JPS6243101A - Heating resistor - 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 heating resistor suitable for use as a heating element for a thermal head or the like.

(Prior Art) Heat-generating resistors made of various materials have been proposed, which are used in heaters, thermal heads, etc., by causing the N-film resistor to generate heat by passing an electric current through the resistor.

In recent years, the application of such heating resistors to thermal heads has attracted attention. Hereinafter, the heating resistor will be explained using a thermal head as an example.

Thermal heads of various structures have been proposed for printing pictures, characters, etc. by coloring the thermal paper and creating a mosaic of dots on the thermal paper.

Such a thermal head is described, for example, in the literature (Metal Surface Technology J 34, (8) (1983) P, 271-
277). In a thin-film thermal head with such a structure, tantalum nitride (Ta2N) is mainly used as the heating resistor.As is well known, when Ta2N is used as an S-film resistor in a hybrid IC, for example, Although the stability of the resistance value is very good, when this Ta2N is used as a heating resistor of a thermal head, the heat resistance of Ta2N, especially its oxidation resistance, is not sufficient. For this reason, Ta2N
When used as a heating resistor, the structure of the thermal head was as shown in Figure 4.

FIG. 4 is a cross-sectional view showing the main parts of a conventional thin-film thermal head. It is. In FIG. 4, +1 indicates an insulating substrate;
A heating resistor 13 made of a Ta2N thin film is provided on this insulating substrate 11h. Further, power feeders 15 and 17 are provided at positions spaced between the heating resistor +31, and the portion of the photothermal resistor 13 between these power feeders 15 and 17 (
In the figure, the shaded part) becomes the heat generating part 19. Look,
Power feeders 15 and 17 and heat generation i'! '[119 and L are sequentially oxidation resistance 1! J21 and a wear-resistant film 23 are provided, and these single-layer films form a protective film for the heating resistor.

This protective film, especially the oxidation-resistant film 21, plays an important role in protecting the life of the thermal head. It is a l membrane.

Further, Ta2N has a specific resistance of 300 gΩ·cm or more. For this reason, if the resistor film thickness is set to t-minutes so that the heating resistor can be used for a long time, its resistance value will be smaller than the desired resistance value. Therefore, in order to obtain the power necessary for printing, it is necessary to increase the current value supplied to the heating resistor. However, due to restrictions such as the wiring II + 1 route and the firing method, 'X
Is there an emission that increases the practical resistance value? l! The shape of the resistor must be determined, and for this reason, a method was used in which the resistance of the heat generating resistor was increased by 1 - by making it a mianta shape as shown in Figure 5 (B). .

(Problem to be Solved by the Invention) However, conventional heating resistors used in thermal heads do not have a protective film, especially an oxidation-resistant film, on the heating resistor, or If the thickness is insufficient, when the energy necessary for printing is applied to the heating resistor 13, the resistance value of the heating resistor increases due to oxidation, and the heating resistor 1 deteriorates. Therefore, there is a problem that thermal recording can only be performed for an extremely short period of time +5. was there.

Furthermore, if this protective film is provided as thick as necessary, the temperature rise (fS response) of the thermal head with respect to the application/stopping of the supply current to the photothermal resistor (fS response) will be reduced.
I was worried that high-speed printing would not be possible.

Furthermore, in recent years, there has been a demand for higher definition printing using thermal heads. Therefore, it is necessary to make the shape of the heat-generating resistor of Mianta shape into a rough and fine shape in order to realize more precise printing, but this has a limit depending on the technique. Therefore, a simple shape, for example, Fig. 5 (A
) A resistor material is desired that can provide a desired resistance value in a rectangular heating resistor as shown in FIG. As such resistor materials, Ta-3i-N, Ta-3i
-Of high-resistance materials have been developed, but these materials also have poor heat resistance and #oxidation properties, and their film formation is performed using gases such as nitrogen and MX by reactive sputtering. Therefore, there was a problem in that it was difficult to control the resistance value of the S film.

An object of the present invention is to provide a heating resistor that has excellent heat resistance and oxidation resistance, has a large specific resistance I1, and is easy to manufacture. ,
The purpose of this invention is to enable high-definition thermal heads and the like.

(1st stage for solving the problem) In order to achieve this object, according to the present invention, a heating resistor is made of a conductive material containing one or more elements selected from platinum group elements, and a carbonized It is characterized in that it is constructed of an electrically insulating material containing silica.

When applying this invention, three to four conductive materials are used in the heating resistor. It is preferable to include %.

(Function) According to such a configuration, since both the platinum group element and silicon carbide are chemically stable, a heating resistor with excellent oxidation resistance can be obtained.

