Synthetic method of metal complex for advanced process

Abstract

The invention discloses a synthesis method of a metal complex for an advanced process, which comprises the following steps: adding dimethylamine, an n-butyllithium solution and n-hexane into a container to form a reaction solution under anhydrous and anaerobic conditions; cooling the reaction liquid to a temperature A, and then adding hafnium tetrachloride into the reaction liquid; stirring the reaction liquid at room temperature, and after the temperature of the reaction liquid is increased to a temperature B, adding 1-methyl-3-propylcyclopent-1, 3-diene into the reaction liquid; and stirring the reaction liquid at room temperature for reaction, after the reaction is completed, removing the solvent under reduced pressure, and removing the solvent under reduced pressure to obtain a finished product of the metal complex. The tetra (dimethylamino) hafnium is directly synthesized in a water-free and oxygen-free low-temperature environment by adopting a one-pot synthesis method, and the method has the advantages of high yield, high purity, high synthesis efficiency, low cost and the like.

Description

Technical Field

[0001] The invention belongs to the field of semiconductors and relates to the synthesis of metal complexes, and in particular to a method for synthesizing metal complexes for advanced processes. Background Art

[0002] Improving the local capacitance of semiconductor devices has always been a strong demand for high-end processes. Since the design of highly integrated chips has encountered a space technology bottleneck by increasing the capacitance of devices by expanding the area or reducing the thickness, it is currently the best solution to improve the intrinsic dielectric constant of the material to achieve this goal. Atomic layer deposition (ALD) is the main deposition technology for atomic-level film preparation and is also one of the necessary means to build capacitor devices in current advanced processes. In order to obtain ideal film properties (such as low impurities, high uniformity, and high quality) using ALD technology, ideal precursor molecules are essential. In high-k (high dielectric constant) dielectrics, IVB group-based materials such as titanium dioxide, hafnium oxide, and zirconium dioxide are very promising. In the past, M(NR2)4 (M=Ti, Hf, Zr) type precursors were used. However, they are not stable enough at high temperatures and have low step coverage.

[0003] Recently, cyclopentadienyl (Cp) precursors have attracted people's attention, especially IVB group Cp precursors, which are suitable for high uniformity and high quality vapor phase film deposition. The main raw material of the existing cyclopentadienyl hafnium precursor is tetrakis (dimethylamino) hafnium, and there are many problems in the actual synthesis process, as follows:

[0004] 1. Low yield. The maximum yield of the existing synthesis method is only 53%, which is difficult to meet market demand;

[0005] 2. The synthesis method is complicated. Since tetrakis(dimethylamino)hafnium has the characteristics of low melting point, easy sublimation, difficult quantification and easy deterioration, multiple steps must be added to eliminate the influence of these characteristics, resulting in numerous steps, complex synthesis methods, high synthesis costs and low synthesis efficiency.

[0006] 3. The synthesis cost is high. Since the raw material of tetrakis(dimethylamino)hafnium is very expensive, the synthesis cost is very high. Summary of the invention

[0007] Purpose of the invention: In order to overcome the deficiencies in the prior art, a method for synthesizing a metal complex containing cyclopentadienyl hafnium for advanced processes is provided, which has many advantages such as high yield, high purity, high synthesis efficiency and low cost.

[0008] Technical solution: To achieve the above-mentioned purpose, the present invention provides a method for synthesizing a metal complex for advanced processes, comprising the following steps:

[0009] S1: under anhydrous and oxygen-free conditions, dimethylamine, n-butyl lithium solution and n-hexane are added into a container to form a reaction solution;

[0010] S2: cooling the reaction solution to temperature A, and then adding hafnium tetrachloride to the reaction solution;

[0011] S3: stirring the reaction solution of step S2 at room temperature, and after the temperature of the reaction solution is raised to temperature B, adding 1-methyl-3-propylcyclopenta-1,3-diene thereto;

[0012] S4: stirring the reaction solution of step S3 at room temperature to react. After the reaction is completed, removing the solvent under reduced pressure, and distilling the solvent under reduced pressure to obtain a finished metal complex.

[0013] Furthermore, in step S1, the input ratio of dimethylamine and n-butyl lithium solution is 1:1.

[0014] Furthermore, the mass concentration of the n-butyllithium solution in step S1 is 22-24%.

[0015] Furthermore, in step S2, the temperature A is -22°C to -18°C.

