JPH0661013A - Thick film positive temperature coefficient thermistor composition and manufacture thereof as well as thick film positive temperature coefficient thermistor using the composition - Google Patents

Abstract

PURPOSE:To avoid the deterioration in temperature coefficient of resistance(TCR) even if the composition is mixed with glass particles to be heated for baking step by a method wherein RuO2 and positive TCR driver, e.g. CuO is previously solid phase-reacted to be turned into a metallic conductive oxide having larger TCR. CONSTITUTION:Ag-Pd base electrodes 2, 2 are formed by printed-baking step close to opposite ends of an aluminum substrate 1 printed with thick film positive temperature coefficient(PTC) thermistor paste and baked so as to be electrically connected striding over these electrode 2, 2 for manufacturing a thick film PTC thermistor body 3. At this time, the thick film PTC thermistor composition is composed of at least two kinds of either one combinations out of Cu and Ru or oxide, hydroxide, carbonate, oxalate comprising Cu and Ru to be mixed with each other for heating and baking steps. Through these procedures, the thick film PTC thermistor having excellent linearity in the resistance temperature coefficient can be manufactured without deterioration in TCR.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick film positive temperature coefficient (positive temperature coefficient of resistance) thermistor composition for a thick film positive temperature coefficient thermistor, a method for producing the same, and a thick film positive temperature coefficient thermistor using the composition. It is a thing.

[0002]

2. Description of the Related Art Conventionally, as a resistor having a positive temperature coefficient, there is known a resistor in which Ni or Ni-Cr is deposited on, for example, an alumina substrate and a circuit pattern is formed by a technique such as etching. .

However, since these are manufactured by the thin film method, the manufacturing method is complicated and strict conditions are required. Therefore, there is a demand for a simpler, less expensive product that can be mass-produced and a method for manufacturing the same.

[0004]

In the thick film method, since heating and baking are performed in air, Ni or Ni-C, which is easily oxidized, is used.
Metals such as r cannot be used.

A metal generally becomes a semiconductor or an insulator when it becomes an oxide, and RuO ₂ in it is known as an oxide exhibiting metallic conductivity. This RuO ₂ has a temperature coefficient of about +3000 ppm / ° C., but when it is mixed with glass powder and baked by heating, it decreases to about +800 ppm / ° C. Recently, additives have been added to this, about ± 100 pp
It has been prepared to be about m / ° C.

The additives in this case are Nb ₂ O ₅ , TiO ₂ and Mn ₂ as additives (negative TCR driver) that reduce the temperature coefficient of resistance (TCR).
O ₃ , NiO, Sb ₂ O _{3 and the} like are known, and CuO is known as a positive TCR driver.

However, the purpose of using these additives is to add a very small amount in order to set the TCR of the resistance paste mainly composed of RuO ₂ within a certain limited range (eg ± 100 ppm / ° C). Yes, there is a difference in the object, configuration, and effect of the present invention.

According to the present invention, RuO ₂ and a positive TCR driver, for example, CuO, are preliminarily solid-phase reacted to form a metallic conductive oxide having a larger TCR, and even if mixed with glass and heated and fired, the TCR is obtained. Provided are a thick film positive temperature coefficient thermistor composition and a method for producing the same, and a thick film positive temperature coefficient thermistor using the composition.

[0009]

The present invention has been made for the purpose of solving the above-mentioned problems, and has the following structure as one means for solving the above-mentioned problems. That is, a compound obtained by mixing and heating at least two kinds of at least Cu and Ru, or at least any combination of oxides, hydroxides, carbonates and oxalates composed of Cu and Ru, and glass. And a thick film positive temperature coefficient thermistor composition.

The above thick film positive temperature coefficient thermistor composition comprises at least two of at least any combination of oxides, hydroxides, carbonates and oxalates consisting of at least Cu and Ru or at least Cu and Ru. A thick film paste is manufactured by mixing the seeds mixed and heated and fired with each other, the step A in which the compound is further crushed and weighed, the step B in which the glass powder is weighed, and the powders obtained in the steps 2 and A of the weighing 2 steps are mixed. It is manufactured by a C process and a D process of heating and baking the thick film paste obtained in the C process.

Then, this is applied to a thick film positive temperature coefficient thermistor.

[0012]

In the above structure, at least Cu and Ru,
Or a compound obtained by mixing and heating at least two kinds of a combination of compounds consisting of Cu and Ru, so that the resistance is low, the TCR is not lowered, and the linearity of the resistance-temperature characteristic is good. A positive temperature coefficient thermistor composition can be provided. In addition, by using this thick film positive temperature coefficient thermistor composition, it is possible to improve the production efficiency, and at the time of forming a hybrid integrated circuit (HIC), a thick film positive temperature coefficient circuit can be simultaneously formed. A thermistor can be provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings.

[First Example] CuO and RuO ₂ were mixed in advance in a molar ratio of 1: 1 and a mixed powder of CuO and RuO ₂ was molded and then placed in a magnetic crucible and heated at 900 ° C. for 1 hour. The mixture was heated and baked for a time to cause a solid phase reaction. Then, this oxide was ball-milled into a powder. When this powder was analyzed by X-ray diffraction, it was identified as a compound called CuRuO ₃ . And 45w of this product powder
t% and lead borosilicate glass powder 55 wt% are weighed and mixed by an automatic mixer or a ball mill to form a mixture.

Here, as an organic vehicle, 7 wt% is further added.
Butyl carbitol containing ethyl cellulose was added so as to be 25 wt% of the above mixture, and thoroughly mixed with a three-roll or the like to obtain a thick film positive temperature coefficient thermistor paste.

