A method for preparing electronic grade bis(1-dimethylamino-2-methyl-2-butoxy) copper

Abstract

This invention relates to a method for preparing electronic-grade bis(1-dimethylamino-2-methyl-2-butoxy)copper, comprising the following steps: S1, 1-dimethylamino-2-methyl-2-butanol and a silanizing agent are subjected to a first heating reaction in the presence of an organic solvent, followed by the addition of anhydrous non-halogenated copper carboxylate to the reaction system, and a second heating reaction is carried out. After the reaction is completed, the mixture is cooled, filtered, and the filtrate is collected; S2, the filtrate is subjected to vacuum distillation and short-path distillation sequentially to obtain the bis(1-dimethylamino-2-methyl-2-butoxy)copper. This invention uses anhydrous non-halogenated copper carboxylate and in-situ silanized amino alcohol ligands as reactants to prepare bis(1-dimethylamino-2-methyl-2-butoxy)copper. The operation is simple, easy to purify, and the product yield and purity are high, with a metal purity up to 6N. Furthermore, it exhibits good volatility and low residue, making it suitable as a precursor material for electronic-grade copper.

Description

Technical Field

[0001] This invention relates to the fields of organic chemistry and microelectronic materials technology, specifically to a method for preparing electronic-grade bis(1-dimethylamino-2-methyl-2-butoxy)copper. Background Technology

[0002] Copper-based thin film materials have important applications in semiconductor interconnects, advanced packaging, microelectronic devices, seed layers, and related functional thin film fabrication due to their excellent electrical conductivity, good electromigration resistance, and low cost. With the continuous miniaturization of feature sizes in microelectronic devices, the requirements for thin film deposition technologies are becoming increasingly stringent. Atomic layer deposition (ALD) and chemical vapor deposition (CVD) technologies, with their excellent controllability of film thickness and step coverage capabilities, have become key technologies for preparing high-quality copper thin films. The development of these technologies has placed more stringent requirements on the volatility, thermal stability, residue rate, metal impurity content, and feed stability of copper precursor materials.

[0003] bis(1-dimethylamino-2-methyl-2-butoxy)copper (chemical formula: C 14 H 32 N₂O₂Cu, abbreviated as Cu(dmamb)₂ (CAS No. 872130-16-0), is a class of copper aminoalkoxide complexes. These compounds contain aminoalkoxide ligands, exhibiting good volatility and coordination stability, enabling gas-phase transport at relatively low temperatures. They are also fluorine-free, avoiding fluorine contamination of the deposition chamber and the film. Studies have shown that using Cu(dmamb)₂ as a precursor, self-limiting ALD growth can be achieved under mild conditions of 140-160 °C, resulting in Cu₂O films with excellent conformability and stoichiometry. Furthermore, the reaction of Cu(dmamb)₂ with NH₃ can be used to prepare copper nitride films, which can be further reduced to metallic copper films through annealing, demonstrating promising applications in copper seed layer preparation. Therefore, bis(1-dimethylamino-2-methyl-2-butoxy)copper is a highly valuable copper precursor material for vapor deposition.

[0004] Currently, the preparation methods of copper aminoalkoxide complexes can be mainly classified into two technical routes: one is the direct reaction between copper alkoxides and amino alcohol ligands. In this route, the copper alkoxide raw materials (such as Cu(OEt)2, Cu(OBu)2, etc.) are extremely sensitive to water and oxygen, and the preparation, storage, and feeding processes must be carried out under strict anhydrous and oxygen-free conditions, which has high operational requirements and a narrow process window. The other route uses copper halides (such as CuCl2, CuBr2, etc.) to carry out salt exchange reactions with alkali metal aminoalkoxides (such as lithium, sodium, and potassium aminoalkoxides). However, this route has the following problems: First, the use of copper halide raw materials can easily introduce halogen impurities such as chlorine and bromine into the product. Even if halogen impurities exist in trace amounts, they may corrode the cavity, affect the film quality, and adversely affect the reliability of the device during subsequent CVD / ALD deposition; second, the use of alkali metal aminoalkoxides inevitably introduces alkali metal impurities such as lithium, sodium, and potassium. Alkali metal ions are extremely harmful impurities in semiconductor devices, and even at the part-in-a-billion level, they can seriously affect the insulation performance and electrical reliability of the product. Thirdly, the reaction produces a large number of inorganic salt byproducts (such as LiCl, NaCl, KCl, etc.), which increases the difficulty of filtration and purification, and the post-processing is cumbersome, which is not conducive to the preparation of electronic-grade products.

