JP6562500B2 - Surface-treated aluminum material and manufacturing method thereof - Google Patents

Description

  The present invention relates to a surface-treated aluminum material obtained by applying an anodic oxide film to aluminum or an aluminum alloy, and further forming a dense hydrated alumina film having excellent corrosion resistance on the surface thereof, and a method for producing the same.

In general, a vacuum apparatus such as a CVD (Chemical Vapor Deposition) apparatus, a PVD (Physical Vapor Deposition) apparatus, or a dry etching apparatus is provided with an anodized film applied to an aluminum (hereinafter referred to as Al) or Al alloy member, and then vacuumed. Corrosion resistance against corrosive chlorine gas and plasma introduced into the equipment is guaranteed.
Conventionally, stainless steel has been mainly used as a material for such a vacuum device. However, a stainless steel vacuum device is heavy and requires heavy construction on the base, and stainless steel has thermal conductivity. There was a problem that it was not sufficient and time was required for baking during operation. Furthermore, heavy metals such as chromium (hereinafter referred to as Cr), which is a component of stainless steel, may be released during the process for some reason and become a source of contamination. Therefore, development of a vacuum device made of Al or Al alloy, which is lighter than stainless steel and excellent in thermal conductivity and at the same time has no fear of heavy metal contamination, has been activated.

  As described above, a material having an anodized surface has been used for Al or Al alloy members in these vacuum devices, but the film formed by anodizing has a porous structure. Because it has a large surface area, it easily adsorbs moisture and the like. For this reason, there has been a problem that it takes a long time for the gas to be outgas and reach a predetermined degree of vacuum during evacuation.

  Specifically, this will be described with reference to FIGS. FIG. 8 is a conceptual diagram showing the structure of a conventional surface-treated aluminum material. In FIG. 8, the surface-treated aluminum material 13 is formed with an anodized film layer 15 sealed on the surface of an aluminum base material 14 by anodizing treatment and subsequent sealing treatment. Since the anodic oxide coating layer 15 forms a porous structure having a large number of fine holes 16, the coating surface area is large as described above. Further, although the lid is closed by the sealing process, it cannot be processed so as to completely seal the fine hole 16, and as described above, outgas is generated and a long time is required for evacuation.

FIG. 9 is a scanning electron microscope (SEM) photograph of an anodized film layer of a conventional surface-treated aluminum material. It can be confirmed that fine fine holes are formed in the cross section.
Furthermore, since a corrosive gas containing a halogen element such as chlorine or fluorine is introduced as a reaction gas or etching gas into a vacuum apparatus such as a CVD apparatus, corrosion resistance against the corrosive gas is required. In addition, in the case of a thermal plasma CVD apparatus or the like, in addition to such a corrosive gas, halogen-based plasma is also generated, so that corrosion resistance to plasma (plasma resistance) is also important.

  For such a situation, the corrosion resistance is improved by increasing the thickness of the anodized film or forming a double barrier layer under the pore formed in the anodized film when anodizing. It was. For example, Patent Document 1 discloses an invention in which corrosion resistance is improved by making the final voltage higher than the initial voltage of the anodizing treatment.

  Further, in Patent Document 2, an organic solvent and pure water are used instead of caustic soda in the degreasing process to suppress the release of impurities from the aluminum surface even when exposed to plasma, thereby preventing the adhesion of impurities on the wafer surface. An invention for preventing IC failure is disclosed.

  Patent Document 3 discloses an invention in which a barrier-type film is formed using a solution containing boric acid when anodizing the surface of a vacuum chamber member made of Al or an Al alloy.

Further, Patent Document 4 discloses an invention made by improving the prior art by the applicant of the present application, and is a dense corrosive chlorine gas introduced into a vacuum apparatus such as a CVD apparatus or a PVD apparatus. A surface-treated aluminum material that has excellent corrosion resistance against plasma and wear resistance, and ability to suppress outgas, and can reach a predetermined degree of vacuum at high speed, and a method for producing the same are disclosed.
A scanning electron microscope (SEM) photograph of the anodized film layer and the hydrated alumina film layer of the surface-treated aluminum material produced by the conventional invention disclosed in Patent Document 4 is shown in FIG.

JP-A-8-260196 JP-A-8-124920 Japanese Patent Laid-Open No. 10-237692 JP 2005-29891 A

  However, in the above-mentioned conventional techniques, in Patent Document 1 and Patent Document 2, although the corrosion resistance is improved by these treatments, the anodic oxide film still has a porous structure, and is long before reaching a predetermined degree of vacuum. It took time, and in particular, the formation of an anodized film on the sheet surface of the vacuum chamber was avoided. As a result, the corrosion resistance of the sheet surface was poor, and the corrosion resistance of the entire member was also affected.