Further, a heating resistor having a desired resistivity can be obtained by adjusting the content of the conductive material contained in the heating resistor. Furthermore, silicon carbide can be easily etched by dry etching using a gas such as CFa. Therefore, it had a desired resistance value. A heating resistor of arbitrary shape and size can be easily produced.

(Example) Hereinafter, an example of the present invention will be described using an example in which the heating resistor of the present invention is used in a thermal head. It should be noted that FIGS. 1 to 3 used for explaining the following embodiments are merely schematic representations to the extent that the present invention can be understood, and the dimensions, shapes, and arrangement relationships of each component are not shown in the illustrated examples. It's not something to be driven by.

FIG. 1 is a cross-sectional view of the main part showing the structure of the thermal heater of the present invention, and like FIG. FIG.

In FIG. 1, reference numeral 11 indicates an insulating substrate, and the insulating substrate 11 is made of, for example, platinum-silicon carbide (Pt) made of platinum (Pt) as a conductive material and silicon carbide (SiC) as an electrically insulating material. -5iC) A heating resistor 31 made of a resistive film is provided.

Further, power feeders 15 and 17 are provided in two spaced apart areas on the heating resistor 31, and these power feeders 15
The portion of the heating resistor 31 between and 17 (the shaded portion in the figure) becomes the heating portion 18. Further, a wear-resistant film 23 is provided on the hills between the power feeders 15 and 17 and the heat generating portion 18.

Hereinafter, the method for forming the heating resistor of the present invention will be explained in accordance with the manufacturing of the thermal head.

First, a Pt-5iC resistance film as a heating resistor is formed on a glazed alumina substrate as an insulating substrate 11 by high frequency sputtering (RF sputtering). This Pt
The -5i C film was formed as follows. As shown in a top view in FIG. 2, a small Pt piece 35 of a certain shape is brought close to the SiC target 33h, and SiC and Pt are simultaneously sputtered with high frequency. By increasing or decreasing the number of these Pt pieces, the amount of PT contained in SiC can be increased or decreased,
Control the resistance value of the PL-3iC film. In this example,
The substrate temperature was 200°C, and the argon (Ar) gas pressure was 5°C.
X10 jTorr, Pt of SiC target h
The exposed surface area of PT excluding the side area of the small piece and the Pt small piece are 1
! A Pt-3iC resistive film having a thickness of 350 OA was formed on the glazed alumina substrate 11 with a ratio of 1:5 to the exposed area of the SiC target other than the exposed area (referred to as surface area ratio). The surface resistance of the Pt-5iC resistive film obtained under these film-forming conditions was 900Ω/hole. Therefore, this Pt
If a -3iC resistive film is used, a desired resistance value can be obtained without making the shape of the single heating resistor 31 into a meandering shape. Therefore, in the present invention, the heating resistor 31 is formed by patterning in a predetermined square shape as shown in FIG. 5(A). Thereafter, the power feeders 15 and 17 were formed on the heating resistor 31h, and then Ta205 with a thickness of 8 μm was formed as the wear-resistant film 23 to obtain a thermal head having the heating resistor of the present invention.

On the other hand, as a comparative sample, the shape of the heating resistor and the thickness of the protective film were the same as those of the thermal head having the heating resistor of the present invention, but the heating resistor was constructed of a Ta-5t-N film, and Surface resistance IKΩ with film thickness of 320OA
A thermal head having 10 heating resistors was manufactured.

A lifespan test was conducted using these two types of thermal spars. The life test conditions are a pulse width of 0.8m5ec,
Pulses were continuously applied to the heating resistor at a repetition time of 3 msec, and changes in resistance I1 of the heating resistor were measured. The test results are shown in FIG. 3, with the rate of change in resistance of the heating resistor plotted on the vertical axis and the number of pulses applied on the horizontal axis. In addition, the characteristic curve indicated by ■ in the figure is the Pt-3 of this invention.
Showing the characteristics of a thermal head with an iC heating resistor tip,
The characteristic curve indicated by (2) shows the characteristics of a thermal head having a Ta-5t-N heating resistor.

As is clear from FIG. 3, the thermal head having the heating resistor of the present invention has a higher resistance to change in resistivity of the heating resistor with respect to continuous pulse application than the thermal head having the Ta-5t-N heating resistor. There are very few, therefore,
The lifespan of the thermal helmet is significantly improved. The reason for this is that in a thermal head with a Ta-3i-N heating resistor, the resistance value first decreases due to crystallization of the heating resistor.
Subsequently, it is presumed that the resistance value rapidly increased due to oxidation of the heating resistor. On the other hand, in the thermal head having the pt-SiC heating resistor of the present invention, only partial crystallization of Pt occurs, so it is estimated that the resistance value decreases moderately.

