Aluminum alloy plate for semiconductor equipment and preparation method thereof

Abstract

The invention discloses an aluminum alloy plate for semiconductor equipment and a preparation method thereof, and relates to the technical field of aluminum alloy plates. Step 1: CNC milling the aluminum alloy; washing with water and drying with nitrogen to obtain an aluminum alloy substrate; Step 2: degreasing the surface of the aluminum alloy substrate, pickling and polishing, washing with water, and drying with nitrogen to obtain a pretreated aluminum alloy substrate; Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution for primary anodization to obtain an aluminum alloy plate A; Step 4: placing the aluminum alloy substrate A in an etching solution for chemical etching, and sequentially transferring to a lithium salt solution and hot water for infiltration treatment to obtain an aluminum alloy plate B; Step 5: placing the aluminum alloy plate B in a sulfuric acid solution for secondary anodization to obtain an aluminum alloy plate C; Step 6: sealing the aluminum alloy plate C with hot water, drying with nitrogen, and standing to obtain an aluminum alloy plate. The prepared aluminum alloy plate has excellent corrosion resistance and thermal cracking resistance.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy plates, in particular to an aluminum alloy plate for semiconductor equipment and a preparation method thereof. Background Art

[0002] With the rapid development of China's semiconductor industry, the demand for chips continues to rise. Among them, semiconductor equipment is one of the indispensable keys in chip manufacturing. Aluminum alloy has the advantages of light weight and good thermal conductivity, and is the most commonly used material for semiconductor equipment.

[0003] At present, the demand for aluminum plates in the semiconductor industry is increasing, and it is of great significance to increase production capacity and achieve green development; and by optimizing CNC milling processing parameters, improving processing efficiency and reducing machine tool energy consumption; promoting the optimal balance of interests such as processing quality, processing efficiency, and energy loss is one of the current research and development directions; on the other hand, due to the high precision of semiconductor equipment and the specificity of the application environment, the pursuit of the surface performance of the aluminum alloy plates used in it is the second current research and development direction. Among them, general semiconductor equipment generally faces corrosive gas or plasma environment, as well as thermal environment during the process; therefore, aluminum alloy plates used in semiconductor equipment are generally treated by anodizing, micro-arc oxidation, etc., to form an oxide layer on its surface to improve its applicability in related environments; however, in the prior art, the oxide layer formed on the surface of the aluminum alloy plate has the following problems: when the surface oxide layer is thin, it will lead to poor surface wear resistance and corrosion resistance, affecting the surface cleanliness during processing; when the surface oxide layer is too thick, although the surface wear resistance is good, there is a problem of increased internal stress, which will increase the tendency to crack and reduce the durability of the surface oxide film.

[0004] In summary, it is of great significance to solve the above problems, prepare an aluminum alloy plate for semiconductor equipment, improve its thermal surface performance, and increase its applicability in semiconductor equipment. Summary of the invention

[0005] The object of the present invention is to provide an aluminum alloy plate material for semiconductor equipment and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for preparing an aluminum alloy plate for semiconductor equipment comprises the following steps:

[0008] Step 1: CNC milling the aluminum alloy, the process parameters include: spindle speed of 25000-30000r / min, feed speed of 8000-10000mm / min, cutting depth of 0.5-1mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0009] Step 2: degreasing, pickling and polishing, washing with water, and drying with nitrogen to obtain a pretreated aluminum alloy substrate;

[0010] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution for anodization to obtain an aluminum alloy plate A;

[0011] Step 4: placing the aluminum alloy substrate A in an etching solution for chemical etching, and then transferring it to a lithium salt solution and hot water for immersion treatment in sequence to obtain an aluminum alloy plate B;

[0012] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution for secondary anodization to obtain an aluminum alloy plate C;

[0013] Step 6: Seal the aluminum alloy plate C with hot water, blow dry with nitrogen, and let it stand to obtain an aluminum alloy plate.

[0014] Among them, in the CNC milling process, the process parameters of spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, and cooling method of oil mist are optimized; the roughness can be guaranteed to be 2-3μm.