Further, in Patent Document 3, although a barrier film can be formed and generation of outgas can be suppressed, since a conventionally formed porous layer is not formed, the overall film thickness is thin, and corrosion resistance and wear resistance are reduced. There remained a challenge in gender.
That is, in the above-described conventional technology, there is a problem that it is not possible to satisfy both the suppression of outgas and the improvement of corrosion resistance and wear resistance.

  In Patent Document 4, although it is possible to provide a surface-treated aluminum material that is excellent in corrosion resistance, wear resistance, and outgas suppression ability and can reach a predetermined degree of vacuum at high speed, in recent semiconductor devices, Due to the demand for higher performance, the material is also required to have high purity, and more severe conditions are imposed on contamination. Especially in etching equipment for semiconductor device manufacturing, damage and deterioration of the inner wall of the equipment caused by excited halogen gas, contaminants Contamination of the wafer due to the occurrence of this must be suppressed as much as possible, and the structural material has been further required to smooth and thicken the surface of a dense film having etching resistance.

  The present invention has been made in response to such a conventional situation, and is provided with a dense, high smoothness and film thickness structure in a vacuum apparatus such as a CVD apparatus or a PVD apparatus or in an etching apparatus for semiconductor devices. It has excellent corrosion resistance, wear resistance and outgas suppression ability against corrosive chlorine gas and plasma introduced into the chamber, can reach a predetermined degree of vacuum at high speed, and further enhances etching resistance to generate pollutants. An object of the present invention is to provide a surface-treated aluminum material that can be suppressed and a method for producing the same.

In order to achieve the above object, a surface-treated aluminum material according to the first invention includes an aluminum substrate made of aluminum or an aluminum alloy, an anodized film layer formed on the surface of the aluminum substrate, and the anodized film. A hydrated alumina coating layer formed on the layer, and the arithmetic average roughness of the surface of the hydrated alumina coating layer is Ra = 10 nm or less.
In the surface-treated aluminum material having the above-described structure, a dense hydrated alumina film layer is formed on the anodized film layer, and the structural arithmetic average roughness is set to Ra = 10 nm or less, thereby reducing the surface area of the treatment. In particular, it acts to increase the outgas suppression ability and the etching resistance.

The surface-treated aluminum material according to a second aspect of the present invention is the surface-treated aluminum material according to claim 1, wherein the hydrated alumina coating layer has a thickness of 2 μm or more and 20 μm or less.
In the surface-treated aluminum material having the above structure, a plurality of anodic oxide film layers formed on the anodized film layer by forming a dense hydrated alumina film layer having a thickness of 2 μm or more and 20 μm or less on the anodized film layer. It exhibits wear resistance while sealing the fine pores with the hydrated alumina coating layer, and the corrosive chlorine gas and plasma introduced into the vacuum device corrode the anodic oxide coating layer and aluminum substrate. While having the effect | action of suppressing reliably, it has the effect | action which improves the intensity | strength of the hydrated alumina membrane | film | coat layer itself, and gives durability.
Further, it acts to enhance the etching resistance and suppress the generation of contaminants in the semiconductor device etching apparatus.

The method for producing a surface-treated aluminum material according to a third aspect of the present invention includes an anodizing treatment step in which an aluminum base material made of aluminum or an aluminum alloy is immersed in an electrolytic solution and energized, and the aluminum base material is heated steam or 95 ° C or higher. A surface-treated aluminum material manufacturing method having a sealing treatment step of sealing with high-temperature water, wherein the dissolved aluminum concentration of the electrolytic solution is 0-5 g / liter, and the temperature of the electrolytic solution is 0-20. And the electrolyte contains 10-50 g / liter of any one of oxalic acid, malic acid, melonic acid, malonic acid, or tartaric acid, or a mixed acid thereof. The temperature rise of high-temperature water is characterized in that the arrival time to 100 ° C. is controlled for 20 minutes or more and the rise time from 80 ° C. to 100 ° C. is controlled to 5 minutes or more. It is intended.
The method for producing a surface-treated aluminum material having the above-described structure has the effect of increasing the activity of the electrolytic solution by reducing the dissolved aluminum concentration of the electrolytic solution to 0-5 g / liter. In addition, by setting the temperature of the electrolytic solution to a low temperature of 0-20 ° C., the solubility of the electrolytic solution in aluminum oxide Al ₂ O ₃ which is a component of the anodic oxide film layer formed on the anode surface is lowered, so that the aluminum oxide is electrolyzed. It has the effect of suppressing elution into the liquid. Furthermore, it has the effect | action of making the liquid property of electrolyte solution acidic by making acids, such as oxalic acid, contain in electrolyte solution.
Moreover, the temperature rise of the heating steam or the high-temperature water in the sealing treatment process elutes a large amount of accumulated aluminum ions by controlling the speed of the temperature rise over the time required to reach 100 ° C. over 20 minutes. It acts to increase the film thickness. In addition, by controlling the temperature so that the rising time from 80 ° C. to 100 ° C., which is considered to start crystallization, takes 5 minutes or more, the crystallization of the surface is suppressed and the surface of the hydrated alumina coating layer is smoothed. Act on.

