JPH04192304A - Critical temperature resistor and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a critical temperature resistor having a large current capacity and high selection freedom of resistance value, by quenching thin layer ceramic plates, constituting a plurality of semiconductor ceramic plates having critical temperature characteristics, and laminating said plates. CONSTITUTION:Semiconductor ceramic plates 1a-1e having critical temperature characteristics are laminated, via conductive paste 2a-2d and glass paste 3a-3d. The conductive paste 2a-2d are turned into Ag electrodes, and the glass paste 3a-3d are turned into insulating glass layers by stoving. Outer electrodes 4 are formed on both ends of the laminate, and electrically bonded to the inner electrodes 2a-2d. By laminating a plurality of semiconductor ceramic plates having critical temperature characteristics in the above manner, the total volume is enlarged, and the allowable current value can be incresed.

Description

DETAILED DESCRIPTION OF THE INVENTION (AlIndustrial Field of Application) This invention relates to a rapid change thermistor whose electrical resistance rapidly changes at a certain temperature and a method for manufacturing the same. It is a semiconductor device whose electrical resistance rapidly decreases as the temperature rises in a temperature range.The sudden change thermistor currently in practical use has a basic composition of VO2, and the crystal structure of VO2 changes to a semiconductor at around 70℃.
It utilizes the transition of one metal.

Normally, a sudden change thermistor is ■20. B, Si.

One or two types of oxides such as P, Mg, Ca, Sr, Ba, La, Pb are mixed, and 800 to 900
After heat treatment at °C and crushing and forming into bead shape, 1
It is manufactured by firing in a reducing atmosphere at 000°C and then rapidly cooling.

(e) Problems to be solved by the invention In the conventional sudden change thermistor, its sudden change resistance characteristics largely depend on the manufacturing process, and it was necessary to set detailed manufacturing conditions in order to obtain good sudden change characteristics. . In particular, the rapid cooling process, like the reducing atmosphere treatment process, is the process that most affects the rapid change characteristics, and in order to obtain good characteristics, it is necessary to
It must be rapidly cooled at temperatures above 00°C. For this reason,
It is difficult to obtain good sudden change characteristics with large sudden change thermistors such as disk types that are difficult to cool homogeneously, so small devices such as bead types and thin film types have become mainstream. However, in such a small element, the allowable current value is limited to several tens of mA or less, and furthermore, the degree of freedom in selecting the resistance value in the usage range is low. For this reason, it has not been possible to meet a wide range of demands, such as for use as inrush current suppressing elements.

An object of the present invention is to provide a sudden change thermistor that has a high allowable current value and a high degree of freedom in selecting resistance values, and a method for manufacturing the same.

(d) Means for Solving the Problem In order to increase the allowable current value, it is necessary to increase the size of the entire device and also to perform the rapid cooling process reliably.The inventors etc. applied a rapid cooling process to a thin-layer ceramic plate, and each sudden change occurred. It has been found that by configuring a plurality of semiconductor ceramic plates having thermistor characteristics and laminating them, a sudden change thermistor without the above-mentioned drawbacks can be obtained.

The sudden change thermistor neta according to claim 1 of the present invention has a structure in which a plurality of semiconductor ceramic plates having sudden change thermistor characteristics are laminated, an electrode layer is provided at the electrical connection part of the plurality of semiconductor ceramic plates, and a glass layer is provided at the electrically insulating part of the plurality of semiconductor ceramic plates. A method for manufacturing a sudden change thermistor according to claim 2, characterized in that a plurality of layers are formed respectively, a conductive paste is applied to the electrical connection parts of a plurality of semiconductor ceramic plates having sudden change thermistor characteristics, and a glass paste is applied to the electrically insulating parts. The conductive paste and the glass paste are baked to integrate the conductive paste and the glass paste.

Further, the method for manufacturing a sudden change thermistor according to claim 3 is such that a sheet material obtained by printing a conductive paste and a glass paste on a combustible sheet is sandwiched between a plurality of semiconductor ceramic plates having sudden change thermistor characteristics, and the plurality of semiconductor The present invention is characterized in that ceramic plates are laminated and the combustible sheet is burned by baking to integrate the conductive paste and the glass paste.

