JPH1036961A - Film formation by sputtering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of foreign matter and nodules on a target material by specifying the partial pressures of gaseous Kr and gaseous Xe or the total of the partial pressures in an atmosphere within a reaction vessel. SOLUTION: In an atmosphere within a reaction vessel in which thin coating film is formed on the surface of a substrate by sputtering, the partial pressures of gaseous Kr or gaseous Xe or the total partial pressure of the gaseous mixture therebetween is regulated to >=70% of the total pressure. In this way, the quality of the thin coating film to be obtd. and the producibility of sputtering can be improved only by changing the atmosphere in the reaction vessel with the conventional sputtering device as it is. For example, in the atmosphere within the reaction vessel, the total pressure is regulated to about 0.4Pa, the ratio of the partial pressures of gaseous Kr and gaseous Xe is regulated to >=70% of the total pressure, that of oxygen is regulated to 0.008Pa, and the balance gaseous Ar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a film forming method using a sputtering method, and more particularly, to an atmosphere in a reaction vessel for performing sputtering.

[0002]

2. Description of the Related Art In a film forming method by sputtering, a target material such as a metal, an alloy, a sulfide, an oxide or a nitride is used as a cathode, and discharge is caused in a reaction vessel reduced in pressure from 100 Pa to about 0.1 Pa. Sputtering grows a thin film on the surface of the substrate, which is the anode.

As a process gas introduced into the reaction vessel, argon (Ar) or a mixed gas of argon and a reactive gas such as oxygen, nitrogen, water vapor, and hydrogen peroxide is generally used.

[0004] The sputtering method is widely used industrially as a method for obtaining a high quality thin film. For example,
Magnetic recording media include Co / Cr and carbon films of hard disks, CoCrTa-based films, silicon nitride (SiN _x ) and TbFeCo-based films of magneto-optical disks, and WSi of semiconductors.
System film, MoSi system film, Al film of a compact disk, and a transparent conductive film such as a liquid crystal and an indium tin oxide (ITO) film such as a heat ray reflective glass.

[0005]

However, in an atmosphere in a reaction vessel mainly composed of argon gas, carbon film, WS
As the sputtering of i, MoSi, ITO or the like is continued, foreign substances are generated on the surface of the target material. The foreign matter is a product using the target material and the gas in the reaction vessel as a raw material. Specifically, a cylindrical shape at the beginning of sputtering,
Fine foreign matters such as cones and plates are generated, which grow as the sputtering time is increased, and grow into visible foreign matters called "nodules". The foreign matter causes a reduction in the film forming speed, abnormal discharge and occurrence of a film defect, and also causes a deterioration in the quality and productivity of the thin film. Attempts have been made to prevent the generation of such foreign matter by changing the design of the sputtering apparatus, but it was necessary to take measures to improve the conventional sputtering apparatus regardless of the design change.

Accordingly, the present invention provides a method for suppressing the generation of foreign matter and nodules on a target material and improving the quality of a thin film obtained by a simple means of changing the atmosphere in a reaction vessel in a conventional sputtering apparatus. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention provides a method for forming a film by sputtering.
Using an alloy, oxide or nitride as a target material, the target material as a cathode in the reaction vessel, the substrate as an anode,
In sputtering the target material to form a thin film of the target material on the surface of the substrate, in an atmosphere in the reaction vessel, a partial pressure of a Kr element gas or a Xe element gas, or a mixed gas of these elements. The total sum of the partial pressures is 70% or more of the total pressure.

[0008]

EXAMPLES The present inventors have observed in detail how a target surface is etched in order to search for sputtering conditions for suppressing generation of foreign matter. As a result, it has been found that the gas introduced into the container is ionized, accelerated by the electric field, and the generation of foreign matter is suppressed as the molecular mass of the ions incident on the target surface increases.

Further, a gas of a Kr element and / or a Xe element, which is heavier than the Ar element, is introduced into the atmosphere in the reaction vessel during sputtering, and the partial pressure of Kr or Xe or the total partial pressure is 70% or more of the total pressure. By using the conventional sputtering apparatus as it is, it is possible to suppress the generation of foreign matter and nodules on the target material by simple means simply changing the atmosphere in the reaction vessel, and to improve the quality of the obtained thin film and The present inventors have found that the productivity of sputtering can be improved, and have reached the present invention. Hereinafter, the present invention will be described more specifically with reference to examples.

