at a temperature equal to or higher than the softening point of glass, and then crush it. It is a conductive composite powder made of The present invention also provides a resistance composition comprising this conductive composite powder dispersed in an organic vehicle, optionally together with glass powder and/or additive powder. The present invention also includes a method for producing a conductive composite powder, which is characterized in that the conductive composite powder is mixed with a conductive powder, heat treated in an inert atmosphere at a temperature equal to or higher than the softening point of glass, and then pulverized.

The tantalum metal powder has an average particle size of 5M or less, preferably 1-
The following are used: Especially average particle size 0.1-0.5
A grade of about a is preferable.

The glass powder is not particularly limited as long as it is commonly used in resistance compositions.For example, borosilicate alkaline earth metal glass, borosilicate alkaline earth metal aluminum glass, etc. are typical examples.The particle size is the average particle size. A diameter of 10 μs or less, preferably 1.about.5 μs is used.

The ratio of tantalum to glass is approximately 80/20 by weight.
It is in the range of ~10/9G. If the ratio is smaller than 10/90, current noise, resistance temperature characteristics, resistance value variations, etc. will deteriorate, making it unsuitable for use.

Additives that are generally known for adjusting the resistance value, resistance temperature characteristics, and other characteristics of tantalum-based resistors can be used.For example, boron, titanium, tungsten, zirconium oxide, zinc oxide, etc. , nickel oxide,
Cobalt oxide, tantalum oxide, vanadium oxide, titanium oxide, barium oxide, tungsten oxide, tantalum nitride, titanium nitride, molybdenum silicide, magnesium silicate, etc. can be added in an amount of 50% by weight or less of tantalum.

Heat treatment of a mixture of tantalum metal powder and glass powder, or a mixture with additive powder added thereto, is carried out in an inert atmosphere of N2, Ar, etc. at a temperature at which the glass is sufficiently softened and fluidized to facilitate reaction with tantalum. This treatment temperature varies depending on the type of glass, but is approximately 500 to 1
The temperature is about 300°C.

After the heat treatment, the mixture is cooled and pulverized by a conventional means such as a ball mill to obtain a composite powder having a predetermined particle size. The average particle size of the No. 11 mixture powder is desirably 10 or less, particularly about 1 to 5 particles.

The composite powder of the present invention can be used alone or mixed with untreated glass powder or additive powder and dispersed in a conventional organic vehicle to form a paint-like or paste-like resistance composition.

A feature of the present invention is that conductive powder and glass powder, or conductive powder, glass powder, and additives are heat-treated in advance and re-pulverized to form a composite. By firing a resistor composition using this composite powder, 10 process sensitivity, that is, variations in characteristics due to changes in the firing atmosphere, etc., are reduced, and variations in resistance values are reduced. For this reason, 10Ω/mouth ~ 1
A thick film resistor having stable characteristics can be obtained in a wide resistance value range of 00 to Ω/mm. Furthermore, the resistor of the present invention is
It also has much better current noise characteristics than the conventional one, and also exhibits improved ESD characteristics.

The reason why such an effect can be obtained is considered as follows.

When a resistance composition consisting of tantalum metal powder and glass frit was fired in a nitrogen atmosphere and the changes due to firing were examined by XIIA diffraction, the intensity of the Ta peak weakened and Ta20
A crystalline peak of 5 appears. The appearance of this crystal phase varies depending on the firing time, firing temperature, oxygen concentration in the firing atmosphere, etc., so the degree of progress of the reaction varies greatly depending on these firing conditions, and as a result, the resistance value changes from the conductivity before firing. It is thought that the variation is not determined by the ratio of powder to glass, and the variation becomes large. In particular, the closer to the high resistance region where the number of conductive particles decreases, the more the characteristics tend to deteriorate.

However, in the present invention, if the tantalum powder and glass are reacted in advance by heat-treating and are made into a composite from the beginning, even if a resistive composition using this conductive composite powder is fired, it will be much easier. There is no change in the crystalline phase, which reduces the variation in resistance values and greatly improves reproducibility. Furthermore, it is thought that the conductive particle matrix formed in the resistor has been stabilized and noise and ESD characteristics have been improved.
This makes it possible to manufacture a resistor with excellent characteristics even in a relatively high resistance range of 100Ω/mouth.

Note that even if a composite powder with a relatively high Ta content is used in combination with untreated glass powder, the effects of the present invention will not change.
Further, although the additive may be added alone to the resistance composition, it is preferable to compound the additive with the conductive particles and glass in advance, since this stabilizes the reaction between each component and makes the dispersion state uniform.

Back Top Example 1 60 parts by weight of Ta powder and 40 parts by weight of glass powder (composition is Ba 036.0-MQ O2,5-820s in weight%)
38.0-Ni O5,0-8i 0217. (1-A
I20s1.5) was mixed, ground in a ball mill, heat treated at 900°C for 2 hours in a N2 atmosphere, then slowly cooled, and ground again in a ball mill to obtain a conductive composite powder.

For 100 parts by weight of this composite powder, 1 part by weight of ethyl cellulose and 2.2.4-trimethyl-
30 parts by weight of 1,3-bentanediol monoisobutyrate was added and kneaded to prepare a resistance paste.

This resistance paste was printed in a 1 m x 1 square pattern on an alumina substrate on which copper thick film electrodes had been baked in advance, dried in air at 150°C for 10 minutes, and then dried at a maximum temperature of 900°C in an N2 atmosphere. Firing was carried out under the conditions of holding for 40 minutes and cycling for 40 minutes. The sheet resistance value, resistance value variation (CV), and current noise of the obtained resistor were 31.
It was 0Ω/mouth, 2.4%, -30dB or less. In addition, C
v is a value for 80 resistors.

