Surface-treated aluminum material, method for producing same, and member for semiconductor processing device

Abstract

A surface-treated aluminum material (1) is provided with: a base material (2) comprising aluminum or an aluminum alloy; and a protective film (3) that contains an oxide of aluminum and a hydrated oxide and is formed on at least a part of the surface of the base material (2). The thickness of the protective film (3) is 2 [mu] m or more. When the mass ratio of the elements in the protective film (3) is analyzed in the depth direction by glow discharge luminescence analysis, the ratio (CH / CAL) of the integrated value (CH) of the mass ratio of hydrogen atoms to the integrated value (CAL) of the mass ratio of aluminum atoms in the range from the surface of the protective film (3) to a position at a depth of 1 [mu] m is 0.2-0.7.

Description

Technical Field

[0001] The present invention relates to a surface-treated aluminum material, a method for producing the same, and a member for a semiconductor manufacturing apparatus. Background Art

[0002] Aluminum materials including aluminum or aluminum alloys are used for various applications. An anodic oxide film is sometimes provided on the surface of these aluminum materials for the purpose of surface protection.

[0003] For example, Patent Document 1 describes a component for a substrate processing device, which is characterized in that the component for a substrate processing device that performs plasma processing on a substrate is provided with a coating, the coating is formed on the surface of the component by connecting the component to the anode of a DC power supply and performing an anodic oxidation treatment by immersing the component in a solution mainly composed of an organic acid, and a semi-sealing treatment using boiling water is performed on the coating.

[0004] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2008-81815 Summary of the Invention Problems to be solved by the invention However, the component of Patent Document 1 has a problem in that the pores of the anodic oxide film are not completely closed, and therefore the durability against corrosive gas and plasma is low.

[0005] On the other hand, in the component of Patent Document 1, a method of completely sealing the pores of the anodic oxide film is considered to improve durability against corrosive gases and plasma. However, in this case, when the temperature rises, cracks may easily form in the anodic oxide film, resulting in the generation of foreign matter including small pieces of the anodic oxide film. To suppress the generation of such foreign matter, it is desirable to further improve the heat resistance of aluminum materials having an anodic oxide film on their surfaces.

[0006] The present invention has been made in view of the above background, and an object of the present invention is to provide a surface-treated aluminum material having excellent corrosion resistance to corrosive gas and plasma and capable of suppressing the generation of cracks, a method for producing the same, and a member for semiconductor manufacturing equipment.

[0007] Technical solutions to problems One embodiment of the present invention is a surface-treated aluminum material having: a base material comprising aluminum or an aluminum alloy; and a protective film comprising aluminum oxide and hydrated oxide and formed on at least a portion of the surface of the base material; The thickness of the protective film is greater than 2 μm. When the mass ratio of elements in the protective film is analyzed in the depth direction by glow discharge emission spectrometry, the integral value C of the mass ratio of hydrogen atoms in the range from the surface of the protective film to a depth of 1 μm is H The integral value C of the mass ratio relative to aluminum atoms Al Ratio C H / C Al It is 0.2 or more and 0.7 or less.

[0008] Another embodiment of the present invention is a method for producing a surface-treated aluminum material, which is the method for producing a surface-treated aluminum material of the aforementioned embodiment, wherein the method for producing a surface-treated aluminum material comprises: an anodic oxidation step of forming an anodic oxide film having fine pores on the base material by performing an anodic oxidation treatment on the base material; and In a sealing step, the base material is immersed in hot water to seal the pores of the anodic oxidation film, thereby forming the protective film on the base material. The product of the temperature T [° C.] of the hot water in the sealing step and the immersion time t [hour] is greater than 20° C.·hour and less than 75° C.·hour.

[0009] Effects of the Invention A protective coating is provided on the surface of a base material in the surface-treated aluminum material (hereinafter referred to as "aluminum material"). The protective coating has a thickness of 2 μm or more and contains aluminum oxide and hydrated oxide. The oxide and hydrated oxide are distributed in the protective coating such that, when analyzed in the depth direction by glow discharge emission spectrometry, the integral value C of the mass ratio of hydrogen atoms is 1.13 Å. H The integral value C of the mass ratio relative to aluminum atoms Al Ratio C H / C Al The aluminum material has high corrosion resistance and can suppress the occurrence of cracks by providing such a protective film on the base material.

