JP2002285317A - Anodized aluminum product and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating the surface of an anodized aluminum product so that the product is suited to use at high temperatures, and to obtain an anodized aluminum product treated by the same method. SOLUTION: The anodized aluminum product is heated in a vacuum to generate a crack 3 on an oxide film 2. The anodized aluminum product in a state where the crack 3 has been generated is exposed to oxygen plasma generated by exciting a gas at least containing oxygen atoms. In this way, the surface of a base metal 1 of the anodized aluminum product in the part exposed by the generation of the crack 3 is oxidized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating the surface of an alumite product and an alumite product treated by the method, and more particularly to a plasma treatment apparatus for treating an object to be treated using plasma. The present invention relates to a method for treating an inner wall surface of a vacuum vessel of a part of an anodized product, and an anodized product treated by the method.

[0002]

2. Description of the Related Art One of semiconductor manufacturing apparatuses is a plasma processing apparatus, which is an apparatus for forming semiconductor devices, electronic parts, etc., and generates plasma by irradiating a reactive gas with microwaves. And, using this plasma,
It performs etching of a thin film formed on the surface of a silicon wafer or the like, ashing of a resist, and the like. This plasma processing apparatus is an extremely important apparatus for manufacturing highly integrated semiconductor elements, electronic components, and the like.

[0003] In general, a plasma processing apparatus generates plasma inside the vacuum vessel. Therefore, components exposed on the inner wall surface of the vacuum vessel and the internal space of the vacuum vessel must take some measures. Is expected to be damaged by the plasma, ions and active species generated therein. Therefore, anodized products having an oxide film formed on the surface are used in portions where such damage is expected. Specifically, an alumite product having an aluminum oxide film formed on the inner wall surface thereof is used for a vacuum vessel of a plasma processing apparatus, and further, a component disposed inside the vacuum vessel and exposed to plasma. The anodized products are also used in the locations where they are located.

[0004] Generally, anodized aluminum products have excellent electrical properties as an insulator, plasma resistance, and corrosion resistance. Some alumite products form an aluminum oxide film in order to seal the pores of the film.

[0005]

The alumite product is sometimes used in a high temperature environment due to its characteristics. However, when a thermal stress is applied to the alumite product, cracks occur in the oxide film. For example, when an alumite product having an aluminum oxide film with a film thickness of 10 to 30 microns is heated to 100 ° C. or more and observed, it can be confirmed by an optical microscope or the like that cracks are generated on the surface of the alumite product. it can. In addition, the temperature is 200 ° C
The increase in the number of cracks is obviously increased. As described above, since the amount of cracks increases with an increase in the heating temperature, it is considered that the cracks are caused by thermal stress.

When an ashing process is performed in a plasma processing apparatus provided with a vacuum vessel (alumite product) having an aluminum oxide film formed on an inner wall, when the vacuum vessel is heated to increase the wall surface temperature, the temperature rises. It was found that the ashing rate was reduced. Generally, a plasma processing apparatus generates plasma inside the vacuum vessel, and the temperature of the wall surface of the vacuum vessel near the plasma generation region becomes 100 ° C. or higher.

When the temperature of the wall surface of the vacuum vessel rises in this way, cracks occur in the aluminum oxide film formed on the inner wall surface, and aluminum or aluminum alloy as a base material is partially exposed. And
It is considered that the ashing rate is lowered because the exposed base material portion reacts with the oxygen radical. Further, in the case of performing etching by generating plasma with a gas to which a fluorine-based gas is added in a plasma processing apparatus, the base material portion exposed due to the generation of cracks reacts with fluorine radicals to generate AlF _3. The etching rate fluctuates.

The present invention has been made in view of the above-mentioned circumstances, and provides a method for treating the surface of an alumite product so as to be suitable for use under a high temperature, and an alumite product treated by the method. In particular, it is an object of the present invention to provide a method of treating the surface of an alumite product so as to be suitable for a component of a plasma processing apparatus, and an alumite product treated by the method.

[0009]

In order to solve the above-mentioned problems, the present invention provides a method for treating the surface of an alumite product having an oxide film formed on the surface, the method comprising: A crack is generated in the oxide film by heating, and the alumite product in a state in which the crack is generated is exposed to oxygen plasma generated by exciting a gas containing at least oxygen atoms, thereby exposing by the generation of the crack. The surface of the base material of the anodized aluminum product is oxidized.

Preferably, the crack is generated by heating the alumite product to a temperature between 100 ° C. and 250 ° C.

Preferably, the oxygen plasma is 1
Produced under a pressure of 00 Pa or less.

Preferably, the alumite product is a vacuum vessel constituting a part of a plasma processing apparatus for processing an object to be processed using plasma, and the inner wall of the vacuum vessel has the oxidized product. A film is formed, and the oxygen plasma is generated by introducing the gas containing at least oxygen atoms into the inside of the vacuum vessel of the plasma processing apparatus to excite the gas.

