JPS60261104A - Method of producing thick film positive temperature coefficient semiconductor element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a thick-film positive temperature coefficient semiconductor element that does not require glass frit, among planar heating elements used for heat insulation and heating of equipment, etc. It is.

Conventional configuration and its problems BaTi0. Elements made of , based semiconductors have switching characteristics in which the resistance value increases rapidly above a predetermined temperature and self-heating characteristics after switching, have fast temperature rise characteristics, have a self-temperature control function, and can be controlled by external control circuits. It is widely used because it is not required.

Conventional positive temperature coefficient thermistor heating elements are obtained by pressure molding (and later firing) BaTiO3-based semiconductor powder, but it has been considered difficult to obtain a practical thick film positive temperature coefficient thermistor heating element. .

Conventionally, the following methods are known for processing BaTi0-based semiconductors into a film.

■ After forming into a disk shape, the fired product is polished into thin pieces.

■ Form a thin film on the substrate by vacuum evaporation.

(2) Conductive additives and glass frit are added to BaTiO3-based semiconductor powder to form a paste, which is screen printed on a substrate and then fired.

However, in the method (2), since the BaTiO3-based semiconductor has a large crystal grain size and is brittle, it is extremely difficult to polish the BaTiO3-based semiconductor into a film. Furthermore, the method (2) is cumbersome to operate, and it is difficult to obtain a large amount of power suitable for the heating element.

Furthermore, method (2) above tends to have a high sheet resistance and is difficult to control, and is not suitable for heating elements.The glass frit must be prepared and fired beforehand, which is troublesome and difficult to control. 4Ba depending on the quality
It deteriorates the switching characteristics and self-heating characteristics of the 5ic3 semiconductor. By adding glass frit, the BaTiO3 semiconductor and the glass frit are susceptible to thermal shock due to the difference in heat exchange performance and thermal expansion coefficient, and heat conduction is hindered. In addition, conductive additives and glass foam')
'tr It is difficult to mix uniformly, and this is one of the causes of variations in characteristics.

Purpose of the Invention Therefore, the present invention solves the drawbacks of the above-mentioned conventional technology, which are complicated in manufacturing, and creates a film with excellent thermal shock resistance and thermal conductivity, and uniform properties by forming a thick film without using glass frit. The purpose of the present invention is to provide a method for easily manufacturing a thick film type positive temperature semiconductor device having the following characteristics.

Structure of the Invention The method for manufacturing a thick film type positive temperature semiconductor device of the present invention includes
1.0-60.0% by weight of DYP in iO3-based semiconductor powder
In addition, the present invention attempts to obtain a thick film type positive characteristic semiconductor element by coating a paste-like mixture on a substrate to form a thick film and then firing it.

In the conventional method using conductive additives and glass frit If, conductive additives are required for electrical connection between BaT03-based semiconductor powders, and glass frit is required to physically connect BaTiO3-based powders together. It was necessary.

However, the present invention is characterized in that DyP is used as a material that functions as both a conductive additive and a glass frit. This DyP is a conductor at room temperature, and when the temperature reaches 1000-1100°C or higher, a portion of it decomposes and P2O3 precipitates on the particle surface, but the inside of the particle remains the original 1-1 and the P2O5 film on the surface prevents decomposition. be done. Therefore, when 13aTiO5-based semiconductor powder and DyP powder are mixed and fired, bowl P precipitates on the surface of DyP.
Since 2O5 plays the same role as glass frit, and the inside of the particle plays the role of a conductive additive, a thick film type positive characteristic semiconductor element that does not require any glass frit can be obtained by simply adding DYP f,H.

In fact, by adding a conductive metal, thermal conductivity becomes better than glass frit, which has poor thermal conductivity, and thermal shock resistance also improves.

DESCRIPTION OF EMBODIMENTS Below, embodiments of the present invention will be specifically explained with reference to FIG.

Example 1 1.0 mo/lz% Nb2O5 was added to BaTiO5 and fired at 1300'C, followed by pulverization to obtain a BaTio5-based semiconductor powder. A paste-like mixture 1 is prepared by adding 10.0% by weight of DYP powder based on the total weight to the BaTi03 semiconductor powder and mixing uniformly, and then adding α-terpineol.

On the other hand, a pair of electrodes 3.4 made of a conductive material such as Ag are provided in advance on a substrate 2 made of Al2O3, etc., so that a part of the electrodes 3.4 remains on the electrodes 3 and 4. The paste-like mixture was coated by 1ff screen printing or the like, heated from room temperature to 1350°C'' at a rate of 10'C/min, held for 1 hour, and then left to cool in the furnace. In this way, a thick film type positive characteristic semiconductor device was obtained.

Example 2 3.0 mol% L was added to BaTiO3 in the same manner as in Example 1.
After adding a 20 s and firing at 1250''C, it is pulverized to obtain a BaTi0!-based semiconductor powder.The BaTi
05 series semiconductor powder contains 18.0% by weight of D based on the total weight.
Add yP powder and mix uniformly, and then add a-terpineol to make paste mixture 1. Next, as in Example 1, the electrodes 3 and 4 were previously provided on the substrate 2, and the paste mixture 1 was applied by screen printing or the like so that a portion of the electrodes 3 and 4 remained.
The temperature was raised from room temperature to 1300''C at a heating rate of 10''C/min, held for 30 minutes, and then allowed to cool in the furnace. In this way, a thick film semiconductor element was obtained.

The sheet resistance at room temperature of the thick film semiconductor device thus obtained was 6. In the case of Example 2, it was 3.2 Ω/oJ, and the relationship between each temperature and resistance value was as shown in FIG. 2. In Fig. 2, B is the characteristic of the device obtained in Example 1, and B is the characteristic of the device obtained in Example 2. Effects of the Invention As described above, according to the manufacturing method of the present invention, the DyP powder is different from that of the conventional one. It plays the role of both a conductive additive and a glass frit, and is sufficiently effective for electrical and physical connections, making it possible to obtain a thick-film positive characteristic semiconductor element without the need for a glass frit.

-! In addition, DyPf, a conductive metal with good thermal conductivity, can be used instead of glass frit, which has poor thermal conductivity. It is easy to work and can be mass-produced.

In the present invention, any BaTiO10-based semiconductor powder may be used as long as it is made into a semiconductor by adding various additives to BaTiO3. The reason why the amount of DyP powder added was specified as 1 to 60% by weight based on the total weight was 1.
If it is less than 60% by weight, the area resistance becomes too large, making it unsuitable for a heating element, and the BaTiQ3 powder cannot be physically fixed together. On the other hand, if it exceeds 60% by weight, the area resistance becomes too small, resulting in self-control characteristics (PTC characteristics). This is because it becomes small and unsuitable for use as a heating element. Furthermore, an organic solvent (
In the examples, α-terpineol) was used, but any material that can be made into a paste may be used.

As described above, according to the present invention, it is possible to easily manufacture a thick film type positive characteristic semiconductor device that does not require a glass frit.
Its practical effects are significant.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing a thick film positive temperature coefficient semiconductor device obtained by the method of the present invention, and FIG. 2 is a diagram showing the relationship between temperature and resistance value of the device according to an embodiment of the present invention. 1... Paste-like mixture, 2... Substrate, 3,
4... Electrode.

Claims (1)

[Claims] 1.1.1% of DyP was added to the 13aTi03-based semiconductor powder. o~60.
1. A method for producing a thick film type positive characteristic semiconductor element, comprising: applying 0% by weight of a paste-like mixture onto a substrate to form a thick film, and then firing the mixture.