[0010] In the aforementioned method for producing an aluminum material, after anodizing the base material to form an anodic oxide film, the pores of the anodic oxide film are sealed under the aforementioned specific conditions, thereby forming the protective film on the base material. This makes it possible to easily obtain the aluminum material.

[0011] As described above, according to the above-mentioned aspect, it is possible to provide a surface-treated aluminum material having excellent corrosion resistance to corrosive gas and plasma and capable of suppressing the occurrence of cracks, a method for producing the same, and a member for a semiconductor manufacturing apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a cross-sectional view showing a main part of the aluminum material in the example.

[0013] Figure 2 This is a cross-sectional view of a main portion of a base material showing a state after the anodizing step is completed in the production process of the aluminum material of the example.

[0014] Figure 3 It is an explanatory diagram showing the distribution of the mass ratio of hydrogen atoms in the protective film of the test material S1 in the depth direction. DETAILED DESCRIPTION

[0015] (Aluminum) The material of the base material in the aluminum material can be appropriately selected from the group consisting of aluminum and aluminum alloys according to the use of the aluminum material. For example, in the case of wanting to reduce outgassing from the aluminum material, it is preferred that the base material is composed of 1000 series aluminum or 3000 series aluminum alloy. As a 3000 series aluminum alloy, for example, an aluminum alloy having the following chemical composition can be used: containing Mn (manganese): 1.0 mass% or more and 1.5 mass% or less, and containing one or more elements selected from the group consisting of Si (silicon), Fe (iron), Cu (copper), Mg, Cr (chromium), Zn (zinc) and Ti (titanium) as arbitrary components, and the remainder containing Al and unavoidable impurities.

[0016] More specifically, as the 1000 series aluminum constituting the base material of the aluminum material, for example, aluminum having a chemical composition represented by alloy numbers AA1100, AA1100A, AA1200, AA1200A, AA1300, AA1110, AA1120, AA1230, AA1230A, AA1235, AA1435, AA1145, AA1345, AA1445, AA1150, AA1350, AA1350A, AA1450, AA1370, AA1275, AA1185, AA1285, AA1385, AA1188, AA1190, AA1290, AA1193, AA1198 or AA1199 can be used.

[0017] In addition, as the base material of the aluminum material, 3000 series aluminum alloys such as AA3002, AA3102, AA3003, AA3103, AA3103A, AA3103B, AA3203, AA3403, AA3004, AA3004A, AA3104, AA3204, AA3304, AA3005, AA3005A, AA3105, AA3105A, AA3105B, AA3007, AA3108, AA3109, AA3110, AA3111A, AA3111B, AA3112, AA3113, AA3114, AA3115 , AA3107, AA3207, AA3207A, AA3307, AA3009, AA3010, AA3110, AA3011, AA3012, AA3012A, AA3013, AA3014, AA3015, AA3016, AA3017, AA3019, AA3020, AA3021, AA3025, AA3026, AA3030, AA3130 or AA3065.

[0018] In addition, when it is desired to increase the strength of the aluminum material, it is preferred that the base material be composed of a 5000 series aluminum alloy or a 6000 series aluminum alloy. As a 5000 series aluminum alloy, for example, an aluminum alloy having the following chemical composition can be used: containing Mg (magnesium): 0.5 mass% or more and 5.0 mass% or less, and containing one or more elements selected from the group consisting of Si, Fe, Cu, Mn, Cr, Zn, and Ti as arbitrary components, with the remainder containing Al and unavoidable impurities. In addition, as a 6000 series aluminum alloy, for example, an aluminum alloy having the following chemical composition can be used: containing Mg: 0.3 mass% or more and 1.5 mass% or less, Si: 0.2 mass% or more and 1.2 mass% or less, and containing one or more elements selected from the group consisting of Fe, Cu, Mn, Cr, Zn, and Ti as arbitrary components, with the remainder containing Al and unavoidable impurities.