[0005] For electronic-grade copper precursors, metallic impurities, alkali metal impurities, halogen impurities, volatile residues, and feed stability all directly affect the subsequent thin film deposition process and film quality. For example, metallic impurities (such as Fe, Ni, Cr, etc.) can form deep-level defects in the film, affecting the electrical performance of the device; alkali metal impurities (Li, Na, K, etc.) are prone to migration under the influence of an electric field, leading to threshold voltage drift and decreased reliability of the device; halogen impurities (Cl, Br, etc.) can not only corrode the deposition equipment but also introduce additional carrier scattering centers into the film; excessive volatile residues can clog gas pipelines during deposition, affecting feed stability and shortening the lifespan of the precursor.

[0006] Therefore, there is an urgent need to develop an electronic-grade method for the preparation and purification of bis(1-dimethylamino-2-methyl-2-butoxy) copper, which is different from the copper alkoxide route and the copper halide / alkali metal alkoxide route. This method aims to avoid the risk of introducing halogen and alkali metal impurities at the source, simplify the post-processing, and obtain high-purity, low-residue electronic-grade copper precursor materials suitable for vapor deposition. Summary of the Invention

[0007] To address the technical problems in existing technologies where the preparation of copper aminoalkoxide complexes using copper halides and alkali metal aminoalkoxides easily introduces halogen and alkali metal impurities, and generates a large amount of inorganic salt byproducts leading to purification difficulties, resulting in product purity, volatility, and residue rates that fail to meet the requirements for electronic-grade vapor deposition precursors, this invention provides a method for preparing electronic-grade bis(1-dimethylamino-2-methyl-2-butoxy)copper. This method uses anhydrous non-halogenated copper carboxylate and in-situ silanized amino alcohol ligands as reactants, and bis(1-dimethylamino-2-methyl-2-butoxy)copper can be prepared through ligand transfer-depressurized purification. This preparation process is not only simple to operate and easy to purify, but also yields products with high yield and purity (metal purity reaching 6N), good volatility, and low residue rates, making it suitable for use as an electronic-grade copper precursor material.

[0008] Specifically, the following technical solutions are provided: The first aspect of this invention provides a method for preparing electronic-grade bis(1-dimethylamino-2-methyl-2-butoxy)copper, comprising the following steps: under a protective atmosphere, S1. 1-Dimethylamino-2-methyl-2-butanol is reacted with a silanizing agent under heating in the presence of an organic solvent. Then, anhydrous non-halogenated copper carboxylate is added to the reaction system, followed by a second heating reaction. After the reaction is complete, the mixture is cooled, filtered, and the filtrate is collected. The chemical formula of the anhydrous non-halogenated copper carboxylate is Cu(RCOO)2, where R is selected from C. 1-12 Alkyl (including straight-chain or linear alkyl), C 3-12 One of cycloalkyl or aryl (e.g., phenyl); S2. The filtrate is subjected to vacuum distillation and short-path distillation in sequence to obtain the bis(1-dimethylamino-2-methyl-2-butoxy)copper.

[0009] This invention uses anhydrous non-halogenated copper carboxylates (such as anhydrous copper neopentanoate, anhydrous copper acetate, anhydrous copper isooctanoate, etc.) as the copper source, avoiding the use of copper halides and eliminating halogen impurities at the source. Simultaneously, the 1-dimethylamino-2-methyl-2-butanol ligand is activated through in-situ silanization, i.e., the silanizing reagent reacts with an amino alcohol to generate an O-silyl amino alcohol intermediate. This intermediate undergoes a ligand transfer reaction with the copper carboxylate to generate the target product, bis(1-dimethylamino-2-methyl-2-butoxy)copper. The byproduct is a volatile organosilicon carboxylate, eliminating the need for cumbersome operations such as filtration. The product can be removed by vacuum distillation, thus avoiding the generation of inorganic salt byproducts and the residue of alkali metal impurities in the traditional alkali metal amino alkoxide route. Subsequently, under vacuum conditions, a combination of de-boiling and short-path distillation is carried out to further remove solvents, free ligands and low-boiling byproducts. The target fraction is collected, and the metal purity of the product can reach up to 6N as detected by ICP-MS. Thermogravimetric analysis shows that it has good volatility and low residue rate, which meets the strict requirements of electronic-grade vapor deposition precursors. Moreover, the whole process is simple to operate and easy to scale up, avoiding the dependence of copper alkoxide route on water and oxygen sensitive raw materials.

