JPS63278202A - Heating resistor - Google Patents

Abstract

PURPOSE:To obtain a heating resistor whose electric resistivity is high and whose temperature dependency with respect to resistivity is low by laminating electric conductor layers which are composed of a metal M and insulation layers which are composed of silicon carbide SiC, thereby forming a multilayer structure. CONSTITUTION:A multilayer having three layers or more at least is made up by laminating electric conductor layers 27 which are composed of a metal M and insulation layers 29 which are composed of silicon carbide SiC. It is suitable that the metal M makes up the electric conductor layers using one kind of metal or a mixture of 2 kinds or more of metals which are chosen out of Ru, Rh, Pd, Os, Ir, and Pt. In this way, the temperature dependency with respect to resistivity of its resistor is low and its electric resistivity is high and when it is applied to a thermal head, it exhibits and excellent durability during driving.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heating resistor used in thermal heads, heaters, and other electronic devices.

(Conventional technology) Conventionally, by applying electric power, it becomes a heating element,
Various heat generating resistors for use in heaters, thermal heads, etc. have been taught.

In recent years, one example of the use of this heating resistor is to arrange the heating resistor in the form of a thin film and conduct an electric current, and use the heat generated at this time to color thermal paper and create a dot-shaped mosaic. , f for printing pictures, characters, etc.
! Thin-film thermal heads with various structures have been proposed and are attracting attention.

As an example of such a thin film type thermal head (hereinafter simply referred to as a thermal head), for example, the literature ("Metal Surface Technology" Japan, (6), +983. Nos. 271-277)
Page) is known.

In the thermal head having the structure disclosed in the above-mentioned literature, the material constituting the heating resistor is mainly tantalum nitride (
TaJ) is used. As is well known, tantalum nitride (TaJ) is used, for example, as a thin film resistor in hybrid ICs (it has excellent resistance value stability). When using tantalum (Ta2N), the heat resistance of tantalum nitride (TaJ), especially the acid resistance, was not sufficient.For this reason, when tantalum nitride (TaJ) is used as a heating resistor, In order to improve oxidation resistance, it is common to provide protective films such as an oxidation-resistant film and a wear-resistant layer.

Hereinafter, a conventional thermal head will be described as an example of the use of a heating resistor with reference to the drawings.

FIG. 5 is an explanatory diagram showing a schematic cross-sectional view of the main part of the thermal head in order to explain the conventional thermal head;
FIG. 6(A) is a plan view showing the arrangement of the heating resistor shown in FIG. 5. FIG. In these figures, hatchings indicating cross sections are omitted except for some.

In FIG. 5, reference numeral 11 indicates an insulating substrate made of ceramics, glazed alumina, or any other suitable material, and the surface of the insulating substrate 11 is coated with tantalum nitride (T
Figure 6 (A)
It is provided in a rectangular shape as shown in .

Further, the upper surface of this heating resistor 13 is coated with gold (A), for example.
u) Separate power supplies 15 and 17 made of nichrome (Ni-Cr) or other suitable material are arranged spaced apart from each other, with a corresponding heating resistor between them. A portion of the body 13 (the shaded portion in FIG. 5) constitutes a heat generating portion 19.

Roughly speaking, an oxidation-resistant film 21 and a wear-resistant layer 23 are provided on the upper side of the power supply bodies 15 and 17 and the heating resistor 13 corresponding to the heat generating part 19.
These two layers constitute a protective film for the heating resistor 13.

Further, tantalum nitride (TaJ) has an electrical resistivity of about 300Ω·cm. Here, for example, if the heating resistor is configured to have a sufficient film thickness so that the thermal head can withstand long-term use, the resistance value of the heating resistor 13 will be lower than the desired resistance value. There were also cases where it showed a small value. Therefore, in order to obtain the amount of heat necessary for printing, it was necessary to increase the value of the current supplied to the heating resistor 13. However, due to the limitations of the wiring circuit, the driving method, and other components (all not shown), it is necessary to obtain the same amount of heat within a limited current value range. Therefore, as shown in the plan view of FIG. 6(B), there is a known technique for increasing the resistance value of the heating resistor 13 by arranging the heating resistor 13 in a meandering shape. It is being

On the other hand, in order to improve printing quality, it is required to miniaturize the heating resistor 13 disposed in the thermal head. Therefore, the heating resistor 1 formed as a meander type
3) Although it is necessary to make the shape roughly fine, there is a limit to this miniaturization due to processing technology. Therefore, there is a demand for a resistor material that can provide a desired resistance value with a heating resistor having a simple shape, such as the rectangular shape illustrated in FIG. 6(A), for example.