[0019] More specifically, as the base material of the aluminum material, 5000 series aluminum alloys such as AA5182, AA5183, AA5005, AA5005A, AA5205, AA5305, AA5505, AA5605, AA5006, AA5106, AA5010, AA5110, AA5110A, AA5210, AA5310, AA5016, AA5017, AA5018, AA5018A, AA5019, AA5019A, AA5119 ,AA5119A,AA5021,AA5022,AA5023,AA5024,AA5026,AA5027,AA5028,AA5040,AA5140,AA5041,AA5042,AA5043,AA504 9. AA5149, AA5249, AA5349, AA5449, AA5449A, AA5050, AA5050A, AA5050C, AA5150, AA5051, AA5051A, AA5151, AA5251, AA 5251A, AA5351, AA5451, AA5052, AA5252, AA5352, AA5154, AA5154A, AA5154B, AA5154C, AA5254, AA5354, AA5454, AA555 4. AA5654, AA5654A, AA5754, AA5854, AA5954, AA5056, AA5356, AA5356A, AA5456, AA5456A, AA5456B, AA5556, AA5556A, A Aluminum alloys having a chemical composition represented by A5556B, AA5556C, AA5257, AA5457, AA5557, AA5657, AA5058, AA5059, AA5070, AA5180, AA5180A, AA5082, AA5182, AA5083, AA5183, AA5183A, AA5283, AA5283A, AA5283B, AA5383, AA5483, AA5086, AA5186, AA5087, AA5187 or AA5088.

[0020] In addition, as the base material of the aluminum material, for example, 6000 series aluminum alloys having alloy numbers AA6101, AA6101A, AA6101B, AA6201, AA6201A, AA6401, AA6501, AA6002, AA6003, AA6103, AA6005, AA6005A, AA6005B, AA6005C, AA6105, AA6205, AA6305, AA6006, AA6106, AA6206, AA6306, AA6401, AA6501, AA6002, A6008, AA6009, AA6010, AA6110, AA6110A, AA6011, AA6111, AA6012, AA6012A, AA6013, AA6113, AA6014, AA6015, AA6 016, AA6016A, AA6116, AA6018, AA6019, AA6020, AA6021, AA6022, AA6023, AA6024, AA6025, AA6026, AA6027, AA6028, AA6031, AA6032, AA6033, AA6040, AA6041, AA6042, AA6043, AA6151, AA6351, AA6351A, AA6451, AA6951, AA6053, AA6 055, AA6056, AA6156, AA6060, AA6160, AA6260, AA6360, AA6460, AA6460B, AA6560, AA6660, AA6061, AA6061A, AA6261 , aluminum alloy with the chemical composition represented by AA6361, AA6162, AA6262, AA6262A, AA6063, AA6063A, AA6463, AA6463A, AA6763, A6963, AA6064, AA6064A, AA6065, AA6066, AA6068, AA6069, AA6070, AA6081, AA6181, AA6181A, AA6082, AA6082A, AA6182, AA6091 or AA6092.

[0021] A protective coating comprising aluminum oxide and hydrated aluminum oxide is provided on the base material. The protective coating is obtained, for example, by subjecting the base material to anodizing treatment to form a porous anodic oxide coating comprising aluminum oxide and having a large number of pores on the surface of the base material, followed by a pore sealing treatment to seal the pores of the anodic oxide coating with hydrated aluminum oxide.

[0022] The thickness of the protective coating is 2 μm or more. In this way, the base material can be protected from the influence of corrosive gases and plasma, and the corrosion resistance of the aluminum material can be improved. From the perspective of corrosion resistance, there is no particular upper limit to the thickness of the protective coating. The thicker the thickness of the protective coating, the more it can improve the corrosion resistance of the aluminum material. From this viewpoint, the thickness of the protective coating is preferably 5 μm or more, more preferably 10 μm or more. It should be noted that the manufacturing upper limit of the thickness of the protective coating is, for example, 200 μm. From the perspective of suppressing the generation of cracks in the protective coating, the thickness of the protective coating is preferably 100 μm or less.

[0023] The aluminum oxide and hydrated oxide in the protective film are distributed as follows: when the mass ratio of elements in the protective film is analyzed in the depth direction by glow discharge emission spectrometry, the integrated value C of the mass ratio of hydrogen atoms in the range from the surface of the protective film to a depth of 1 μm is H The integral value C of the mass ratio relative to aluminum atoms Al Ratio C H / C Al The ratio C of the integral values ​​is 0.20 or more and 0.70 or less. H / C Al Indicates the amount of hydrated oxide present near the surface of the protective film, which is higher than C H / C Al A higher value of means a greater amount of hydrated oxide present near the surface of the protective film.

[0024] Therefore, it is considered that the ratio of the integral value C H / C Al In the protective film with a ratio C of 0.20 or more, the pores generated by the anodic oxidation treatment are fully closed by the hydrated oxide. H / C Al When the ratio C is 0.20 or more, it is possible to inhibit corrosive gases, plasma, etc. from entering the pores, thereby improving the corrosion resistance of the aluminum material. H / C Al The value of is preferably 0.22 or greater, more preferably 0.24 or greater, further preferably 0.26 or greater, particularly preferably 0.28 or greater, and most preferably 0.30 or greater.

