JP4421180B2 - Surface treatment method and vacuum containers - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface treatment method and vacuum containers for depositing a homogeneous film with little gas emission on the surface of vacuum containers such as a vacuum container of a vacuum apparatus.
[0002]
[Prior art]
Conventionally, in evacuation of a vacuum vessel, in order to increase the pressure drop rate of the vessel, titanium nitride or silicon (see Patent Document 1) is formed to reduce the gas release rate from the surface of the inner wall of the vacuum vessel. It was done. In forming these films, it is often desirable to use a solid such as titanium or silicon as a raw material. In addition, parallel plate CVD using a gas such as silane as a raw material is performed in the electronics industry to form amorphous silicon.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-286772 (Claims)
[0004]
[Problems to be solved by the invention]
However, in order to reduce outgassing, the entire surface of the vacuum vessel must be covered with a film with low outgassing. However, the shape of the vacuum vessel is generally complicated, and the former method using a solid as a raw material is difficult. Therefore, it has been technically difficult to form a homogeneous film with little outgassing on the entire surface. Further, the latter method using parallel plate CVD using a gas such as silane as a raw material has a problem in that a film cannot be formed on the inner wall of a vacuum vessel of a three-dimensional structure.
The present invention solves the problems of the prior art as described above, and provides a surface treatment method and vacuum vessels for forming a homogeneous film with little gas release on the entire surface of the inner wall of the vacuum vessel of a vacuum apparatus. It is an object.
[0005]
[Means for Solving the Problems]
In order to achieve the object, the surface treatment method of the present invention uses, as a raw material, a silicon compound containing at least one element of nitrogen and oxygen, hydrogen, and carbon , as described in claim 1 , A raw material is introduced into a processing vessel depressurized to a pressure of 10 ⁻³ to 10 ⁻⁵ Pa in a gas state, and plasma is generated from the raw material, thereby at least one element of oxygen and nitrogen, silicon, and hydrogen And a homogeneous film containing less carbon and less outgassing is deposited on the entire inner surface of the processing vessel.
The surface processing method according to claim 2, wherein, in the surface treatment method of claim 1, characterized by the silicon compound and two or more kinds.
The surface processing method according to claim 3, wherein, in the surface treatment method according to claim 1 or 2, in said container helium, by introducing an inert gas such as argon gas to the cleaning process Then, the film is deposited.
The surface treatment method according to claim 4 is the surface treatment method according to any one of claims 1 to 3 , wherein the deposited film is heated to a temperature of 100 to 500 ° C in the atmosphere or in a vacuum. It is characterized by heating with.
Moreover, the vacuum containers of the present invention are characterized in that, as described in claim 5, surface treatment is performed by the method according to any one of claims 1 to 4.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Examples of a silicon compound containing at least one element among hydrogen, carbon, nitrogen, and oxygen, which are raw materials used in the surface treatment method of the present invention, include siloxanes such as tetramethyldisiloxane and hexamethyldisiloxane, tetra Examples include alkoxysilanes such as methoxysilane and tetraethoxysilane, and silazanes such as heptamethyldisilazane and hexamethyldisilazane. These raw material silicon compounds may be used alone or in combination of two or more.
That is, any silicon compound can be used as long as a silicon-oxygen-carbon, silicon-nitrogen-carbon, or silicon-oxygen-nitrogen-carbon composite film can be formed.
[0007]
The inside of the processing vessel is depressurized to a pressure of about 10 ⁻³ to 10 ⁻⁵ Pa, the raw material is introduced into the reduced pressure processing vessel in a gaseous state, and plasma is generated from the raw material, thereby generating silicon, hydrogen, And a film containing at least one element of carbon, oxygen, and nitrogen is deposited on the surface of the inner wall of the processing vessel, and the surface treatment is performed using the processing vessel itself as a vacuum vessel to be processed. .
[0008]
If the film is deposited after introducing an inert gas such as helium or argon gas into the processing container and performing the cleaning process, better film formation can be performed.
[0009]
The temperature in the processing vessel may be set to room temperature to about 500 ° C. to deposit the film. This is because a dense film that is not porous can be formed.
[0010]
Further, by heating the deposited film in the atmosphere or at a temperature of 100 to 500 ° C., excess gas taken in the film and excess moisture adsorbed on the surface can be removed. It is preferable to perform such heat treatment.
[0011]
The vacuum containers to be subjected to the surface treatment method include a vacuum container of a vacuum apparatus and the like, and are intended for the treatment container itself used in the surface treatment method.