  As described above, in the surface-treated aluminum material of the first invention, since a smoothed hydrated alumina coating layer can be formed, the corrosion resistance against plasma and corrosive gas and plasma can be improved. In particular, the ability to suppress outgas and the etching resistance can be significantly increased.

  Further, in the surface-treated aluminum material of the second invention, in addition to the first invention, the hydrated alumina coating layer further thickened and thickened on the anodized coating layer having a plurality of micropores Thus, it is possible to suppress the generation of outgas from the fine holes during vacuum discharge. In addition, both corrosion resistance and plasma resistance against corrosive gas and plasma can be improved, and the strength and etching resistance of the surface film can be improved.

  Finally, in the surface-treated aluminum material production method of the third invention, a surface-treated aluminum material capable of exhibiting the effects of the first invention and the second invention can be produced.

It is a conceptual diagram of the surface treatment aluminum material which concerns on embodiment of this invention. (A) is a field emission scanning electron microscope (FE-SEM) photograph of the surface state of the hydrated alumina coating layer of the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the prior art (treatment 1 in Table 2). (B) is the same (100,000 times), and (c) is the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the present embodiment (treatment 6 in Table 2). 2 is a field emission scanning electron microscope (FE-SEM) photograph (10,000 times) of the surface state of the hydrated alumina coating layer, and (d) is the same (100,000 times). It is a flowchart which shows the process of the surface treatment aluminum material manufacturing method which concerns on embodiment of this invention. It is a conceptual diagram which shows the manufacturing method anodizing process of the surface treatment aluminum material which concerns on this Embodiment. (A) is a scanning probe microscope (SPM) photograph of the surface morphology of the hydrated alumina coating layer of the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the prior art (treatment 1 in Table 2) (1,000 times) (B) is a scanning probe microscope (SPM) of the surface morphology of the hydrated alumina coating layer of the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the present embodiment (treatment 6 in Table 2). ) A photograph (1,000 times), and (c) is a scanning probe microscopic (SPM) photograph (1,000 times) in a state where (b) is polished. (A) is a field emission scanning electron microscope (FE-SEM) photograph of a cross-sectional state of a hydrated alumina coating layer of a surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the prior art (treatment 1 in Table 2). (B) is a field emission of a cross-sectional form of a hydrated alumina coating layer of a surface-treated aluminum material produced by the method for producing a surface-treated aluminum material according to the present embodiment (treatment 6 in Table 2). Is a scanning electron microscope (FE-SEM) photograph (2,000 times), and (c) is a field emission scanning electron microscope (FE-SEM) photograph (2,000 times) of the same (process 7 in Table 2). . It is a graph which shows the temperature profile by the temperature management in the sealing treatment process of the surface treatment aluminum material manufacturing method which concerns on this Embodiment, and the temperature management in a prior art. It is a conceptual diagram which shows the structure of the conventional surface treatment aluminum material. It is a scanning electron microscope (SEM) photograph of the anodized film layer of the conventional surface treatment aluminum material. It is a scanning electron microscope (SEM) photograph of the anodic oxide film layer and the hydrated alumina film layer of the surface treatment aluminum material produced by the manufacturing method of the surface treatment aluminum material conventionally invented by the present applicant.

Hereinafter, embodiments of the surface-treated aluminum material according to the present invention will be described with reference to FIGS.
FIG. 1 is a conceptual diagram of a surface-treated aluminum material according to an embodiment of the present invention. In FIG. 1, a surface-treated aluminum material 1 according to the present embodiment is composed of three layers: an aluminum base 2 made of aluminum or an aluminum alloy as a substrate, an anodized film layer 3, and a hydrated alumina film layer 4. The hydrated alumina film layer 4 having a higher density and higher hardness is formed on the anodized film layer 15 of the conventional surface-treated aluminum material 13 shown in FIG. The formation process of the anodized film layer 3 and the hydrated alumina film layer 4 will be described later.

