JPH08311692A - Parts for vacuum chamber and production thereof - Google Patents

Abstract

PURPOSE: To provide parts for a vacuum chamber to be used for a CVD device, PVD device, dry etching device, etc., exhibiting excellent corrosion resistance to a corrosive gas or plasma introduced in the vacuum chamber and to provide a producing method therefor. CONSTITUTION: In the parts for the vacuum chamber in which an anodically oxidized film of an Al-based alloy layer having >=20nm thickness and forming a solid soln. with 0.1-10atom% more than one kind elements selected from Ta, Nb, V, Fe, Co and rare earth elements on the surface of a base material consisting of Al or an Al alloy, an anodically oxidizing treatment is executed after forming the Al-based alloy layer by a physical deposition method or an ion implantation method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a component for a vacuum chamber used in a CVD apparatus, a PVD apparatus, a dry etching apparatus, etc., and is excellent in corrosive gas and plasma introduced into the vacuum chamber. The present invention relates to a vacuum chamber component that exhibits corrosion resistance and a method for manufacturing the same.

[0002]

2. Description of the Related Art Since a corrosive gas containing a halogen element such as Cl or F is introduced as a reaction 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 referred to as gas corrosion resistance) is required. In the case of a thermal plasma CVD device, etc.,
In addition to the above corrosive gas, halogen-based plasma is also generated, and therefore corrosion resistance to plasma (hereinafter referred to as plasma resistance) is also important.

Therefore, stainless steel has been mainly used as the material for the vacuum chamber. However, the vacuum chamber made of stainless steel has a problem that it is heavy and requires a large amount of work on the base, and the thermal conductivity is not sufficient, and it takes a long time to bake at the time of operation. Further, heavy metals such as Cr, which is an alloy component of stainless steel, may be released during the process as a pollution source for some reason. Therefore, development of a vacuum chamber made of Al or Al alloy, which is lighter than stainless steel, excellent in thermal conductivity, and free from the risk of heavy metal contamination, is under study.

However, the surface of a bare metal of Al or Al alloy is not necessarily good in gas corrosion resistance and plasma resistance, and it is considered necessary to perform some kind of surface treatment, and various studies have been conducted. For example, Japanese Patent Publication No. 5-538
No. 70 discloses a vacuum chamber component that improves the gas corrosion resistance of Al or Al alloy by anodizing the surface of the Al or Al alloy vacuum chamber component to form an anodized film. An invention is disclosed. However, the anodic oxide film does not cause a reaction with the corrosive gas or plasma at all, and reaction products are generated as fine particles when corroded during use, for example, when used as a semiconductor manufacturing apparatus. The fine particles may cause defective products, and improvement has been desired.

Further, Japanese Patent Publication No. 5-53871 discloses a film having excellent corrosion resistance (for example, TiN, TiC, Al ₂ O ₃₎ formed on the surface of a vacuum chamber component made of Al or Al alloy by using an ion plating method. Etc.) is disclosed. However, according to this method, due to the film stress generated at the time of film formation, there was a problem that cracks occurred in the film during use or peeling of the film occurred, causing corrosion from there. .

[0006]

The present invention has been made in view of the above circumstances, and an object thereof is to provide a vacuum chamber component having excellent gas corrosion resistance and plasma resistance, and a method for manufacturing the same. Is.

[0007]

A vacuum chamber component according to the present invention, which has achieved the above object, has a thickness of 20 nm or more on a surface of a base material made of Al or an Al alloy, and T
an anodized film of an Al-based alloy layer in which 0.1 to 10 at% of one or more elements selected from the group consisting of a, Nb, V, Fe, Co and rare earth elements is formed as a solid solution. It is a summary.

In manufacturing the above-mentioned vacuum chamber component, T is formed on the surface of a base material made of Al or Al alloy.
After forming an Al-based alloy layer in which 0.1 to 10 at% of one or more elements selected from the group consisting of a, Nb, V, Fe, Co and rare earth elements are formed as a solid solution, anodization is performed on the Al-based alloy layer. A manufacturing method of forming an anodized film having a thickness of 20 nm or more by applying a treatment may be adopted, and it is recommended that the Al-based alloy layer be formed by a physical vapor deposition method or an ion implantation method.

In the present invention, the vacuum chamber component means
Not only the structural material of the vacuum chamber but also members such as a gas diffusion plate (GDP), a clamper, a shower head, a susceptor, a clamp ring, and an electrostatic chuck, which are arranged in the vacuum chamber, and are made of Al alloy. All of these members are collectively referred to as a vacuum chamber component in the following description. However, in a vacuum chamber to be actually manufactured, not all of its members have to be configured by the improved product of the present invention, but other improved Al alloys, conventionally known stainless steels, ceramics / plastics composites. In some cases, there is no problem even if it is manufactured by combining it with a material.