[0015] More optimally, in step 2, the specific process is: placing the aluminum alloy substrate in isopropanol, degreasing it at 30-50°C for 20-40 minutes; placing it in a mixed acid solution, chemically polishing it at 70-80°C for 1-3 minutes, washing it with water, and blowing it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution includes the following raw materials: by weight, 16-18 parts of phosphoric acid, 1-1.2 parts of nitric acid, 4-5 parts of deionized water, and 0.4-0.6 parts of copper sulfate.

[0016] More optimally, in step 3, the specific process is: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15-20°C, anodizing it at a voltage of 25-30V for 20-40 minutes, washing it with water, and obtaining an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 40-50g / L oxalic acid, 3-6g / L ammonium heptamolybdate, 10-15g / L glacial acetic acid, and the solvent is deionized water.

[0017] More optimally, in step 4, the specific process is: placing the aluminum alloy substrate A in an etching solution, chemically etching at 50-60°C for 15-30 minutes; transferring to a lithium salt solution at 70-80°C for immersion for 5-6 minutes; transferring to hot water at 90-100°C for immersion for 1-2 minutes; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3-3.5wt% phosphoric acid, 1-1.2wt% chromic acid, 0.8-1wt% glycine, and the rest is deionized water.

[0018] More optimally, the preparation method of the lithium salt solution is: 0.1-0.2 mol / L lithium carbonate solution is adjusted to pH = 12±0.2 using a lithium hydroxide solution with a concentration of 5-6 g / L to obtain a lithium salt solution.

[0019] More optimally, in step 5, the specific process is: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10-20°C, secondary anodizing at a voltage of 10-15V for 40-60 minutes, and washing with water; obtaining the aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 80-100g / L sulfuric acid, 20-30g / L oxalic acid, 10-12g / L zirconium sol, and the solvent is deionized water.

[0020] More optimally, the preparation method of the zirconium sol is: adding zirconium oxychloride and cerium nitrate to a mixed solvent of ethanol and deionized water; adding a mixed solution of triazine derivatives and citric acid, stirring evenly and reacting it in a water bath at 90-95° C. for 72 hours to obtain zirconium sol;

[0021] The zirconium sol comprises the following raw materials: by weight, 20-25 parts of ethanol, 75-80 parts of deionized water, 13.5-13.7 parts of zirconium oxychloride, 3.1-3.2 parts of cerium nitrate, 1.5-2 parts of triazine derivatives, and 9-10 parts of citric acid.

[0022] More optimally, the preparation method of the triazine derivative is as follows: (1) adding caprolactam and sodium hydroxide solution to deionized water in sequence, heating to 95-98°C, stirring for 2-3 hours, keeping warm for 4-5 hours, cooling, and obtaining a hydrolyzed caprolactam solution; (2) adding 2,4,6-trichloro-1,3,5-triazine to acetonitrile; heating to 45-55°C, adding allylglycine, stirring for 20-30 minutes; adding the hydrolyzed caprolactam solution, adjusting the pH to 10±0.5 with sodium hydroxide solution, heating to 90-95°C, reacting at normal pressure for 2-3 hours, cooling; adjusting the pH to 3±0.5 with sulfuric acid solution; filtering, washing with water, and drying to obtain vinyl triazine; (3) adding vinyl triazine, mercapto tetraethylene glycol hydroxyl, and azobisisobutyronitrile to tetrahydrofuran, stirring under ultraviolet light for 2-4 hours, filtering, washing with water, and drying to obtain a triazine derivative;

[0023] In the raw materials for hydrolyzing caprolactam solution, the mass ratio of caprolactam, sodium hydroxide solution and deionized water is 11-12:12-13:180; the mass fraction of the sodium hydroxide solution is 30-35wt%; in the raw materials for vinyl triazine, the molar ratio of 2,4,6-trichloro-1,3,5-triazine, allyl glycine and caprolactam is 1:1:2; in the raw materials for triazine derivatives, the mass ratio of vinyl triazine to mercapto tetraethylene glycol hydroxyl is 6:2-2.5.

[0024] More optimally, in step 6, the specific steps are: sealing the aluminum alloy plate C in hot water at 95-100° C. for 30-60 minutes, drying with nitrogen, and standing for 1-2 days to obtain an aluminum alloy plate.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] (1) This application optimizes milling parameters to balance machining efficiency and machining quality, so that the surface achieves the best surface roughness. The milling in the scheme is high-speed milling. By limiting the spindle speed, feed speed and milling depth, fast and efficient machining efficiency is achieved while producing better surface quality, providing a basis for subsequent surface treatment.