  In the conventional surface-treated aluminum material 13 as shown in FIG. 8, that is, the surface-treated aluminum material having a two-layer structure of the aluminum base material 14 and the anodized film layer 15, the anodized film layer is subjected to sealing treatment. Since there are a plurality of micropores 16 formed in the interior of 15, all of these cannot be completely filled. Therefore, when it is used as a vacuum apparatus such as a CVD apparatus or a PVD apparatus, it has not only poor corrosion resistance against corrosive gas and plasma, but also has a rough coating texture, relatively low strength and a large surface area. Moisture or the like is adsorbed in the fine holes 16 that are not completely sealed when the material 13 is manufactured, and these are eluted as outgas from the fine holes 16 during vacuum evacuation, thereby reducing the degree of vacuum in the vacuum apparatus. . That is, the efficiency of the evacuation work is lowered.

On the other hand, the surface-treated aluminum material 1 according to the present embodiment covers such an anodic oxide film layer 3 with a dense and high-strength hydrated alumina film layer 4 and at the same time the hydrated alumina film in the micropores 5. Sealed with layer 4, water is not adsorbed in the anodic oxide coating layer 3 or the hydrated alumina coating layer 4 when the surface-treated aluminum material 1 is manufactured, and outgassing is generated during evacuation, thereby hindering the evacuation operation. There is an effect that there is no.
Moreover, it is much thicker than the surface-treated aluminum material developed in the past by the applicant of the present application (see FIG. 10), and is excellent in smoothness. Accordingly, in a CVD apparatus, a PVD apparatus, and particularly an etching apparatus for manufacturing a semiconductor device, the purity can be increased by suppressing damage or deterioration of the inner wall of the apparatus due to excited halogen gas and contamination of the wafer due to generation of contaminants.

FIG. 2A shows a field emission scanning electron microscope (FE-) of the surface state of the hydrated alumina coating layer of the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the prior art (treatment 1 in Table 2). SEM) is a photograph (10,000 times), (b) is the same (100,000 times), and (c) is a surface produced by the method for producing a surface-treated aluminum material according to the present embodiment (treatment 6 in Table 2). It is a field emission scanning electron microscope (FE-SEM) photograph (10,000 times) of the surface state of the hydrated alumina coating layer of the treated aluminum material, and (d) is the same (100,000 times). Among these photographs, when comparing the surface-treated aluminum material according to the prior art of treatment 1 and the surface-treated aluminum material according to the present embodiment of treatment 6, the surface-treated aluminum material of treatment 1 has nano-order acicular crystals. It was confirmed that the surface-treated aluminum material of treatment 6 was smooth in the nano-order.
Therefore, it is expected that the surface area of the hydrated alumina coating layer 4 in the surface-treated aluminum material of the treatment 1 is obviously larger than that of the treatment 6, and the arithmetic average roughness (Ra) of the surface of the hydrated alumina coating layer 4 is also Process 1 is expected to be clearly larger.
As shown in FIG. 2, at first glance, the difference between the conventional technology and the surface-treated aluminum material according to the present embodiment is clear, but for the detailed characteristics of the cross-sectional form and surface form of these surface-treated aluminum materials, This will be described later with reference to examples.

Next, an embodiment of the method for producing a surface-treated aluminum material according to the present invention will be described with reference to FIGS.
FIG. 3 is a flowchart showing the steps of the method for producing a surface-treated aluminum material according to the embodiment of the present invention.
In FIG. 3, step S1 and step S2 show an anodizing process and a sealing process, respectively. Each of these steps will be described with reference to FIGS.

FIG. 4 is a conceptual diagram showing an anodizing process of the method for producing a surface-treated aluminum material according to the present embodiment.
When anodizing is performed, as shown in FIG. 4, an acidic electrolytic solution 7 containing an acid such as 10-50 g / liter oxalic acid and aluminum ions having a dissolved concentration of 0-5 g / liter is used in an electrolytic cell 6. Then, a workpiece 8 serving as an anode, that is, aluminum or an aluminum alloy corresponding to the aluminum substrate 2 in FIG. The work 8 and the cathode 12 are energized. Reference numeral 10 denotes a power supply device. In addition to oxalic acid, the electrolyte solution 7 may be any acid usually used for anodizing aluminum such as malic acid, melonic acid, malonic acid, sulfuric acid, phosphoric acid or tartaric acid. One acid may be used alone or in a mixed acid state.
Since an electric current flows in the direction 11 of the electric current in the electrolytic cell 6, aluminum ions are generated on the surface of the work 8 from the work 8 that is the aluminum base 2. In addition, since oxygen and hydrogen are generated from the anode, that is, the work 8 and the cathode 12, respectively, by electrolysis of water, the surface of the work 8 is oxidized by oxygen generated by aluminum ions and has a plurality of fine holes. The film is formed on the workpiece 8, that is, the aluminum substrate 2. This is an anodized film layer. In addition, the electrolyte solution conditions of the anodizing process of the manufacturing method of the surface treatment aluminum material of this invention are the same as the electrolyte solution conditions which the applicant of this application developed and already disclosed by patent document 4. FIG.