[0010] Furthermore, the protective atmosphere includes one or more of nitrogen and inert gases (such as argon).

[0011] Further, in step S1, the anhydrous non-halogenated copper carboxylate includes one or more of anhydrous copper neopentanoate, anhydrous copper acetate, and anhydrous copper isooctanoate. For example, the reaction equation for preparing the bis(1-dimethylamino-2-methyl-2-butoxy)copper from anhydrous copper neopentanoate is as follows: .

[0012] Further, in step S1, the molar ratio of 1-dimethylamino-2-methyl-2-butanol to the silanyl group in the silanizing agent is 1:0.9-1.4.

[0013] Further, in step S1, the molar ratio of the anhydrous non-halogenated copper carboxylate to the 1-dimethylamino-2-methyl-2-butanol is preferably 1:(2-3), for example 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, etc., including but not limited to the molar ratios listed above.

[0014] Further, in step S1, the silanizing agent includes one or more of hexamethyldisilazane, N,O-bistrimethylsilylacetamide, and N-trimethylsilylimidazol, such as hexamethyldisilazane, which reacts with 1-dimethylamino-2-methyl-2-butanol to generate O-trimethylsilyl-1-dimethylamino-2-methyl-2-butanol; preferably, the molar ratio of 1-dimethylamino-2-methyl-2-butanol to hexamethyldisilazane is 1:(0.45-0.70), for example, 1:0.52.

[0015] Further, in step S1, the organic solvent is selected from one or more of anhydrous toluene, n-hexane, n-heptane, tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether, and is used to dissolve the reactants and products and promote the reaction.

[0016] Furthermore, in step S1, the temperature of the first heating reaction is 50-80 °C, and the time is 2-8 h.

[0017] Furthermore, in step S1, the temperature of the second heating reaction is 60-100 °C, and the time is 8-20 h.

[0018] Furthermore, step S1 also includes a step of washing the filter cake produced by filtration with an organic solvent, and combining the resulting solutions with the filtrate.

[0019] Further, in step S2, the vacuum distillation step involves a pressure of 2 Torr, a temperature of 80-90°C, and a time of 4 h to remove solvent, excess ligands, and low-boiling byproducts.

[0020] Furthermore, in step S2, the short-path distillation step involves a pressure of 2 Torr, a temperature of 110-120°C, and a time of 2 h. Under these conditions, the fraction of the target product can be collected, and the impurity content can be reduced.

[0021] Furthermore, in step S2, the purity of the bis(1-dimethylamino-2-methyl-2-butoxy)copper is not less than 5N.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for preparing electronic-grade bis(1-dimethylamino-2-methyl-2-butoxy)copper, which differs from the traditional copper halide / alkali metal amino alkoxide route. It uses anhydrous non-halogenated copper carboxylate as the copper source, eliminating halogen impurities at the source. Simultaneously, it activates the amino alcohol ligand through in-situ silanization, avoiding the use of alkali metal amino alkoxides such as lithium, sodium, and potassium, thus eliminating the risk of residual alkali metal impurities. The reaction byproduct is an organosilicon carboxylate, which can be directly removed by vacuum distillation without cumbersome filtration, resulting in simple and efficient post-treatment. Furthermore, the copper carboxylate raw material used is chemically more stable than copper alkoxides, exhibiting lower sensitivity to water and oxygen, and ensuring high safety in the process operation. The combined purification method of vacuum deboiling and short-path distillation results in a simple purification path with mild conditions, facilitating industrial-scale production.

