JPH111797A - Vacuum chamber member made of al or al alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum chamber member made of Al or Al alloy on which an anodic oxidation coating is formed, improved in resistance to gas and plasma to a greater extent than heretofore. SOLUTION: This member is a vacuum chamber member constituted by forming an anodic oxidation coating on the surface of a base material made of Al or Al alloy. At this time, S concentration in the anodic oxidation coating is regulated so that it is higher on the surface side than on the base material side, or the anodic oxidation coating is constituted of two or more layers so prepared that the chemical composition on the surface side is different from that on the base material side to incorporate S into the layer on the surface side and no to incorporate S into the layer on the base material side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CVD apparatus, a PV
A vacuum chamber member made of Al or Al alloy used for a D apparatus, a dry etching apparatus, etc., which has excellent corrosion resistance to corrosive gas or plasma introduced into the vacuum chamber. It relates to a chamber member.

[0002]

2. Description of the Related Art A corrosive gas containing a halogen element such as Cl or F is introduced as a reactive gas or an etching gas into a vacuum chamber used in a CVD apparatus, a PVD apparatus, a dry etching apparatus, or the like. , Corrosion resistance to corrosive gas (hereinafter sometimes referred to as gas resistance)
Is required. Further, in the case of a thermal plasma CVD apparatus or the like, halogen-based plasma is generated in addition to the corrosive gas, so that corrosion resistance to plasma (hereinafter, sometimes referred to as plasma resistance) is also important.

[0003] Therefore, stainless steel materials have been mainly used as the vacuum chamber material. However, the vacuum chamber made of stainless steel has a problem that it is heavy and requires large-scale construction on a base. Further, there is a problem that thermal conductivity is not sufficient and baking during operation takes time. Furthermore, heavy metals such as Cr, which is a component of stainless steel, may be released during the process for some reason and become a contamination source. Therefore, it is lighter than stainless steel,
Al with excellent thermal conductivity and no risk of heavy metal contamination
Alternatively, the development of a vacuum chamber made of an Al alloy is being studied.

However, the metal surface of Al or Al alloy is not always good in gas resistance and plasma resistance, and it is considered that some surface treatment is required, and various studies have been made. For example, Japanese Patent Publication 5-5387
No. 0 discloses an invention in which the surface of an Al or Al alloy vacuum chamber member is subjected to anodic oxidation treatment to form an anodized film, thereby improving the gas resistance of Al or the Al alloy to form a vacuum chamber member. It has been disclosed. FIG.
FIG. 2 is a partially sectional explanatory view showing a schematic structure of an anodic oxide film formed on the surface of a vacuum chamber member made of Al or an Al alloy by anodizing treatment. The anodic oxide film is composed of a porous layer 10 having a pore 3 formed in the center of the cell 2 and a barrier layer 20 located between the porous layer 10 and the substrate 1.
Since the barrier layer 20 has no pores and no gas permeability,
The gas can be prevented from contacting the substrate 1 of Al or Al alloy.

[0005] However, the anodic oxide film does not cause a reaction with the corrosive gas or plasma at all. When it is corroded during use, a reaction product is generated as fine particles, and it is used in, for example, semiconductor manufacturing. It may cause defective products, and improvement has been desired.

Japanese Patent Publication No. 5-53871 discloses a technique for forming a coating (eg, TiN, TiC, etc.) having excellent corrosion resistance on the surface of a vacuum chamber member made of Al or an Al alloy by employing an ion plating method. Is disclosed. However, when the above-mentioned film is formed by a vapor phase synthesis method such as ion plating, there is a problem that a considerable processing cost is required.

[0007] The inventors of the present invention have conducted various studies to provide a vacuum chamber member made of Al or Al alloy having excellent corrosion resistance, on the premise that a cost-effective anodic oxidation method is adopted. It has been found that the gas resistance and the plasma resistance can be improved by controlling the internal structure and the component composition in the film, and have been proposed earlier (for example, JP-A-8-193295 and JP-A-8-1440088).
In other words, in order to obtain excellent plasma resistance, the pore diameter on the surface side of the porous layer is formed as small as possible, while the pore diameter on the substrate side is formed as large as possible and the barrier layer is thickened. The present inventors have found that the properties can be greatly improved, and have disclosed this. B, C, N,
Two or more elements selected from the group consisting of F, P, S
He also disclosed that the inclusion in the anodic oxide film further improves the corrosion resistance to gas and plasma.