[0027] (2) In the present application, two anodizations are performed, and acid treatment, lithium salt, and hot water treatment are combined between the two anodizations; and zirconium sol is introduced during the secondary anodization process to effectively ensure the surface wear resistance while improving the corrosion resistance and cracking resistance, thereby improving the durability of the aluminum alloy plate and its applicability in semiconductor equipment.

[0028] First, the scheme uses two anodizations, one anodization with low hardness and the second anodization with high hardness (high hardness means higher surface wear resistance), so as to effectively reduce the internal stress of the overall oxide layer, increase toughness, reduce cracking tendency, and improve its crack resistance and corrosion resistance. Among them, the first anodization process is in oxalic acid solution. Since oxalic acid solution is easily oxidized, glacial acetic acid is introduced to reduce the dissolution activity of the original solution; at the same time, the introduction of glacial acetic acid will cause a large number of shallow pits in the film, reduce the hardness of the film, improve the toughness of the inner layer, and reduce stress cracking. At the same time, ammonium heptamolybdate is introduced in the scheme. The introduction of molybdenum element improves corrosion resistance. At the same time, it introduces a reduction in surface aluminum dissolution, improves the growth of the oxide film under oxalic acid, and improves pore regularity. In this way, a more ordered primary anodized film is produced, which provides good interface connectivity for the high-hardness secondary anodized film.

[0029] Among them, the secondary anodization is mainly sulfuric acid, oxalic acid is introduced to form a mixed acid, and the temperature and oxidation time are controlled under a constant voltage to obtain a surface oxide film with good corrosion and crack resistance; at the same time, in order to improve the flatness of the surface film, thereby improving corrosion resistance, wear resistance and crack resistance, zirconium sol is introduced into the anodizing liquid. Zirconium sol is a substance with a thermal expansion coefficient similar to that of metal; it can fill the pores in the anodizing process, reduce surface defects, improve surface flatness, and reduce the internal stress of the film during thermal cracking, inhibit the occurrence of cracks, and improve durability. At the same time, in the preparation process of zirconium sol, triazine-based derivatives are introduced, which can effectively improve the dispersibility of zirconium sol and its adsorption load on the oxide film. Effectively improve corrosion resistance.

[0030] Secondly, the etching solution is introduced between the two anodizations to modify the film produced by the first anodization, which effectively promotes the nucleation of the secondary anodization, improves the orderliness of the secondary anodized film, and improves the overall surface performance. Among them, during the etching process, the solution will verify the vertical etching of the nanopores, reduce the thickness of the primary anodized film, and improve the surface regularity. At the same time, compared with the common etching solution, glycine is also introduced, which is a dual ion substance containing amino and carboxyl groups, which can cooperate to produce honeycomb pores and increase flatness. At the same time, after etching, the metal layered compound is formed in situ before the lithium salt solution, and the corn flake structure is formed by hot water; the infiltration of the two substances improves the surface flatness, and the subsequent secondary anodization is used to order the nucleation, thereby effectively improving the orderliness of the secondary anodized film, improving corrosion resistance and surface wear resistance. It should be noted that the time of lithium salt treatment and hot water treatment needs to be controlled. Too long will produce a lot of precipitation, reduce the surface flatness, which is not conducive to the flatness and orderliness of the secondary anodized film, and reduce the surface performance. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that the following parts are calculated by weight, and there is no special restriction on the purchase manufacturers of all raw materials involved in the present invention, and they are all commercially purchased.