[0010]

The present inventors have conducted intensive studies for the purpose of improving the gas corrosion resistance and plasma resistance of vacuum chamber parts using Al or an Al-based alloy. As a result, an anodized film obtained by forming an Al alloy layer in which a specific metal element is solid-solved on the surface of the vacuum chamber component and then subjecting the Al alloy layer to anodization treatment has a high withstand voltage. It has been found that, as compared with an Al ₂ O ₃ anodized film formed by a conventional method or a vapor-phase synthesized coating film, it exhibits extremely high gas corrosion resistance and plasma resistance.

The above-mentioned specific metal elements are Ta, Nb,
At least one selected from the group consisting of V, Fe, Co and rare earth elements (hereinafter referred to as the alloying element according to the present invention). The rare earth element refers to Y, a lanthanoid element, and an actinide element. Among the rare earth elements, Y and L
a, Nd, Gd, Dy and Tb are desirable as alloying elements.

The anodic oxide film containing an alloying element according to the present invention has a high dielectric strength depending on the content of the alloying element and the film thickness, and the corrosion resistance improves as the dielectric strength increases. The strong correlation between the dielectric strength and the corrosion resistance can be explained as follows. That is, the dielectric strength is brought about by the electrostatic barrier property of the anodized film, and the degree of this electrostatic barrier property is defined by the denseness of the anodized film, the defect density, the presence or absence of holes, etc. and the quantitative degree. To be done. This is because the leakage current due to the dielectric breakdown mainly flows through defects, holes and grain boundary portions of the anodic oxide film. On the other hand, the corrosion resistance is the denseness of the anodized film,
It is strongly influenced by the microscopic structure such as the defect density and the presence or absence of holes. This is because the corrosion resistance of the Al alloy originally originates from the chemical barrier property of the oxide film (barrier property against the passage and diffusion of atoms), and the denseness of the film, the defect density, the presence or absence of holes, etc. Controls local corrosion. From the above,
Both the dielectric strength and the corrosion resistance reflect the microscopic structure of the anodic oxide film. Since the dielectric strength and the corrosion resistance are the same cause, the dielectric strength and the corrosion resistance have a strong correlation. Therefore, it is possible to evaluate the corrosion resistance from the dielectric strength and the dielectric strength from the corrosion resistance.

The solid solution amount of the alloying element in the Al alloy layer must be 0.1 to 10 at%. When the amount of the solid solution is less than 0.1 at%, the formation of complex oxides by the refinement of crystal grains and anodization is not sufficient, and the effect of improving gas corrosion resistance and plasma resistance cannot be remarkably exhibited. The lower limit of the solid solution amount is 0.5
At% is preferable. On the other hand, when it exceeds 10 at%, it is not necessarily solid-solved in the Al matrix, and an additional element which is not solid-solved in the Al matrix is precipitated as an intermetallic compound when forming an Al alloy layer or during anodization. As a result, the homogeneity of the film is impaired and the gas corrosion resistance and the plasma resistance are adversely affected, and the strength of the film is lowered to cause cracks and peeling. Therefore, the content is set to 10 at% or less. The upper limit of the solid solution amount is more preferably 5 at% or less.

In the present invention, the thickness of the anodized film is set to 20 nm or more because if the anodized film is too thin, sufficient gas corrosion resistance and plasma resistance cannot be exhibited. It is more preferable if there is.
From the viewpoint of improving gas corrosion resistance and plasma resistance,
The thicker the anodized film is, the more preferable. However, in order to increase the thickness of the anodic oxide film, it is necessary to increase the thickness of the underlying Al alloy layer, which impairs the productivity. Therefore, a thickness of 1000 nm or less is sufficient for the anodized film.

The alloying element according to the present invention does not form a solid solution in the Al matrix even when added as an alloying element of Al in ordinary Al casting, and exists as an intermetallic compound. In the method of the present invention, by adopting the physical vapor deposition method or the ion implantation method, the Al alloy layer in which the alloying element according to the present invention is dissolved in Al can be formed on the surface of the substrate, and the Al alloy layer is anodized. By performing the treatment, excellent corrosion resistance can be exhibited, and cracks and peeling, which frequently occur in the film by the conventional method, can be prevented, that is, a component for a vacuum chamber having excellent crack resistance can be obtained. The reason why the anodized film obtained by the method of the present invention can exhibit excellent corrosion resistance and crack resistance can be speculated as follows.