[0008] According to these methods, excellent corrosion resistance can be obtained. However, for example, in the case of being used as a member for a semiconductor manufacturing apparatus, a vacuum chamber member having higher durability is demanded in accordance with high integration of semiconductor devices in the future.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is an Al or Al alloy vacuum chamber member having an anodized film formed thereon.
It is an object of the present invention to provide a vacuum chamber member having more excellent gas resistance and plasma resistance.

[0010]

The Al or Al alloy vacuum chamber member according to the present invention, which has achieved the above objects, comprises:
A vacuum chamber member having an anodized film formed on the surface of a substrate made of Al or Al alloy, wherein the S concentration on the surface side of the anodized film is higher than the S concentration on the substrate side. It is an abstract. Therefore, the anodic oxide film is composed of two or more layers having different component compositions on the surface side and the substrate side, and the layer on the surface side (hereinafter sometimes referred to as a surface layer).
And the layer on the substrate side (hereinafter sometimes referred to as the substrate side layer)
When comparing the concentrations, the S concentration of the surface layer may be increased. Further, the S concentration in the intermediate portion other than the surface layer and the substrate side layer of the anodic oxide film can be any concentration, and may be the same concentration as the surface layer or the substrate side layer. Or low concentration. Further, in increasing the S concentration of the surface layer of the anodic oxide film and lowering the S concentration of the substrate side layer, the S concentration in the intermediate portion may be continuously changed, and may be changed stepwise in layers. Alternatively, a continuously changing portion and a non-changing portion of the density may be combined.

In order to achieve the above object, the anodic oxide film is composed of two or more layers having different component compositions on the surface side and the base material side. May be configured not to contain S. Also in this case, the S concentration of the intermediate layer between the surface layer and the substrate side layer can be any concentration, and may be the same concentration as the surface layer or the substrate side layer, or may be a high concentration. May also be at a low concentration.

In the present invention, the above-mentioned surface layer and substrate side layer are, as shown in FIG. 2, at least one-fifth of the thickness (A) of the anodic oxide film. Well (A ×
0.2), the surface layer is a region of the thickness A × 0.2 of the anodic oxide film from the outermost surface, and the base material side layer is A × 0.2 mm from the interface between the anodic oxide film and the base Al alloy. It is an area of 0.2.

The S concentration on the surface side is preferably 0.5% by weight or more, and the S concentration on the substrate side is preferably 5.0% by weight or less (however, the S concentration on the substrate side is not more than 0.5% by weight). It is necessary that the concentration of S is lower than the S concentration on the side) and that one or more elements selected from the group consisting of B, C, N, and P are contained in the anodic oxide film to improve gas resistance and plasma resistance. Can be achieved.

Further, an anodic oxide film composed of a porous layer having a large number of pores and a barrier layer having no pores is formed on the surface of the vacuum chamber member, and the pore diameter of the porous layer is reduced on the surface side and increased on the substrate side. Is effective for improving gas resistance and plasma resistance, and the thickness of the barrier layer in the anodic oxide film is desirably larger than half the average thickness of the cell wall formed in the porous layer.

In the present invention, the Al or Al alloy vacuum chamber member means not only the structural material of the Al or Al alloy vacuum chamber, but also a clamper, a shower head, a susceptor, and a damper provided in the vacuum chamber. Members such as an upper electrode, a lower electrode, a gas diffusion plate, a heater block, a pedestal, and a chuck base, all of which are made of Al or an Al alloy, can be applied. In the following description, these members will be referred to. All of them are collectively referred to as an Al or Al alloy vacuum chamber member.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted further studies from the viewpoint of the component composition of an anodic oxide film in order to improve the corrosion resistance of a vacuum chamber member made of Al or an Al alloy against corrosive gas and plasma. As a result, the following findings were obtained. That is, the anodic oxide film containing S shows very high resistance to plasma, but has low resistance to corrosive gas. It has been found that the gas resistance of the anodic oxide film can be ensured by exhibiting plasma resistance and suppressing or suppressing the content of S on the base material side.

The present invention has been made based on such knowledge, and the present invention relates to a vacuum chamber member in which an anodic oxide film is formed on the surface of a substrate made of Al or an Al alloy. The concentration is made higher than the S concentration on the substrate side, or the anodic oxide film is composed of two or more layers having different component compositions on the surface side and the substrate side, and the surface side layer has S concentration.
And the layer on the side of the base material does not contain S, so that Al has simultaneously excellent gas corrosion resistance and plasma resistance.
Alternatively, a vacuum chamber member made of an Al alloy is obtained.

The S concentration on the surface side is required to be 0.02% by weight or more in order to exhibit plasma resistance.
It is preferably at least 5% by weight, more preferably at least 2% by weight. The effect of improving gas resistance can be obtained by making the S concentration of the base material side layer smaller than the S concentration on the surface side, but is preferably 5% by weight or less, more preferably 2% by weight or less. Need not be contained.