[0023] 2. The bis(1-dimethylamino-2-methyl-2-butoxy)copper prepared by the method provided in this invention achieves a metal purity of 6N (99.9999%) as determined by ICP-MS, effectively controlling metallic impurities such as Fe, Ni, and Cr, as well as alkali metal residues such as Na and K. Furthermore, TGA analysis shows good volatility and extremely low residue levels, allowing for stable feeding under mild conditions and preventing pipeline blockage. The product is free of halogen impurities introduced by the process, meeting the stringent requirements for trace impurities in electronic-grade copper precursors. This provides a reliable high-purity material basis for the preparation of high-performance copper-based thin films using the CVD / ALD method, and plays a positive role in improving the reliability and yield of microelectronic devices. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of bis(1-dimethylamino-2-methyl-2-butoxy)copper.

[0025] Figure 2 The image shows the 1H NMR spectrum of bis(1-dimethylamino-2-methyl-2-butoxy)copper prepared in Example 1.

[0026] Figure 3 The results of ICP-MS analysis of bis(1-dimethylamino-2-methyl-2-butoxy)copper prepared in Example 1 are shown.

[0027] Figure 4 The TGA test curve of bis(1-dimethylamino-2-methyl-2-butoxy)copper prepared in Example 1 is shown. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms “comprising” or “including” used in this invention may also be replaced with the closed form “is” or “consisting of”.

[0030] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the data analysis is performed using conventional statistical analysis methods. Where no specific techniques or conditions are specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Unless otherwise specified, the reagents and materials mentioned can be obtained commercially or prepared by known methods.

[0031] Example 1 This embodiment relates to the preparation of bis(1-dimethylamino-2-methyl-2-butoxy)copper, and the specific operation is as follows: Under nitrogen protection, 0.880 mol of 1-dimethylamino-2-methyl-2-butanol was added to a 2 L reaction flask, followed by 1000 mL of anhydrous toluene. The mixture was stirred to form a homogeneous solution. 0.460 mol of hexamethyldisilazane was then added while stirring. The mixture was heated to 70 °C and maintained at this temperature for 4 h, resulting in the in-situ formation of O-trimethylsilyl-1-dimethylamino-2-methyl-2-butanol.

[0032] Subsequently, under nitrogen protection, anhydrous copper neopentanoate (0.400 mol) was added in portions to the above reaction solution, and the system temperature was controlled at 80 °C. The reaction was stirred for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered under nitrogen protection, and the filter cake was washed with 120 mL of anhydrous toluene. The filtrates were combined.

[0033] The filtrate was transferred to a vacuum distillation apparatus that had been dried and purged with nitrogen. Under stirring, the vacuum was gradually increased to 2 Torr, and the oil bath temperature was controlled at 80-90 °C. Toluene, excess ligands, and trimethylsilyl neopentyl ester byproducts were removed under reduced pressure. The removal of low-boiling substances took 4 h until no obvious low-boiling substances were distilled off, yielding a dark purple crude product.

[0034] The obtained deep purple crude product was transferred to a dried and nitrogen-purged short-path distillation apparatus and distilled under 2 Torr conditions, with the oil bath temperature controlled at 110-120 °C. The deep purple target fraction was collected over approximately 2 hours, yielding a total of 103.7 g of deep purple liquid, which was identified as bis(1-dimethylamino-2-methyl-2-butoxy)copper. The 1H NMR spectrum of the product is shown below. Figure 2As shown, the proton NMR spectrum is affected by the paramagnetism of the copper center, resulting in peak broadening or shifting anomalies. In the figure, the signal appearing at approximately 7.16 ppm in the low-field region is the residual peak of the test solvent (deuterium benzene); the broadened signal appearing in the range of 0.8-3.0 ppm corresponds to the hydrogen signals related to alkyl and dimethylamino groups in the target ligand. The above peak broadening phenomenon is consistent with the NMR characteristics of Cu(II) paramagnetic complexes.

[0035] ICP-OES test results: The theoretical value of Cu content is 19.6%, and the test value is 19.3%, which further demonstrates that the target product bis(1-dimethylamino-2-methyl-2-butoxy)copper was successfully prepared in this embodiment.