As shown in step S1 of FIG. 3, the dissolved aluminum concentration in the electrolytic solution used for the anodic oxidation treatment is 0-5 g / liter, and the temperature of the electrolytic solution is 0-20 ° C.
The operational effects of step S1 are as already disclosed in Patent Document 4, but are described again below.

The dissolved aluminum concentration in the electrolytic solution 7 is reduced by reducing the reaction activity with the electrolytic solution 7 by mixing the same metal ions as the metal constituting the workpiece 8 in the anodic oxidation treatment. In order to suppress a typical dissolution and form a film as dense as possible, the concentration is adjusted to a certain level such as about 15 g / liter. In this embodiment, the dissolved aluminum concentration is set to 0 to 5 g / liter, By increasing the reaction activity with the liquid 7, aluminum ions are easily dissolved on the surface of the workpiece 8, and an aluminum oxide film is easily formed.
The reaction activity on the surface of the aluminum oxide film is suppressed by lowering the temperature of the electrolytic solution 7. However, since the effect of suppressing the reaction activity due to the decrease in the temperature of the electrolytic solution 7 is weak inside the aluminum oxide film, the inner wall surface of the micropore 5 of the aluminum oxide film is activated as compared with the former, and in the subsequent sealing treatment step The fine holes 5 are filled with aluminum ions or organoaluminum ions which are the elements of the dense hydrated alumina coating layer 4 to be formed.

In the present embodiment, a voltage higher than usual is applied to the electrodes. In the anodizing treatment step of the surface-treated aluminum material manufacturing method of the present invention, by applying a voltage of 100 to 150 V higher than the normal applied voltage of 55 to 65 V to the electrode, a larger current flows in the workpiece 8 or the electrolytic solution 7. Thus, the Joule heat generated from the workpiece 8 is increased.
That is, by applying a voltage larger than usual to the electrode, current is supplied more than usual to increase Joule heat, and the activity of aluminum of the work 8 is enhanced both electrically and thermally. Thus, a state is created in which a large amount of aluminum ions can be eluted into the electrolyte solution 7. In addition, as described above, the aluminum ions are also filled in the micropores 5 of the aluminum oxide film.

Furthermore, in the present embodiment, the temperature of the electrolytic solution 7 is controlled to be lower than usual.
In addition to lowering the solubility of the electrolytic solution 7 by maintaining the liquid temperature lower by about 5 ° C. to 30 ° C. than usual, it has the effect of removing the generated Joule heat and cooling the surface of the workpiece 8. . While suppressing the reaction activity on the surface of the work 8, aluminum ions are eluted from the work 8 to the electrolytic solution 7, and at the same time, the aluminum oxide film formed on the surface of the work 8 is prevented from being dissolved again in the electrolytic solution 7. It is.

  The above description relates to step S1 in FIG. 3. In this step, a part of aluminum oxide forms an anodized film layer 3 on the aluminum substrate 2 of the surface-treated aluminum material 1 shown in FIG. Thus, a state in which a large amount of highly active aluminum ions not used for forming the anodic oxide film is accumulated in the micropores 5 of the anodic oxide film layer 3 is created. This is a state that occurs when a large amount of aluminum ions are eluted into the electrolytic solution 7 due to a decrease in the concentration of dissolved aluminum in the electrolytic solution 7 and high-voltage energization.

