JPH0488181A - Surface treatment for metal - Google Patents

Abstract

PURPOSE:To remove adsorbed contaminants from the surface in the synchrotron orbital radiant light irradiated region by irradiating a metal with synchrotron orbital radiant light in an atmosphere containing a gas liable to combine with carbon or in vacuum. CONSTITUTION:A metal is placed in an atmosphere containing a gas liable to combine with carbon, such as gases of oxygen, hydrogen, chlorine, etc., or in vacuum, and this metal is irradiated with synchrotron orbital radiant light. At this time, the above metal can be irradiated with the synchrotron orbital radiant light in the state reflected by a metallic film mirror. As a result, contaminants, such as carbon, adsorbed by the metallic surface in the part to which polishing cannot be applied are excited by the high energy radiant light, released from the surface, and removed. Further, if the temp. of the above metal is regulated to a temp. not lower than ordinary temp., e.g., about 200-300 deg.C, the energy of the contaminants is increased and the removal of the contaminant is facilitated, and moreover, if the metal is previously polished, the removal of the contaminants is facilitated to a greater extent because the amount of the contaminants on the surface is remarkably reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a metal surface treatment method, the purpose is to remove contaminants on the surface of vacuum mechanism parts that are difficult to apply composite electric field polishing to, in an atmosphere containing a gas that easily combines with carbon, or Place a metal in a vacuum, irradiate the metal with synchrotron orbital synchrotron radiation,
The method includes removing adsorbed contaminants on the irradiated HNi surface.

[Industrial application field]

The present invention relates to a metal surface treatment method, and more particularly to a metal surface treatment method for removing contaminants from a metal surface.

[Conventional technology]

BACKGROUND OF THE INVENTION As semiconductor device structures become ultra-thin and ultra-fine, an ultra-clean atmosphere without contamination is desired in the process of manufacturing semiconductor devices.

In order to achieve this, it is necessary to keep the inside of the vacuum chamber used for film growth, processing, etc. and the mechanical parts around it as clean as possible. In particular, contamination due to carbon-based gas released from metal surfaces is a problem, and various methods have been adopted to solve this problem.

As one of these efforts, improvements have been made to the polishing technology for stainless steel plates, which are the materials used in vacuum chambers, etc., and a typical example is composite electropolishing, which combines electrolytic polishing and precision mechanical polishing. It has been confirmed that when a chamber treated by this method is used, the release of contaminant gases can be suppressed and the internal pressure can be brought to a vacuum level of 1×10 days Torr or higher.

[Problem to be solved by the invention]

However, it is not easy to apply such polishing technology to the inside of metal gas introduction pipes and bellows connected to the chamber, bearings, and other various IR groove Wle parts, and it is difficult to apply these polishing techniques to There is a problem in that it becomes difficult to create a higher vacuum in the chamber due to the release of contaminant gas.

The present invention has been made in view of these problems, and an object of the present invention is to provide a metal surface treatment method that can remove contaminants contained in the surfaces of vacuum mechanism parts that are difficult to apply complex electric field polishing to. shall be.

[Means to solve the problem]

The above-mentioned problem is to place a metal in an atmosphere containing a gas that easily combines with carbon or in a vacuum, irradiate the metal with synchrotron orbital synchrotron radiation, and remove contaminants adsorbed on the surface of the irradiated area. A metal surface treatment method characterized in that the metal is placed in an atmosphere containing a gas that easily combines with carbon or in a vacuum, and the metal is irradiated with synchrotron orbital radiation reflected by a metal film mirror, and the irradiated portion is This is achieved by a metal surface treatment method characterized by removing contaminants adsorbed on the surface of the metal.

[For production]

According to the present invention, metal is irradiated with synchrotron orbital synchrotron radiation.

For this reason, when synchrotron orbital synchrotron radiation is irradiated onto parts of metal parts that cannot be polished or where contaminants cannot be completely removed by polishing, contaminants such as carbon adsorbed on the metal surface are exposed to high energy. is excited by the synchrotron radiation of
It will be released from the surface and removed.

Therefore, if this treatment is applied to the inner surface of the vacuum chamber and its peripheral equipment, the amount of contaminant gas inside the vacuum chamber in a reduced pressure state will be reduced, making it possible to create an even higher vacuum inside the vacuum chamber.