As the method of changing the concentration of S between the surface side and the substrate side, the following methods can be mentioned.
Either method may be adopted, but two or more methods may be combined. The surface layer is formed at a low current density, and the substrate side layer is formed at a high current density. The stirring speed of the electrolytic flow during the formation of the surface layer is increased, and the stirring speed during the formation of the substrate side layer is decreased. Using two or more types of electrolytes, the S concentration in the electrolyte used when forming the surface layer is increased, and the S concentration in the electrolyte when forming the substrate side layer is reduced.

In order to improve the gas resistance and plasma resistance, it is recommended that at least one selected from the group consisting of B, C, N, and P be contained. As an amount (in% by weight) of the element to be contained in the anodic oxide film, B is 0.1%.
It is preferably at least 015%, more preferably at least 0.3%. C is preferably 0.01% or more, and more preferably 0.5% or more. N is preferably at least 0.01%, and more preferably at least 0.7%. P is 0.01
It is preferably at least 5%, more preferably at least 1%.

In forming the anodic oxide film according to the present invention, conditions for performing electrolysis may be controlled.
Solution composition, solution temperature, electrolysis conditions (voltage, current density,
By controlling the current-voltage waveform) and the like, a vacuum chamber member in which the component composition and the internal structure of the anodic oxide film are changed can be obtained.

The composition of the solution is as follows.
_{^{4 2-, SO 3 2-, HSO}} 4 -, CO 3 2-, C 2 O 4 2-, COO
_{^{H -, NO 3 -, NO}} 2 -, BO 3 3-, B 4 O 7 2-, PO 4
_{^{3-, HPO 4 2-, H 2}} PO 4 -, HPHO 3 - selects an appropriate combination in accordance with the chemical composition of interest from the ion components such as, the processing solution of a compound containing the above-described components Just add it.

The amount of the compound to be added to the anodizing solution is preferably 0.1 g / L or more, and preferably less than 0.1 g / L, in terms of the amounts of the respective elements B, C, N and P. In some cases it is difficult to exert a noticeable effect.

In addition to the method of adding the above compound to the anodizing treatment solution, an Al alloy of the base material containing an element according to the present invention as an alloying element may be used. Alternatively, a method may be employed in which the above element is contained only in the surface layer of the base material by the surface modification method, and then anodizing treatment is performed. Regardless of which method is used, the gas resistance and plasma resistance of the anodic oxide film can be improved by finally including two or more elements according to the present invention.

In the present invention, the S concentration on the surface side of the anodic oxide film is made higher than the S concentration on the substrate side, or the anodic oxide film has two layers having different component compositions on the surface side and the substrate side. By forming S on the surface-side layer and not containing S on the base material side, a vacuum chamber member made of Al or Al alloy excellent in gas corrosion resistance and plasma resistance at the same time is obtained. However, also in the present invention, it is possible to improve the corrosion resistance by making the pore diameter of the porous layer on the substrate side larger than the pore diameter on the surface side. To obtain excellent plasma resistance, the surface side pore diameter should be 80 nm.
It is preferably at most 50 nm, more preferably at most 50 nm, even more preferably at most 30 nm. In order to sufficiently exhibit gas resistance, the thickness of the barrier layer is 5
0 nm or more is preferable, and 80 nm or more is more preferable.

In order to obtain excellent gas resistance, the thickness of the barrier layer in the anodic oxide film is preferably larger than half the average thickness of the cell wall formed in the porous layer. It is more desirable if it is 2/3 or more.

Although the present invention does not limit the thickness of the anodic oxide film, it is necessary that the thickness be 0.00.0
The thickness is preferably 5 μm or more, and more preferably 0.1 μm or more. However, if the thickness of the film is too large, cracks occur due to the influence of internal stress and the like, resulting in insufficient coating on the surface, and furthermore, the film is peeled off.

