JPS6028125B2 - Manufacturing method of carbide film resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a carbide film resistor in which a thin film of carbide resistor material is formed on an electrically insulating substrate surface by sputtering.

Traditionally, this type of sputtering has been used as a method for manufacturing electronic components such as resistors and capacitors by thinning target materials such as conductors, semiconductors, dielectrics, and insulators. It is common knowledge. Sputtering is a phenomenon in which ionized gas molecules are accelerated by an electric field and collide with a target electrode (material), and the target material is released in the form of molecules or atoms.

Sputtering is broadly classified into ordinary sputtering, which suppresses reactions, and reactive (or chemical) sputtering. The former method uses a rare gas to make the sputtering gas atmosphere particularly inert, and at least the formed film has a composition similar to that of the target material.

The latter method actively utilizes the effect of a reactive gas during sputtering, and is a method in which sputtering is performed in a sputtering gas atmosphere containing a reactive gas.

Most of these produced films are obtained in the form of oxides, nitrides, etc., and are often at least electrically insulators or similar to them. For example, it is widely known that thin film dielectrics such as Ta205, Si02, Si3N4, and Ti02 are obtained by sputtering the dielectric materials mentioned above. The volume resistivity of these materials is at least 1 and 30 or more. Further, oxygen, nitrogen, etc. are often used as these reactive gases, and are usually added at a ratio of 5 ol % or more to the rare gas.

In addition, when making a carbide resistor belonging to a semiconductor into a thin film,
Usually, ordinary sputtering is used.

In the case of thinning a carbide resistor, the substrate temperature is usually 700 pm.
, high frequency power FOXW, sputtering gas pressure XIO-汀orr,
In an argon atmosphere with sputtering gas of 99.9999%,
The sputtering time was 4 to 8 hours. This is an example of a method for forming a produced film with NTC thermistor characteristics, but this method has a large specific resistance and is further affected by residual gas in the sputtering chamber, resulting in a resistance value that is the basic characteristic of a thermistor.
It was very difficult to stabilize the thermistor constant. Also,
Regarding the sputtering time dependence of the resistance value, we were able to obtain a lower resistance value because the resistance temperature characteristics change depending on the sputtering time. That is, there was a drawback that the resistance value was not necessarily inversely proportional to the film thickness. Furthermore, the element (
The shape of the film (see Figure 1) is determined by the relationship between the film thickness and specific resistance, so if the specific resistance is large, it will fall within the practical resistance value range (when measured at the 50th point: 1 to 100 female Q). Therefore, it was difficult to obtain a miniaturized element. Therefore, the material
This led to the disadvantage of high costs due to the large amount of energy and labor required. When a carbide resistor material is sputtered in a sputtering atmosphere containing a large amount of impure gas such that the reaction product of the carbide material and impure gas becomes an insulator, the resulting film has a large amount of insulating properties due to the reaction with the impurity gas. It is clear that the reaction products are mixed and become an electrical insulator.

Focusing on this, we researched the manufacturing method of carbide film resistors and found that by adding a very small amount of impurity gas, the resistivity was even lower than that of a film made in an atmosphere containing only rare gases. We have identified and determined the characteristic range of resistivity, and have discovered that it is possible to create a sufficiently practical carbide film resistor.

It is clear that this belongs to reactive sputtering because as the impurity gas concentration increases, the volume resistivity increases and eventually it becomes an insulator. That is, the present invention aims to provide a novel method for manufacturing a carbide film resistor that eliminates the above-mentioned conventional drawbacks by utilizing such reactive sputtering.

In the present invention, the film produced by adding a small amount of impurity gas to at least a rare gas in the sputtering gas atmosphere is affected by the reaction of the impurity gas, and the specific resistance increases according to the amount of the impurity gas added. The method of manufacturing a carbide film resistor is characterized in that the carbide resistor material is sputtered onto the surface of an electrically insulating substrate in a range lower than the specific resistance of the film produced in an atmosphere containing only a rare gas.

Hereinafter, a detailed explanation of the present invention will be given with reference to Examples.

Example 1 The configuration of a resistor element was as shown in FIG. 1, and an alumina substrate 1 (0.5 mm thick) with a purity of 96% was selected as an electrically insulating substrate on which a resistor film was formed.

Next, on the surface on which the resistor film is to be formed, a crystalline film of a conductive paste such as Ag, Al-Ag-Pd, Au-Pt, etc. is formed as the electrode 2 . This 2-electrode pattern is configured in a geometric pattern and has a width of 2. It consisted of two electrodes on the proboscis and one electrode of the same size facing each other, and the distance between these three electrodes was 0.3. A desired resistor film is formed on the surface of the substrate configured in this way. In the following experiments, the substrate prepared as described above was used as a tit piece.

The sputtering equipment is a high-frequency bipolar type, and the vacuum chamber is 3500 x 2.
A general-purpose type consisting of 5 skins was used.

The setting conditions for sputtering are high frequency power 2. Dish W sputtering time 2. The temperature of the substrate was 650° C., and the sputtering pressure was 10× orr. First, the sputtering vacuum chamber is sufficiently evacuated to x10-6 Torr,
Next, a predetermined amount of an impure gas selected for the rare gas is introduced.

Next, as the target material, silicon carbide aggregates were selected as the carbide resistor material.