[0025] On the other hand, the ratio of the integral value C H / C Al When the ratio is less than 0.20, the pores tend to be insufficiently closed, which may lead to a decrease in the corrosion resistance of the aluminum material.

[0026] In addition, if the ratio of the integral values ​​C H / C Al If the value of becomes too high, the protective coating may be prone to cracking when the temperature of the aluminum material rises. The reason for this is not necessarily clear, but the following reasons are considered, for example. H / C Al When the value of is too high, it is considered that the protective film becomes a state in which the amount of hydrated oxide is too large and the crystallinity of the hydrated oxide is too high. H / C Al If the value is too high, the thermal expansion in the protective film becomes non-uniform due to the difference in thermal expansion coefficients among the base material, aluminum oxide, and hydrated aluminum oxide, and cracks are likely to occur when the temperature rises.

[0027] From the viewpoint of suppressing the occurrence of cracks in the protective film, the ratio of the integral values ​​C H / C Al The value of C is less than 0.70. H / C Al The value of is preferably 0.68 or less, more preferably 0.66 or less, and further preferably 0.64 or less.

[0028] The ratio of the integral value in the protective film C H / C Al When the preferred range is , the aforementioned integral value ratio C can be arbitrarily combined. H / C Al For example, the ratio of the integral value C H / C Al The preferred range of may be 0.22 or more and 0.68 or less, 0.24 or more and 0.68 or less, 0.26 or more and 0.66 or less, 0.28 or more and 0.66 or less, or 0.30 or more and 0.64 or less.

[0029] The ratio C of the integral values ​​in the protective film H / C Al The specific calculation method is as follows. First, after cleaning the surface of the aluminum material, a glow discharge luminescence analyzer (e.g., the "GD750" manufactured by SPECTRUMA Analytik GmbH) is used to obtain the distribution of the luminescence intensity of aluminum atoms and hydrogen atoms along the depth direction of the protective coating. The measurement conditions of the glow discharge luminescence analyzer are: anode diameter: 2.5 mm, output: 25 W, gas pressure: 3.5 hPa, and the luminescence intensity acquisition interval is set to 0.2 to 0.24 seconds. It should be noted that the sputtering rate of the protective coating measured under these conditions is approximately 50 to 90 nm / second.

[0030] The obtained distribution of the luminescence intensity of aluminum atoms and hydrogen atoms in the depth direction is converted into a distribution of mass ratios based on a pre-prepared calibration curve. The mass ratios of each atom are then integrated from the surface of the protective film to a depth of 1 μm, and the integrated value C of the mass ratio of hydrogen atoms is calculated. H and the integral value C of the mass ratio of aluminum atoms Al By making the integral value C of the mass ratio of hydrogen atoms obtained by the above operation H Divide by the integral value C of the mass ratio of aluminum atoms Al , can calculate the ratio of the integral value C H / C Al .

[0031] When a sealing degree test is performed according to the method specified in JIS H8683-2:2013, the mass reduction per unit area of ​​the aluminum material is preferably 0.2 g / dm 2 In this case, the corrosion resistance of the aluminum material can be further improved.

[0032] It should be noted that the specific method of the sealing degree test is as follows. First, 35 mL of phosphoric acid and 20 g of chromic anhydride are dissolved in water to prepare 1 L of test solution. Next, a test piece containing a protective coating is collected from the aluminum material, and the area of ​​the protective coating in the test piece is measured. After removing the stains on the surface of the test piece, the mass of the test piece is measured. Then, the test piece is immersed in the test solution maintained at a temperature of 38°C ± 1°C for 15 minutes ± 5 seconds.

[0033] After the test piece is immersed in the test solution, rinse it with running water and then with deionized or distilled water. After the rinsed test piece is fully dried, measure the mass of the test piece.

[0034] The area A (unit: dm 2 ), the mass m1 (unit: g) of the test piece before immersion in the test liquid, and the mass m2 (unit: g) of the test piece after immersion in the test liquid, the mass reduction per unit area δ can be calculated based on the following formula (1): A (Unit: g / dm 2 ).