Next, since a plurality of micro holes 5 are formed in step S1 in FIG. 3 and the corrosion resistance is insufficient, the sealing process shown in step S2 in FIG. 3 is performed. The sealing treatment according to the present embodiment uses ultrapure water, but has four treatment conditions from step S2-1 to step S2-4.
In the sealing treatment, by applying this, a part of the aluminum oxide that is a component of the anodized film absorbs moisture and boehmite (Al ₂ O ₃ .H ₂ O) or bayerite (Al ₂ O ₃ .3H _2). O), and further expands to seal the micropores 5 of the anodized film layer 3 to improve the corrosion resistance and wear resistance of the surface-treated aluminum material.
In the present embodiment, first, in step S2-1, hot water of 60 ° C. or less is set as the initial temperature setting of high-temperature water or pressurized steam.
This is due to the fact that the hydrated alumina coating layer 4 does not grow even if the workpiece is anodized as in the invention disclosed in Patent Document 4 unless proper temperature control is performed during the sealing treatment. It is.
Specifically, even in the method disclosed in Patent Document 4, in the hydrated alumina coating layer 4, the needle crystals are densely embedded, thereby forming a film. If the temperature during the sealing treatment is not gradually controlled from a low temperature, a large amount of water near the aluminum ions is rapidly evaporated by rapid heating. This rapid evaporation of water causes crystallization with a non-uniform aluminum ion concentration, which promotes the growth of needle-like crystals, and consequently increases the surface area of the crystals. Furthermore, since the hydrated alumina film layer 4 can grow only at most about 1 μm and cannot uniformly cover the anodic oxide film layer 3, the surface area is increased due to the needle-like crystals as described above. In combination with this, outgassing could not be suppressed.

Therefore, first, in step S2-1, the initial sealing temperature is not immersed in high temperature water or pressurized steam from the beginning, but is immersed in warm water of 60 ° C. or less as the initial temperature setting for the sealing process. A control process is added. Note that it is desirable that the temperature is 60 ° C. or less and about 0 ° C. The reason is that when the temperature rises rapidly, highly active aluminum ions filled in the micropores crystallize rapidly and cannot be formed as a film. Therefore, it is important to gradually raise the temperature as described later while setting in such a temperature range.
Thereafter, the temperature is gradually raised, but the speed of the rising temperature is also controlled. Specifically, as shown in step S2-2 of FIG. 3, it is provided with a temperature raising control process in which a temperature raising time up to 100 ° C. is applied for 20 minutes or more. Further, as shown in step S2-3, 80 ° C. to 100 ° C. The constant temperature control process of 5 minutes or more is provided. The constant temperature treatment at 80 ° C. to 100 ° C. for 5 minutes or longer means a treatment in which the temperature rise is stopped at any temperature from 80 ° C. to 100 ° C. and maintained at that temperature for 5 minutes or longer. ing.
And as shown to step S2-4, as the whole exposure process which combined the temperature rising control process and the constant temperature control process from the initial temperature control process, a process is performed for 30 minutes or more.
In this way, by controlling the initial temperature and the rate of the rising temperature in the sealing treatment process of step S2, the film can be thickened without eluting the accumulated large amount of aluminum ions. In addition, since the film can be densified by combining such an initial temperature control process, a temperature increase control process, and a constant temperature control process, it is considered that it contributes to the mitigation of stress generation due to the thick film.
Further, by controlling the temperature so that the temperature rise from 80 ° C. to 100 ° C. considered to start crystallization takes 5 minutes or more, the surface crystallization is suppressed, and the surface of the hydrated alumina coating layer 4 is smoothed. It becomes possible.
The warm water of ultrapure water used for the sealing treatment may be boiling water or heated steam in a high temperature state. Furthermore, the pressurized steam may be saturated steam or unsaturated steam.

Finally, evaluation of the cross-sectional form and surface form of the surface-treated aluminum material according to the present embodiment using examples, and corrosion resistance performance and plasma resistance performance by a chromic acid chromic acid aqueous solution immersion test according to JIS H8633: 2013 Since the gas release characteristic was examined, this will be described.
For the purpose of comparison, after completing the anodizing treatment step under the same electrolyte conditions while using samples having the same material and dimensions, the sealing treatment according to the present invention and the sealing treatment according to the technique of Patent Document 4 are performed. A comparative study was conducted using the obtained surface-treated aluminum materials.

Each surface-treated aluminum material is treated according to the anodizing electrolytic conditions shown in Table 1. Specifically, an aluminum base material A5052 having dimensions in the column of sample dimensions is applied to an electrolytic solution having an oxalic acid concentration of 35 g / liter, a dissolved aluminum concentration of 3 g / liter in the electrolytic solution, and an electrolytic solution temperature of 13 ° C. Was electrolyzed at an electrolysis voltage of 120 V and a current density of 1.5 A / dm ² for 40 minutes.
Thereafter, in the sealing treatment step, as shown in Table 2, for the sample numbers 1 to 4, the conventional sealing method disclosed in Patent Document 4 is adopted, and for the sample numbers 5 to 7, the sealing of the present invention is adopted. The treatment method was adopted.
In this example, an aluminum alloy was used as a sample. Even if it is aluminum, the same anodic oxidation treatment and sealing treatment are possible.