The noble gas is 99.9999% pure argon, the impure gas is 99.999% pure nitrogen, and the impure gas is 99.999% pure.
Oxygen, purity 99.99% Carbon dioxide, purity 99.99%
Carbon monoxide, atmospheric air, or a representative mixture of these groups (78.50% nitrogen, 21.45% oxygen)
%) carbon dioxide (concentration prepared to 0.05%) was used. These rare gases and impurity gases were introduced in predetermined amounts with varying partial pressure ratios, and sputtering was performed at a sputtering pressure of 10-2 Ton. The resistance characteristics of each of the temperature-dependent silicon carbide film resistance elements produced in this way were measured in a 50 mm oil bath. The results are shown in Figure 2. FIG. 2 shows the relationship between the amount of each impurity gas added, the resistance value (measured at 50 qC), and the specific resistance. Point A in FIG. 2 was created using the conventional method, using only argon as the sputtering gas atmosphere, and using the same method as above for other setting conditions (hereinafter referred to as blank). In Figure 2, curve A shows the effect of adding nitrogen, curve 2 shows the effect of adding oxygen, curve 2 shows the effect of carbon dioxide, curve 2 shows the effect of carbon monoxide, wood shows the effect of air, and curve 2 shows the effect of adding mixed gas. Second
From the figure, it can be seen that by adding a small amount of each impurity gas, the characteristics that could only be obtained in the blank range at point A using the secondary method can be obtained over a wide range over the curves shown in A to B.

This shows that the resistance value or specific resistance can be easily controlled over a wide range from very low to large, and that a stable film resistor can be obtained by adjusting the amount of impurity gas added. In addition, the rare gas was replaced with 99.99% pure xenon, 99.99% pure neon, and 99.99% pure krypton from argon, and the amount of each impurity gas was reduced to 3. Pus formation was carried out under the same conditions as described above for argon when the argon concentration was fixed at 100% and 100%.

The results are shown in Table 1 (see below). Table 1. 1~
3 shows the effect of rare gases (xene, neon, krypton) on nitrogen, and similarly M. 4 to 6 are oxygen,
The gunwale. 7 to 9 are carbon dioxide, M. 10 to 12 are carbon monoxide, M. 13 to 15 are air, M. 16 to 18 are representatively selected mixed gases (same as the formulations described above). From the results using argon in Figure 2 and the results in Table 1, it can be seen that the same effect of impurity gas addition is obtained when the rare gas is xenon, neon, or krypton. For each of the P. aeruginosa resistors, including the blank, a high temperature storage test (left at 350°C for 100 ms),
Thermal shock resistance test (held at room temperature for 15 minutes ~ 18 at 350qo)
3000 cycles were carried out, with one cycle consisting of a minute hold.

As a result, the resistance change rate was almost within 8%, and no difference was observed from the blank. Similar studies were also attempted on carbides other than silicon carbide such as boron and zirconium compounds, but some films peeled off during thermal shock resistance tests.

Table 1 The claimed range of the amount of impure gas added according to the present invention is determined from the minimum value of each resistivity of the curves shown in A to A of FIG.
It is indicated by the addition range of each impurity gas, which is represented by the range where the resistivity is equal to or less than the specific resistance of the film formed in an atmosphere containing only rare gases, as indicated by the dots.

In this case, the most useful thing is specific resistance, and the resistance values shown in the examples are based on the electrode configuration shown in FIG.

Therefore, it is clear that by finely structuring this electrode structure using photolithography, electron beam or X-ray lithography techniques, a sufficiently practical resistance value can be achieved even in the case of the resistivity shown here. If more than this, for example, 50% or more of impurity gas is added, the resulting film has a composition close to that of oxides, nitrides, etc., and is usually used as a dielectric or an insulator.

It is clear that reactive sputtering, which obtains a reaction product film by adding a large amount of impure gas, and the present invention are on the same line from the electrical characteristics, and are reactive sputtering. However, regarding the method of manufacturing a carbide film resistor according to the present invention, the resistivity is lower than that of a carbide film resistor produced in an atmosphere containing only a rare gas by sputtering with the intention of adding a small amount of impurity gas and causing a reaction. There is no report that a carbide film resistor of 100% can be obtained. In addition, the reason why the optimum range of the amount of impurity gas added is determined from the range of the amount of impurity gas added that is represented by the minimum value in the resistance value and specific resistance curves shown in This is because the minimum value of resistance occurs when the added amount is the same.

The amount of each impurity gas added to reach this maximum value of 4 is approximately several percent. Contrary to the present invention, in a production method below that range, when the amount of impurity gas added increases, the resistivity or resistivity value tends to decrease, and the resulting film also has a tendency to decrease due to the target material containing no reaction products. The film has the same composition. From this, it is clear that this production method can be distinguished from the method of the present invention. Note that carbide resistor materials have various compositions, and among these, silicon carbide resistors have excellent heat resistance as described above.

Therefore, silicon carbide resistors can be said to be one of the most useful temperature-sensitive resistors from a practical standpoint.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the structure of a carbide film resistance element obtained by the manufacturing method of the present invention, and FIG. 2 is a characteristic diagram according to the amount of impurity gas added in the manufacturing method of the present invention. 1... Alumina substrate, 2... Electrode, 3
...Resistive film forming part. Figure 1 Figure 2

Claims (1)

[Claims] 1. A film formed in a rare gas atmosphere in a sputtering gas atmosphere has a specific resistance lower than that of a film formed in an atmosphere containing only a rare gas, and the specific resistance increases according to the amount of impurity gas added. , a method of manufacturing a carbide film resistor by sputtering a carbide resistor material onto an electrically insulating substrate surface by adding a small amount of impurity gas. 2. The method for manufacturing a carbide film resistor according to claim 1, wherein the rare gas is at least argon, xenon, or krypton. 3 The impure gas is at least nitrogen, oxygen,
2. The method for manufacturing a carbide film resistor according to claim 1, wherein carbon dioxide, carbon monoxide, air, or a mixed gas of one or more selected from these groups is used. 4. The method of manufacturing a carbide film resistor according to claim 1, wherein the carbide resistor material is at least silicon carbide.