JPH0343985A - Thin high temperature heater and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase adhering power of resistor film for heater to an insulating member and reduce a resistance change at the time of use to improve the reliability by providing an adhesive layer made up of Ti formed on an insulating member and a resistor layer made up of a Ti compond formed on the insulating member through the adhesive layer. CONSTITUTION:An adhesive layer 2 made up of Ti is installed on an insulating member 1, and a resistor layer 3 which is installed on the insulating member 11 through the adhesive layer 2 and made up of a Ti compound of a single substance or a mixture of, e.g. TiC, TiN and TiCN. So, Ti film 2 works to improve adhering power of the insulating member 1 to the resistor layer 3 for heater and, as the Ti compound or the resistor layer 3 is ceramics, has better high temperature stability than the heater made up of metallic material. Moreover, even if a surplus Ti component is diffused from the sdhesive layer 2 to the resistor layer 3, this has no bad influence on the resistor layer 3 because it contains a Ti compound and the adhesive layer 2 is stabilized. The adhesion between the resistor layer 3 and the insulating 1 is, therefore, great, and also a change in resistance at the time of use is reduced so that the reliability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure and manufacturing method of a thin high-temperature heater whose operating temperature is about 1000'C, such as a small heater for high-temperature heating or a heater for an electron gun.

[Prior Art] Conventionally, flat plate heaters have been disclosed in Japanese Patent Publication No. 55-24646, for example.
As described in the publication, the circuit was manufactured using a so-called thick film circuit forming technique such as screen printing. Third
The figure is a cross-sectional configuration diagram showing an electron tube cathode device using a conventional heater manufactured in this manner. In the figure, <10) is the seventh minx substrate, (11) is the heating element layer, (12> is the insulating layer, <13) is the cathode layer, and (14) is the insulating layer.
) is a cathode lead layer, and <15) is a base metal layer.

Next, the manufacturing method will be explained. First, raw materials constituting the Seven Minx substrate <10> are prepared, and a heating element layer (11) is formed in a desired pattern on a sheet by extrusion or casting printing technology by passing between rolls.
form. This heating element layer (11) is formed by screen printing a paste containing a heating agent and a baking aid on the substrate (10). After screen printing, high temperature (1000
-2000'C) to form a flat plate heater.

In this method, a high-temperature treatment process is involved during manufacturing, so when the heater is used at a temperature below this treatment temperature, high-temperature long-term stability as a heater, such as a small change in resistance over time, was expected. However, the pattern accuracy obtained by screen printing is low, and it is difficult to control the thickness (thinning) of the heating element (11), resulting in high power consumption and large variations in resistance among multiple heaters. Therefore, PVD and CV are methods that can form patterns with high precision.
Development of a film forming method using D was in progress.

FIG. 4 shows a conventional method for manufacturing a thin flat heater using a thin film forming method. Smooth ceramic substrate (insulating member)
), a resistor film (3) for the heater (usually made of a metal such as W) is formed in the shape of -, then a desired heater pattern is formed by etching, and a lead wire (not shown) is formed on this. ) was used to create a thin flat heater.

[Problems to be Solved by the Invention] When manufacturing a flat thin heater using the above-described film formation method, there is a problem that the adhesion between the resistor film 3) for the heater and the insulating member (1) is small. It was a huge problem. Therefore, in order to increase the adhesion between the heater resistor film 3) and the insulating member (1), a method has been adopted in which an adhesion layer is inserted. Usually, this adhesion layer consists of several tens to several 1100 nanometers of Ti.
By providing a film and forming a resistor film on it ()
A thin, high-temperature heater was realized. However, while applying voltage to the lead wire and using it as a heater,
During a high temperature load of 00°C, Ti deteriorates at high temperatures, causing problems such as heater breakage. The reference drawing shows an SEM photograph of the disconnected state. (In the photo, 20.0 KV means the accelerating voltage of the scanning electron microscope, x350 means 350 times as much, and 100 μm means that the length of the line directly above it corresponds to 100 μm. ) The reason for this is thought to be that Ti has an α-β transformation point (hereinafter abbreviated as “transformation point”) at 882°C, and that this transformation point is repeatedly passed through by using a heater. Further, the resistance of thin film resistors usually changes during use. Figure 5 shows the change in resistance value over time. The reason why the resistance initially decreases is that recrystallization of the thin film progresses and the crystal grains in the film become coarser. For example, if a resistor (heating element) is formed of W (tungsten) without an adhesive layer and used at 100°C, 1000°C corresponds to the recrystallization temperature of W, so
Recrystallization progresses. Next, the reason why the resistance increases over time is due to impurities being mixed into the film or being oxidized due to the atmosphere during use. Therefore, thin high-temperature heaters based on the conventional thin film method are unstable as heaters and lack long-term reliability.

This invention was made to solve the above-mentioned problems, and provides a highly reliable thin high-temperature heater that has high adhesion between the heater resistor film and the insulating member, and has little resistance change during use. is intended to provide.

[Means for Solving the Problems] A thin high temperature heater according to the present invention includes an adhesion layer made of Ti formed on an insulating member, and a Ti compound formed on the insulating member via this adhesion layer. , ).

Further, in the method for manufacturing a thin high-temperature heater according to another aspect of the present invention, in forming an adhesive layer made of Ti and a resistor layer made of a Ti compound on an insulating substrate, both the adhesive layer and the resistor layer are It is formed at a temperature below the α-β transformation point of Ti, or both the adhesive layer and the resistor layer are formed at a temperature above the transformation point.

[Function] In the present invention, the Ti film acts to improve the adhesion between the insulating member and the resistor layer for the heater, and the Ti film, which is the resistor layer,
Since Ti compounds such as TiN, T1CN alone or their mixtures are ceramics, they have superior high-temperature stability compared to heaters made of metal materials, and also act as an adhesion layer during use of the heater, allowing excess Ti components to be transferred to the resistor layer. Even if it diffuses, since the resistor layer also contains the Ti component, it will not have an adverse effect, and the adhesion layer will be stabilized.

Further, in another aspect of the present invention, since the formation temperatures of the adhesive layer and the resistor layer are both lower than or higher than the transformation point of Ti, high temperature deterioration of Ti is prevented during manufacturing of the heater. Nor. In other words, if both are lower than the transformation point, α-β transformation of Ti will not occur during heater manufacturing, so deterioration due to volume change will be less likely to occur, and if both are higher than the transformation point, there will be no need to Since the Ti component is diffused during manufacturing, high-temperature deterioration due to the α-β transformation of Ti does not occur even if it is subsequently used at a temperature higher than the transformation point.

[Example] An example of the present invention will be described below based on the drawings. FIG. 1 is a sectional view showing a thin high temperature heater according to an embodiment of the present invention. In the figure, <1) is an insulating member, <2> is a Ti adhesion layer with the insulating member <1), (
3) is provided on the insulating member (1) via the adhesive layer (2>) and is made of, for example, TiC or TiN.

The resistor layer is made of a Ti compound such as T1CN alone or a mixture thereof. For example, it is desirable for the insulating member 1) to satisfy the following requirements. It has good thermal conductivity and a coefficient of thermal expansion close to that of the resistor layer (3);
It must be a long wire edge, not cause dielectric breakdown at high temperatures, and be smooth. Therefore, considering availability, AIN, Al2O
3rd prize is possible.

Here, the reason why the resistor layer (3) is formed of a Ti compound such as TiC, TiN, T1CN alone or a mixture thereof is that the recrystallization temperature is high and the electrical stability at high temperatures is high. For example, it is conceivable to form it with a general heater material such as W or Mo.

However, such material systems are formed using, for example, an Al2O3 substrate as the insulating member (1), and when used at a high temperature of about 1000"C, the oxygen in the substrate (1) is taken away (
(reduction) to form oxides with high vapor pressure and scatter. That is, the resistor layer is etched and its shape changes. Therefore, the environment in which it can be stably used as a heater, such as the substrate (1) material, atmosphere, and temperature, is limited.

This is for the reasons mentioned above.

Here, a single crystal sapphire substrate (
A1203) will be selected and two methods will be described for an example of manufacturing a thin high-temperature heater.

First, the first method will be explained by giving an example.

A desired thickness of several μm is deposited on an Al2O3 substrate by sputtering.
A Ti film having a thickness of m to 10/l□ is uniformly formed. The T1 film forming temperature at this time is, for example, 200 to 300°C. Thereafter, it is etched into a desired pattern shape using a wet or dry method. For example, in the case of a wet method, etching is performed using a very general process shown in FIG. Next, the patterned sample was placed in a vacuum furnace for ion nitriding, and T
Temperature below the transformation point of i, for example 400-500'C;
Perform ion nitriding to diffuse N from the Ti surface, and
Let it be N. The depth of nitriding reaches approximately several 71 m to 10 nm, and nitridation is performed up to or including a layer (10 nm or less) that contributes to adhesion between Ti and Al2O3 at the interface with the substrate. When ion nitriding is performed using a C power source, only the electrically conductive Ti is nitrided without damaging the insulating material Al2O3.