[0016] Furthermore, in step S3, the stirring time is 0.9 to 1.1 h, and the temperature B is -12°C to -8°C.

[0017] Furthermore, in step S3, the relationship between the amount of 1-methyl-3-propylcyclopenta-1,3-diene added and hafnium tetrachloride, dimethylamine, and n-butyl lithium solution is: hafnium tetrachloride: dimethylamine: n-butyl lithium solution: 1-methyl-3-propylcyclopenta-1,3-diene = 1:4:4:1.2.

[0018] Furthermore, the stirring time in step S4 is 2.5 to 3.5 hours.

[0019] Furthermore, the reaction formula of steps S1 to S4 is expressed as:

[0020]

[0021] The synthesis method of the present invention has the following key points:

[0022] 1. Anhydrous and oxygen-free conditions. All operations involving chemicals in the present invention need to be carried out under anhydrous and oxygen-free conditions. Because n-butyl lithium solution is prone to ignition when exposed to air or moisture. Operations on n-butyl lithium should be carried out after being isolated from water vapor and O2, and safety equipment such as goggles and anti-corrosion gloves should be worn.

[0023] 2. Temperature control. When adding hafnium tetrachloride and 1-methyl-3-propylcyclopenta-1,3-diene dropwise, attention should be paid to temperature control. Temperature control determines whether the synthesis method of the present invention can be successful. If the temperature is too low, the raw materials will not react; if the temperature is too high, the raw materials will decompose, resulting in a low reaction yield.

[0024] 3. Selection of solvent. After many solvent replacement experiments, it was found that n-hexane is the most suitable solvent for this experiment.

[0025] 4. The order of chemical drug reactions. The present invention changes the raw materials of the existing synthesis method, greatly reducing the synthesis cost and successfully improving the yield.

[0026] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0027] 1. The one-pot synthesis method is used to directly synthesize tetrakis(dimethylamino)hafnium in an anhydrous and oxygen-free low-temperature environment, which not only avoids the sublimation and deterioration problems of the tetrakis(dimethylamino)hafnium raw material, but also facilitates the experimental quantitative reaction, thereby simplifying the synthesis process steps, not only improving the synthesis efficiency, but also making the reaction more thorough, thereby improving the yield, and at the same time, avoiding the generation of by-products and improving the product purity.

[0028] 2. The method of synthesizing tetrakis(dimethylamino)hafnium is adopted instead of directly using tetrakis(dimethylamino)hafnium raw material, which greatly reduces the raw material cost and the overall synthesis cost is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the H-NMR spectrum of the product prepared in Example 1. DETAILED DESCRIPTION

[0030] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0031] Embodiment 1:

[0032] This embodiment provides a method for synthesizing a metal complex containing cyclopentadienyl hafnium, comprising the following steps:

[0033] 1) Under anhydrous and oxygen-free conditions, dimethylamine (56.31 g, 1.25 mol), 23% n-butyllithium solution (347.83 g, 1.25 mol) and 2.0 L n-hexane were added to a 3 L three-necked flask to form a reaction solution;

[0034] 2) After the reaction solution was cooled to -20°C, hafnium tetrachloride (100 g, 0.31 mol) was added to the reaction solution;

[0035] 3) The reaction solution was stirred at room temperature for 1 h. After the temperature of the reaction solution was raised to -10°C, 1-methyl-3-propylcyclopenta-1,3-diene (45.79 g, 0.37 mol) was added thereto;

[0036] 4) The reaction solution was stirred at room temperature for 3 hours. After the reaction was completed, the solvent was removed under reduced pressure. The solvent was removed by distillation under reduced pressure to obtain about 88.73 g (yield 65.8%) of a light yellow liquid, which was a metal complex containing cyclopentadienyl hafnium.

[0037] In this example, a nuclear magnetic resonance instrument was used to verify the purity and accuracy of the product, and the following Figure 1 The H-NMR diagram shown is from Figure 1 It can be seen that the product has high purity and high accuracy.