The results of measuring the surface morphology of each surface-treated aluminum material thus produced using an electrolytic emission scanning electron microscope (FE-SEM) and a scanning microscope (SPM) are shown in FIGS. 2 and 5, respectively. Moreover, the result of having produced a cross section with the ion milling apparatus and measuring the cross-sectional form with FE-SEM is shown in FIG.
FIG. 2 has already been described.

FIG. 5 shows surface roughness measurement using a scanning probe microscope (SPM). (A) shows the hydration of the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the prior art (Process 1 in Table 2). It is a SPM photograph (1,000 times) of the surface form of an alumina coating layer, (b) is hydration of the surface treatment aluminum material produced with the surface treatment aluminum material manufacturing method concerning this embodiment (treatment 6 of Table 2). It is a SPM photograph (1,000 times) of the surface form of an alumina coat layer, and (c) is a SPM photograph (1,000 times) in the state where polish processing was given to (b).
In the treatment 1 (FIG. 5A) in which the sealing treatment is a conventional treatment, the surface roughness is Ra = 17.43 nm, while the treatment 6 (FIG. 5B) subjected to the sealing treatment in the present invention. ), The surface roughness is Ra = 7.84 nm, so it can be seen that the smoothness is greatly improved (less than half). Furthermore, when the polishing process is performed in addition to the sealing process in the present invention (FIG. 5C), the surface roughness is Ra = 2.12 nm, and the surface is smoothed in the nano order by the polishing process. It was confirmed that
Such a polishing process is a process by general buffing or slurry polishing, and a film thickness of about 2 μm is necessary to perform these processes. In the surface-treated aluminum material according to the present embodiment, the film thickness is Since it was sufficient, the polishing treatment could be performed.

FIG. 6 is a field emission scanning electron microscope (FE-SEM) photograph, but (a) shows the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the prior art (Process 1 in Table 2). The cross-sectional state (20,000 times) of the hydrated alumina coating layer is shown, and (b) and (c) show the hydration of the surface-treated aluminum material produced by the technique of this embodiment (Process 6 and Process 7 in Table 2). It is a cross-sectional form (2,000 times) of the alumina coating layer.
From FIG. 6, in treatment 1 of (a), the hydrated alumina coating layer is 0.5 μm or more but 1 μm or less, and acicular crystals can be confirmed, but treatment 6 of (b), treatment of (c) In No. 7, it can be confirmed that a needle-like crystal was not found and the film was thickened.

Further, FIG. 7 is a graph showing temperature profiles (change over time) by temperature management in the sealing treatment step of the surface-treated aluminum material manufacturing method according to the present embodiment and temperature management in the prior art.
From FIG. 7, in order to increase the thickness of the hydrated alumina coating layer, the temperature rising rate from the temperature at the start of the sealing treatment to 100 ° C. is increased to 20 ° C., and the constant temperature treatment at 100 ° C. It can be confirmed that it is important to spend more than a minute. That is, it can be understood that each of steps S2-1, S2-2, S2-3, and S2-4 as the sealing treatment conditions in FIG. 3 is related to the thickening of the hydrated alumina coating layer.

Next, the corrosion resistance, plasma resistance, and emission gas characteristics of the surface-treated aluminum material produced by the surface-treated aluminum material manufacturing method according to the present embodiment will be described through comparison with the surface-treated aluminum material produced by the conventional technique.
Table 3 shows the results of the phosphoric acid-chromic acid aqueous solution immersion test based on JISH8633-2: 2013, regarding the surface-treated aluminum material subjected to the sealing treatment step of the surface-treated aluminum material manufacturing method according to the present embodiment. Corrosion resistance is shown. In the test, a test piece of an appropriate size was cut out from a sample of the surface-treated aluminum material, and a hole for hanging was used for the test.
The mass reduction amount of the sample by phosphoric acid-chromic acid shown in Table 3 indicates the amount of aluminum ions corroded by the corrosive gas introduced into the vacuum apparatus as the reaction gas or etching gas. If the film formed on the surface of the aluminum substrate is highly corrosive to acids, a high concentration of aluminum ions dissolves in the phosphoric acid-chromic acid solution. That is, the amount of aluminum dissolved in the phosphoric acid-chromic acid solution increases. On the contrary, if the corrosiveness of the film is small, the amount of aluminum dissolved in the phosphoric acid-chromic acid solution becomes small. Therefore, looking at the amount of aluminum dissolved in the acid solution in Table 3, according to JIS standards, the amount of film dissolved should be 30 mg / dm ² or less, but the surface-treated aluminum material production according to the present embodiment The mass loss per unit area of the surface-treated aluminum material subjected to the sealing treatment step of the method was almost zero, which was very good. That is, it can be seen that the surface-treated aluminum material produced by the present invention is particularly excellent in corrosion resistance.