[0033] The preparation method of the triazine derivative is as follows: (1) 11.3 parts of caprolactam and 12.5 parts of 30 wt% sodium hydroxide solution are added to 180 parts of deionized water in sequence, the temperature is raised to 95° C. and stirred for 3 hours, the temperature is kept for 4 hours, and the solution is cooled to obtain a hydrolyzed caprolactam solution; (2) 18.4 parts of 2,4,6-trichloro-1,3,5-triazine are added to 100 parts of acetonitrile; the temperature is raised to 50° C., 15.2 parts of allylglycine are added, and the solution is stirred for 30 minutes; and the mixture is added Hydrolyze caprolactam solution (containing 22.6 parts), adjust pH to 10.4 with sodium hydroxide solution, heat to 95°C and react at normal pressure for 2 hours, and cool; adjust pH to 3.2 with sulfuric acid solution; filter, wash with water, and dry to obtain vinyl triazine; (3) add 18 parts of vinyl triazine, 6.9 parts of mercaptotetraethylene glycol hydroxyl group, and 0.2 parts of azobisisobutyronitrile to tetrahydrofuran, stir under ultraviolet light for 2 hours, filter, wash with water, and dry to obtain a triazine derivative.

[0034] The preparation method of zirconium sol is as follows: 13.7 parts of zirconium oxychloride octahydrate and 3.2 parts of cerium nitrate hexahydrate are added to a mixed solvent of 25 parts of ethanol and 75 parts of deionized water; the mixed solution (containing 1.7 parts of triazine derivatives, 10 parts of citric acid, and 40 parts of deionized water) is added, stirred evenly, and reacted in a water bath at 95°C for 72 hours to obtain zirconium sol.

[0035] Embodiment 1: A method for preparing an aluminum alloy plate for semiconductor equipment, comprising the following steps:

[0036] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0037] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0038] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0039] Step 4: placing the aluminum alloy substrate A in an etching solution, chemically etching at 55°C for 20 minutes; transferring to a lithium salt solution at 75°C for soaking for 5 minutes; transferring to hot water at 95°C for soaking for 1.5 minutes; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3.2wt% phosphoric acid, 1wt% chromic acid, 0.8wt% glycine, and the rest is deionized water; the preparation method of the lithium salt solution is: adjusting the pH of 0.15mol / L lithium carbonate solution to 12.1 using a lithium hydroxide solution with a concentration of 5g / L to obtain a lithium salt solution;

[0040] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 100 g / L sulfuric acid, 25 g / L oxalic acid, 10 g / L zirconium sol, and the solvent is deionized water;

[0041] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0042] Embodiment 2: A method for preparing an aluminum alloy plate for semiconductor equipment, comprising the following steps:

[0043] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0044] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water, and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0045] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0046] Step 4: placing the aluminum alloy substrate A in an etching solution, chemically etching at 55°C for 20 minutes; transferring to a lithium salt solution at 70°C for immersion for 6 minutes; transferring to hot water at 100°C for immersion for 1 minute; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3.5wt% phosphoric acid, 1.2wt% chromic acid, 0.8wt% glycine, and the rest is deionized water; the preparation method of the lithium salt solution is: adjusting the pH of 0.15mol / L lithium carbonate solution to 12.1 using a lithium hydroxide solution with a concentration of 5g / L to obtain a lithium salt solution;

[0047] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 80g / L sulfuric acid, 30g / L oxalic acid, 10g / L zirconium sol, and the solvent is deionized water;

[0048] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0049] Embodiment 3: A method for preparing an aluminum alloy plate for semiconductor equipment, comprising the following steps:

[0050] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0051] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water, and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0052] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0053] Step 4: placing the aluminum alloy substrate A in an etching solution, chemically etching at 55°C for 20 minutes; transferring to a lithium salt solution at 80°C for soaking for 5 minutes; transferring to hot water at 95°C for soaking for 2 minutes; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3wt% phosphoric acid, 1wt% chromic acid, 1wt% glycine, and the rest is deionized water; the preparation method of the lithium salt solution is: adjusting the pH of 0.15mol / L lithium carbonate solution to 12.1 using a lithium hydroxide solution with a concentration of 5g / L to obtain a lithium salt solution;

[0054] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 100 g / L sulfuric acid, 20 g / L oxalic acid, 12 g / L zirconium sol, and the solvent is deionized water;

[0055] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0056] Comparative Example 1: Referring to Example 1, the original step 4 is omitted, and pickling and related treatments are not performed; the specific process is as follows:

[0057] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0058] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water, and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0059] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0060] Step 4: placing the aluminum alloy plate A in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 100 g / L sulfuric acid, 25 g / L oxalic acid, 10 g / L zirconium sol, and the solvent is deionized water;