The Al alloy layer is made of Al or Al of the base material.
The crystal grains are remarkably finer than those of the alloy, and as a result, the anodized film obtained by subjecting the Al alloy layer to anodization becomes dense and the surface can be formed flat. Therefore, it is considered that the erosion of the corrosive gas or plasma does not locally concentrate, the corrosive gas or plasma can be prevented from entering the inside, and excellent corrosion resistance is exhibited.

Further, since the Al alloy layer is homogeneous, the components of the anodized film obtained by subjecting the Al alloy layer to anodizing treatment are Al ₂ O ₃ and oxides of additional elements mixed uniformly. It becomes a complex oxide in the state of being. This composite oxide exhibits excellent corrosion resistance because its chemical properties are more stable than that of Al ₂ O ₃ alone (that is, its reactivity to corrosive gas and plasma is low).

Furthermore, since the coating is uniform as described above, internal stress is not concentrated in the coating, so that it is considered that no crack or peeling occurs and the crack resistance is excellent.

As the physical vapor deposition method for forming the Al alloy layer in the present invention, known methods such as a vacuum vapor deposition method, an ion plating method and a sputtering method may be adopted. Particularly, the DC magnetron sputtering method is alloyed. It is recommended as a preferable method because it allows non-equilibrium solid solution of elements to efficiently form a polycrystalline Al alloy film in which alloying elements uniformly exist.

The present invention does not limit the anodizing treatment method, and an ordinary anodizing treatment method using sulfuric acid, phosphoric acid, oxalic acid, chromic acid or the like may be used. It is desirable to use it as an oxidation treatment liquid, and it is recommended to use salts of organic acids such as phthalic acid, citric acid, tartaric acid among others. It is desirable that the anodizing solution has a pH in the vicinity of neutrality, and a hydrophilic organic solvent such as ethylene glycol (an organic solvent that dissolves in water).
It is desirable to dilute with. The range of dilution is aqueous solution:
Generally, the organic solvent is about 1: 1 to 1:20.

Regarding the current density during the anodic oxidation treatment, the lower the current density is set, the more precise the anodic oxide film having excellent corrosion resistance can be obtained. However, if the current density is too low, it takes a long time for the anodic oxidation process, which leads to a decrease in productivity. Therefore, it is preferable to perform the current density at 0.5 to 1.5 mA / cm ² .

The present invention is not particularly limited to the applied voltage during the anodizing treatment, but since the applied voltage and the anodized film thickness are in a proportional relationship, 25 V is required to form an anodized film of 20 nm or more. It is preferable to apply the voltage above, and more preferably 50 V or more.

In the present invention, the underlying Al alloy layer may be entirely changed to an anodized film, but the Al alloy layer remaining after the anodizing treatment acts as a buffer for stress and improves crack resistance. Is effective for. Therefore, the underlying Al
The alloy layer is preferably formed thicker than the anodized film, and it is desirable that the Al alloy layer is formed to have a thickness twice or more that of the anodized film.

Examples will be described below, but the present invention is not limited to the following examples, and it is within the technical scope of the present invention to make appropriate modifications within the spirit of the preceding and the following.

[0025]

EXAMPLES Example 1 Al-xT was formed by a DC magnetron sputtering method.
a, Al-xFe, Al-xNd (x = 0.01 to 20)
An Al alloy film having a composition of at%) was formed on a glass substrate to a thickness of 500 nm. Next, a stripe pattern having a width of 100 μm was formed by photolithography and wet etching to form a comb-shaped electrode. In performing the anodizing treatment, the above-mentioned comb-shaped electrode was used as the working electrode and the Pt electrode was used as the counter electrode.

In the electrolytic bath, an equal amount of 3% tartaric acid aqueous solution and ethylene glycol were mixed, and then ammonia water was added to adjust the pH.
Was used in the range of 7.0 ± 0.5. Immerse the electrode in this electrolytic bath, voltage 72V, bath temperature 25 ℃
Was subjected to anodizing treatment by a constant voltage electrolysis method to form an anodized film on the substrate. The thickness of the anodized film obtained at this time was 150 nm in all Al alloy films.

A pure Al film having a thickness of 500 nm is formed on the anodized comb-shaped electrode by a sputtering method, and a stripe pattern having a width of 100 μm is formed by photolithography in a direction orthogonal to the stripe pattern of the comb-shaped electrode. A test piece was formed by the wet etching method.

A prober was brought into contact with the orthogonal wiring pattern of the test piece, and the voltage until the dielectric breakdown was measured while gradually applying the voltage to examine the withstand voltage, which is an index of corrosion resistance.

FIG. 1 shows the relationship between the amount of alloying element added and the dielectric strength. By adding the alloy element in an amount of 0.1 at% or more, the withstand voltage is significantly increased. The anodized film of pure Al formed and measured in the same manner as in this example has a withstand voltage of about 30V.
In comparison with Ta, Fe, Nd 0.1 at
It can be seen that the corrosion resistance is improved by adding more than 100%.
When added in excess of 10 at%, the withstand voltage decreased in any alloy system.

