JP3708796B2 - Thick film resistor - Google Patents

Description

【００１３】
【発明の効果】
以上の如く本発明による厚膜抵抗器は、抵抗ペースト及び電極ペーストを高温で焼成する際に生じる材料相互の拡散を小さく抑え得る構造を持ち、高温焼成も可能となるので端子電極と絶縁基板との間で十分な接着力も確保できる。又、前記抵抗素子の両端と端子電極の一部が完全に重合しない為に、薄型の厚膜抵抗器を製造できる他、両者が形成される以前に抵抗値を測定することが可能となるので、製造する抵抗器の仕様によってはトリミング工程を省略し製造工程を簡素化することもできる。而して、抵抗値のばらつきが少なく、抵抗値の温度係数が小さい小型高精度の厚膜抵抗器を比較的安価に提供できることとなる。
【図面の簡単な説明】
【図１】本発明による厚膜抵抗器の一例を示す断面図である。
【図２】本発明による厚膜抵抗器の一例を示す断面図である。
【図３】従来の厚膜抵抗器の一例を示す断面図である。
【図４】本発明による厚膜抵抗器の製造方法の一例を示す工程図である。
【符号の説明】
１ 絶縁基板
２ 抵抗膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resistive element and a thick film resistor in which an electrode thereof is formed by a thick film technique in which a resistance paste and an electrode paste are printed and fired on the surface of an insulating substrate.
[0002]
[Prior art]
A conventional thick film resistor comprises a resistance element made of ruthenium oxide or the like and an electrode made of silver palladium alloy on the surface of an insulating substrate made of ceramic or the like, and polymerizes both ends of the resistance element and a part of the electrode. By connecting with each other, electrical continuity was ensured.
[0003]
[Problems to be solved by the invention]
Conventionally, such a thick film resistor has had a problem that a variation in a constant of the resistor and a temperature coefficient become large due to mutual diffusion caused when the resistor paste and the electrode paste are fired at a high temperature. . In addition, the tendency of variation in resistance value and large temperature coefficient becomes more conspicuous as the resistance element becomes smaller, and this has been a factor that hinders downsizing required for higher integration. In addition, because the structure is based on the premise that both ends of the resistance element and a part of the electrode are superposed, the resistance value cannot be measured before both are formed, and the subsequent trimming process However, there is a drawback that it is difficult to simplify the process.
[0004]
The present invention has been made in view of the above circumstances, and provides a thick film resistor having a structure in which diffusion between a resistance element and an electrode material can be suppressed, and having a small variation in resistance value and a small temperature coefficient. With the goal.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, a thick film resistor according to the present invention is provided with a resistance film at the center of the surface of an insulating substrate and electrodes at both right and left ends of the insulating substrate. Are connected only by joining the two end faces to ensure electrical continuity.
[0006]
Note that the resistance film and the end face of the electrode are faces facing each other in the direction in which both are arranged and facing each other. This surface is not necessarily an upright surface, and it may form a curved surface depending on the printing state of the resistance paste or electrode paste. For example, it is assumed that a partial multilayer structure is formed by the resistance film and the electrode. Also refers to those without contact with the property of increasing the thickness of the thick film resistor.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a thick film resistor according to the present invention will be described below with reference to the drawings.
In the example shown in FIG. 1, a resistance film 2 is provided at the center of the surface of the insulating substrate 1, and terminal electrodes 3 are provided at both left and right ends of the insulating substrate 1, and the resistance film 2 and the terminal electrode 3 are connected to both. An end face electrode 4 that secures end face continuity of the insulating substrate 1 and a protective film 5 that protects the resistance film 2 are formed by connecting only end faces.
[0008]
As a manufacturing process of the thick film resistor, the one shown in FIG. In this example, an insulating substrate 1 with an alumina purity of 96%, which is partitioned by grooves 6 running vertically and horizontally so that a plurality of thick film resistors are arranged vertically and horizontally, is used, and an electrode paste of silver or silver palladium alloy is used as the insulating substrate. The terminal electrode 3 is formed by printing on the surface of 1, drying at 150 ° C. and firing at 850 ° C. Next, a resistive paste based on ruthenium oxide is printed so as to be in contact with the end face of the terminal electrode 3, dried at 150 ° C., and baked at 850 ° C. to form the resistive film 2.
[0009]
A glass paste to be the lower layer coat 7 is printed on the resistance film 2, dried at 150 ° C. and fired at 600 ° C., followed by laser trimming. Next, a glass paste to be the upper layer coat 8 is printed, similarly dried at 150 ° C., and baked at 600 ° C. to form the protective film 5. It should be noted that either the terminal electrode 3 or the resistive film 2 may be formed first in the processes up to now, and both the firing of the electrode paste and the resistive paste are performed simultaneously after finishing the printing of the electrode paste and the printing of the resistive paste. You can go.
[0010]
The main part of the thick film resistor is constituted by the above steps. These thick film resistors are divided into unit pieces, and a predetermined process is performed on the terminal electrode 3 at the time of division. That is, the substrate 9 having been subjected to the above-described process is divided so that the thick film resistors are formed in a strip shape in which a plurality of pieces are arranged side by side. The electrode paste is formed by drying at 150 ° C. and firing at 600 ° C. Then, the strip-shaped substrate 10 is divided into unit pieces, and finally the exposed surface of the terminal electrode 3 is plated with nickel / tin solder to complete the thick film resistor. In some cases, the conductor film 11 is deposited as shown in FIG. 2 for the purpose of adjusting the resistance value by adjusting the bonding area or reinforcing the bonding between the resistance film 2 and the terminal electrode 3.
[0011]
Considering the characteristics of the thick film resistor manufactured as described above based on Table 1, even when any of the resistance pastes of A, B, C, and D recommended for various resistance bands is used, the temperature is extremely low. It can be observed that characteristics are obtained. Note that the overlap dimension of 0 μm to 90 μm shown in this table may constitute a partial multilayer structure with the resistive film 2 and the terminal electrode 3 depending on the film thickness within the practical range of the terminal electrode 3 and the resistive film 2. Even if this is the case, a range that does not increase the thickness of the thick film resistor is considered to be possible, and numbers less than 5 μm are rounded down. For example, when the film thickness of the resistance film 2 is about 10 μm, it is desirable that the overlap dimension / resistance film thickness is about 100 percent or less, such that the overlap dimension is about 10 μm.
[0012]
[Table 1]