(81 Effect) In the sudden change thermistor according to claim 1 of the present invention, a plurality of semiconductor ceramic plates having sudden change thermistor characteristics are laminated, and an electrode layer and an electrically insulating part are provided at the electrical connections between the plurality of semiconductor ceramic plates. A glass layer is formed on each layer.With this structure, a plurality of semiconductor ceramic plates having abruptly changing thermistor characteristics are laminated together through an electrode layer and a glass layer, and are electrically connected through the electrode layer. By stacking a plurality of semiconductor ceramic plates having abruptly changing thermistor characteristics in this way, the overall customer base can be expanded and the allowable current value can be increased.Also, depending on the thickness of the semiconductor ceramic plates and the number of layers, the desired value can be adjusted. You can get the resistance value.

In the method for manufacturing a sudden change thermistor according to claim 2, a conductive paste is applied to the electrically connected portions of the plurality of semiconductor ceramic plates having sudden change thermistor characteristics, and a glass paste is applied to the electrically insulated portions. The respective semiconductor ceramic plates are laminated and baked. As a result, the conductive paste becomes an electrode layer, the glass paste becomes a glass layer, and the adjacent semiconductor ceramic plates are laminated and integrated via the electrode layer and the glass layer.
In the method for manufacturing a sudden change thermistor according to claim 3, a conductive paste and a glass paste are printed on a combustible sheet,
A plurality of semiconductor ceramic plates having abruptly changing thermistor characteristics are laminated via this sheet material and baked. As a result, the flammable sheet burns, the conductive paste becomes an electrode layer, the glass paste becomes a glass layer,
A plurality of semiconductor ceramic plates are laminated and integrated via an electrode layer and a glass layer.

(f) Embodiment Claim 1 and Claim 2 of this invention as a first embodiment
The sudden change thermistor corresponding to the above and its manufacturing method will be explained in the order of manufacturing steps.

First, desired amounts of V20s, PzOs, and BaO are weighed and mixed uniformly. This mixed powder is heated and melted into a glassy state, and then heat-treated in a reducing atmosphere and pulverized to create a raw material powder. A vinyl acetate binder, a dispersant, and a plasticizer are added to this raw material powder, and a green sheet is created using a doctor blade method.

After canting the green sheets to a size of 50.0 x 20.0w, they were stacked and thermocompression bonded so that the sheets had a thickness of 0.3 m. Then, place the stacked pressure-bonded sheets in step 7.
Press the cut crimping sheet to Ox6.3wa.
After firing at 000° C. for 5 minutes, it was taken out of the furnace and rapidly cooled. As a result, a semiconductor ceramic plate having a rapidly changing thermistor characteristic in which VO2 and oxides of P and Ba are combined is obtained.

Next, a conductive paste for forming an electrode layer and a glass paste for forming an insulating layer are respectively printed on the semiconductor ceramic plate. FIG. 1 is a perspective view showing a state before lamination of semiconductor ceramic plates each printed with a conductive paste and a glass paste. In FIG. 1, 1a to 1e are semiconductor ceramic plates having abruptly changing thermistor characteristics, 2a to 2d are conductive pastes, and 3a to 3d are glass pastes. Here, as the conductive paste, a paste obtained by kneading Ag, an ohmic component, a varnish, a frit, and a solvent is used. The glass paste is made by kneading glass powder, varnish, free glue, and a solvent into a paste. Semiconductor ceramic plates printed with conductive paste and glass paste are laminated as shown in Figure 2. do. After that, bake 2a to 2d
are respectively made into Ag electrode layers, and 3a to 3d are made into insulating glass layers, respectively.

Thereafter, as shown in FIG. 3, external electrodes 4 are provided at both ends of the laminate to establish electrical connections with internal electrodes 2a to 2d.

In addition, although the number of layers of the semiconductor ceramic plate is reduced in FIGS. 1 and 2 for explanation purposes, the size is 5.8×5 with 50 layers of semiconductor ceramic plates having abruptly changing thermistor characteristics.
．． When a sudden change thermistor of 0x15.0■ was made and its characteristics were measured, the resistance value was 0.1 Ω and the allowable current value was IA.Next, as a second embodiment, claim 1 of the present invention A sudden change thermistor and a method for manufacturing the same according to claim 3 will be explained in the order of manufacturing steps.