Example 2 Anodized films were formed on various Al alloy films (thickness: 500 nm) by the same method as in Example 1 and the dielectric strength was measured. Further, for the purpose of evaluating the halogen-based gas corrosion resistance of the above anodic oxide film, a gas corrosion test was performed in a 5% chlorine-argon mixed gas at 300 ° C. for 4 hours, and the appearance after the test was gas corrosion resistance. Was evaluated. [Gas corrosion resistance] ○: No corrosion occurrence △: Corrosion occurrence area ratio less than 5% ×: Corrosion occurrence area ratio 5% or more

Further, a chlorine plasma irradiation test was performed for 90 minutes under a low bias condition, and the plasma resistance and crack resistance were evaluated from the appearance as follows. [Plasma resistance] ○: No corrosion occurrence △: Corrosion occurrence area ratio less than 5% ×: Corrosion occurrence area ratio 5% or more [Crack resistance] ○: No cracks or peeling occurred ×: No cracks or peeling occurred Shown in 1.

[0032]

[Table 1]

From the results shown in Table 1, No. 1
It can be seen that all of Nos. 10 to 10 have a large withstand voltage and are excellent in all characteristics of gas corrosion resistance, plasma resistance, and crack resistance. On the other hand, No. 1 in which a conventional film that does not satisfy the requirements of the present invention is formed. Nos. 11 to 13 have low withstand voltage, and are poor in at least one of gas corrosion resistance, plasma resistance, and crack resistance. Further, in the comparative example (No. 14) containing Ni, the withstand voltage was almost zero, and both the gas corrosion resistance and the plasma resistance were low.

Example 3 Al-2a was formed by a DC magnetron sputtering method.
t% Ta, Al-2 at% Fe or Al-2 at% N
An Al alloy film having a composition of d
A film having a thickness of 0,100,500 nm was formed on a glass substrate. Using the obtained test piece, an anodized film was formed in the same manner as in Example 1 and the withstand voltage was measured.

FIG. 2 shows the relationship between the film thickness of the anodic oxide film of each test piece and the withstand voltage. 20n in any alloy system
It can be seen that with a film thickness of m or more, the withstand voltage increases, that is, excellent corrosion resistance is obtained.

Example 4 Al-2a was formed by a DC magnetron sputtering method.
t% Ta, Al-2 at% Fe or Al-2 at% N
An Al alloy film having a composition of d
A film having a thickness of 0,100,500 nm was formed on a glass substrate. Using the obtained test piece, an anodized film was formed by the same method as in Example 1, and a gas corrosion test and a plasma irradiation test were further performed by the same method as in Example 2,
The gas corrosion resistance and plasma resistance were evaluated. The results are shown in Table 2.
Shown in

[0037]

[Table 2]

From the results shown in Table 2, it can be seen that, in any of the alloy systems, excellent gas corrosion resistance and plasma resistance are exhibited at a film thickness of 20 nm or more.

[0039]

As described above, the present invention can provide a vacuum chamber component having excellent gas corrosion resistance and plasma resistance as well as crack resistance, and a method of manufacturing the same.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of alloying elements added and the dielectric strength of an anodized film.

FIG. 2 is a graph showing the relationship between the film thickness of an anodized film and the withstand voltage.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01L 21/203 H01L 21/203 Z 21/205 21/205 21/3065 21/302 B (72) Inventor Kazuo Yoshikawa 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel Works, Ltd. Kobe Research Institute

Claims (3)

[Claims] 1. A surface of a base material made of Al or an Al alloy having a thickness of 20 nm or more and one or more elements selected from the group consisting of Ta, Nb, V, Fe, Co and rare earth elements in an amount of 0. A vacuum chamber component, characterized in that an anodic oxide film of an Al-based alloy layer which forms a solid solution at 1 to 10 at% is formed. 2. A method of manufacturing a component for a vacuum chamber, which comprises subjecting an Al or Al alloy vacuum chamber component to anodizing treatment to form an anodized film, wherein Ta or Ta is formed on a surface of a base material made of Al or Al alloy. , Nb,
After forming an Al-based alloy layer in which 0.1 to 10 at% of one or more elements selected from the group consisting of V, Fe, Co and rare earth elements are formed as a solid solution, the Al-based alloy layer is anodized. Is used to form an anodic oxide film with a thickness of 20 nm or more. 3. The manufacturing method according to claim 2, wherein the Al-based alloy layer is formed by a physical vapor deposition method or an ion implantation method.