Examples of such resistor materials include tantalum-silicon-nitrogen (Ta-8i-N) or tantalum-silicon-oxygen (Ta-3i-0), which have high electrical resistivity (approximately 103 to 105 μΩ·cm). Resistor materials have been developed.

(Problem to be solved by the invention) However, while the above-mentioned conventional resistor materials have high electrical resistivity, they also have temperature dependence in terms of electrical resistivity, and as the temperature of the heating resistor increases, the electrical resistance increases. There is a tendency for resistivity to decrease. Therefore, for example, when a heating resistor made of a conventional resistor material is continuously driven as a thermal head, the electrical resistivity varies depending on the temperature of the heating resistor, and In addition, as the resistor generates heat, if the temperature of the resistor or its nearby components rises, the amount of heat generated by the resistor increases additively, so the above-mentioned There was a problem in that it was difficult to control the applied power.

In view of the above-mentioned conventional problems, an object of the present invention is to provide a heating resistor that has high electrical resistivity and low temperature dependence regarding the resistivity, and to provide an excellent electronic The purpose is to provide equipment.

(First Means to Solve the Problem) In order to achieve this objective, the heating resistor of the present invention includes a conductive layer made of metal (M) and an insulating layer made of silicon carbide (SiC). It is characterized by having a multilayer structure by laminating the above.

In addition, in carrying out this invention, the above-mentioned metal (M)
Ruthenium (Ru), rhodium (Rh), palladium (Pd), osminium (Os), iridium (Ir)
It is preferable that the conductor layer is made of one type of metal selected from the group consisting of metals and platinum (Pt) or a mixture of two or more types of metals.

(Function) According to the configuration of the heating resistor of the present invention, since the heating resistor is constructed by laminating the conductive layer made of the above-mentioned metal and the insulating layer made of silicon carbide (SiC), the heating resistor The temperature dependence of body resistivity can be reduced.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below will be described under specific numerical conditions, materials, Mold arrangement relationships, and other conditions preferred by this application, but these are merely examples, and the present invention will be described below. It should be understood that the present invention is not limited to the embodiments described herein.

FIG. 1(A) is a schematic cross-sectional view for explaining an embodiment in which the heating resistor of the present invention is used in a thermal head as an example of the use of the heating resistor of the present invention, and FIG. 1(B) FIG. 1 is a sectional view of a main part showing an example of a laminated structure of the heating resistor shown in FIG. 1(A). In the figure, components having the same functions as the components already explained using FIG. 5 are designated by the same reference numerals, except for the components that are characteristic of the present invention. Further, in the same figure, hatchings indicating cross sections are omitted except for a part.

First, according to the conventional thermal head manufacturing method explained using FIG. 5, an insulating substrate 1 made of glazed alumina similar to the conventional one is made as shown in the cross-sectional view of FIG.
A heating resistor 25 is formed on the upper side of the heating resistor 1. Here, as shown in FIG. 1(B), the heating resistor 25 of the present invention includes a conductive layer 27 made of the various metals (M) described above and silicon carbide (SiC). It is constructed as a multilayer structure of at least three or more layers, in which an insulator layer 29 is laminated. Therefore, in order to facilitate the comparison of the examples described below, regardless of the number of laminated layers of the conductor layer 27 and the insulator layer 29 constituting the heat generating resistor 25, the total thickness of both layers is about 3000. The heating resistor 25 is formed on the upper side of the insulating substrate 11 so that the heat generating resistor 25 is formed on the insulating substrate 11. Thereafter, the heat generating resistor 25 deposited on the insulating substrate 11 is patterned to have a rectangular shape of approximately 50 μm x 75 μm, and the density of the heat generating resistor 25 having the rectangular shape is 16 dots/cm.