[0035] δ A = (m1-m2) / A···(1) As mentioned above, the aluminum material has excellent corrosion resistance to corrosive gases, plasma, etc., and can suppress the generation of cracks in the protective coating even when the temperature rises. Therefore, the aluminum material is suitable for applications such as covers arranged around fans of heating and cooking appliances and components for semiconductor manufacturing equipment. More specifically, the aluminum material is suitable for use in chambers in semiconductor manufacturing equipment such as film forming equipment and etching equipment, and components arranged in chambers. Examples of film forming equipment include PVD (physical vapor deposition) equipment and CVD (chemical vapor deposition) equipment. In addition, examples of etching equipment include dry etching equipment.

[0036] (Aluminum Manufacturing Method) The manufacturing method of the aluminum material has the following characteristics: an anodic oxidation step of forming an anodic oxide film having fine pores on the base material by performing an anodic oxidation treatment on the base material; and In the sealing step, the base material is immersed in hot water to seal the pores of the anodic oxide film, thereby forming the protective film on the base material.

[0037] In the sealing step, the product of the temperature T (unit: °C) of the hot water and the immersion time t (unit: hour) exceeds 20°C·hour and is less than 75°C·hour.

[0038] In the anodizing process, a direct current is passed between a base material and a counter electrode while the base material and the counter electrode are immersed in an electrolyte, thereby forming an anodic oxide film on the surface of the base material. The anodic oxide film thus formed comprises a barrier layer densely formed on the base material and a porous layer having a large number of pores formed on the barrier layer. The barrier layer and the porous layer are composed of an aluminum oxide such as aluminum oxide.

[0039] The electrolyte used in the anodizing process may be, for example, an acidic electrolyte containing electrolytes such as sulfuric acid and phosphoric acid, or an alkaline electrolyte containing electrolytes such as sodium metaborate. From the viewpoint of being easier to form an anodic oxide film having a desired structure in the anodizing process, and further being easier to form the protective film, the electrolyte used in the anodizing process is preferably an acidic electrolyte, more preferably an acidic electrolyte containing an inorganic acid as an electrolyte, and further preferably an acidic electrolyte containing sulfuric acid as an electrolyte. It should be noted that sometimes anions from the electrolyte are mixed into the interior of the anodized film generated on the surface of the aluminum material by the anodizing process, for example, in an anodizing process using sulfuric acid, an anodized film containing sulfur from sulfate ions is formed.

[0040] The current density of the direct current in the anodizing treatment can be, for example, from 1 mA / cm 2Above and 20mA / cm 2 The temperature of the electrolyte in the anodizing treatment step can be appropriately set within the range of, for example, 0° C. to 40° C. inclusive.

[0041] The thickness of the anodic oxide film formed in the anodic oxidation treatment step is preferably 2 μm or more. By setting the thickness of the anodic oxide film to 2 μm or more, the thickness of the protective film after the sealing step can be more easily set to 2 μm or more.

[0042] In the pore sealing step, the base material, on which an anodic oxide film has been formed in the anodizing step, is immersed in hot water. When the anodic oxide film is immersed in hot water, the aluminum oxide constituting the anodic oxide film reacts with water to form a hydrated oxide. This hydrated oxide seals the pores of the anodic oxide film, thereby forming the protective film.

[0043] In the sealing process, the base metal is immersed in hot water in such a manner that the product of the temperature T (unit: °C) and the immersion time t (unit: hours) exceeds 20°C·hour and is less than 75°C·hour, preferably is greater than 21°C·hour and less than 73°C·hour, and more preferably is greater than 23°C·hour and less than 71°C·hour. By immersing the base metal in hot water with a product of the temperature and the immersion time exceeding 20°C·hour, the aluminum oxides that constitute the anodic oxide film react with the hot water sufficiently, and the pores of the anodic oxide film are fully sealed. This results in a protective film with excellent corrosion resistance. If the product of the temperature and the immersion time is less than 20°C·hour, the reaction between the aluminum oxides and the hot water is insufficient, and the pores are likely to be insufficiently sealed. Consequently, in this case, the corrosion resistance of the aluminum material may be reduced. From the viewpoint of more reliably obtaining a protective film having excellent corrosion resistance, the product of the hot water temperature and the immersion time is preferably 21° C.·hour or more, and more preferably 23° C.·hour or more.

[0044] On the other hand, if the product of the hot water temperature and the immersion time is too high, cracks may easily form in the protective coating once the aluminum material's temperature has risen. This is believed to be due to, for example, excessive reaction between aluminum oxide and the hot water. To suppress cracks in the protective coating and improve the aluminum material's heat resistance, the product of the hot water temperature and the immersion time is set to less than 75°C / hour. From the same perspective, the product of the hot water temperature and the immersion time is preferably 73°C / hour or less, and more preferably 71°C / hour or less.

