JPS61101003A - Manufacture of thick film type 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 flint, among planar heating elements used for heat insulation and heating of equipment, etc. It is.

Conventional structure and its problems Elements made of BaTiO3-based semiconductors have switching characteristics in which the resistance value increases rapidly above a predetermined temperature and self-heating characteristics after switching. It is widely used because it has a control function and does not require an external control circuit.

Conventional positive temperature coefficient thermistor heating elements have been obtained by press molding B a T *03 semiconductor powder and then firing it, but it is difficult to obtain a practical thick film positive temperature coefficient thermistor heating element. It was said that

Conventionally, the following method is known as a method for processing a B a TiOs 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 BaTiOa 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. In addition, 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), the sheet resistance tends to be high and control is difficult, and it is not suitable for heating elements, and the glass frit must be prepared and fired twice in advance.
Depending on the material of the glass frit, B
It degrades the switching characteristics and self-heating characteristics of aT 103-based semiconductors. By adding glass frit, the difference in heat resistance and coefficient of thermal expansion between the B a T 103 semiconductor and the glass frit makes it vulnerable to thermal shock and 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 film with excellent thermal shock resistance and thermal conductivity, and a uniform film by forming a thick film without using a glass lift. 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 includes
V3B2, VB, v3B4 and H-V in iO3-based semiconductor powder
At least one type of B2 is added in an amount of 1 to 60% by weight based on the total weight, and the paste-like mixture is applied onto a substrate to form a thick film and then fired to form a thick film type. The purpose is to obtain a characteristic semiconductor element.

The conventional method using conductive additives and glass frit requires conductive additives to electrically connect BaT103-based semiconductor powders, and it is difficult to physically connect BaTiO3-based powders to each other. glass frit was required.

However, according to the present invention, v3B2°VB, v
3B4. The feature is that it uses VB2. These ■3B2, VB, v3B4. ■2 is a conductor at room temperature, and when the temperature exceeds 1000-1100℃, a portion of it decomposes and B2O3 is deposited on the particle surface, but the inside of the particle remains intact and decomposition is prevented by the B2O3 film on the surface. . Therefore, BaTiOaO3 based semiconductor powder v3B
2, VB, v3B4. When vB2 powder is mixed and fired, v3B2, VB, v3B4. 3B2, VB, v3B4. vB
By simply adding 2, it is possible to obtain a thick film type positive characteristic semiconductor element that does not require a glass frit.

1. Adding a conductive metal improves thermal conductivity and thermal shock resistance compared to glass frit, which has poor thermal conductivity.

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

Example 1 1.0-El% Nb2O6 was added to B a T 10a, fired at 1300°C, and then crushed to obtain B a T 1
03 series semiconductor powder is obtained. A paste-like mixture 1 is prepared by adding VB powder in an amount of 5.0% by weight based on the total weight of the B a TiOs semiconductor powder and mixing uniformly, and then adding a-terpineol.

On the other hand, a pair of electrodes 3゜4 made of a conductive material such as Aq is provided in advance on a substrate 2 made of Al2O3, etc., and a part of the electrode 3゜6 vane 4 remains on the electrodes 3, 4. The paste mixture 1 is applied by screen printing or the like, and the temperature is raised from room temperature to 1350°C at a rate of 10°C/min, held for 1 hour, and then left to cool in the oven. 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 Y2O3 was added to BaTiO3 and fired at 1260°C, followed by pulverization to obtain a BaTiO3-based semiconductor powder. Said B a
VB2 powder in an amount of 66% by weight based on the total weight is added to the T i O3 semiconductor powder and mixed uniformly, and α-terpineol is further added to form paste mixture 1. Then, as in Example 1, the electrode 3. is placed on the substrate 2 in advance.
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/min. After holding for a minute, let it cool in the furnace. In this way, a thick film semiconductor element was obtained.

The area of the thus obtained thick film semiconductor device at room temperature is 7.
7 The resistance was s, 9KQ/crl in Example 1, and 2, oKO/ca in Example 2, and the relationship between temperature and resistance value was as shown in FIG. In FIG. 2, A is the characteristic of the device obtained in Example 1, and B is the characteristic of Example 2. Effects of the Invention As described above, according to the manufacturing method of the present invention, VB.

The VB2 powder plays the role of both a conventional conductive additive and a glass frit, has sufficient effects for electrical connection and physical connection, and thick-film positive characteristic semiconductor devices can be obtained without a glass frit. Become.

In addition, by using VB, (2), a conductive metal with good heat conduction, instead of glass frit, which has poor heat conduction, heat conduction is improved and thermal shock resistance is also improved. moreover,
Since it can be manufactured by screen printing, etc., it is easy to work with and mass production is possible.

In the present invention, any BaT 103-based semiconductor powder may be used as long as it is made into a semiconductor by adding various additives to BaT iO3. Also, VB, VB
The reason for specifying the addition amount of the two powders to be 1 to 60% by weight based on the total weight is that if it is less than 1% by weight, the area resistance becomes too large and is not suitable for a heating element. On the other hand, if the weight ratio exceeds 60, the sheet resistance becomes too small, and the self-control characteristic (PTC characteristic) becomes small, making it unsuitable for a heating element. Furthermore, B
Although an organic solvent (alpha-terpineol in the example) was used to make the aTiO3-based semiconductor powder and the VB and VB2 powders into a paste, any solvent may be used as long as it can be made into a paste.

In addition, although the above example shows only the case where only one type of each of VB and VB2 is added, it was confirmed that the same effect as the example can be obtained even when v3B2 and v3B4 are used instead. Also, cholera VB, vB
A similar effect was obtained when multiple types of 2, 3B2 and v3B4 were added at the same time within the above range.

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.

9be-7

[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 mixture, 2... Substrate, 3.4... Electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2: so too tso zoo zs. −i degrees (°s)

Claims (1)

[Claims] V_3B_2, VB, V in BaTiO_3-based semiconductor powder
At least one of _3B_4 and VB_2 is added in a mixed amount of 1 to 60% by weight based on the total weight, and the paste-like mixture is applied on the substrate to form a thick film, and then
A method for manufacturing a thick film type positive characteristic semiconductor element, which comprises firing.