[0013]
【The invention's effect】
As described above, the thick film resistor according to the present invention has a structure that can suppress the mutual diffusion of the material that occurs when the resistor paste and the electrode paste are fired at a high temperature, and can be fired at a high temperature. A sufficient adhesive force can be secured between the two. In addition, since both ends of the resistance element and part of the terminal electrode are not completely polymerized, a thin thick film resistor can be manufactured, and the resistance value can be measured before both are formed. Depending on the specifications of the resistor to be manufactured, the trimming process can be omitted and the manufacturing process can be simplified. Thus, a small and highly accurate thick film resistor with little variation in resistance value and a small temperature coefficient of resistance value can be provided at a relatively low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a thick film resistor according to the present invention.
FIG. 2 is a cross-sectional view showing an example of a thick film resistor according to the present invention.
FIG. 3 is a cross-sectional view showing an example of a conventional thick film resistor.
FIG. 4 is a process diagram showing an example of a method of manufacturing a thick film resistor according to the present invention.
[Explanation of symbols]
1 Insulating substrate 2 Resistive film

Claims (2)

A resistance film (2) is provided at the center of the surface of the insulating substrate (1) formed as a flat plate , electrodes are provided at both left and right ends of the insulating substrate (1), and the resistance film (2) and the electrode are connected to each other. A thick film resistor which is connected only by joining both end faces to ensure electrical conduction.   2. The thick film resistor according to claim 1, wherein the overlapping dimension between the resistance film (2) and the electrode is 0 μm to 90 μm, and the overlapping dimension / resistance film thickness is printed and fired at 100% or less. .

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