[0013] Preferably, the gas containing at least oxygen atoms is a gas containing at least oxygen gas.

[0014] Preferably, the base material is aluminum or an aluminum alloy, and the oxide film is an aluminum oxide film.

In order to solve the above-mentioned problems, the present invention provides an alumite product characterized by being treated by any one of the above-described surface treatment methods for an anodized product, wherein a base material portion and a base material portion are provided. An oxide film formed on the surface, an oxide layer formed on the surface of the base material at a portion exposed by cracks generated in the oxide film at a high temperature,
It is characterized by having.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a surface treatment method for an alumite product according to an embodiment of the present invention and an alumite product treated by the method will be described.

FIG. 1 is a conceptual diagram showing a schematic configuration of a plasma processing apparatus to which the surface treatment method for an alumite product according to the present embodiment is applied. As shown in FIG. 1, the plasma processing apparatus includes a vacuum vessel 10 capable of evacuating the inside, and a reaction chamber 11 is formed inside the vacuum vessel 10. In the reaction chamber 11, a processing table 12 on which the workpiece W is placed is provided.

An outlet end of the microwave waveguide 13 is attached to the upper portion of the vacuum vessel 10, and a microwave transmission is provided between the outlet end of the microwave waveguide 13 and the inside of the vacuum vessel 10. A window member 14 is interposed. Further, the entrance end of the microwave waveguide 13 is connected to a microwave (MW).
Is generated.
The microwave propagating in the microwave waveguide 13 passes through the microwave transmitting window member 14 and passes through the vacuum vessel 10.
Introduced within. In addition, as a dielectric material forming the microwave transmitting window member 14, quartz, Teflon (registered trademark),
Alumina or the like can be used.

A gas inlet 16 for introducing a process gas is formed in the upper portion of the reaction chamber 11 in the vacuum chamber 10. The process gas introduced into the vacuum chamber 10 through the gas inlet 16 is supplied to the vacuum chamber 10. The waves are irradiated to generate plasma. Further, an exhaust port 1 is provided at a lower portion of the vacuum vessel 10.
7 are formed.

When processing the workpiece W by the above-described plasma processing apparatus, first, the workpiece W is loaded into the reaction chamber 11 evacuated through the exhaust port 17 and placed on the processing table 12. Place on. Next, after the inside of the reaction chamber 11 reaches a required degree of vacuum, a process gas is introduced into the vacuum vessel 10 through the gas inlet 16. Here, for example, when performing ashing of the resist, oxygen gas (O ₂ ) is used as the process gas, or CF ₄ or NF _{3 is used} as the oxygen gas.
For example, a gas to which a fluorine-based gas such as the above is added is used. In order to increase the efficiency of the ashing process, the workpiece W
Are heated by heating means not shown.

Next, when the degree of vacuum in the reaction chamber 11 is stabilized, the microwave transmitter 15 is operated to generate a microwave, and the microwave is propagated through the microwave waveguide 13. The microwave that has propagated through the microwave waveguide 13 propagates through the microwave transmitting window member 14 and is introduced into the upper portion of the vacuum vessel 10. Then, the process gas introduced into the vacuum chamber 10 from the gas inlet 16 is excited by the microwave to generate plasma.

The vacuum vessel 10 of the plasma processing apparatus shown in FIG. 1 uses an alumite product having an aluminum oxide film formed on an inner wall surface thereof.
Alumite products are also used for components located inside the vacuum vessel 10 and located at positions exposed to plasma.

FIG. 2A shows a partial cross section of an alumite product at room temperature (25 ° C.). An aluminum oxide film 2 is formed on the surface of an aluminum base material 1. When this alumite product is heated to 100 ° C., FIG.
As shown in FIG. 2, cracks occur in the aluminum oxide film 2, and when the temperature is further increased to 200 ° C., the amount of cracks increases as shown in FIG.

If the cracks occur in the aluminum oxide film 2 as described above, inconveniences such as a decrease in the ashing rate are brought about, as described above. Using the processing method, the vacuum vessel 1
Process alumite products such as 0.

First, the vacuum vessel 10 made of an alumite product is heated to 200 ° C., and oxygen gas is introduced into the vacuum vessel 10 from the gas inlet 16. Then, with the internal pressure of the vacuum vessel 10 set at around 30 Pa, the output of the microwave transmitter 15 is set to about 1 kW, and microwaves are introduced into the vacuum vessel 10. Then, a microwave is applied to the oxygen gas, and a discharge is generated inside the vacuum vessel 10 to generate plasma. In this state, the discharge is continued for about 4 hours.

The heating temperature of the vacuum vessel 10 is 200 ° C.
The temperature is not limited to 100 ° C. and can be set to a temperature from 100 ° C. to 250 ° C. The internal pressure of the vacuum vessel 10 is 3
The value is not limited to 0 Pa and can be set to a value of 100 Pa or less.