In the above examples, CuO and RuO ₂ were used as the starting materials of Cu-Ru-O system, but the present invention is not limited to this, and for example, Cu and R may be used.
It may be u, or a hydroxide, carbonate or oxalate of Cu and Ru. Using the obtained thick film positive temperature coefficient thermistor paste, as shown in FIGS. 1 and 2, Ag-Pd was formed in the vicinity of the facing end faces of the alumina substrate 1.
The system electrodes 2 and 2 are formed by printing and baking, and the thick film positive temperature coefficient thermistor paste is printed so as to electrically connect across the electrodes 2 and 2, and baking is performed at 850 ° C. for 10 minutes to form the thick film normal characteristics. The characteristic thermistor body 3 is obtained. If necessary, the thick film PTC thermistor body 3 may be trimmed 4 to adjust the resistance value. Next, an electrically insulating protective film 5 (eg, epoxy resin) is applied or printed so as to cover the entire surface of the thick film positive temperature coefficient thermistor body 3 and the trimming 4 and a part of the electrodes 2 and 2, and then dried. To cure. After that, the surface of the electrodes 2 and 2 not covered with the protective film 5 is Ni, S
Then, electrodes 6 and 6 which can be soldered are formed by means of plating or sputtering. Here, the protective film 5 may be glass or the like.

The resistance value of the obtained thick film positive temperature coefficient thermistor is 91.3Ω when the area is 1 mm ^{2 and the} film thickness is 10 μm.
(25 ° C), TCR is 2852ppm / ° C (25 ° C / 1
The characteristics were stable at 25 ° C.

Table 1 shows the composition ratio, resistance value and TCR of the thick film positive temperature coefficient thermistor sample Nos. 1 to 3 and CuRuO ₃ of the present invention.

[0019]

[Table 1] In Table 1, the resistance value of each sample is 25 μC and the film thickness is 10 μm.
The area is a value of 1 mm ² , and the TCR is given by the following mathematical formula 1.

[0020]

[Equation 1] According to this, in this composition range, Cu for glass is
It can be seen that the resistance value tends to decrease and the TCR tends to increase as the content of RuO ₃ increases.

In the above examples, CuO and RuO ₂ were used as the Cu source and the Ru source, respectively.
If it becomes an oxide of Ru and Ru, a combination of other Cu compound and Ru compound may be used. From Table 1, the thick film positive temperature coefficient thermistor formed by using the composition of the present invention is Cu and Ru,
Or at least an oxide or a hydroxide composed of Cu and Ru,
The compound obtained by mixing and heating at least two kinds of any combination of carbonate and oxalate is used as a metallic conductive oxide, so that the TCR does not decrease even when mixed with glass powder and baked. . Therefore, a thick film PTC thermistor having a low resistance and a high TCR can be obtained by printing the above thick film PTC thermistor composition so as to straddle the opposing electrodes of the ceramic substrate and heating and firing.

[0022]

As described above, according to the present invention,
It is possible to obtain a thick film positive temperature coefficient thermistor which has a low resistance, does not lower the TCR even when mixed with glass powder and heated and fired, and has a good linearity of resistance temperature characteristics. Further, since the positive temperature coefficient thermistor part has a normal thick film shape, it can be manufactured in the same process as or in the same process as the chip resistor, and new factory equipment is not required. Therefore, it is suitable for mass production, the production efficiency is improved, and the manufacturing cost can be reduced. Further, in the case of forming a hybrid integrated circuit (HIC), it is possible to simultaneously form the temperature compensation circuit at the time of manufacturing the hybrid integrated circuit (HIC). A thick film positive temperature coefficient thermistor composition, a method for producing the same, and a thick film positive temperature coefficient thermistor using the composition can be provided.

[Brief description of drawings]

FIG. 1 is a plan view of a thick film positive temperature coefficient thermistor formed by using a thick film positive temperature coefficient thermistor composition according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view taken along line AA of the above.

FIG. 3 is a temperature characteristic diagram of the resistance value of sample number 1 of the thick film positive temperature coefficient thermistor showing one embodiment of the present invention.

FIG. 4 is a temperature characteristic diagram of the resistance value of sample number 2 of the thick film positive temperature coefficient thermistor showing one embodiment of the present invention.

FIG. 5 is a temperature characteristic diagram of the resistance value of sample number 3 of the thick film positive temperature coefficient thermistor showing one embodiment of the present invention.

FIG. 6 is a characteristic diagram of a composition ratio and a resistance value of a thick film positive temperature coefficient thermistor composition in the thick film positive temperature coefficient thermistor of the present invention.

[Explanation of symbols]

 1. Substrate 2,6. Electrode 3. Thick film positive temperature coefficient thermistor body 4. Trimming 5. Protective film

Claims (3)

[Claims] 1. At least Cu and Ru, or Cu and Ru
A thick film positive characteristic comprising a compound obtained by mixing and heating at least two kinds of at least two kinds of a combination of at least an oxide, a hydroxide, a carbonate and an oxalate, and glass. Thermistor composition. 2. At least Cu and Ru or Cu and Ru
And at least two oxides, hydroxides, carbonates, and oxalates are mixed and heated and calcined, and the compound A is further crushed and weighed, and glass powder is weighed. The process B includes a process B, a process C in which the powders obtained in the weighing processes A and B are mixed to produce a thick film paste, and a process D in which the thick film paste obtained in the process C is heated and fired. A method for producing a thick film positive temperature coefficient thermistor composition, comprising: 3. A substrate having a predetermined size of electrical insulation, electrodes formed near at least opposite ends of the substrate, and at least Cu and Ru formed so as to connect between the electrodes, or Thick film positive temperature coefficient thermistor composition composed of glass and a compound obtained by mixing and heating at least two kinds of any combination of oxides, hydroxides, carbonates and oxalates composed of Cu and Ru And a protective film covering the thick film thermistor composition and a part of the electrode.