[0045] The temperature T of the hot water in the sealing process is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher. By using high-temperature hot water in the sealing process, the immersion time required to achieve the desired sealing degree can be easily shortened. As a result, the productivity of the aluminum material can be further improved. It should be noted that the upper limit of the temperature T of the hot water in the sealing process is 150°C. That is, in the sealing process, the base material can be immersed in boiling water, or superheated water vapor can be brought into contact with the base material.

[0046] The base material used in the anodizing step can be produced by any method.

[0047] For example, the method for manufacturing the aluminum material may further include: a casting step of producing an ingot containing aluminum or an aluminum alloy; a homogenization step of maintaining the ingot at a temperature of 500° C. to 560° C. for 5 hours to 10 hours; and In the hot rolling step, the ingot subjected to the homogenization treatment is hot rolled at a temperature of 500° C. to 560° C. to produce the base material.

[0048] As a casting method in the casting step, for example, DC casting can be adopted. The thickness of the ingot obtained in the casting step is not particularly limited, and the ingot can have a thickness of, for example, 600 mm or more.

[0049] In the homogenization step, the ingot obtained in the casting step is held at a temperature of 500°C to 560°C for 5 to 10 hours. By setting the holding temperature and holding time in the homogenization step within the specific ranges, the structure of the ingot can be sufficiently homogenized.

[0050] In the hot rolling process, the homogenized ingot is hot rolled at a temperature of 500°C to 560°C. This produces a base material. If the starting temperature during hot rolling is too low, the ingot's deformation resistance increases, potentially causing cracks during rolling and deteriorating productivity. On the other hand, if the starting temperature during hot rolling is too high, the ingot may partially melt due to heat generated during hot rolling.

[0051] In the manufacturing method, the base material obtained as described above can be directly supplied to the anodizing step. In addition, the manufacturing method can also have a heat treatment step of performing a heat treatment such as annealing on the base material as needed after the hot rolling step and before the anodizing step.

[0052] Furthermore, the manufacturing method may include a pretreatment step of pretreating the base material after the hot rolling step and before the anodizing step. Examples of pretreatment of the base material include degreasing treatments such as alkali degreasing, and grinding treatments such as mechanical grinding, chemical grinding, and electrolytic grinding. In the pretreatment step, depending on the desired properties of the aluminum material, one of the above-mentioned pretreatments may be performed alone, or two or more pretreatments may be appropriately combined.

[0053] Performing an alkaline degreasing treatment during the pretreatment process can reduce the gloss of the anodic oxide film obtained after the anodizing treatment, resulting in an aluminum material with a dull appearance. Furthermore, performing a polishing treatment during the pretreatment process can improve the gloss of the anodic oxide film obtained after the anodizing treatment, resulting in an aluminum material with a glossy appearance. To further enhance the gloss of the aluminum material, it is preferable to perform an electrolytic polishing treatment on the base material during the pretreatment process.

[0054] Example Reference Figures 1 to 3 The surface treated aluminum material and its manufacturing method are described in detail below. Figure 1 As shown, the surface-treated aluminum material 1 of this example comprises: a base material 2 comprising aluminum or an aluminum alloy; and a protective film 3 comprising aluminum oxide and hydrated oxide, formed on at least a portion of the surface of the base material 2. The thickness of the protective film 3 is 2 μm or greater. Furthermore, when the mass ratio of elements in the protective film 3 along the depth direction was analyzed by glow discharge luminescence spectrometry, the integral value C of the mass ratio of hydrogen atoms in the range from the surface of the protective film 3 to a depth of 1 μm was 2 μm. H The integral value C of the mass ratio relative to aluminum atoms Al Ratio C H / C Al It is 0.2 or more and 0.7 or less.