Generation of foreign matter and nodules [Examples 1 to 5] A sputtering device CFS-8EP manufactured by Tokuda Seisakusho was used as a sputtering device, and an ITO target having a diameter of 5 inches was used as a target. The atmosphere in the reaction vessel was set to a total pressure of 0.4 Pa, Kr gas, Xe gas, and oxygen gas of 0.008 Pa having partial pressures shown in Table 1 were introduced, and the rest was Ar gas. The sputtering current was 0.8 A, and the sputtering voltage was 270 V.

[0011]

[Table 1]

In Examples 1 to 5, when the target material was observed for a total sputtering time of 75 hours, no foreign matter or nodule was found in any case.

Comparative Example 1 Sputtering was performed under the same conditions as in Examples 1 to 5, except that the total pressure of the atmosphere in the reaction vessel was 0.4 Pa, the partial pressure of Ar was 98%, and the partial pressure of oxygen was 2%. ,
When the target material was observed at a total sputtering time of 75 hours, many foreign substances and nodules were observed on the target.

Film formation and evaluation Under the conditions of Examples 1 to 5 and Comparative example 1, a 1000 Å ITO film was formed on a 10 cm square glass plate at a film formation temperature of 200 ° C. by sputtering for 5 minutes.
Then, the performance of the ITO film was examined. Table 2 shows the results. The number of pinholes indicates the number of glass plates having pinholes visually. The electric resistance is an average value of 10 sheets. It can be seen that Examples 1 to 5 are superior to Comparative Example 1 in the number of pinholes and the electrical resistance.

[0015]

[Table 2]

[Examples 6 to 10] A target having a diameter of 5 inches, which was obtained by mixing 5.7 Wt% of Ga ₂ O ₃ with ZnO and sintered, was sputtered at a sputtering current of 0.7 A for 75 hours under the atmosphere conditions shown in Table 3. Sputtering on a 10 cm square glass plate for 5 minutes, film formation temperature 200 ° C
Then, ten ZnO.Ga films having a thickness of 1000 Å were formed, and the performance of the ZnO.GaO film was examined. Table 4 shows the results. The number of pinholes was visually indicated by the number of glass plates having pinholes. The electric resistance is an average value of 10 sheets.

[Comparative Example 2] Except that Ar was set to 100%,
Table 4 shows the results obtained by performing film formation by sputtering under the same conditions as in Examples 6 to 10, and examining the performance.

[0018]

[Table 3]

[0019]

[Table 4]

From Table 4, it can be seen that Examples 6 to 1 correspond to Comparative Example 2.
0 indicates that the specific resistance and the number of pinholes are improved.

[Examples 11 to 15, Comparative Example 3] Example 6
With the gas composition and sputtering conditions of Comparative Examples 2 and 10,
WSi density 99% target and MoSi density 98.5%
Was performed at room temperature. After the sputtering for 75 hours, a film was formed on 10 6-inch round Si substrates by sputtering for 5 minutes, and the number of pinholes was examined.
For pinholes on the Si substrate, pinholes of 1 μm or more were measured with a pinhole measuring device using laser light. Table 5 shows the results.

[0022]

[Table 5]

From Table 5, it is found that the number of pinholes is in Examples 11 to 15.
It can be seen that the value is greatly reduced as compared with Comparative Example 3. Therefore, regarding the introduction of the Kr element gas or the Xe element gas,
Not only TO but also a target material such as MoSi, WSi or Ti has an effect of suppressing generation of foreign matter.

[0024]

Since the present invention is configured as described above, the generation of foreign matter and nodules on the target material can be suppressed by a simple means of changing the atmosphere in the reaction vessel of the conventional sputtering apparatus. The quality and productivity of the obtained thin film could be improved.

Claims (1)

[Claims] In a reaction vessel, a target material made of a metal, an alloy, an oxide or a nitride is used as a cathode and a substrate is used as an anode, and a thin film of the target material is formed on the surface of the substrate by sputtering the target material. In the method of forming a film, a Kr element gas, a Xe element gas, or a mixed gas thereof is introduced into the atmosphere in the reaction vessel, and a partial pressure of the Kr element gas or the Xe element gas or a total of these partial pressures is determined as a total gas pressure. A film formation method by a sputtering method characterized by being 70% or more of the above.