[0012]
【Example】
Embodiments of the present invention will be described below together with reference examples based on the drawings.
FIG. 1 shows a reference example in which a surface treatment is performed by placing a vacuum vessel for surface treatment in a (vacuum) treatment vessel for film formation.
In FIG. 1, 1 is a vacuum container to be processed on which a silicon compound is formed, 2 is a current introduction terminal, 3 is a DC power source, 4 is a raw material silicon compound, 5 is a mass flow controller, 6 is a pressure gauge, 7 Is a processing container for forming a film, and 8 is a variable conductance valve.
[0013]
In this reference example , a vacuum vessel 1 to be processed on which a silicon compound film was formed was made of stainless steel and the inner surface was electropolished. Put this treated vacuum container 1 (vacuum) treatment chamber 7 was evacuated (vacuum) treatment chamber 7 to about 10 ^-4 Pa.
[0014]
In this reference example , hexamethyldisiloxane is used as the raw material silicon compound 4, and this raw material hexamethyldisiloxane 4 is introduced into the (vacuum) processing vessel 7 through the mass flow controller 5, and the pressure gauge 6 is While adjusting the pressure to 10 Pa, a voltage of 1 kV was applied to the DC power source 3 to generate plasma by glow discharge, and a silicon-oxygen-carbon composite film was formed on the entire surface of the vacuum chamber 1 to be processed.
[0015]
The film thickness of the silicon-oxygen-carbon composite film formed was different depending on the location, and was formed to a thickness of about 0.05 μm to 0.4 μm. The film composition other than hydrogen analyzed by Auger electron spectroscopy was about 50 at% for Si, about 40 at% for C, and about 10 at% for O.
[0016]
Next, FIG. 2 shows the exhaust characteristics of a vacuum vessel in which a silicon-oxygen-carbon composite film is formed as a reference example . FIG. 2 shows the pressure change in the vacuum vessel from the start of exhaustion after exposure to an atmosphere with a relative humidity of 50% for 1 hour.
FIG. 6A shows a vacuum vessel in which a silicon-oxygen-carbon composite film of a reference example of the present invention is formed, and FIG. 5B shows a silicon-oxygen-carbon composite film for comparison. The measured values of the previous vacuum container, the vacuum container in which TiN was formed in the same figure (C), and the vacuum container in which Si was formed by the magnetron sputtering method are plotted in the same figure (D).
From FIG. 2, the vacuum vessel in which the silicon-oxygen-carbon composite film of the reference example of the present invention was formed has a pressure drop rate about 10 times larger than the electrolytically polished stainless steel vessel before film formation. It became clear that The TiN film formation also increases the pressure drop rate slightly compared to the electropolished stainless steel, but the effect of the silicon-oxygen-carbon composite film of the present invention is greater than that of the TiN film formation. it is obvious. In addition, the pressure drop rate is equivalent to that of the magnetron sputtering method, but the present invention is superior in that it can be easily formed into a complicated shape compared to the sputtering method using a solid material as a raw material because the present invention uses a vaporized compound as a raw material. Yes.
[0017]
In this reference example , vaporized hexamethyldisiloxane was used as the raw material, but similar characteristics were obtained with hexamethyldisilazane containing nitrogen. The composition other than hydrogen of the Si—C—N film formed at this time was about 50 at% Si, about 40 at% C, and about 10 at% N.
[0018]
Further, although a direct current is used in this reference example , an alternating current may be used.
[0019]
Thus, in this reference example , the desorption rate of water at room temperature can be increased by replacing the surface of stainless steel with a silicon-oxygen-carbon composite film.
[0020]
In the case shown in FIG. 1, the film to be formed is a vacuum container. However, a part to be placed in the vacuum container may be accommodated in a (vacuum) processing container instead of the vacuum container.
[0021]
FIG. 3 shows an example in which an auxiliary electrode is used so that a film can be easily formed on the inner wall of the vacuum chamber 1 to be processed by the method shown in FIG.
In FIG. 3, 1 is a vacuum vessel in which a silicon compound film is formed on the surface, 2 is a current introduction terminal, 3 is a DC power source, 4 is a raw material silicon compound, 5 is a mass flow controller, 6 is a pressure gauge, and 7 is a component. A container for carrying out the membrane, 8 is a variable conductance valve.
[0022]
FIG. 4 is a reference example in the case where the film formation of FIG.