FIGS. 3A and 3B show a state in which the alumite product constituting the vacuum vessel 10 is heated to generate cracks 3 in the aluminum oxide film 2.
Shows a state before the surface treatment of the alumite product according to the present embodiment, and (b) shows a state after the surface treatment. As shown in FIG. 3B, by performing the surface treatment according to the present embodiment, the oxide layer 4 is formed on the portion of the aluminum base material 1 exposed due to the occurrence of the cracks 3.

FIG. 4 is a graph showing the dependence of the resist ashing rate on the inner wall surface temperature of the vacuum vessel 10 before and after the surface treatment of the alumite product according to the present embodiment. As can be seen from FIG. 4, before the surface treatment, the resist ashing rate decreases as the inner wall surface temperature of the vacuum vessel 10 increases. On the other hand, after performing the surface treatment according to the present embodiment, even if the inner wall surface temperature of the vacuum vessel 10 is heated from about 50 ° C. to about 200 ° C., the resist ashing rate is the value at the time of about 50 ° C. (About 5 μm / min.).
When the inner wall surface temperature of the vacuum vessel 10 is around 50 ° C., no significant change is observed in the resist ashing rate before and after the surface treatment according to the present embodiment.

FIG. 5 is a graph showing the influence of the addition of CF _{4 on} the resist ashing rate before and after the surface treatment of the alumite product according to the present embodiment. As can be seen from FIG. 5, before the surface treatment according to the present embodiment was performed, a decrease in the resist ashing rate was observed when the CF ₄ -added plasma was generated, but after the surface treatment, the CF ₄ -added plasma was reduced. No decrease in the resist ashing rate was observed even if it occurred.

[0030]

As described above, according to the present invention, the alumite product is heated to generate cracks in the oxide film, and an oxide layer is formed on the base material exposed by the cracks. Therefore, for example, when using an alumite product as a vacuum container of a plasma processing apparatus, by performing the surface treatment according to the present invention on the inner wall surface of the vacuum container prior to processing of an object to be processed such as a semiconductor substrate, Even when the vacuum vessel is heated during the processing of the object to be processed, since the oxide layer is formed in advance at the crack generating portion,
The characteristics of the etching process and the ashing process by the plasma processing apparatus do not change.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a schematic configuration of a plasma processing apparatus to which a surface treatment method for an alumite product according to an embodiment of the present invention is applied.

FIGS. 2 (a), (b) and (c) show room temperature,
Sectional drawing which showed some alumite products at 100 degreeC and 200 degreeC.

FIGS. 3A and 3B are enlarged cross-sectional views of part A of FIG. 2C, wherein FIG. 3A shows a state before surface treatment according to an embodiment of the present invention is performed, and FIG. This shows the state after the processing.

FIG. 4 is a diagram showing the dependency of the resist ashing rate on the inner wall surface temperature of the vacuum vessel before and after the surface treatment of the alumite product according to one embodiment of the present invention.

FIG. 5 is a diagram showing the influence of the addition of CF _{4 on} the resist ashing rate before and after the surface treatment of the alumite product according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum base material 2 Aluminum oxide film 3 Crack 10 Vacuum container

Claims (7)

[Claims] 1. A method for treating a surface of an alumite product having an oxide film formed on a surface thereof, wherein the alumite product is heated in a vacuum to generate a crack in the oxide film, and the crack is generated. Exposing the anodized aluminum product in an excited state to a gas containing at least oxygen atoms, thereby oxidizing the surface of the base material of the anodized aluminum product exposed by the generation of the cracks. Characteristic surface treatment method for alumite products. 2. The method according to claim 1, wherein the alumite product is heated from 100.degree.
The method according to claim 1, wherein the crack is generated by heating to a temperature between ℃. 3. The method according to claim 1, wherein the oxygen plasma is generated under a pressure of 100 Pa or less. 4. The vacuum processing apparatus according to claim 1, wherein the alumite product is a vacuum vessel that forms part of a plasma processing apparatus that processes an object to be processed using plasma, and the oxide film is formed on an inner wall surface of the vacuum vessel. 4. The method according to claim 1, wherein the oxygen plasma is generated by introducing the gas containing at least oxygen atoms into the inside of the vacuum vessel of the plasma processing apparatus to excite the gas. A surface treatment method for an anodized aluminum product according to any one of the preceding claims. 5. The method according to claim 1, wherein the gas containing at least oxygen atoms is a gas containing at least oxygen gas. 6. The surface treatment method for anodized aluminum according to claim 1, wherein the base material is aluminum or an aluminum alloy, and the oxide film is an aluminum oxide film. 7. An anodized aluminum product processed by the surface treatment method for an anodized aluminum product according to claim 1, wherein the base material portion and a surface of the base material portion are provided. An oxide layer formed on the surface of the base material exposed by cracks generated in the oxide film at a high temperature,
Alumite products characterized by comprising: