JPH01204760A - Heating resistor device - Google Patents

Abstract

PURPOSE:To enable the title heating resistor device to withstand service for a long time by having high electric resistivity, a small temperature dependent characteristic of a resistant value, and efficient heat resistance, by a method wherein a heating resistor formed on a substrate has a laminated structure in which a metal silicide film and a silicon oxide film are alternately piled, and above-mentioned metal silicide film is made not less than two layers. CONSTITUTION:A glaze layer 2, a heating resistor 3, electric conductors 4 and 5 such as Au or the like, and a protective film 6 composed of a SiC film are formed on an alumina substrate 1 as insulating substrate. A part 3a between above-mentioned electric conductors 4 and 5 is a heating part. Then, the heating resistor 3 is made to have a laminated structure wherein a metal silicide film as an electric conductor and a silicon oxide film as an insulator are alternately piled, and not less than two layers of the metal silicide film are provided. Thereby, a characteristic as a whole differs from a property of each material comprising it, which comes to have characteristics of high electric resistivity and small temperature dependent property of a resistant value. This is a phenomenon caused by flowing of an electric current through a thinned silicon oxide film existing among the metal silicide films.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat generating resistor device suitable for a thermal head or the like, and particularly to a device equipped with a thin film type heat generating resistor.

[Conventional technology]

Conventionally, this type of heating resistor device has been used, for example (
Metal Surface Technology J (V) published by Metal Surface Technology Association
ol, 34 No. 6.1983. P271-277
) has been disclosed. FIG. 2 is a sectional view showing the main parts of such a conventional example. In the figure, 11 is an insulating substrate, 12 is a glaze layer, 13 is a tantalum nitride (T" a 2 N > film) as a heating resistor, and 14 and 15 are Ta.
This is an electric conductor for supplying power to the 2N film 13, and a portion 13a between the electric conductors 14 and 15 becomes a heat generating portion. Further, 16 is a protective layer that protects the 'I' a 2 N I layer 13 from oxidation, and 17 is a wear-resistant layer.

By the way, the characteristics required for a heating resistor for a thermal head are that it has excellent heat resistance and can withstand long-term use, that it has high electrical resistivity and can provide sufficient heat generation I, and that it is resistant to temperature changes. One example is that the value is stable.

On the other hand, although Ta2N has very stable resistance value versus temperature characteristics, it does not have sufficient properties in terms of heat resistance. For this reason, T a 2 N IB! 13, there is a risk of thermal damage due to the application of driving power pulses,
To make it durable for long-term use, Ta2N film13
It was necessary to form a thick film. However, the electrical resistivity of Ta2N is not very high, less than 300μΩ・■, and T
If the a 2 N I pattern 13 is formed thickly, the resistance value of the heat generating portion 13a becomes too low, making it impossible to obtain a sufficient amount of heat necessary for printing. In order to obtain a sufficient amount of heat, it is necessary to increase the current value, but the control method of increasing the current value has limitations in terms of circuit wiring and drive method, and from the viewpoint of power saving. was also undesirable.

Therefore, there is a proposal to prevent the increase in resistance value caused by thickening the Ta2N film by changing the shape of the heat generating part. FIG. 3 is a plan view showing the shape of a meandering heating element known as a typical example of such a proposal. A meander-type heating element is one in which the width of the heating element is narrowed and the heating element is made longer by turning the heating element to increase the resistance value of the heating part and to obtain a large amount of heat generation.

[Problem to be solved by the invention]

However, in the above conventional example, the meander-shaped heating part has a structure that does not easily turn the electrode conductor.
A processing technique is required to form a finer pattern than when formed in a straight line.

Therefore, if an attempt is made to reduce the area of the heat generating part in order to enable high-definition printing, there is a problem in that the difficulty of power generation becomes even more difficult and the manufacturing cost increases. That is, there is a problem in that the increase in manufacturing cost becomes an obstacle to reducing the area of the heat generating part.

Therefore, various resistor materials with high electrical resistivity have been studied, such as Ta-3t-N and Ta-3t-0.
High-resistance materials such as

However, these materials are complete mixtures of Ta, St, N, 0, etc. at the molecular level, and have high electrical resistivity (103~
105 μΩ·an), however, there was a problem in that the resistance value had a large temperature dependence, and the resistivity significantly decreased at high temperatures.

Therefore, the present invention was made to solve the above-mentioned problems, and its purpose is to have excellent heat resistance,
It is an object of the present invention to provide a heating resistor device having high electrical resistivity and having a small temperature dependence of resistance value.

[Means to solve the problem]

A heating resistor device according to the present invention includes a substrate and a heating resistor formed on the substrate, and the heating resistor has a laminated structure in which metal silicide films and silicon oxide films are alternately stacked. The metal silicide film is characterized in that it has two or more layers of the metal silicide film.

[For production]

In the present invention, the heating resistor formed on the substrate has a laminated structure in which metal silicide films and silicon oxide films are alternately stacked, and has two or more metal silicide films. That is, this laminated structure is basically a three-layer structure in which a silicon oxide film is interposed between two metal silicide films, and the metal silicide film is a three-layer structure. i! The basic three-layer structure described above is stacked in one or more layers so that the J film and the silicon oxide film are alternately overlapped.

By the way, metal silicide itself has properties similar to metals and does not have very high electrical resistivity, and silicon oxide itself has properties that are highly electrically insulating.

However, in a heating resistor that has a laminated structure in which metal silicide and silicon oxide films are thinned (about a few hundred holes) and metal silicide films and silicon oxide films are stacked alternately, the overall properties are not the same. Unlike the properties of the respective materials constituting the material, the material has characteristics of high electrical resistivity and low temperature dependence of resistance value. This phenomenon is thought to be due to the current flowing through the thin silicon oxide film interposed between the metal silicide films.

〔Example〕

The present invention will be explained below based on illustrated embodiments.

FIG. 1 is a sectional view showing a first embodiment in which a heating resistor device according to the present invention is applied to a thermal head. In the figure, 1 is an alumina substrate as an insulating substrate, 2 is a glaze layer, 3 is a heating resistor, 4 and 5 are electrical conductors such as Au, and 6
is a protective film made of a SiC film. Here, electric conductor 4
The portion 3a between and 5 becomes a heat generating part.

In this embodiment, the heating resistor 3 has a laminated structure (not shown) in which metal silicide films as an electrical conductor and silicon oxide films as an insulator are alternately stacked, and two metal silicide films are stacked alternately. It is a 'JKII structure with more than one layer. Here, tartan disilicide (TaS12) is used as the metal silicide film.
Silicon dioxide (S) is used as a silicon oxide film.
02) film was used, and the film thickness of the heating resistor 3 was set to 3000A. Further, the film thickness ratio of the Ta5l film and the Si02 film was set to 1:1.3.

Actually, in the above film thickness and film thickness ratio, 3 layers, 9 layers
A heating resistor of 19 layers, 19 layers, and 29 layers was formed, and the temperature dependence of the resistance value was measured for each layer in the range of 0 to 120°C. FIG. 4 is a characteristic curve diagram showing the measurement results of the temperature dependence of the resistance value of the above structure and the temperature dependence of a Ta-3t-0 resistor film having a film thickness of 30θ 00A as a comparative example.

From this characteristic curve diagram, it can be seen that the characteristic curves of this example are both T
It can be seen that the slope is smaller than that of the a-3t-0 resistor film, that is, the temperature dependence of the resistance value is small.

Moreover, the heating resistor of this example has Ta-
It can be seen that the electrical resistivity is higher than that of the 3i-0 resistor film.

Therefore, the heating resistor of this embodiment has characteristics suitable for a thermal head, such as a small temperature dependence of resistance value and a high electrical resistivity.

Furthermore, Ta5i2II5! The magnetron sputtering method is used to form the Si02 and Si02 films, and TaSi2 is used as the target to form the TaSi2 film, and SiOJ
l! The formation is performed using 5iO7 as a target and Ar gas as a sputtering gas. and,
In actual sputtering, a substrate provided with a glaze layer was heated in advance at 200° C. for 30 minutes in a vacuum, and then cooled with water to bring it to room temperature. Furthermore, during sputtering, the Ta512 target and the SiO2 target are placed in separate rooms equipped with shutters, and the Ta512 target and SiO2 target are placed in separate rooms equipped with shutters.
The two targets were sputtered simultaneously with DC and the 5102 target with RF, and one of the shutters was opened to ensure that only one of the sputtered materials adhered to the substrate, which was performed several times by switching the shutters. 'I'
aSi2M and S l 02 II! A multilayer film structure was formed.

FIG. 5 relates to a second embodiment of the present invention, in which titanium disilicide (TTIS l) is used as the metal silicide film of the heating resistor 3.
2 is a characteristic curve diagram showing the results of measuring the temperature dependence of the heating resistor when the film thickness ratio of the WA and SiO□ films is 1:1.2. Note that this second embodiment has the same structure as that in FIG.

Incidentally, this example has three layers, similar to the first example above.
9-layer, 19-layer, and 29-layer heating resistors were formed, and the temperature dependence of the resistance value of each was measured in the range of 0 to 120°C.

From this characteristic curve diagram, it can be seen that in this second example, the slope is smaller than that of the Ti-3t-0 resistor film as a comparative example, and the temperature dependence of the resistance value is small. Further, it can be seen that the heating resistor of this example has a higher electrical resistivity than the Ti-3L-0 resistor film in all ranges.

Therefore, the heating resistor of this embodiment also has characteristics suitable for a thermal head, such as a small temperature dependence of resistance value and a high electrical resistivity.

Next, a description will be given of the results of testing the life of the first and second embodiments and the conventional one using Ta2N as a heating resistor when applied to a thermal head. The tests were conducted using the heating resistor of the first embodiment with a 19-layer structure, the heating resistor of the second embodiment with a 19-layer structure, and the conventional structure of the heating resistor of Ta. This was done by examining the number of applied pulses and the rate of change in resistance value for a structure made of 2N. Here, the shape of the heating resistor is 50X
A 75 μm rectangle arranged at a density of 16 dots/mm was used, and a 4 μm SiC film was used as the protective film.

In addition, during driving, pulses of 0.8 ms width were repeatedly driven at 2 ms intervals, and the supplied power was adjusted so that sufficient coloring could always be obtained on the thermal paper.

FIG. 6 is a characteristic curve diagram showing the results of a life test of the thermal head under the above conditions. In the figure, curve A shows the case of the first embodiment, curve B shows the case of the second embodiment, and curve C shows the case of the conventional example. As can be seen from this characteristic curve diagram, in curve C, the resistance value changes slightly after 102 pulses are input, and the resistance value changes significantly after 104 pulses are input. On the other hand, in the case of the first and second embodiments, the resistance value is approximately stable until 106 and 105 pulses or more are input, respectively, and the use period is more than 10 times longer than that of the conventional example. It depends on what you can withstand.

As explained above, the heating resistor device of this example not only has high electrical resistivity and low temperature dependence, but also can withstand long-term use and has characteristics suitable for thermal heads. We are prepared.

In addition, in the above embodiment, the case where Ta or ]i silicide was used as the metal silicide film was explained.
The present invention is not limited thereto, and silicides of other metals such as W, Nb, Mo, and Cr may be used.

Furthermore, in the above embodiments, the sputtering method was used to form the metal silicide film and the silicon oxide film, but other methods such as vapor deposition and CVD may also be used.

Furthermore, regarding the layer thickness, layer thickness ratio, and number of layers in the above examples,
It is not limited to the above values, and can be selected as an appropriate value depending on various conditions such as the required resistance value.

〔Effect of the invention〕

As explained above, the heating resistor device of the present invention has characteristics that were not found in the past, such as high electrical resistivity, low temperature dependence of resistance value, and excellent heat resistance and ability to withstand long-term use. It has the following. These characteristics are suitable for thermal heads, and the application of this heating resistor device to thermal heads allows for high-Kn, high-speed printing with less power, and also extends the life of the thermal head. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a thermal head in which the heating resistor device according to the present invention is applied, FIG. 2 is a sectional view showing the configuration of a conventional thermal head, and FIG. 3 is a plan view of a meander-shaped heating element. Figure 4 is a characteristic curve diagram of the first embodiment of the present invention, Figure 5 is a characteristic curve diagram of the second embodiment of the present invention, and Figure 6 is the life test result of the first and second embodiments. FIG. 1... Alumina substrate (substrate), 2... Glaze layer,
3...Heating resistor (metal silicide film, silicon oxide film)
3a... Heat generating part, 4... Electric conductor, 5... Protective film. Patent applicant Oki Electric Industry Co., Ltd. Agent Patent attorney Former 1) Actual

Claims (1)

[Scope of Claims] A substrate, and a heating resistor formed on the substrate, wherein the heating resistor has a laminated structure in which metal silicide films and silicon oxide films are alternately stacked, and A heating resistor device characterized by having two or more layers of metal silicide films.