JP2705069B2 - Thin film resistor and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film resistor used for various electronic devices and a method for manufacturing the same. 2. Description of the Related Art As a material used for a resistor, a resin, a carbon film, a metal film, a metal oxide film, ruthenium oxide, and the like are used. Of these, thin-film resistors made of metals and metal oxides are generally created using a vacuum process, but the present inventors have already developed a ruthenium oxide-based thin-film resistor created by the thermal decomposition of organic substances containing metals in the structure. did. FIG. 3 shows a cross-sectional view thereof. In FIG. 3, reference numeral 11 denotes a support substrate such as alumina, 12 denotes a glass thin film formed on the support substrate 11, and 13 denotes a resistor thin film made of a sintered body of fine particles. Problems to be Solved by the Invention When manufacturing a conventional thin film resistor, a vacuum device such as sputtering or vapor deposition has been used. In this case, the temperature of the support substrate 11 is heated to 200 to 300 ° C. in order to strengthen the adhesion of the film.
For this reason, expensive vacuum equipment is required, and a supporting substrate is required.
It was necessary to wait for cooling of 11, which inevitably increased costs. On the other hand, when making a thin film resistor by the thermal decomposition of an organic substance having a metal in the structure, gas such as H ₂ O and CO ₂ comes out of the film during the thermal decomposition process, so fine holes are likely to be formed . Further, since the film is not formed by activated high-energy particles as in the case of sputtering or vapor deposition, mutual diffusion and growth of an intermediate compound, which are factors that increase adhesion, are unlikely to occur. Due to the above factors, when making ruthenium oxide-based thin film resistors by thermal decomposition of metal organic substances, the adhesion is insufficient for use in applications that are exposed to thermal cycling and mechanical friction, and there is a problem with durability. is there. Then, since the film shrinks during the thermal decomposition, the film is easily peeled off in the firing step. However, there is no need to use a vacuum device, and mass production can be performed with an inexpensive device, which is advantageous. The present inventors have already found that the glass thin film 12 is used as an adhesion layer in order to solve the above problems.
However, when glass is used, sufficient adhesion cannot be obtained unless low-melting glass having a melting point of about 500 ° C. is used. Therefore, when the resistor thin film 13 is used as a heating element, the glass thin film 12 is used as an adhesion layer. Can not do. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a high-quality thin film resistor having high durability against thermal shock and mechanical friction, which solves the above-mentioned problems of the ruthenium oxide thin film resistor. Means for Solving the Problems In order to solve the above problems, the present invention is characterized in that a ruthenium oxide-based thin film resistor is formed on a supporting substrate via a bismuth oxide thin film. Operation With the above configuration, it is possible to obtain a thin-film resistor having high-speed response, good power characteristics, and high durability by a simple method. Examples Hereinafter, examples of the present invention will be described. Conventional thin-film resistors have been manufactured using a vacuum process such as sputtering or vapor deposition, so that an increase in the cost of the resistors has been unavoidable. However, in the present invention, in order to manufacture a resistor inexpensively, an organic compound having a metal in a structure is laminated on a supporting substrate on which a bismuth oxide thin film is formed, and then thermally decomposed into a metal oxide, and then the metal oxide is formed. The feature is that the oxide is sintered to form a thin film resistor. In the above description, the thermal decomposition and sintering of the metal oxide are described separately, but the steps can be performed in the same manner. The support substrate used here can be arbitrarily selected as long as it can withstand the firing temperature of the organic compound having a metal in the structure. For example, various types of glass plates, ceramic plates, enamel plates and the like can be used. The bismuth oxide thin film is formed with a thickness of about 300 to 1000 ° on an alumina substrate or the like having good thermal conductivity when heat dissipation characteristics are important. Conversely, when an appropriate heat storage property such as a thermal head is required, a bismuth oxide thin film is formed on an alumina substrate coated with a glass glaze of about 10 to 80 μm. Thus, the feature of the present invention is that the heat radiation characteristics can be selected depending on the substrate. When a thin film is formed on bismuth oxide by the thermal decomposition of an organic substance having a metal in the structure, the melting point of bismuth oxide is generally lower than that of other metal oxides, and thus has an effect of bonding the thin film to the substrate. At that time, the thin film resistor becomes mechanically strong, and the improvement in the adhesiveness hardly affects the resistance value. As a result of examining the crystal structure by X-ray diffraction, a mixed crystal system of ruthenium oxide and bismuth oxide was formed in the resistor layer, and the bismuth oxide diffused into the grain boundaries of the ruthenium oxide sintered body to increase the adhesion. It is thought that it is. Since the melting point of bismuth oxide is 800 ° C. or higher, the resistor does not deteriorate even when the temperature of the resistor reaches 500 to 600 ° C. The above is the feature of the present invention. The thin film resistor according to the present invention is a fixed resistor, a variable resistor,
