JPS60206104A - 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 the Invention The present invention relates to a method for manufacturing a thick-film positive temperature coefficient semiconductor element that does not require a glass frit, which is a sheet heating element used for heat insulation and heating of equipment, etc. It is something.

Conventional configuration and its problems Elements made of B aT 103 semiconductors have switching characteristics in which the resistance value increases rapidly above a predetermined temperature and self-heating characteristics after switching, and have fast temperature rise characteristics and self-temperature control functions. It is widely used because it does not require an external control circuit.

Conventional positive temperature coefficient thermistor heating elements were obtained by press-molding BaTiO3-based semiconductor powder and then firing it, but it was considered difficult to obtain a practical thick film positive temperature coefficient thermistor heating element. .

Conventionally, the following methods are known for processing a BaT IO3-based semiconductor 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 B a TiO3 semiconductor powder to form a paste, which is screen printed on a substrate and then fired.

However, in the method (2), since the crystal element diameter of the B a T 103 semiconductor is large and brittle, it is extremely difficult to polish it into a film. Unfortunately, method (2) above 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 be high and control is difficult, making it unsuitable for heating elements.Furthermore, the glass frit must be prepared and fired in advance, which is troublesome and depends on the material of the glass frit. is B
aTi Degrades the switching characteristics and self-heating characteristics of the i○3 semiconductor. Adding glass frit makes it vulnerable to thermal shock due to the difference in heat resistance and coefficient of thermal expansion between the B a T i O 3 -based semiconductor and the glass frit, and thus hinders heat conduction. 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 solves the manufacturing complexity that was a drawback of the prior art, and creates a thick film without using glass frit, which has excellent thermal shock resistance and thermal conductivity, and has uniform properties. It is an object of the present invention to provide a method for easily manufacturing a thick film type positive characteristic 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 comprises B a
Fe3Si, Fe5Si in T103 semiconductor powder
3. FeSi.

At least one type of powder from F e S 12
．． The purpose is to obtain a thick-film type positive characteristic semiconductor element by applying a mixture of 0 to 6o and 0 weight coefficients and applying paste on a substrate to form a thick film, and then firing it.

In the conventional method of using conductive additives and glass frit, a conductive additive is required to electrically connect BaTiO3-based semiconductor powders, and it is necessary to physically connect BaTiOs-based powders together. Glass frit was required.

However, according to the present invention, Fe5S1°Fe5 serves as both a conductive additive and a glass frit.
S13. It is characterized by using at least one type of Feat and Fe5x2.

These Fe5Sl, Fe6Si3. FeSi, Fe5
12 is a conductor at room temperature, and when the temperature reaches 1000 to 1100° C. or higher, a portion of it decomposes and 3102 precipitates on the particle surface, but the inside of the particle remains the original IT and decomposition is prevented by the 5IQ2 film on the surface. Therefore, B a T z Os
based semiconductor powder, Fe3Sx, Fe5Szs, Fe
When Si and Fe5x2 powders are mixed and fired, F relaxation S
i, Fe5Si3゜FeSi, 5102 precipitated on the surface of FeSi2 plays the same role as glass frit,
Since the inside of the particle acts as a conductive additive, Fe5Sl
, Fe5Sz3. Feai.

By simply adding Fe512, it is possible to obtain a thick film type positive characteristic semiconductor element that does not require a glass frit.

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 BaTi○3K 1.0 mol% of Nb2O was added and 1
After firing at 30 oc, it is pulverized to obtain BaTi○3-based semiconductor powder. 12.% based on the total weight of the B a T 103 semiconductor powder. ○ Add the weight of FeSi powder and mix uniformly, and further add α-terpineol to make paste mixture 1.

On the other hand, a pair of electrodes 3.4 made of a conductive material such as Aq are provided in advance on a substrate 2 made of Al206 etc. Paste-like mixture 1 was applied by screen printing, etc., and heated at a heating rate of 1Q°C/min from room temperature to 13°C.
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 mol of Y was added to BaTiO3.
After adding 2O3 and firing at 1250℃, it is crushed to form BaT.
An i○3-based semiconductor powder is obtained. 20% of the total weight of the BaT i○3-based semiconductor powder. ○Weighter's F e S
12 powder is added and mixed uniformly, and α-terpineol is further added to form paste mixture 1. Next, as in Example 1, the electrodes 3 and 4 are placed on the substrate 2'' in advance.
The paste-like mixture 1 was applied by screen printing or the like so that a part of the electrodes 3 and 4 remained, and the temperature was raised from room temperature to 1300'C at a rate of 10°C/min. After holding for a minute, let it cool in the furnace. In this way, a thick film semiconductor device was obtained.

The sheet resistance at room temperature of the thick film semiconductor device thus obtained was 3.6 Ω/ci in the case of Example 1, and 0.8 KQ/rsl in the case of Example 2. The relationship was as shown in Figure 2. In Figure 2, A is Example 1
Characteristics of the element obtained by B are the characteristics of Example 2.

Here, instead of FeSi and FeSi2, Fe3Si,
Even when Fe5Si3 was used, the same effect as described above could be obtained, and furthermore, there was no problem even when these were used in combination.

Effects of the Invention As described above, according to the manufacturing method of the present invention, the powder plays the role of both a conventional conductive additive and a glass frit, and has sufficient effects for electrical connection and physical connection. A thick film positive characteristic semiconductor element can be obtained without a glass frit.

Fe3Si, a conductive metal with good thermal conductivity, has replaced glass frit, which has poor thermal conductivity.

Fe5Si3. By using FeSi or FeSi2, 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 BaTi○3-based semiconductor powder may be used as long as it is made into a semiconductor by adding various additives to BaTzO3. Also, Fe5S1°F e ei S 13 , F e S 11 F
The reason why the amount of addition of S12 powder was defined as 1 to 6Q weight ratio based on the total weight is that if it is less than 1 weight ratio, the area resistance becomes too large and it is unsuitable for a heating element, and the physical fixation of BaTiO3 powders On the other hand, if the weight coefficient exceeds 60, the sheet resistance becomes too small, making it unsuitable for a heating element with small self-control characteristics (PTC characteristics). Furthermore, in the above examples, B a T 103-based semiconductor powder and Feat.

An organic solvent (α-terpineol in the example) was used to make the FeSi2 powder into a paste, but 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 glass 7 watts.
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. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 14 Figure 2 51L degrees (°C)

Claims (1)

[Claims] Fe3Si, Fe6S in BaTlO3-based semiconductor powder
i3. FeSi. At least one type of powder of Fe512 is 1.0 to 6
1. A method for manufacturing a thick-film type positive characteristic semiconductor device, comprising: applying 0.0% by weight of a paste-like mixture onto a substrate to form a thick film, and then firing the mixture.