[0055] Specific examples of the aluminum material 1 (test materials S1 to S5) are shown in Table 1. The manufacturing method of the test materials S1 to S5 is as follows. First, as the base material 2, an aluminum plate having a chemical composition represented by alloy number A6016 and a thickness of 1.1 mm is prepared. The base material 2 is subjected to a pre-treatment of anodizing treatment. Specifically, as a pre-treatment, the base material 2 is first immersed in a sodium hydroxide aqueous solution having a concentration of 5% by mass and a temperature of 55°C to perform an alkali etching treatment. Then, the base material 2 is immersed in nitric acid having a concentration of 30% by mass to perform a decontamination treatment. Then, the base material 2 is immersed in a mixed solution of phosphoric acid and sulfuric acid at a volume ratio of phosphoric acid: sulfuric acid = 7:3 and a temperature of 85°C to perform a chemical polishing treatment. After the chemical polishing treatment, the decontamination treatment is performed again under the same conditions as the above conditions.

[0056] After the base material 2 is pretreated as described above, the base material 2 is anodized to form an anodic oxide film 30 on the surface of the base material 2. The electrolyte used in the anodizing treatment is a sulfuric acid aqueous solution with a concentration of 15% by mass, and the temperature of the electrolyte is set to 5°C. In addition, the current density in the anodizing treatment is set to 10 mA / cm 2 The anodic oxide film 30 thus formed is a so-called porous anodic oxide film. Figure 2 As shown, there is a barrier layer 31 formed on the base material 2, and a porous layer 32 formed on the barrier layer 31 and having a large number of pores 321. The thickness of the anodic oxide film 30 formed by the anodic oxidation treatment under the above conditions is about 15 μm.

[0057] After the anodizing treatment, the base material was immersed in hot water under the conditions shown in Table 1 to perform a sealing treatment. Through the above operations, test materials S1 to S5 shown in Table 1 were obtained. It should be noted that test materials R1 to R3 shown in Table 1 are test materials used for comparison with test materials S1 to S5. The production method of test materials R1 to R3 is the same as the production method of test materials S1 to S5, except that the temperature of the hot water and the immersion time in the sealing treatment were changed as shown in Table 1.

[0058] Next, the evaluation method of each characteristic of the test materials S1 to S5 and the test materials R1 to R3 shown in Table 1 will be described.

[0059] [Distribution of hydrogen and aluminum atoms] After cleaning the surface of each test material, a glow discharge luminescence analyzer (GD750, manufactured by SPECTRUMA Analytik GmbH) was used to measure the luminescence intensity distribution of aluminum and hydrogen atoms along the depth direction of the protective coating. The measurement conditions for the glow discharge luminescence analyzer were an anode diameter of 2.5 mm, an output of 25 W, and a gas pressure of 3.5 hPa. The luminescence intensity was acquired at intervals of 0.2 to 0.24 seconds. The sputtering rate of the protective coating measured under these conditions was approximately 50 to 90 nm / second.

[0060] The distribution of the luminescence intensity of aluminum atoms and hydrogen atoms in the depth direction thus obtained is converted into the distribution of mass ratio based on a pre-made calibration curve. Figure 3 , the distribution of the mass ratio of hydrogen atoms in the test material S1 is shown as an example. Figure 3The vertical axis represents the mass ratio of hydrogen atoms (unit: mass %), and the horizontal axis represents the depth from the surface of the protective film (unit: μm). In the distribution thus obtained, the mass ratio of each atom is integrated from the surface of the protective film to a depth of 1 μm, and the integral value C of the mass ratio of hydrogen atoms is calculated. H and the integral value C of the mass ratio of aluminum atoms Al By making the integral value C of the mass ratio of hydrogen atoms obtained by the above operation H Divide by the integral value C of the mass ratio of aluminum atoms Al , thus calculating the ratio C H / C Al .

[0061] [Sealing degree of protective film] A sealing degree test was performed by the method specified in JIS H8683-2:2013, and the mass reduction per unit area of ​​each test material was measured.

[0062] [Heat resistance] Heat resistance was evaluated based on the base material exposure rate measured using the following method. First, the test material was heated in an oven set at 200°C for 4 hours. After being removed from the oven and cooled to room temperature, an evaluation area was defined on the protective film, and the surface of the test material excluding the evaluation area was covered with silicone resin.

[0063] Next, a 5% by mass NaCl aqueous solution and a 99.7% acetic acid solution were prepared. Acetic acid was added to the NaCl aqueous solution at a volume ratio of 1000:1. This prepared measurement solution was used. The test piece, counter electrode, and reference electrode, all electrically connected to the potentiostat, were immersed in this solution and allowed to stand for 30 minutes to stabilize the potential at the measurement site. For example, an Ag / AgCl electrode can be used as the reference electrode.