In FIG. 4, 1 is a vacuum vessel in which a silicon compound film is formed on the surface, 2 is a current introduction terminal, 3 is a DC power source, 4 is a raw material silicon compound, 5 is a mass flow controller, 6 is a pressure gauge, and 7 is a component. A container for carrying out the membrane, 8 is a variable conductance valve.
[0023]
FIG. 5 shows an embodiment in which the vacuum container to be processed itself is a (vacuum) processing container during film formation.
In FIG. 5, 1 is a vacuum container in which a silicon compound film is formed on the surface, 2 is a current introduction terminal, 3 is a DC power source, 4 is a raw material silicon compound, 5 is a mass flow controller, 6 is a pressure gauge, and 7 is a component. A container for carrying out the membrane, 8 is a variable conductance valve.
[0024]
FIG. 6 shows another embodiment in which the vacuum container to be processed itself is a (vacuum) processing container during film formation. 1 is a vacuum container in which a silicon compound is formed on the surface, 2 is a current introduction terminal, 3 is a DC power source, 4 is a raw material silicon compound, 5 is a mass flow controller, 6 is a pressure gauge, 7 is a container for film formation, 8 is a variable conductance valve, 9 is an insulator, 10 Is a protective cover.
[0025]
In each of the examples and reference examples of FIGS. 1 and 3 to 6, in any case, a gas line for introducing an inert gas such as Ar is provided, and Ar or the like is formed in the same manner as in the Si—C film formation. By generating plasma with an inert gas, the surface can be cleaned before the formation of the Si—C film.
[0026]
【The invention's effect】
As described above, according to the present invention, the silicon-oxygen-carbon, silicon is decomposed by discharging a gaseous silicon compound containing at least one element of hydrogen, carbon, nitrogen, and oxygen. - nitrogen - carbon, or silicon - oxygen - nitrogen - so forming a composite film of carbon, it is possible to form a less homogeneous film with the entire surface outgassing of the vacuum vessel surface, object during evacuation It is possible to shorten the exhaust time until the vacuum state is reached. Thus, vacuum containers having a homogeneous film with little outgassing can be obtained.
To elaborate, Group IV materials such as carbon, silicon, and germanium have a low initial sticking probability of water, and silicon and germanium materials are naturally oxidized by water and oxygen in the atmosphere to stabilize the surface. Oxide or hydroxide. The oxides and hydroxides thus formed are inert and have the property that water is less likely to adsorb than stainless steel and aluminum alloys that are usually used as materials for vacuum containers. These properties do not change even if the film contains non-metallic elements such as hydrogen, oxygen, and nitrogen. Even when Si—C—O or Si—C—N is used as the coating, these surfaces are naturally oxidized to form these oxide coatings. The inner wall of the container covered with such an oxide film is less likely to adsorb water, so that the water in the container is easily discharged during vacuum evacuation, shortening the exhaust time until the target vacuum state is reached. can do.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a processing apparatus for carrying out a reference example of a surface treatment method . FIG. 2 is a characteristic diagram showing an exhaust characteristic of a vacuum vessel treated in a reference example of a surface treatment method together with a comparative example. FIG. 3 is an explanatory diagram of a processing apparatus for carrying out another reference example of the surface treatment method . FIG. 4 is an explanatory diagram of a processing apparatus for carrying out yet another reference example of the surface treatment method . description diagram of the processing apparatus for carrying out another embodiment of the surface treatment method of the description diagram of a processing apparatus for performing an embodiment of a surface treatment method [6] the present invention of the present invention

Claims (5)

A silicon compound containing at least one element of nitrogen and oxygen, hydrogen, and carbon is used as a raw material, and the raw material is put in a gas state in a processing vessel depressurized to a pressure of 10 ⁻³ to 10 ⁻⁵ Pa. By introducing and generating plasma from the raw material, a homogeneous film containing at least one element of oxygen and nitrogen, silicon, hydrogen, and carbon and having a low gas emission is formed on the inner wall of the processing vessel . A surface treatment method characterized by depositing on the entire surface. The surface treatment method according to claim 1, wherein two or more types of silicon compounds are used. 3. The surface treatment method according to claim 1 , wherein the film is deposited after introducing an inert gas such as helium or argon gas into the processing container and performing a cleaning process. 4. . The surface treatment method according to claim 1, wherein the deposited film is heated at a temperature of 100 to 500 ° C. in the atmosphere or in a vacuum. Vacuum containers characterized in that they are surface-treated by the method according to any one of claims 1 to 4 .

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