JPS60261109A - 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] Industrial Application Field The present invention is a method for manufacturing a thick-film positive temperature coefficient semiconductor element that does not require a glass frit among planar heating elements used for heat insulation and heating of equipment. It is related to.

Conventional configuration and its problems Elements made of BaT i○3 semiconductors have switching characteristics in which the resistance value increases rapidly above a certain temperature and self-heating characteristics after switching, and have fast temperature rise characteristics and self-temperature control. It is widely used because it has many functions and does not require an external control circuit.

Conventional positive temperature coefficient thermistor heating elements were obtained by press-molding B a T 103 semiconductor powder and then firing it, but it was found that it was difficult to obtain a practical thick film positive temperature coefficient thermistor heating element. It had been.

Conventionally, a C1-order method is known as a method for processing BaTiO3-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 BaTi○3-based semiconductor powder to form a paste, which is screen printed on a substrate-1- and then fired.

However, in the method (■) above, since the crystal grain size of the B a T 103 semiconductor is large and brittle, it cannot be polished until it becomes a film.
It is extremely difficult to do 6. Still, use method ① above;
J operation is troublesome, and it is difficult to generate a large amount of power suitable for the heating element. Furthermore, the above-mentioned method (2) tends to increase the sheet resistance and is difficult to control, making it unsuitable for heating elements.
Further, the glass frit must be prepared and fired in advance, which is troublesome and, depending on the material of the glass frit, may deteriorate the switching characteristics and self-heating characteristics of the B a T 103 semiconductor. Addition of glass frit makes it vulnerable to thermal shock due to the difference in heat resistance and coefficient of thermal expansion between the BaTiO3 semiconductor and the glass frit, which impedes 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 by forming a thick film without using glass frit, it 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
Adding SrBe to T10s semiconductor powder from 1.0 to
The purpose is to obtain a thick-film type semiconductor device with 11 characteristics by applying a paste-like mixture to a 60.0 weight coefficient onto a substrate to form a thick film and then firing it.

In the conventional method using conductive additives and glass frit, electrical connection between B a T 103 semiconductor powders is difficult.
A conductive additive is required, and E a T IO3
A glass frit was required to physically connect the powders together.

1. According to the present invention, S r Be serves as both a conductive additive and a glass frit.

It is characterized by the use of This S r B
e is a conductor at room temperature, but at temperatures above 1oOo~1100°C, part of it decomposes and B2O3 precipitates on the particle surface, but the inside of the particle remains the original it and decomposition is prevented by the B2O3 film on the surface. . Therefore, when BaTiO3-based semiconductor powder and SrBe powder are mixed and fired, B
The B2O3 precipitated on the surface of rB plays the same role as a glass frit, and the inside of the particle plays the role of a conductive additive, making it possible to create a thick-film type positive temperature semiconductor that does not require a glass frit by simply adding S r B e. An element is obtained.

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

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

Example 1 1.0 mol% of Nb2O5 was added to B a T 103, fired at 13000C, and then ground to obtain a BaTiO3-based semiconductor powder. A paste-like mixture 1 is prepared by adding 10.0 weight ratio of SrBe powder to the BaTiO3-based semiconductor powder and mixing uniformly, and then adding α-terpineol.

On the other hand, on a substrate 2 made of Al2O3 or the like, a pair of electrodes 4ij! made of a conductive substance such as Aq! 314 was provided, and the paste mixture 1 was applied by screen printing or the like so that a part of the electrodes 3 and 4 remained on the electrodes 3 and 4, and the temperature was increased from room temperature at a rate of 10'Q/mm. The temperature was raised to 135°C=l:, and after holding for 1 hour, it was allowed to cool in the furnace. In this way, a thick film type positive characteristic semiconductor element was obtained.

Example 2 In the same manner as in Example 1, 3.0 mol of Y2O3 was added to B a T i O3 and fired at 126σC, followed by pulverization to obtain a B a T 10s semiconductor powder. Said B a
S r B 6 powder in an amount of 18.5 weight percent based on the total weight is added to the T IO3 semiconductor powder and mixed uniformly, and α-terpineol is further added to form a paste mixture 1. Next, as in Example 1, the electrodes 3 and 4 are provided on the substrate 2 in advance, and the paste mixture 1 is applied by screen printing or the like so that a portion of the electrodes 3 and 4 remains. The temperature was raised from 10°C to 1300°C at a 4-temperature 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 r was obtained.

The sheet resistance at room temperature of the thick-film semiconductor device thus obtained was 5.6 KQ/ca in Example 1 and 2.9 KQ/cnf in Example 2, and the resistance values of each temperature and resistance value were The relationship was as shown in Figure 2. In Figure 2, Ail,
Characteristics of the element obtained in Example 1, B are characteristics in Example 2.

Effects of the Invention As described above, according to the manufacturing method of the present invention, S r Be
The powder acts as both a conventional conductive additive and a glass frit, has sufficient effects for electrical and physical connections, and thick-film positive temperature semiconductor devices can be obtained without the need for a glass frit. Become.

Furthermore, by using S r B 6, a conductive metal with good heat conduction, instead of glass frit, which has poor heat conduction, the heat conduction is improved and the thermal shock resistance is 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 BaT10s. 1, S r B 6
The reason why the amount of powder to be added is defined as 1 to 60 parts by weight based on the total weight is that if it is less than 1 part by weight, the area resistance becomes too large and it is not suitable for a heating element, and it is difficult to physically fix the B a T IO3 powder together. On the other hand, if the weight coefficient exceeds 60, the sheet resistance becomes too small and the self-control characteristic (PTC characteristic) becomes too small, making it unsuitable for a heating element. Furthermore, B
An organic solvent (Idy, -terpineol in the example) was used to make the aTIO3-based semiconductor powder and SrBe 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 a glass frit.
Its practical effects are significant.

[Brief explanation of drawings]

Figure 1 shows a thick film type plate obtained by the method of the present invention, especially 1゛1.
2 is a partially cutaway perspective view showing a conductive element; FIG. 2 is a diagram showing the relationship between temperature and resistance value of the element according to an embodiment of the present invention. 1- Paste-like mixture, 2... Substrate, 3.4- Electrode.

Claims (1)

[Claims] Add 1 S r B 6 to B a T IOs semiconductor powder
．． 1. A method for manufacturing a thick-film type positive characteristic semiconductor device, comprising: adding 0 to 60.0% by weight, forming the mixture into a paste, coating the mixture on a substrate to form a thick film, and then firing the mixture.