In addition, if the temperature of the metal is raised to above room temperature, the energy of the contaminants increases and becomes easier to release, making it easier to remove the contaminants using synchrotron orbital synchrotron radiation.
Furthermore, if the metal is previously polished, the amount of contaminants on its surface is greatly reduced, making contaminant removal easier.

Furthermore, since the path of the synchrotron orbital synchrotron radiation is changed by the metal film mirror, it becomes possible to irradiate the light to places that are difficult to directly irradiate with the synchrotron radiation, such as the interior of the bellows or the corners of parts.

〔Example〕

Therefore, the details of the present invention will be explained below based on the drawings.

FIG. 1 is a schematic diagram showing a method according to an embodiment of the present invention, and reference numeral 1 in the figure is a metal plate made of stainless steel placed in a vacuum. Synchrotron Orbita '77
It is configured to irradiate high-energy synchrotron radiation generated from the radio waves (SOR).

By the way, since the SOR synchrotron radiation has high energy ranging from vacuum ultraviolet to X-rays, this synchrotron radiation is transmitted to the metal plate 1.
If the surface is irradiated with water, contaminants that are difficult to desorb, such as carbon, adsorbed on the surface will be excited and emitted to the outside.

Regarding the stainless steel plate 1 without surface treatment, surface treatment by mechanical polishing, electric field polishing, and combined electric field polishing, 2
After heat treatment at a temperature of 50°C for 10 hours or more,
When we irradiated SOR synchrotron radiation in an ultra-high vacuum and measured the carbon-based gas emitted from each surface using a mass spectrometry system, we obtained synchrotron radiation dose and gas release characteristics as shown in Figure 2. Ta.

According to this, regarding the stainless steel plate 1 that has been subjected to electropolishing or composite electropolishing, carbon-based gas (C(h,
It can be seen that Co, CH2, etc.) were released and became a source of pollution. Furthermore, it has been revealed that when these are irradiated with SOR synchrotron radiation at a dose of about 100 mA·h, the amount of carbon-based gas and hydrogen emitted from the surface of the stainless steel plate 1 is reduced even more. Furthermore, even for samples that have been mechanically polished, the release of contaminant gases can be reduced to the same extent by applying SOR synchrotron radiation.

Therefore, it can be seen that ideal surface treatment is possible by using polishing treatment and synchrotron radiation treatment in combination.

Furthermore, for an unpolished sample, by irradiating it with a large amount of SOR radiation, the emission of contaminant gas is reduced.

In the above example, the sample was placed in an ultra-high vacuum and subjected to SOR synchrotron radiation treatment, but if the sample is placed in a gas that easily bonds with carbon, such as hydrogen, oxygen, chlorine, etc. The reaction of the contaminants excited by the light with these gases removes the contaminants.

Further, when the SO'R irradiation light is irradiated to the metal object heated to above room temperature, for example, above 200 to 300° C., the removal of the contaminant becomes easier due to the combined effect of thermal excitation and thermal diffusion of the contaminant.

Next, a method of irradiating SOR radiation will be specifically explained.

FIG. 3 is a cross-sectional view showing an example of irradiating SOR radiation into the metal tube 2. Inside the metal tube 2, two small metal tubes 3.4 with small diameters are installed in a bundle. There is.

When removing contaminants from the inner surface of the small-diameter metal tubes 3.4, the axial direction of these metal tubes 3.4 and the traveling direction of the SOR synchrotron radiation beam are relatively tilted, or while being tilted. By rotating the metal tube, the entire inner surface of the small diameter metal tube 3.4 is irradiated with the emitted light.

In addition, the code|symbol 5 in the figure shows a hero, and 7 shows a flange.

Further, FIG. 4 is a cross-sectional view showing an example of irradiating SOR radiation onto a thin metal tube 8, and this metal tube 8 has a single-shaped bent portion 9 that is difficult to polish. In order to remove contaminants adsorbed on the inner surface of the bent portion 9, SOR radiation is passed through the metal tube 8 and irradiated onto the bent portion 9, so that the contaminants on the inner surface of the bent portion 9 are removed. will be removed. In this case as well, if the thin metal tube 8 is tilted with respect to the direction of propagation of the synchrotron radiation, or if the metal tube 8 is rotated while being tilted, the SOR synchrotron radiation is irradiated not only on the bent portion 9 but also on its entire inner surface. can do.