Subsequently, after forming a power supply body 15 or 17 made of gold (Au) and nichrome (Ni-Cr) with a film thickness of 2 LIm on the upper side of the heating resistor 25 described above, a silicon carbide film is formed in accordance with conventionally well-known manufacturing conditions. The protective film 31 made of (SiC) is about 4
A thermal head was formed by depositing the film to a film thickness of 1 um.

Hereinafter, embodiments of the heat generating resistor of the present invention will be described in more detail with reference to the drawings.

In this first embodiment, platinum (Pt) is used as the metal (M) constituting the conductor layer 27, and silicon carbide (SiC) is used as the insulator layer 29. Furthermore, in this first embodiment, a conductor layer 27 is first laminated on the upper side of the insulating substrate 11, and an insulator layer 29 is laminated on the upper side of the conductor layer 27. After that, the conductor layer 27 and the insulator layer 29 are sequentially laminated, and the number of laminated layers in the heating resistor 25 is 3, 9, and 1.
Four types of thermal heads were created, each having 9 layers or 29 layers. Here, as already mentioned, the thickness of the heating resistor 25 is constant at about 3000, and the ratio of the thicknesses of the conductive layer 27 and the insulating layer 29 is 1:1.

Next, a method for depositing the conductive layer and the insulating layer constituting the heating resistor will be explained.

The deposition method of this embodiment uses a conventionally well-known magnetron sputtering method, in which a target made of platinum (Pt) is sputtered with direct current (DC) to form the conductor layer 27, and the insulator layer 29 is sputtered with direct current (DC). In forming, exchange (
RF) to sputter a silicon carbide (SiC) target. When actually performing sputtering, in order to clean the surface of the insulating substrate 11 on which the heating resistor 25 is attached, the substrate 11 is first heated for 20 minutes in a vacuum.
After heating at a temperature of 0° C. for 30 minutes, the temperature is lowered to room temperature by water cooling. Thereafter, using argon (Ar) as a sputtering gas, sputtering is simultaneously performed using the above-mentioned PT target with DC and SiC target VRF. At this time, by switching the shutter provided in the sputtering device, one of the particles to be sputtered (i.e., p
The conductive layer 27 and the insulating layer 29 are simultaneously formed on the insulating substrate 11 (in such a manner that the heat generating resistor 25 is not deposited on the insulating substrate 11).

In order to compare the characteristics of the heat generating resistors of this example obtained in this way, the temperature dependence of the electrical resistivity of the above-mentioned four types of heat generating resistors with different numbers of layers was measured from 0°C to 12°C.
Measurements were made in a temperature range of 0°C.

In addition, for the purpose of comparing the heating resistor of the first embodiment of the present invention with a heating resistor similar to the conventional one, the heating resistor was
As a comparative example, a thermal head made under the same structural conditions except that it was composed of only one layer of t-3t-C was measured.

FIG. 2 is a characteristic curve diagram for explaining the measurement results of the temperature dependence of the electrical resistivity mentioned above. In FIG. 2, the vertical axis shows the electrical resistivity (UΩ·cm) in %, and the horizontal axis shows the temperature of the heating resistor (° C.). Furthermore, in the above-described embodiments, when the heating resistor 25 has a three-layer structure, the curved line is constructed so that the heating resistor 25 has a three-layer structure. It is shown for the case where it is configured. Furthermore, curve (2) shows the measurement results regarding the heating resistor as the comparative example described above.

As can be understood from this figure, as the temperature increases from 0°C to 120°C, the conventional heating resistor (curve ■)
is 8.90 to - based on the resistivity at 25°C.
In the range of 24.2%, there is a change in resistivity of approximately 2500 uΩ"cm. On the other hand, in the four types of heating resistors according to the first embodiment of the present invention, the resistance is The degree of decrease in rate is small, at most 2.89--11.2
Approximately +3oouΩcm in the range of % (curve ■), and approximately 900uΩcm in the range of 2.09 to -8.79% at the minimum
(curve ■), and the curve shows an almost linear decreasing tendency, which can be understood to indicate that the above-mentioned temperature dependence is extremely low.

In addition, the four types of heating resistors of this first example can maintain high resistivity relatively stably even at high temperatures compared to the heating resistor of the conventional configuration (Pt-St-C). I can understand.

In addition, in the above measurement, only the measurement results in the 5 crystallinity range from O''C to 120°C were illustrated and explained. It is not only effective in a surrounding environment, but also when using a thermal or solar cell at a temperature exceeding the above-mentioned temperature range (approximately 500°C).
℃), the same effect as the above measurement result can be obtained.

Next, a second embodiment of the present invention will be explained with reference to the drawings.

In the first embodiment described above, the conductor layer 27 is made of platinum (
The case where Pt) was used was explained. However, the heating resistor of the present invention is not limited to the case where platinum (Pt) of the first embodiment is used.

In this second embodiment, the conductor layer 27 is made of palladium (Pd
) will be explained below.

In accordance with the production method already explained in the first embodiment, this second
In the embodiment, the conductor layer 27 is made of palladium (Pd) as an example of the above-mentioned metal CM), and the insulator layer 29 is made of palladium (Pd).
A study was conducted on the case where the structure was made of silicon carbide (SiC).

In the same manner as described in the first embodiment, this second embodiment
In order to compare the characteristics of the heating resistors of the examples, the temperature dependence of the electrical resistivity of four types of heating resistors, 3 layers, 9 layers, 19 layers, and 29 layers, was measured from 0°C to 120°C. Measured over a temperature range. In this measurement, similarly to the first example,
For the purpose of comparison with a heat generating resistor having a conventional structure, a thermal head manufactured under the same structural conditions except that the heat generating resistor was composed of only one layer of Pd-3i-C was used as a comparative example.

Similar to FIG. 2, FIG. 3 is a characteristic curve diagram for explaining the measurement results of the temperature dependence of electrical resistivity. In addition, the curve (■) represents the heating resistor 25 and 3 in the second embodiment.
In the case of a layered structure, curves (1), (2), and (2) indicate cases in which the heating resistor is constructed with 9 layers, 19 layers, and 29 layers, respectively. Furthermore, similarly to FIG. 2, a curve X shows the measurement results regarding a heating resistor (Pd-3i-C) as a comparative example.

As can be understood from this figure, as the temperature rises from 0°C to 120°C, the resistivity of the conventionally configured heating resistor (curve X) is 10.0 to - -
15.8% with a decrease in resistivity of about 2000 uΩ-cm. On the other hand, in the four types of heating resistors according to the second embodiment of the present invention, the tendency of the resistivity to decrease is almost linear in all cases, and the resistivity decrease is 2.53 at the maximum. Approximately 1000uΩ・cm in the range of ~-9.02%
It can be seen that the above-mentioned temperature dependence is extremely low, with a minimum value of about 900 uΩ''cm (curve ■) in the range of 2.20 to -8.15%.

Furthermore, similar to the first embodiment described above, the second embodiment described above also maintains high resistivity relatively stably even at high temperatures, compared to the conventionally configured heating resistor (Pd-3i-C). I can understand what I'm getting.

The following is a comparison test between the heat generating resistors of the first and second embodiments described above and a conventional heat generating resistor regarding the lifespan when the heat generating resistor is used in a thermal head and driven. The results will be explained below.

In this lifespan comparison test, a thermal head having the same configuration as that used in the temperature dependence comparison described above was driven with a repetition period of V2 ms and a pulse width of 0.8 ms. In addition, the power applied during driving is determined by printing on thermal paper using each thermal head, and coloring the portion printed on the thermal paper (
Optical density (optical density) as an indicator of the degree of blackness
The density (O, D,) was adjusted so that it was always about 1.2.

FIG. 4 is a characteristic curve diagram showing the results of this life comparison test. In the figure, the horizontal axis represents the number of applied pulses, and the vertical axis represents the resistance change rate (ΔR/R expressed as a percentage) calculated from the 6-day difference between the initial resistance value R and the resistance value at the end of each step. ) is plotted. In the figure, curve a is a thermal head having 19 laminated layers of the heat generating resistor of the first embodiment (corresponding to curve ■ in FIG. 2), and curve a is that of the heat generating resistor of the second embodiment. Among them, the one with 19 laminated layers (curve 2 in FIG. 3) and the curve C show the results of a thermal head constructed of tantalum nitride (TaJ) as a heating resistor, which has already been explained as a prior art.

As can be understood from Fig. 4, the conventional thermal head (
In curve C), the resistance change rate starts to fluctuate from the side where the number of applied pulses reaches 102.

On the other hand, in the thermal head according to the first embodiment (curve a), it is about 105, and in the thermal head according to the second embodiment (curve a)
In curve b), no variation in the rate of change in resistance is observed up to the number of applied pulses corresponding to approximately 5×10 3 .

The embodiments of the present invention have been described in detail above, but the heat generating resistor of the embodiment of the present invention has a higher temperature than the conventional heat generating resistor as explained with reference to FIGS. 2 and 3. It has low dependence and, as can be understood from FIG. 4, excellent durability.

Furthermore, in the above-described embodiments, a case has been described in which the heating resistor is constructed using a conductor layer made of platinum (Pt) or palladium (Pd). However, the present invention is not limited only to the above-mentioned embodiments, but includes ruthenium (Ru), rhodium (Rh), 'osminium (Os)
) or iridium (Ir), or a mixture of these metals, the same effects as in the above-mentioned examples were obtained.

In addition, in the above-mentioned embodiment, the case where the conductive layer 27 is first deposited and the insulating layer 29 is laminated on top of the insulating substrate is described, but for example, the insulating substrate is sequentially laminated with the insulating layer 29. , an insulator layer, and a conductor layer may be laminated in this order.In the above embodiment, the number of laminated layers is an odd number, but the number of laminated layers may be an even number, for example, a layer in contact with an insulating substrate A layer laminated under the insulating layer and the protective layer (or the power supply) may be configured as a conductive layer.

Furthermore, in the above-described embodiments, the case where the magnetron sputtering method was used to deposit and form the heating resistor was explained. However, the present invention is not limited to this deposition method; for example, vapor deposition, chemical vapor deposition (
Chemical VaporDeposition:
CVD) or any other suitable deposition method.

It is clear that these material conditions, arrangement relationships, number of laminated layers, adhesion means, film thickness, and other conditions can be arbitrarily and suitably modified and modified in design within the scope of the object of the present invention.

(Effects of the Invention) As is clear from the above description, the heating resistor of the present invention has a conductor layer made of the metal or a mixture of metals and an insulator layer made of silicon carbide (SiC). They are laminated to form a heating resistor. Therefore, the temperature dependence of the electrical resistivity is low and the electrical resistivity is high, and when the present invention is applied to a thermal head, for example, it has excellent durability when driven.

Therefore, using the heating resistor of the present invention (from this point,
It is possible to provide thermal heads, heaters, and various other excellent electronic devices.

[Brief explanation of the drawing]

FIG. 1(A) is an explanatory diagram showing a schematic cross section of a thermal head in order to explain an embodiment of the heating resistor of the present invention, and FIG. 1(B) is an explanatory diagram showing a detailed explanation of the present invention. Therefore, the first
FIG. 2 is a cross-sectional view of main parts to show an example of the laminated relationship of the heating resistor shown in FIG. , FIG. 3 is a characteristic curve diagram for explaining the temperature dependence of the electrical resistivity of the second embodiment, and FIG. 4 is a characteristic curve diagram for explaining the life test results of the embodiment of the present invention. , FIG. 5, FIG. 6 (A), and FIG. 6 (B) are explanatory diagrams for explaining the prior art. 11...Insulating substrate, 13.25...Heating resistor 15, 17...Power supply body, 19...Heating part 21.
... Oxidation-resistant film, 23... Wear-resistant layer 27... Conductor layer, 29... Insulator layer 31... Protective film. Patent applicant: Oki Electric Industry Co., Ltd. Taller U 17 mm 9 ζ-1C Explanatory diagram of the life test of the example and comparative example q Cross-sectional diagram of the thermal head using a conventional heating resistor No. 5
Figure 6: Characteristic curve diagram for the conventional and present invention diagrams

Claims (2)

[Claims] (1) A conductor layer made of metal (M) and silicon carbide (Si
A heat generating resistor characterized by being formed by laminating an insulating layer consisting of C). (2) The metal (M) is ruthenium (Ru), rhodium (Rh), palladium (Pd), osminium (Os)
2. The heating resistor according to claim 1, wherein the heating resistor is made of one or more selected from the group consisting of , iridium (Ir), and platinum (Pt).