JPS6064403A - 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 B A device made of an a T It is widely used because it has a control function and does not require an external control circuit.

The conventional positive temperature coefficient thermistor heating element is B a T i O3
It was obtained by press-molding a semiconductor powder and then firing it.
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 BaT 103-based semiconductors into a film.

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

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

(2) A conductive additive and glass frit are added to the E a TiO3-based semiconductor powder to form a base, which is screen printed on a substrate and then fired.

However, in the method (2), since the crystal grain size of the B a T i O 3 -based semiconductor is large and brittle, it is extremely difficult to polish it 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, in method (2) above, the sheet resistance tends to increase and is difficult to control, making it unsuitable for heating elements. Furthermore, the glass frit must be prepared and fired in advance, which is troublesome, and the material of the glass frit is difficult to control. In some cases, the switching characteristics and self-heating characteristics of BaTiO3-based semiconductors are deteriorated. By adding glass frit, F) B a T t O3 type semiconductor and the glass frit are susceptible to thermal shock due to the difference in heat resistance and coefficient of thermal expansion, and heat conduction is hindered. Furthermore, it is difficult to uniformly mix conductive additives and glass frit, which is one of the causes of variations in properties.

Purpose of the Invention Therefore, the present invention eliminates the complexity of manufacturing, which was a drawback of the prior art, and creates a film with excellent thermal shock resistance and thermal conductivity, and by forming a thick film without using glass frit. It is an object of the present invention to provide a method for easily manufacturing a thick film type positive characteristic semiconductor element having the following characteristics.

Structure of the Invention The method for manufacturing a thick film type positive temperature semiconductor device of the present invention comprises B a
Sm6Si3. Thick film type positive characteristics can be obtained by applying a paste-like mixture of at least one type of SmSi or SmSi2 at 1 to 60% by weight based on the total weight and applying it onto a substrate to form a thick film and then firing it. It is intended to convert semiconductor elements into I(J).

The conventional method using conductive additives and glass frit requires a conductive additive to electrically connect BaTiO3-based semiconductor powders, and it is difficult to physically connect BaTiO3-based semiconductor powders to each other. Glass frit was required.

However, according to the present invention, Sm5si3°SmS acts as both a conductive additive and a glass frit.
i Also, it has a habit of using SmSi2. This Sm5St3. SmSi and SmSi2 are conductors at room temperature, but at temperatures above 1000~1100°C, a portion of them decomposes and 3102 precipitates on the surface of the oscillator, but the inside of each particle remains intact and is formed by the SiO2 film on the surface. Decomposition is prevented. Therefore, BaTi○3 based semiconductor powder and Sm5Si3. Sm5i-! f, or SmSi2 powder is mixed and fired, Sm, Si3. SmSi
Alternatively, Sm5Si3. SmSi or SmS
By simply adding i2, it is possible to obtain a thick film type positive characteristic semiconductor element that does not require glass.

Furthermore, by adding a conductive metal, the thermal conductivity is better than that of a glass slit with poor thermal conductivity, and the thermal shock resistance is also improved.

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

Example 1 1.0 mol of La2O3 was added to E a T IO3, fired at 1300°C, and then pulverized to form B a T i O
A 3-based semiconductor is obtained. A paste-like mixture 1 is prepared by adding 3rnSi powder in an amount of 6.0% by weight based on the total weight of the B a T i O3 semiconductor powder and mixing uniformly, and then adding α-terpineol.

On the other hand, a pair of electrodes 3゜4 made of a conductive substance such as Aq is provided in advance on a substrate 2 made of Al2O3, etc., and a part of the electrodes 3゜4 remains on the electrodes 3, 4. The paste-like mixture 1 was applied by screen printing or the like, and heated at a heating rate of 10°C/mLn from room temperature for 13 min.
After raising the temperature to 50°C and maintaining it for 1 hour, it is allowed to cool in the furnace.

In this way, a thick film type positive characteristic semiconductor device was obtained.

Example 2 In the same manner as in Example 1, 3.0 mole of La2O3 was added to B a T 103 and fired at 1260°C, and then crushed to give a BaTiO3 based semiconductor powder with 20.0 mole of La2O3 based on the total weight. SmS of
Add i2 powder and mix evenly, then add α-terpineol and base! The mixture 1 is made into a mixture 1, and then, as in Example 1, the electrodes 3,
4 was prepared, the paste mixture 1 was applied by screen printing or the like so that a part of the electrode 3.4 remained, and the temperature was raised from room temperature to 1300°C at a rate of 10°C/drive. After holding for a minute, let it cool in the furnace. In this way, an 11IIψ type semiconductor device was obtained.

In this way, the sheet resistance of the thick film semiconductor device at room temperature is 3.7Ω/cdl in the case of Example 1, and 1.4KQlcdt in the case of Example 2, depending on the temperature and resistance value. The relationship was as shown in Figure 2. In FIG. 2, A shows the characteristics of the device obtained in Example 1, and B shows the characteristics in Example 2.

Effects of the Invention As described above, according to the manufacturing method of the present invention, Sm 5S
i3. SmSi or SmSi2 powder plays the role of both a conventional conductive additive and a glass frit, and has sufficient effects for electrical and physical connections, making it possible to obtain thick-film positive characteristic semiconductor devices without a glass frit. It will be.

In addition, instead of glass frit, which has poor thermal conductivity, Sm6Si3°SmSi, a conductive metal with good thermal conductivity,
By using SmS'2, heat conduction is improved and thermal shock resistance is also improved. Furthermore, since it can be manufactured by screen printing or the like, the work is easy and mass production is possible.

In the present invention, any Ba TiO3-based semiconductor powder may be used as long as it is made into a semiconductor by adding various additives to Ba TiOs. Also, Sm6S
The reason why i3゜For addition of SmSi, SmSi2 powder: is specified as 1 to 60% by weight based on the total weight is that if it is less than 1% by weight, the area resistance is too large and it is unsuitable for a heating element.
a T i O3 powder cannot be physically fixed together,
On the other hand, if the amount exceeds 6ON, the area resistance becomes too small.
This is because the self-control characteristic (PTC characteristic) becomes small, making it unsuitable for a heating element.

Further, in the examples, only the case where one type of conductive metal was added was shown, but it was confirmed that the same effect can be obtained if the total amount of multiple types added is within the specified amount.

Furthermore, B a T 10s semiconductor powder and Sm6Si
Although an organic solvent (a-terpineol in the example) was used to make the 3°SmS i and SmS t2 powders into a paste, any solvent may be used as long as it can be made into a paste.

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 the drawing]

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 mixture, 2... Substrate, 3, 4... Electrode.

Claims (1)

[Claims] 5rrh ss to B a Ti O3 based semiconductor powder
After adding 1 to 60% by weight of at least one of is, 5rnS z or SmSi2 to the total weight and applying the paste-like mixture on the substrate to form a thick film,
A method for manufacturing a thick film type positive characteristic semiconductor element, characterized in that it is produced by firing.