First, a semiconductor ceramic plate having abruptly changing thermistor characteristics is prepared in the same manner as in the first embodiment.

On the other hand, paraffin paper was used as a flammable sheet in a 5°6×5.
A conductive paste for forming an electrode layer and a glass paste for forming an insulating layer are printed on both sides. FIG. 4 is a perspective view showing a state before lamination of paraffin paper printed with conductive paste and glass paste and a semiconductor ceramic board. In FIG. 4, 1a to 1e are semiconductor ceramic plates having abruptly changing thermistor characteristics, 5a to 5d are paraffin It, 2a to 2d are conductive pastes, 3a to 3
d is glass paste. Here, the same conductive paste and glass paste as those shown in the first embodiment are used.

Semiconductor ceramic plates were stacked together with the paraffin paper printed with each paste as shown in Figure 5, and after drying,
The conductive paste and glass paste are simultaneously baked by heating to 00°C.

As a result of this baking, the paraffin paper burns and becomes Ag electrodes 2'a to 2d as shown in FIG. 6, which constitute the internal electrodes of the semiconductor ceramic plates 1a to 1e. Also, 3a~
3d is an insulating glass layer.

Thereafter, as shown in FIG. 3, external electrodes 4 are provided at both ends of the laminate.

Although the number of layers of the semiconductor ceramic plate is reduced in FIGS. 4 to 6 for explanation purposes, a sudden change thermistor with dimensions of 5.8 x 5.0 x 15 and Qm was created using 50 layers of semiconductor ceramic plates, and its characteristics were evaluated. When measured, the resistance value was 0.1
The current tolerance was IA at Ω.

(g) Effects of the Invention According to the present invention, each semiconductor ceramic plate in the laminate forming the sudden change thermistor is in the form of a small thin plate;
Rapid cooling treatment can be easily performed and good rapid change thermistor characteristics can be obtained. By laminating a large number of semiconductor ceramic plates having this sudden change thermistor characteristic, the overall capacitance is increased and a sudden change thermistor with a high allowable current value can be obtained. In addition, the resistance value can be set over a wide range by changing the dimensions and number of laminated layers of each semiconductor ceramic plate without changing the composition of the semiconductor ceramic plate. Therefore, it can be applied to, for example, inrush current suppressing elements. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the sudden change thermistor according to the first embodiment in a state in the process of being manufactured, and FIG. 2 is a sectional view showing its laminated state. FIG. 3 is a plan view of the sudden change thermistor according to the first and second embodiments. FIG. 4 is a perspective view showing a state in the middle of manufacturing the sudden change thermistor according to the second embodiment;
The figure is a sectional view showing the laminated state, and FIG. 6 is a sectional view showing the state after baking. 13-Ie - Semiconductor ceramic plate, 2a-2d - Conductive paste and baked internal electrode, 3a-3d - Glass paste and baked insulating glass layer, 4- External electrode, 5a-5d - Paraffin paper ( combustible sheet).

Claims (3)

[Claims] (1) A sudden change characterized in that a plurality of semiconductor ceramic plates having sudden change thermistor characteristics are laminated, and an electrode layer is formed at the electrical connection part of the plurality of semiconductor ceramic plates, and a glass layer is formed at the electrically insulating part. thermistor. (2) Apply conductive paste to the electrical connection parts and glass paste to the electrically insulating parts of a plurality of semiconductor ceramic plates having abruptly changing thermistor characteristics, laminate each of the semiconductor ceramic plates, and apply the conductive paste and glass to the electrically insulating parts. A method of manufacturing a sudden change thermistor, which is characterized by baking a paste and integrating it. (3) A sheet material in which conductive paste and glass paste are printed on a flammable sheet is sandwiched between a plurality of semiconductor ceramic plates having abruptly changing thermistor characteristics, and the plurality of semiconductor ceramic plates are laminated, and the combustible sheet is baked. A method of manufacturing a sudden change thermistor, which comprises burning a sheet to bake and integrate the conductive paste and the glass paste.