[0036] Yield calculation: The molecular weight of bis(1-dimethylamino-2-methyl-2-butoxy)copper is 323.97, and the theoretical yield of 0.400 mol is 129.59 g. The actual product obtained was 103.7 g, with a yield of 80.0%.

[0037] ICP-MS detection results are as follows Figure 3 As shown, the metal purity of the obtained product reaches 6N.

[0038] The product was tested by TGA, and the results are as follows: Figure 4 As shown, it exhibits significant volatilization and weight loss behavior and a low residue rate.

[0039] Example 2 This embodiment relates to the preparation of bis(1-dimethylamino-2-methyl-2-butoxy)copper, and the specific operation is as follows: Under nitrogen protection, 0.880 mol of 1-dimethylamino-2-methyl-2-butanol was added to a 2 L reaction flask, followed by 1000 mL of anhydrous n-heptane. The mixture was stirred to form a homogeneous solution. 0.460 mol of hexamethyldisilazane was then added while stirring. The mixture was heated to 70 °C and maintained at this temperature for 4 h, resulting in the in-situ formation of O-trimethylsilyl-1-dimethylamino-2-methyl-2-butanol.

[0040] Subsequently, under nitrogen protection, anhydrous copper isooctanoate (0.400 mol) was added to the above reaction solution, the temperature was raised to 85°C, and the reaction was stirred for 14 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered under nitrogen protection, and the filter cake was washed with 120 mL of anhydrous n-heptane. The filtrates were combined.

[0041] The vacuum distillation and short-path distillation procedures were the same as in Example 1, and a total of 98.4 g of bis(1-dimethylamino-2-methyl-2-butoxy)copper was collected, with a yield of 75.9%.

[0042] ICP-MS analysis showed that the metal purity of the obtained product reached 5N.

[0043] Example 3 This embodiment relates to the preparation of bis(1-dimethylamino-2-methyl-2-butoxy)copper, and the specific operation is as follows: Under nitrogen protection, 0.880 mol of 1-dimethylamino-2-methyl-2-butanol was added to a 2 L reaction flask, followed by 1000 mL of anhydrous tetrahydrofuran. The mixture was stirred to form a homogeneous solution. 0.460 mol of hexamethyldisilazane was then added while stirring. The mixture was heated to 65 °C and maintained at this temperature for 5 h, resulting in the in-situ formation of O-trimethylsilyl-1-dimethylamino-2-methyl-2-butanol.

[0044] Anhydrous copper acetate (0.400 mol) was then added, the temperature was raised to 75 °C, and the reaction was stirred for 16 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered under nitrogen protection, and the filter cake was washed with 120 mL of anhydrous tetrahydrofuran. The filtrates were combined.

[0045] The vacuum distillation and short-path distillation operations were the same as in Example 1, and a total of 91.2 g of bis(1-dimethylamino-2-methyl-2-butoxy)copper was collected, with a yield of 70.4%.

[0046] ICP-MS analysis showed that the metal purity of the obtained product reached 5N.

[0047] Comparative Example 1 This comparative example relates to the preparation of bis(1-dimethylamino-2-methyl-2-butoxy)copper, and the specific procedures are as follows: Under nitrogen protection, copper methyl methacrylate (Cu(OMe)₂, 0.400 mol) was added to a 2 L reaction flask, followed by 1000 mL of anhydrous toluene. Then, 0.880 mol of 1-dimethylamino-2-methyl-2-butanol was added with stirring. The mixture was heated to 80 °C and stirred for 12 h. After the reaction was complete, the reaction solution was cooled to room temperature, filtered under nitrogen protection, and the filtrate was collected.

[0048] The vacuum distillation and short-path distillation procedures were the same as in Example 1, and a total of 82.4 g of bis(1-dimethylamino-2-methyl-2-butoxy)copper was collected. Based on the amount of copper methoxide fed, the theoretical yield of the target product was 129.59 g, and the actual product obtained was approximately 82.4 g, with a yield of approximately 63.6%.

[0049] ICP-MS analysis showed that the metal purity of the obtained product was approximately 4N.