Next, measurement results of plasma resistance and emission gas characteristics will be described.
Table 4 shows the plasma resistance and outgassing characteristics of the surface treated aluminum materials manufactured by the treatment 1 in which the sealing treatment is a conventional treatment, the treatment 5 and the treatment 6 which have been subjected to the sealing treatment according to this embodiment. The results are shown.
All the samples used for these evaluations are the same as those used for the corrosion resistance evaluation shown in Table 3.
The plasma resistance shown in Table 4 uses a plasma CVD apparatus, the etching gas is CF ₄ (2.0 × 10 ⁻² Pa), the input power is 50 W, and the etching time is 60 minutes. Is evaluated by a surface roughness shape measuring instrument, and it can be said that the smaller the difference in height is, the higher the plasma resistance is because it is not corroded by CF ₄ gas (fluorocarbon gas).
From Table 4, the height difference is smaller in the present invention than in the conventional process. Therefore, it can be understood that the surface-treated aluminum material produced according to the present invention is superior in plasma resistance.

In addition, the gas release characteristics are obtained by using a differential thermal-caloric simultaneous analysis / mass spectrometer and achieving an ultimate temperature of 200 ° C., and mass desorption of a gas species 28 (m / z: mass to charge ratio) considered to be nitrogen. The total number of ions was evaluated by a meter.
From Table 4, compared with the sample of the conventional treatment, the gas considered to be nitrogen decreased in the sample of the present invention, and the treatment 6 having a thicker film showed the minimum value.

  As described above, in the surface-treated aluminum material produced by the surface-treated aluminum material production method according to the present embodiment, the hydrated alumina film is smoother and thicker than the surface-treated aluminum material produced by the conventional technique. Since it is possible to form a layer, all of the corrosion resistance, plasma resistance and emission gas characteristics are superior to the surface-treated aluminum material produced by the prior art, and are outstanding as comprehensive material characteristics Can be effective.

  As described above, the invention described in claims 1 to 3 of the present invention is used as an inner wall material of a vacuum apparatus requiring a particularly high degree of vacuum among a CVD apparatus, a PVD apparatus or a dry etching apparatus. Of course, it can be widely used for building materials, weak electric parts, automobile parts and the like.

  DESCRIPTION OF SYMBOLS 1 ... Surface treatment aluminum material 2 ... Aluminum base material 3 ... Anodized film layer 4 ... Hydrated alumina film layer 5 ... Micropore 6 ... Electrolytic tank 7 ... Electrolyte solution 8 ... Work piece 9 ... Hook 10 ... Power supply device 11 ... Current 12 ... Cathode 13 ... Surface-treated aluminum material 14 ... Aluminum substrate 15 ... Anodized film layer 16 ... Micropores

Claims (3)

A aluminum or aluminum base material made of aluminum alloy, and the anodized film layer formed on the aluminum substrate surface, and hydrated alumina coating layer formed on the anodized film layer, the anodized The micropores formed inside the coating layer are sealed with the hydrated alumina coating layer, and the thickness of the hydrated alumina coating layer formed on the anodized coating layer is 2 μm or more and 20 μm or less. Surface-treated aluminum material.   2. The surface-treated aluminum material according to claim 1, wherein the arithmetic average roughness of the surface of the hydrated alumina coating layer is Ra = 10 nm or less.   An anodizing treatment step in which an aluminum substrate made of aluminum or an aluminum alloy is immersed in an electrolytic solution and energized, and a sealing treatment step in which the aluminum substrate is sealed with heated steam or high-temperature water at 95 ° C. or higher. A surface-treated aluminum material manufacturing method comprising: a dissolved aluminum concentration of the electrolyte solution is 0-5 g / liter, a temperature of the electrolyte solution is 0-20 ° C., and the electrolyte solution is oxalic acid, malic acid, Melonic acid, malonic acid, sulfuric acid, phosphoric acid, tartaric acid or any one of these acids or a mixed acid thereof is contained in an amount of 10-50 g / liter, and the temperature rise of the heating steam or hot water in the sealing treatment step is 100 ° C. The method for producing a surface-treated aluminum material is characterized in that the arrival time to 20 minutes or more and the rising time from 80 ° C. to 100 ° C. are controlled to 5 minutes or more.