In the same way as the Pt-SiC heating resistor described in F was prepared,
A thermal head having a Rh-SiC heating resistor using rhodium (Rh) as the conductive material was fabricated and a life test similar to that described above was conducted. Good durability characteristics similar to those of a thermal head with a heating resistor were obtained.

The conductive material and the electrically insulating material constituting the heating resistor of the present invention are not limited to the above-mentioned examples. , iridium (Ir), osmium (O3)
A conductive material containing a substance other than the platinum group, which may be one or more elements selected from ruthenium (Ru) and ruthenium (Ru), and further contains one or more elements selected from the platinum group elements as a main component. Also, the electrically insulating material is SiC.
An electrically insulating material having L component may also be used.

Also, the reason why the content of metal elements such as Pt to be included in the heating resistor is set to 3 to 40% (insect acid%) is that it is in the practical range of 10" to 10/gΩ・cm for use as a heating resistor. This is to obtain a resistor thin film having a specific resistance of .

Further, in the τ embodiment, a small piece of Pt or Rh was placed on the SiC target L, and these metals and SiC were sputtered simultaneously to form each heating resistor.

Ideally, it is preferable to use a special target obtained by powdering metal and SiC, mixing them, and then sintering them using a hot press.

In addition to the high frequency sputtering method, the i4M resistor can be formed using N
This can be done by f-beam evaporation method.

Hereinafter, the present invention has been explained using an example in which the heat generating resistor of the present invention is used in a thermal head, but the heat generating resistor of the present invention may also be used in other electrical components such as heat generating component 1. suitable.

(Effects of the Invention) As is clear from the above description, according to the present invention, a heating resistor is made of a conductive material containing one or more elements selected from platinum group elements and a carbonized The structure is made of an electrically insulating material containing silicon. Therefore, since both the platinum group element and silicon carbide are chemically stable, a heating resistor with excellent oxidation resistance can be obtained. For this reason, when the heating resistor of the present invention is used in a thermal head, for example, instead of providing a two-layer protective film of an oxidation-resistant film and an abrasion-resistant film on the heat-generating resistor as in the conventional case, only the wear-resistant film is used. Therefore, a thermal head with excellent thermal response can be obtained.

Furthermore, materials that do not contain oxygen element can be selected for both the conductive material and the electrically insulating material. Therefore, since no exchange of oxygen occurs inside the heating resistor, it is expected that a heating resistor with better oxidation resistance will be realized.

Further, a thin film resistor for the heating resistor having a desired specific resistance can be obtained by adjusting the content of the conductive material contained in the heating resistor.

Furthermore, silicon carbide can be easily added by dry etching using CF1'v residue. Therefore, it is possible to easily obtain a small heating resistor having a rectangular shape, for example, so that a thermal head with low durability and high definition can be obtained.

Therefore, it is possible to provide a heating resistor that has excellent heat resistance and oxidation resistance, has a large specific resistance I1, and is easy to manufacture.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a thermal head using the heat generating resistor of the present invention without showing the main parts, Fig. 2 is an explanatory diagram for manufacturing the heat generating resistor of the present invention, and Fig. 3 is a conventional and this invention. A characteristic curve diagram showing the life test results of a thermal head using a conventional heating resistor; Fig. 4 is a sectional view of a main part of a thermal head using a conventional heating resistor; Fig. 5 is a description of the conventional and present invention. FIG. II... Insulating substrate, 15.17... Power feeder 13... Heat generating part, 23... Wear-resistant film 3
1... Heat generating resistor, 33... Electrical insulating material 35... Conductive material. Patent applicant: Oki Electric Industry Co., Ltd. q/f Obaku Mouse 23 Resistance Thickness 15.17'? '4i4+ 3f: Climb to the right side J 144 (1 (/ Fever section This is June's fever \ envoy heather 8 group ``This thermal...
Cross-section circle of D Fig. 1 Date and month f) Exhaustion B Month bO Fig. 2 Dimensions - Mar head h@;gK, Experimental IPI Sword Fig. 3 Conventional q! 11T using the book against poverty 1; Gumarhe Do's CI is an illusion Figure 4

Claims (2)

[Claims] (1) A heating resistor characterized in that it is constructed of a conductive material containing one or more elements selected from platinum group elements and an electrically insulating material containing silicon carbide. (2) The heating resistor according to claim 1, which contains 3 to 40% by weight of a conductive material.