Examples 2 to 4 Ta powder and glass powder were mixed in the ratio shown in Table 1, heat treated in the same manner as in Example 1, and ground to obtain conductive composite powder.

To 1 part by weight of each powder, an organic vehicle consisting of 1 part by weight of ethyl cellulose and 29 to 34 parts by weight of 2.2.4-)dimethyl-1,3-bentanediol monoisobutyrate is added and kneaded. Resistance pastes were prepared for each.

This resistor paste was baked onto an alumina substrate in the same manner as in Example 1, and the resistance value, resistance variation (CV), and current noise of the obtained resistor were investigated and are shown in Table 1.

Example 5 1 part by weight of 25 Ta powder, 70 parts by weight of glass powder having the same composition as in Example 1, and 5 parts by weight of B powder as an additive were mixed and ground in a ball mill. The mixture was heat-treated for a period of time, then slowly cooled, and ball-milled again to obtain a conductive composite powder.

Using this powder, a resistor paste was prepared in the same manner as in Example 1, and baked onto an alumina substrate to obtain a resistor. The characteristics are also shown in Table 1.

Example 6 25 parts by weight of Ta powder, 70 parts by weight of glass powder, and 5 parts by weight of Z'02 powder as an additive were mixed and heat-treated in the same manner as in Example 6. Using a composite powder obtained, a resistance paste was made. This paste was baked on an alumina substrate to obtain a resistor.The characteristics are also shown in Table 1.

Example 7 A conductive composite powder was obtained by heat treatment in the same manner as in Example 1 except that the weight ratio of Ta powder and glass powder was 60:40.

To 100 parts by weight of this conductive composite powder, 20 parts by weight of glass powder was further added and kneaded with an organic vehicle to prepare a resistance paste. The resistor obtained by firing on an alumina substrate has a sheet resistance value of 10 as shown in Table 1.
1Ω/mouth, CV3.3%, current noise -27.0dB,
It had excellent properties.

Comparative Examples 1 to 3 The same Ta powder and glass powder used in Example 1 were mixed in the ratio shown in Table 1, and kneaded with a vehicle without heat treatment to obtain a resistance paste.

A resistor was manufactured in the same manner as in Example 1, and the characteristics are also shown in Table 1.

From Table 1, it can be seen that the resistance value variation and noise characteristics of the resistor obtained by the present invention are greatly improved compared to the comparative example using a powder that is not heat-treated and composited and has a similar resistance value. I know that there is.

(The following is a blank space.) Figures 1 and 2 show Examples 1 to 7 and Comparative Examples 1 to 3 shown in Table 1 to make it easier to understand the effects of the present invention.
3 is a graph in which Cv and current noise are plotted against the sheet resistance value of the resistor. Line A in FIG. 1 is an example, line B is a comparative example, and line C in FIG. 2 is an example,
The line is a comparative example. It is clear from these graphs that the resistor of the present invention has extremely excellent characteristics.

Next, for Examples 3.5 and 6, an ESD test was conducted by discharging once at a voltage of 5 kV using a 150 pF capacitor, and the rate of change in resistance value was -8 and 7, respectively.
%, -2.6%, -9.4%.

When a similar ESC test was conducted on Comparative Example 3, which has a resistance value close to those of these Examples, the resistance change rate was -2
It's extremely large at 1.0%.

The present invention heat-treats tantalum powder and glass powder in advance,
By using them in combination, a resistor having stable and excellent resistance characteristics with low process sensitivity over a wide resistance value range can be manufactured easily and with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between Cv and sheet resistance of the resistors of Examples and Comparative Examples of the present invention, and FIG. 2 similarly shows the relationship between sheet resistance and current noise. It is a graph. cv/Jouwo Ryuukai/dB

Claims (1)

[Claims] 1. A conductive composite powder obtained by heat-treating a mixture of tantalum metal powder and glass powder in an inert atmosphere at a temperature equal to or higher than the softening point of glass and then pulverizing it. 2. A conductive composite powder obtained by heat-treating a mixture of tantalum metal powder, glass powder, and additive powder in an inert atmosphere at a temperature equal to or higher than the softening point of glass and then pulverizing it. 3 The additives consist of boron, titanium, tungsten, zirconium oxide, zinc oxide, nickel oxide, cobalt oxide, tantalum oxide, vanadium oxide, titanium oxide, barium oxide, tungsten oxide, tantalum nitride, titanium nitride, molybdenum silicide, and magnesium silicate. The conductive composite powder according to claim 2, which is one or more selected from the group. 4. A resistance composition obtained by dispersing the conductive composite powder according to any one of claims 1 to 3 in an organic vehicle. 5 further blended with glass powder and/or additive powder,
5. The resistance composition of claim 4. 6 The additives consist of boron, titanium, tungsten, zirconium oxide, zinc oxide, nickel oxide, cobalt oxide, tantalum oxide, vanadium oxide, titanium oxide, barium oxide, tungsten oxide, tantalum nitride, titanium nitride, molybdenum silicide, and magnesium silicate. The resistance composition according to claim 5, which is one or more selected from the group. 7. A method for producing a conductive composite powder, which comprises mixing tantalum metal powder and glass powder, heat-treating the mixture in an inert atmosphere at a temperature equal to or higher than the softening point of the glass, and then pulverizing the mixture. 8. Production of conductive composite powder characterized by mixing tantalum metal powder, glass powder, and additive powder, heat-treating the mixture in an inert atmosphere at a temperature equal to or higher than the softening point of glass, and then pulverizing the mixture. Method.