[0061] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0062] Comparative Example 2: Referring to Example 1, the original step 4 was changed to only pickling; the specific process is as follows:

[0063] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0064] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water, and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0065] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0066] Step 4: placing the aluminum alloy substrate A in an etching solution, chemically etching at 55° C. for 20 minutes; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3.2wt% phosphoric acid, 1wt% chromic acid, 0.8wt% glycine, and the rest is deionized water;

[0067] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 100 g / L sulfuric acid, 25 g / L oxalic acid, 10 g / L zirconium sol, and the solvent is deionized water;

[0068] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0069] Comparative Example 3: Referring to Example 1, the original step 4 was changed and the lithium salt solution treatment time was increased; the specific process is as follows:

[0070] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0071] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water, and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0072] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0073] Step 4: placing the aluminum alloy substrate A in an etching solution, chemically etching at 55°C for 20 minutes; transferring to a lithium salt solution at 75°C for immersion for 30 minutes; transferring to hot water at 95°C for immersion for 1.5 minutes; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3.2wt% phosphoric acid, 1wt% chromic acid, 0.8wt% glycine, and the rest is deionized water; the preparation method of the lithium salt solution is: adjusting the pH of 0.15mol / L lithium carbonate solution to 12.1 using a lithium hydroxide solution with a concentration of 5g / L to obtain a lithium salt solution;

[0074] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 100 g / L sulfuric acid, 25 g / L oxalic acid, 10 g / L zirconium sol, and the solvent is deionized water;

[0075] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0076] Comparative Example 4: Referring to Example 1, without introducing zirconium sol, the specific process is as follows:

[0077] Step 1: CNC milling of 6061 aluminum alloy, process parameters include: spindle speed of 30000r / min, feed speed of 8000mm / min, cutting depth of 0.75mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate;

[0078] Step 2: placing the aluminum alloy substrate in isopropanol and degreasing it at 40°C for 30 minutes; placing it in a mixed acid solution and chemically polishing it at 70°C for 2 minutes, washing it with water, and drying it with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution comprises the following raw materials: by weight, 17 parts of phosphoric acid, 1 part of nitric acid, 5 parts of deionized water, and 0.5 parts of copper sulfate;

[0079] Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15° C., anodizing for 30 minutes at a voltage of 30 V, and washing with water to obtain an aluminum alloy plate A; the oxalic acid solution is composed of the following raw materials: 45 g / L oxalic acid, 4 g / L ammonium heptamolybdate, 12 g / L glacial acetic acid, and the solvent is deionized water;

[0080] Step 4: placing the aluminum alloy substrate A in an etching solution, chemically etching at 55°C for 20 minutes; transferring to a lithium salt solution at 75°C for soaking for 5 minutes; transferring to hot water at 95°C for soaking for 1.5 minutes; washing with water to obtain an aluminum alloy plate B; the etching solution is composed of the following raw materials: 3.2wt% phosphoric acid, 1wt% chromic acid, 0.8wt% glycine, and the rest is deionized water; the preparation method of the lithium salt solution is: adjusting the pH of 0.15mol / L lithium carbonate solution to 12.1 using a lithium hydroxide solution with a concentration of 5g / L to obtain a lithium salt solution;

[0081] Step 5: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10°C, performing secondary anodization at a voltage of 15V for 60 minutes, and washing with water; obtaining an aluminum alloy plate C; the sulfuric acid solution is composed of the following raw materials: 110g / L sulfuric acid, 25g / L oxalic acid, and the solvent is deionized water;

[0082] Step 6: The aluminum alloy plate C is sealed in hot water at 100° C. for 60 minutes, dried with nitrogen, and allowed to stand for 1 day to obtain an aluminum alloy plate.

[0083] Comparative Example 5: Referring to Example 1, vinyl triazine is used in the zirconium sol to replace the triazine derivative, the difference is:

[0084] The preparation method of zirconium sol is as follows: 13.7 parts of zirconium oxychloride octahydrate and 3.2 parts of cerium nitrate hexahydrate are added to a mixed solvent of 25 parts of ethanol and 75 parts of deionized water; the mixed solution (containing 1.7 parts of vinyl triazine, 10 parts of citric acid, and 40 parts of deionized water) is added, stirred evenly, and reacted in a water bath at 95°C for 72 hours to obtain zirconium sol.