[0064] After the potential of the measuring section stabilizes, a voltage is applied between the test piece and the counter electrode using a potentiostat, and the potential of the measuring section is scanned at a scan rate of 20 mV / min until the potential of the measuring section reaches -2000 mV relative to the reference electrode. The polarization curve of the heated test material is obtained by measuring the current density flowing through the measuring section at this time. In addition, the same measurement is performed using a base material that has been pre-treated with anodizing treatment using the above method to obtain a polarization curve for the base material.

[0065] Next, in the polarization curve of the parent material, the center of the potential region representing the diffusion-limiting current of hydrogen is determined. The current density at the center of this potential region is then calculated. Additionally, the current density at the same potential as the center of the aforementioned potential region in the polarization curve of the parent material is calculated in the polarization curve of the heated test material.

[0066] The current density calculated based on the polarization curve of the test material after heating can be used as an indicator of the contact area between the base material and the measuring solution in the test material after heating. The larger the value of the current density, the larger the contact area between the base material and the measuring solution. Therefore, the ratio of the current density calculated using the test piece after heating to the current density calculated using the base material can be used as an indicator of the rate of increase of the exposed area of ​​the base material caused by heating. More specifically, for example, in the case where the protective coating in the test material after heating is formed with defects such as cracks, the base material is sometimes exposed due to the cracks. Therefore, in this case, the current density ratio of the test material after heating relative to the base material becomes larger. The current density ratio of each test material is shown in Table 1.

[0067] [Table 1] As shown in Table 1, the test materials S1 to S5 were sealed in the sealing process so that the product of the hot water temperature and the immersion time was within the above-mentioned specific range. H The integral value C of the mass ratio relative to aluminum atoms Al Ratio C H / C Al Within the specified range. Furthermore, these test materials exhibited low mass loss in the sealing test and exhibited excellent corrosion resistance to corrosive gases, plasma, and the like. Furthermore, these test materials exhibited low current density ratios, suppressing cracking in the protective coating even at elevated temperatures.

[0068] On the other hand, in test materials R1 and R3, the product of the hot water temperature and immersion time during the sealing process exceeded the specified range, causing the hydration reaction between aluminum oxide and the hot water to proceed excessively. Consequently, test materials R1 and R3 had higher current density ratios than test materials S1 to S5, making them more susceptible to cracking at elevated temperatures.

[0069] In test material R2, the product of the hot water temperature and immersion time during the sealing treatment fell below the specified range, resulting in insufficient sealing of the pores in the anodic oxide film. Consequently, test material R2 exhibited a higher mass loss in the sealing degree test than test materials S1 to S5, indicating inferior corrosion resistance.

[0070] The surface-treated aluminum material and the method for manufacturing the same involved in the present invention have been described above based on the embodiments. However, the specific methods of the surface-treated aluminum material and the method for manufacturing the same involved in the present invention are not limited to the methods of the embodiments, and the structure can be appropriately changed within the scope of not damaging the main purpose of the present invention.

Claims

1. A surface-treated aluminum material having: a base material comprising aluminum or an aluminum alloy; and a protective film comprising aluminum oxide and hydrated oxide and formed on at least a portion of the surface of the base material; The thickness of the protective film is greater than 2 μm. When the mass ratio of elements in the protective film is analyzed in the depth direction by glow discharge emission spectrometry, the integral value (C) of the mass ratio of hydrogen atoms in the range from the surface of the protective film to a depth of 1 μm is obtained. H ) relative to the integral value of the mass ratio of aluminum atoms (C Al ) ratio (C H / C Al ) is greater than or equal to 0.2 and less than or equal to 0.

7.

2. The surface-treated aluminum material according to claim 1, wherein: The mass reduction per unit area when the sealing degree test was performed according to the method specified in JIS H8683-2:2013 was 0.2 g / dm 2 the following.

3. A member for semiconductor manufacturing equipment, comprising the surface-treated aluminum material according to claim 1 or 2.

4. A method for producing a surface-treated aluminum material, which is the method for producing a surface-treated aluminum material according to claim 1 or 2, wherein: The method for manufacturing the surface-treated aluminum material comprises: an anodic oxidation step of forming an anodic oxide film having fine pores on the base material by performing an anodic oxidation treatment on the base material; as well as a sealing step of immersing the base material in hot water after the anodizing step to seal the pores of the anodized film, thereby forming the protective film on the base material; The product of the temperature (T) [° C.] of the hot water and the immersion time (t) [hours] in the sealing step is greater than 20° C.·hour and less than 75° C.·hour.

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