In addition, in the above embodiment, a method of forming a Ti film by sputtering method was explained, but electron beam evaporation, laser P
It goes without saying that it can be formed by a method such as a so-called PVD method such as a VD method or ion blating, or a plasma CVD method using TiCl4 gas or the like. Further, in the above embodiment, an example was shown in which ion nitriding was performed after forming a Ti pattern, but it is also possible to perform ion nitriding with a Ti bottom film 1 and then pattern etching with hot nitric acid or the like.

In addition, an example of ion nitriding using N2 gas is shown, for example, il T i C, T i N, T i
A simple substance of CN or a mixture thereof may be formed.

As described above, the first method is a method in which a Ti film is first formed and then modified by nitriding or carbonizing from one surface, although there is a step before pattern formation.

Next, the second method will be explained using an example.

A desired temperature below the transformation point of Ti, e.g. 200-300
A pattern mask is placed on an Al2O3 substrate heated to 'C, and a Ti film is initially formed by the usual Ar sputtering method. When an extremely thin Ti film is formed before the thickness reaches 10 nm, N2 gas is introduced into the sputtering atmosphere,
A reactive spunter is used to make the TN film to the desired thickness of several μnt.
Later, by changing the introduced gas to a gas containing carbon, such as CH4 alone or a mixed gas of CH4 and N2, TiC, TiN
, T1CN alone or a mixture thereof can be formed.

As described above, the second method is a method in which different films, such as Ti-+TiN, are continuously formed during the in-process of forming the film.

In the thin high-temperature heater manufactured in this way, the formation temperature of both the adhesive layer and the resistor layer is lower than the transformation point of Ti, so the α→β transformation of Ti does not occur during heater manufacturing, so the change in volume is Deterioration is less likely to occur, and even if excess Ti components diffuse into the resistor layer as an adhesive layer during use of the heater, there will be no adverse effects as the resistor layer also contains Ti components, and the adhesive layer will be stabilized. be done.

It goes without saying that forming a plurality of thin high-temperature heaters formed using the two methods described above on a substrate is suitable for increasing the area and mass production.

Furthermore, in the above embodiment, both the adhesive layer and the resistor layer are T
Although 1 has been described in the case where the adhesive layer and the resistor layer are formed at a temperature lower than the transformation point of Ti, both the adhesive layer and the resistor layer may be formed at a temperature higher than the transformation point of Ti. Since the Ti component is diffused during manufacture, even if it is subsequently used at temperatures above the transformation point, for example, about 1000° C., high temperature deterioration associated with the α→β transformation of T1 will not occur.

[Effects of the Invention] As described above, according to the present invention, the adhesion layer made of Ti formed on the insulating member and the Ti compound formed on the insulating member via this adhesion layer create a resistance of iJ. Since the resistor layer is provided, there is an effect that a thin high temperature heater with high adhesion between the resistor layer and the insulating member, little change in resistance during use, and high long-term reliability can be obtained.

According to another aspect of the present invention, when forming an adhesion layer made of Ti and a resistor layer made of a Ti compound on an insulating substrate, both the adhesion layer and the resistor layer are made of α of the Ti compound.
Since it is formed at a temperature below the transformation point of →β, or both the adhesive layer and the resistor layer are formed at a temperature above the transformation point, it is possible to prevent Ti from deteriorating at high temperatures during manufacture of the heater 2.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional configuration diagram showing a thin high-temperature heater according to an embodiment of the present invention, FIG. 2 is a process diagram showing a general machining process that is part of the manufacturing process of the thin high-temperature heater of FIG. 1, Figure 3 is a cross-sectional configuration diagram showing an electron tube cathode device using a conventional thin high-temperature heater. Figure 3 is a process diagram showing a method for manufacturing a thin high-temperature heater using a conventional thin film forming method. FIG. 3 is a characteristic diagram showing a change in resistance value over time. In the figure, <1) is the insulation part assembly, <2) is the adhesive layer, and <3
> is a resistor layer. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) An adhesion layer made of Ti formed on the insulating member, and T formed on the insulating member via this adhesion layer.
A thin high temperature heater equipped with a resistor layer made of i-compound. (2) When forming an adhesion layer made of Ti and a resistor layer made of a Ti compound on an insulating substrate, are both the adhesion layer and the resistor layer formed at a temperature below the α→β transformation point of Ti? , or a method for manufacturing a thin high-temperature heater, in which both the adhesive layer and the resistor layer are formed at a temperature equal to or higher than the transformation point.