Furthermore, Fig. 5 shows that the S
FIG. 3 is a cross-sectional view showing an example of irradiating OR synchrotron radiation, in which a metal film mirror 12 having one or more reflective surfaces 11 is inserted inside the bellows 10, and the bellows IO is connected to the metal film mirror 12. It can be rotated around 12 and moved forward, backward, left and right. In addition, the code|symbol 13 has shown the support rod of the metal film mirror 12.

According to this, the SOR radiation light traveling along the length direction of the bellows 10 is reflected by the metal film mirror 12 to change its course.
It becomes possible to irradiate the slopes and corners of bellows IO.

FIG. 6 is a schematic diagram showing the chamber and peripheral parts of the crystal processing apparatus, and the interior of the chamber 15, bellows 16, gas introduction tube 17, etc. and the surface of the sample stage 1B are subjected to SOR irradiation treatment by the method described above. was carried out at 200°C11
It was baked out for 0 hours.

When the pressure inside the chamber 15 was reduced using such a device, it was possible to maintain a degree of vacuum of 5 X I O-'' Torr or more, and when the type of gas was detected using the mass spectrometer 19, CO□, co, It was confirmed that signal peaks such as cL were less than 1/l OO of hydrogen or did not exist at all.

Furthermore, the sample 20 to be processed by this device is placed on the sample stage 18.
When the crystal surface was irradiated with SOR radiation through the window 14 of the chamber 15, carbon-based substances and oxides were removed from the crystal surface because there was no contaminant gas in the surrounding atmosphere. It was found that the gas was removed efficiently and that the state without contaminant gas continued for a long period of time.

〔Effect of the invention〕

As described above, according to the present invention, metal is irradiated with synchrotron orbital synchrotron radiation, so synchrotron radiation is applied to parts of metal parts that cannot be polished or contaminants cannot be completely removed by polishing. By irradiating orbital synchrotron radiation, contaminants such as carbon stuck to the metal surface can be excited with high energy and emitted from the surface to be removed, cleaning the internal surfaces of vacuum chambers, etc. It becomes possible to

In addition, if the temperature of the metal is raised to above room temperature, the energy of the contaminants will be high and will be easily released, making it easier to remove the contaminants using synchrotron orbital synchrotron radiation. This greatly reduces the amount of contaminants on the surface, making contaminant removal easier.

Furthermore, since the path of the synchrotron orbital synchrotron radiation is changed by the metal film mirror, it becomes possible to irradiate the light into places that are difficult to directly irradiate with the synchrotron radiation, such as inside the bellows or at the corners of parts.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram showing an embodiment of the present invention, and Fig. 2 is a schematic diagram showing an embodiment of the present invention.
A characteristic diagram showing changes in the amount of carbon-based gas and hydrogen gas released from the stainless steel surface due to synchrotron radiation irradiation. FIG. 5 is a cross-sectional view showing a second example of irradiation with SOR synchrotron radiation of the present invention. FIG. 6 is a cross-sectional view showing a third example of irradiation with SOR synchrotron radiation of the present invention. FIG. 2 is a schematic diagram showing an example of a crystal processing apparatus that performed the processing. (Explanation of symbols) 1... Stainless steel plate, 2.3.4... Metal tube, 7... Flange, 8... Metal tube, 9... Bent part, 5, IO... Bellow DESCRIPTION OF SYMBOLS 11... Reflection surface, 12... Metal film mirror, 15... Chamber, 16... Bellows 17... Gas introduction tube, 18... Sample stand, 19... Mass spectrometer, 20 ···sample. Applicant Fujitsu Limited

Claims (4)

[Claims] (1) A metal is placed in an atmosphere containing a gas that easily combines with carbon or in a vacuum, and the metal is irradiated with synchrotron orbital synchrotron radiation to remove contaminants adsorbed on the surface of the irradiated area. Metal surface treatment method. (2) The metal surface treatment method according to claim 1, wherein the metal is heated to a temperature higher than room temperature. (3) The metal surface treatment method according to claim 1, wherein the surface of the metal irradiated with synchrotron orbital radiation is polished. (4) A metal is placed in an atmosphere containing a gas that easily combines with carbon or in a vacuum, and synchrotron orbital synchrotron radiation is reflected by a metal film mirror and irradiated onto the metal, and contaminants are adsorbed on the surface of the irradiated part. A metal surface treatment method characterized by removing.