[0085] Performance test: The aluminum alloy plates prepared in the examples and comparative examples were subjected to relevant performance tests; (1) Using a silicon nitride ceramic ball with a load of 980g as the medium and a wear radius of 2mm, the sample was worn for 30 minutes and the wear rate was calculated; (2) Using 5wt% hydrochloric acid as the corrosion resistance test matrix, the sample was subjected to a hydrochloric acid bubble corrosion resistance test, and the time was recorded based on the appearance of >3 bubbles at the same point as the corrosion resistance evaluation standard. (3) The sample was first kept warm for 30 minutes in a 150℃ blast drying oven, and then "heated to 200℃ at 5℃ / min, kept warm for 5 minutes, cooled to 150℃, and kept warm for 15 minutes" as a cycle, and the cycle was repeated 100 times; the sample was placed in a dark place and illuminated with a flashlight at an angle of 45℃ to observe whether cracks appeared on the surface. A+~A- corresponds to level 3, which is basically free of cracks; B+~B- corresponds to level 3, which is a few cracks; C+~C- corresponds to level 3, which is obvious cracks. The obtained data are shown in the following table:

[0086] sample <![CDATA[Wear rate mm 3 / N / m]]> Corrosion resistance min Thermal crack resistance grade Example 1 <![CDATA[9.63×10 -6 ]]> 687 A- Comparative Example 1 <![CDATA[1.03×10 -5 ]]> 588 B- Comparative Example 2 <![CDATA[9.79×10 -6 ]]> 622 B Comparative Example 3 <![CDATA[1.09×10 -5 ]]> 636 B Comparative Example 4 <![CDATA[1.132×10 -5 ]]> 637 B+ Comparative Example 5 <![CDATA[9.95×10 -6 ]]> 649 A-

[0087] Conclusion: The present application optimizes the anodizing process, prepares aluminum alloy plates by two anodizing steps and limited chemical etching, lithium salt treatment, and hot water treatment between the steps; thus, the corrosion resistance and thermal cracking resistance are effectively improved on the basis of ensuring high wear resistance. In addition, it can be seen from the data in the above table that the steps between the two anodizing steps are omitted in Comparative Example 1, only pickling treatment is performed between the two anodizing steps in Comparative Example 2, and the lithium salt treatment time between the two anodizing steps in Comparative Example 3 is increased, which have different effects on the relevant properties, indicating the specificity of the intermediate step process. For Example 4 in which zirconium sol is not introduced, and for Example 5 in which the relevant substances in the zirconium sol are adjusted, the performance changes due to the influence of zirconium sol on the adsorption flatness of the pores.

[0088] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an aluminum alloy sheet for semiconductor equipment, characterized in that: The following steps are involved: Step 1: CNC milling the aluminum alloy, the process parameters include: spindle speed of 25000-30000r / min, feed speed of 8000-10000mm / min, cutting depth of 0.5-1mm, cooling method of oil mist; water washing and nitrogen drying to obtain an aluminum alloy substrate; Step 2: degreasing, pickling and polishing, washing with water, and drying with nitrogen to obtain a pretreated aluminum alloy substrate; Step 3: placing the pretreated aluminum alloy substrate in an oxalic acid solution for anodization to obtain an aluminum alloy plate A; Step 4: placing the aluminum alloy substrate A in an etching solution for chemical etching, and then transferring it to a lithium salt solution and hot water for immersion treatment in sequence to obtain an aluminum alloy plate B; Step 5: placing the aluminum alloy plate B in a sulfuric acid solution for secondary anodization to obtain an aluminum alloy plate C; Step 6: Seal the aluminum alloy plate C with hot water, blow dry with nitrogen, and let it stand to obtain an aluminum alloy plate.

2. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 1, characterized in that: In step 2, the specific process is: placing the aluminum alloy substrate in isopropanol, degreasing at 30-50°C for 20-40 minutes; placing it in a mixed acid solution, chemically polishing at 70-80°C for 1-3 minutes, washing with water, and drying with nitrogen to obtain a pretreated aluminum alloy substrate; the mixed acid solution includes the following raw materials: by weight, 16-18 parts of phosphoric acid, 1-1.2 parts of nitric acid, 4-5 parts of deionized water, and 0.4-0.6 parts of copper sulfate.

3. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 1, characterized in that: In step 3, the specific process is: placing the pretreated aluminum alloy substrate in an oxalic acid solution, setting the temperature to 15-20° C., anodizing for 20-40 minutes at a voltage of 25-30 V, and washing with water to obtain an aluminum alloy plate A; The oxalic acid solution is composed of the following raw materials: 40-50 g / L of oxalic acid, 3-6 g / L of ammonium heptamolybdate, and 10-15 g / L of glacial acetic acid, and the solvent is deionized water.

4. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 1, characterized in that: In step 4, the specific process is: placing the aluminum alloy substrate A in an etching solution, chemically etching at 50-60° C. for 15-30 minutes; transferring to a lithium salt solution at 70-80° C. for soaking for 5-6 minutes; transferring to hot water at 90-100° C. for soaking for 1-2 minutes; Washing with water to obtain an aluminum alloy plate B; The etching solution is composed of the following raw materials: 3-3.5 wt% phosphoric acid, 1-1.2 wt% chromic acid, 0.8-1 wt% glycine, and the rest is deionized water.

5. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 4, characterized in that: The preparation method of the lithium salt solution is as follows: 0.1-0.2 mol / L lithium carbonate solution is adjusted to pH=12±0.2 using a lithium hydroxide solution with a concentration of 5-6 g / L to obtain a lithium salt solution.

6. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 1, characterized in that: In step 5, the specific process is: placing the aluminum alloy plate B in a sulfuric acid solution, setting the temperature to 10-20° C., secondary anodizing at a voltage of 10-15 V for 40-60 minutes, and washing with water; Obtaining an aluminum alloy plate C; The sulfuric acid solution is composed of the following raw materials: 80-100 g / L sulfuric acid, 20-30 g / L oxalic acid, 10-12 g / L zirconium sol, and the solvent is deionized water.

7. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 6, characterized in that: The preparation method of the zirconium sol is as follows: adding zirconium oxychloride and cerium nitrate to a mixed solvent of ethanol and deionized water; adding a mixed solution of triazine derivatives and citric acid, stirring evenly and reacting the mixture in a water bath at 90-95° C. for 72 hours to obtain the zirconium sol; The zirconium sol comprises the following raw materials: by weight, 20-25 parts of ethanol, 75-80 parts of deionized water, 13.5-13.7 parts of zirconium oxychloride, 3.1-3.2 parts of cerium nitrate, 1.5-2 parts of triazine derivatives, and 9-10 parts of citric acid.

8. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 7, characterized in that: The preparation method of the triazine derivative is as follows: (1) adding caprolactam and sodium hydroxide solution to deionized water in sequence, heating to 95-98°C, stirring for 2-3 hours, keeping the temperature for 4-5 hours, cooling, and obtaining a hydrolyzed caprolactam solution; (2) adding 2,4,6-trichloro-1,3,5-triazine to acetonitrile; heating to 45-55°C, adding allylglycine, stirring for 20-30 minutes; adding the hydrolyzed caprolactam solution, adjusting the pH to 10±0.5 with sodium hydroxide solution, heating to 90-95°C, reacting at normal pressure for 2-3 hours, cooling; adjusting the pH to 3±0.5 with sulfuric acid solution; filtering, washing with water, and drying to obtain vinyl triazine; (3) adding vinyl triazine, mercapto tetraethylene glycol hydroxyl, and azobisisobutyronitrile to tetrahydrofuran, stirring for 2-4 hours under ultraviolet light, filtering, washing with water, and drying to obtain a triazine derivative.

9. The method for preparing an aluminum alloy sheet for semiconductor equipment according to claim 7, characterized in that: In step 6, the specific steps are: sealing the aluminum alloy plate C in hot water at 95 to 100° C. for 30 to 60 minutes, drying with nitrogen, and standing for 1 to 2 days to obtain an aluminum alloy plate.

10. An aluminum alloy sheet prepared according to the method for preparing an aluminum alloy sheet for semiconductor equipment according to any one of claims 1 to 9.