The present invention does not limit the Al alloy used as a base material.
Excellent in terms of thermal conductivity, electrical conductivity, and corrosion resistance 5
000 series alloy and 6000 series alloy are useful.
In the case of a system-based alloy, Si is added in an amount of at least 0.1 as an alloy component.
It is preferable that the alloy contains 5% by weight or less and 0.5 to 6.0% by weight of Mg. In the case of a 6000 series alloy, 0.2 to 1.2% by weight of Si is used as at least an alloy component.
It is preferable to contain 0.4 to 1.5% by weight of Mg. In the case of parts in the chamber, other Al alloys such as 1000 series alloys, 2000 series alloys, and 7000 series alloys may be used according to the use and purpose of the parts in addition to the 5000 series alloy and the 6000 series alloy. In particular, since the 1000 series alloy has few precipitates and crystallized substances, defects caused by the precipitates of the anodic oxide film and the like can be extremely reduced.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are not intended to limit the present invention, and any design changes based on the gist of the preceding and following aspects will be described. Are included within the technical scope of

[0030]

EXAMPLES Using various Al alloy plates shown in Table 1, anodic oxide films having various S concentrations shown in Table 1 were formed into test pieces. In changing the S concentration between the surface side and the substrate side, the current density was changed. For example, N
o. In the case of the test piece of No. 1, a solution containing oxalic acid and sulfuric acid was used as an anodizing treatment solution, and when forming an oxide film on the surface side, electrolysis was performed at 0.1 to 0.5 A / cm ^2. When the oxide film on the substrate side is formed, 0.7 to 1.5 A /
Electrolysis was performed in cm ² . Table 1 shows the content elements other than S and the thickness of the anodic oxide film.

For the purpose of evaluating the corrosion resistance of the test piece to a halogen-based gas, a gas corrosion test was performed at 350 ° C. for 5 hours with a 5% Cl—Ar mixed gas, and the appearance after the test was examined. Evaluation was based on criteria. [Gas corrosion test] ○: No corrosion generated △: Corrosion generated area ratio less than 5% ×: Corrosion generated area ratio 5% or more

Further, in order to evaluate the plasma resistance of the test piece, a chlorine plasma irradiation test and a CF ₄ plasma irradiation test were conducted for 90 minutes under a low bias condition, and the etching amount was measured. Was evaluated. [Plasma irradiation test] ：: Amount to be etched is less than 2 μm Δ: Amount to be etched is 2 μm or more and less than 5 μm ×: Amount to be etched is 5 μm or more

The results of the gas corrosion test and the plasma irradiation test are shown in Table 1. In the tables, “elements other than S” are elements contained in the anodic oxide film among B, C, P and N other than S, and the anodic oxide film is Al—O,
O and H are inevitably contained elements because they are made of Al-OH.

[0034]

[Table 1]

As is clear from the results in Table 1, No. satisfying the conditions according to the present invention. Nos. 1 to 9 exhibited excellent gas resistance and plasma resistance. On the other hand, no. 10 to 13 are comparative examples that do not satisfy any of the conditions according to the present invention,
At least one of gas resistance and plasma resistance is insufficient.

[0036]

According to the present invention having the above-described structure, Al or A having excellent gas resistance and plasma resistance is provided.
Thus, a vacuum chamber member made of an alloy can be provided.

[Brief description of the drawings]

FIG. 1 is a partially sectional explanatory view showing a schematic structure of an anodized film.

FIG. 2 is an explanatory view showing a standard of a region of a surface layer of an anodized film and a substrate side layer.

Claims (7)

[Claims] 1. A vacuum chamber member comprising an Al or Al alloy substrate having an anodized film formed on a surface thereof, wherein the S concentration on the surface side of the anodized film is lower than the S concentration on the substrate side.
A vacuum chamber member made of Al or an Al alloy which is superior in gas resistance and plasma resistance characterized by being higher in concentration. 2. A vacuum chamber member having an anodized film formed on a surface of a substrate made of Al or an Al alloy, wherein the anodized film has a different component composition between the surface side and the substrate side.
A vacuum chamber member made of Al or Al alloy excellent in gas resistance and plasma resistance, wherein the layer on the surface side contains S, and the layer on the substrate side does not contain S. . 3. The vacuum chamber member according to claim 1, wherein the S concentration on the surface side is 0.5% by weight or more. 4. The vacuum chamber member according to claim 1, wherein the S concentration on the substrate side is 5.0% by weight or less. 5. An anodic oxide film comprising one or more elements selected from the group consisting of B, C, N, and P.
5. The vacuum chamber member according to any one of 4. 6. An anodic oxide film comprising a porous layer having many pores and a barrier layer having no pores is formed.
The vacuum chamber member according to any one of claims 1 to 5, wherein a pore diameter of a porous layer in the anodic oxide film is smaller on a surface side and larger on a substrate side. 7. An anodic oxide film comprising a porous layer having a large number of pores and a barrier layer having no pores is formed.
The vacuum chamber member according to any one of claims 1 to 6, wherein a thickness of the barrier layer in the anodic oxide film is larger than １ ／ of an average thickness of a cell wall formed in the porous layer. Chamber members.