It can be used for thermal heads and the like. Hereinafter, a specific example will be described. Embodiment 1 FIG. 1 is a perspective view showing the vicinity of a heating element of a thermal head manufactured according to a first embodiment of the present invention. In FIG. 1, 1 is a supporting substrate made of alumina, 2 is a glaze layer,
Reference numerals 3a and 3b denote wiring conductor films, 3a denotes a common electrode commonly connecting one end of the heating element, and 3b denotes an individual electrode connected to the semiconductor element. Reference numeral 4 denotes a heating resistor film formed by printing and firing an organic paste containing a metal in the structure, and reference numeral 5 denotes a wear-resistant protective film. In FIG. 1, a wear-resistant protective film is partially not formed for convenience of explanation. This embodiment will be specifically described below. In the present embodiment, an ink prepared by dissolving bismuth 2-ethylhexanoate and nitrocellulose in a ketone-based solvent is printed on the entire surface of the support substrate 1 on which the glaze layer 2 having a transition point of 800 ° C. or higher is formed. It was calcined at 500 ° C. in the air. A resistance ink made by dissolving ruthenium 2-ethylhexanoate and nitrocellulose in a ketone solvent was printed on the entire surface and fired at 800 ° C. in the air. Although the fired resistor film 4 had a sheet resistance of 1000 Ω / □, the sheet resistance could be freely controlled to about 500 to 10 kΩ / □ by adding barium 2-ethylhexanoate. . Next, a gold resinate (manufactured by Engelhard) was similarly printed on the entire surface and fired at 800 ° C. Thereafter, a photoresist was applied, and the photoresist was exposed to light using a predetermined mask to remove unnecessary portions by etching, thereby forming a pattern shown in FIG. (A part without a wear-resistant protective film in FIG. 1) Next, a wear-resistant protective film 5 containing hard glass as a main component is printed on a portion which comes into contact with paper and baked at 770 ° C.
The thermal head shown in the figure was prepared. FIG. 1 is a view in which a part of the wear-resistant protective film is not formed for convenience of explanation. The variation of the resistance value of the thermal head of the present embodiment prepared in this way was 4% or less even with a B4 size of 8 lines / mm, and image recording was sufficiently possible. In addition, since the thickness of the heating resistor film 4 is about 1000 °, low power consumption and thermal responsiveness can be realized at the same level as a conventional thin-film thermal head. Regarding the durability, even if a pulse of 0.7 W / dott was applied 1 * 10 ⁸ times at a cycle of 1 msec, it was proved that the heating resistor film 4 did not peel off or the like and sufficient durability was obtained. When the same manufacturing method was performed without the bismuth oxide thin film, peeling occurred between the supporting substrate 1 and the thin film resistor. Example 2 As shown in FIG. 2, an ink prepared by dissolving bismuth 2-ethylhexanoate and nitrocellulose in a ketone-based solvent was printed on a support substrate 1 made of alumina, and baked at 500 ° C. to form bismuth oxide. Was formed. A ruthenium 2-ethylhexanoate ink was printed thereon in the same manner and fired at 650 ° C. to obtain a ruthenium oxide resistor film 4. The sheet resistance of the low antibody film 4 was 300.
Ω / □, indicating a resistance temperature coefficient of 400 ppm. It was extremely resistant to mechanical friction and could not be removed by rubbing with a brass needle. Example 3 A bismuth oxide thin film having a thickness of 1000 ° was formed on a supporting substrate of alumina by using an RF sputtering method with a target of bismuth oxide. Ruthenium 2-ethylhexanoate was printed thereon in the same manner as in [Example 2] and fired at 750 ° C. to obtain a resistor film. The sheet resistance of the resistor film was 350Ω.
/ □, indicating a resistance temperature coefficient of 500 ppm. The mechanical strength was sufficient and it could not be removed by rubbing with a brass needle. In addition, there was no change in characteristics even after use at 500 ° C. Effect of the Invention As described above, the thin film resistor of the present invention can be manufactured by giving a high durability to a thin film resistor having high-speed response and good power characteristics while using an inexpensive printing method of manufacturing equipment, It has high industrial value.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one embodiment of a thermal head which is an application example of a thin film resistor according to the present invention, and FIG. 2 shows a thin film resistor according to another embodiment of the present invention. FIG. 3 is a sectional view of a conventional thin film resistor. DESCRIPTION OF SYMBOLS 1 ... Support substrate, 2 ... Glaze layer by bismuth oxide, 3a, 3b ... Wiring conductor film, 4 ... Resistor film, 5 ...
Wear-resistant protective film.

Continuation of front page    (72) Inventor Keisaburo Kuramasu               Matsushita, 1006 Kadoma, Kazuma, Osaka               Kiki Sangyo Co., Ltd.                (56) References JP-A-64-27203 (JP, A)                 JP-A-62-152102 (JP, A)                 JP-A-63-124501 (JP, A)

Claims (1)

(57) [Claims] A thin film resistor comprising a ruthenium oxide thin film resistor formed via a glaze layer of a bismuth oxide thin film formed on a supporting substrate. 2. Forming a glaze layer of a bismuth oxide thin film on a support substrate, and, after thermally decomposing the organometallic compound layer having ruthenium in the structure printed on the glaze layer, sintering the remaining ruthenium oxide. A method for manufacturing a thin film resistor, comprising: 3. 3. The method according to claim 2, wherein the glaze layer formed on the supporting substrate is manufactured by thermal decomposition and sintering of an organic compound having bismuth in the structure.