[0038] Embodiment 2:

[0039] This embodiment provides a method for synthesizing a metal complex containing cyclopentadienyl hafnium, comprising the following steps:

[0040] 1) Under anhydrous and oxygen-free conditions, dimethylamine (56.31 g, 1.25 mol), 22% n-butyl lithium solution (363.64 g, 1.25 mol) and 2.0 L n-hexane were added to a 3 L three-necked flask to form a reaction solution;

[0041] 2) After the reaction solution was cooled to -22°C, hafnium tetrachloride (100 g, 0.31 mol) was added to the reaction solution;

[0042] 3) The reaction solution was stirred at room temperature for 0.9 h. After the temperature of the reaction solution was raised to -12°C, 1-methyl-3-propylcyclopenta-1,3-diene (57.23 g, 0.47 mol) was added thereto;

[0043] 4) The reaction solution was stirred at room temperature for 2.5 hours. After the reaction was completed, the solvent was removed under reduced pressure. The solvent was removed by distillation under reduced pressure to obtain about 81.31 g (yield 60.3%) of a light yellow liquid, which was a metal complex containing cyclopentadienyl hafnium.

[0044] In this example, a nuclear magnetic resonance instrument was used to verify the purity and accuracy of the product, and the specific results are as follows:

[0045] Embodiment 3:

[0046] This embodiment provides a method for synthesizing a metal complex containing cyclopentadienyl hafnium, comprising the following steps:

[0047] 1) Under anhydrous and oxygen-free conditions, dimethylamine (56.31 g, 1.25 mol), 24% n-butyl lithium solution (333.33 g, 1.25 mol) and 2.0 L n-hexane were added to a 3 L three-necked flask to form a reaction solution;

[0048] 2) After the reaction solution was cooled to -18°C, hafnium tetrachloride (100 g, 0.31 mol) was added to the reaction solution;

[0049] 3) The reaction solution was stirred at room temperature for 1.1 h. After the temperature of the reaction solution was raised to -8°C, 1-methyl-3-propylcyclopenta-1,3-diene (38.15 g, 0.31 mol) was added thereto;

[0050] 4) The reaction solution was stirred at room temperature for 3.5 hours. After the reaction was completed, the solvent was removed under reduced pressure. The solvent was removed by distillation under reduced pressure to obtain about 88.70 g (yield 65.8%) of a light yellow liquid, which was a metal complex containing cyclopentadienyl hafnium.

[0051] In this example, a nuclear magnetic resonance instrument was used to verify the purity and accuracy of the product, and the specific results are as follows:

[0052] Comparative Example 1:

[0053] In this comparative example, the products obtained by the synthesis methods of Examples 1 to 3 are compared and analyzed with the existing synthesis method directly using tetrakis(dimethylamino)hafnium as a raw material. The specific comparative data are shown in the following table:

[0054]

[0055] It can be seen from the above table that the output, yield and purity of Examples 1 to 3 are all higher than the existing synthesis method directly using tetrakis(dimethylamino)hafnium as a raw material, thereby verifying the effectiveness and practical effect of the method of the present invention.

Claims

1. A method for synthesizing a metal complex for advanced processes, characterized in that: The steps include: S1: under anhydrous and oxygen-free conditions, dimethylamine, n-butyl lithium solution and n-hexane are added into a container to form a reaction solution; S2: cooling the reaction solution to temperature A, and then adding hafnium tetrachloride to the reaction solution; S3: stirring the reaction solution of step S2 at room temperature, and after the temperature of the reaction solution is raised to temperature B, adding 1-methyl-3-propylcyclopenta-1,3-diene thereto; S4: stirring the reaction solution of step S3 at room temperature to react. After the reaction is completed, removing the solvent under reduced pressure, and distilling the solvent under reduced pressure to obtain a finished metal complex.

2. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: In the step S1, the input ratio of dimethylamine and n-butyl lithium solution is 1:

1.

3. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: The mass concentration of the n-butyl lithium solution in step S1 is 22-24%.

4. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: The temperature A in step S2 is -22°C to -18°C.

5. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: In step S3, the stirring time is 0.9 to 1.1 h, and the temperature B is -12°C to -8°C.

6. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: The relationship between the amount of 1-methyl-3-propylcyclopenta-1,3-diene added and hafnium tetrachloride, dimethylamine, and n-butyl lithium solution in step S3 is: hafnium tetrachloride: dimethylamine: n-butyl lithium solution: 1-methyl-3-propylcyclopenta-1,3-diene = 1:4:4:1.

2.

7. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: The stirring time in step S4 is 2.5 to 3.5 hours.

8. The method for synthesizing a metal complex for advanced processes according to claim 1, characterized in that: The reaction formula of steps S1 to S4 is expressed as:

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