[0050] Compared to Examples 1-3, Comparative Example 1, which uses copper methoxide as a raw material to prepare bis(1-dimethylamino-2-methyl-2-butoxy)copper, not only has more sensitive raw materials to water and oxygen, but also has higher requirements for preparation and storage, and the resulting product has low yield and low metal purity.

[0051] Comparative Example 2 This comparative example relates to the preparation of bis(1-dimethylamino-2-methyl-2-butoxy)copper, and the specific procedures are as follows: Under nitrogen protection, 0.880 mol of 1-dimethylamino-2-methyl-2-butanol was added to a 2 L reaction flask, followed by 1000 mL of anhydrous tetrahydrofuran. Sodium hydride (0.880 mol, 21.12 g, 100% concentration) was added in portions at 0–10 °C, and the mixture was stirred for 2 h to obtain the corresponding sodium aminoalkoxide reaction solution. Subsequently, 0.400 mol, 53.80 g of anhydrous copper chloride was added, and the mixture was heated to room temperature and stirred for 12 h. After the reaction was complete, the inorganic salts were removed by filtration, and the filtrate was collected.

[0052] The vacuum distillation and short-path distillation procedures were the same as in Example 1, and a total of 74.6 g of bis(1-dimethylamino-2-methyl-2-butoxy)copper was collected. Based on the amount of copper chloride fed, the theoretical yield of the target product was 129.59 g, and the actual product obtained was approximately 74.6 g, with a yield of approximately 57.6%.

[0053] ICP-MS analysis showed that the purity of the obtained metal was approximately 4N.

[0054] Compared to Examples 1-3, Comparative Example 2, which uses sodium aminoalkoxide and copper chloride as raw materials to prepare bis(1-dimethylamino-2-methyl-2-butoxy)copper, generates inorganic salt byproducts such as sodium chloride, making filtration and post-processing more difficult and posing a risk of sodium and chlorine residues. After purification by vacuum distillation and short-path distillation, the metal purity of the collected product was still only about 4N.

[0055] The embodiments described above are merely preferred examples to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A method for preparing electronic-grade bis(1-dimethylamino-2-methyl-2-butoxy)copper, characterized in that, Includes the following steps: Under a protective atmosphere, S1. 1-Dimethylamino-2-methyl-2-butanol is reacted with a silanizing agent in the presence of an organic solvent under heating for the first time. Then, an anhydrous non-halogenated copper carboxylate is added to the reaction system, and a second heating reaction is carried out. After the reaction is completed, the mixture is cooled, filtered, and the filtrate is collected. The anhydrous non-halogenated copper carboxylate includes one or more of anhydrous copper neopentanoate, anhydrous copper acetate, and anhydrous copper isooctanoate. The silanizing agent includes one or more of hexamethyldisilazane, N,O-bis(trimethylsilylacetamide), and N-trimethylsilylimidazole. The molar ratio of 1-dimethylamino-2-methyl-2-butanol to the silanyl group in the silanizing agent is 1:(0.9-1.4); the molar ratio of the anhydrous non-halogenated copper carboxylate to the 1-dimethylamino-2-methyl-2-butanol is 1:(2-3). The first heating reaction is carried out at a temperature of 50-80 ℃ for 2-8 h; the second heating reaction is carried out at a temperature of 60-100 ℃ for 8-20 h. S2. The filtrate is subjected to vacuum distillation and short-path distillation in sequence to obtain bis(1-dimethylamino-2-methyl-2-butoxy)copper.

2. The preparation method according to claim 1, characterized in that, In step S1, the organic solvent is selected from one or more of anhydrous toluene, n-hexane, n-heptane, tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

3. The preparation method according to claim 1, characterized in that, Step S1 also includes washing the filter cake produced by filtration with an organic solvent, and combining the resulting solutions with the filtrate.

4. The preparation method according to claim 1, characterized in that, In step S2, the vacuum distillation process involves a pressure of 2 Torr, a temperature of 80-90°C, and a time of 4 hours.

5. The preparation method according to claim 1, characterized in that, In step S2, the short-path distillation process involves a pressure of 2 Torr, a temperature of 110-120°C, and a time of 2 hours.

6. The preparation method according to claim 1, characterized in that, In step S2, the purity of the bis(1-dimethylamino-2-methyl-2-butoxy)copper is not less than 5N.

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