Method for preparing and purifying high-purity tris (dimethylamino) silane

Abstract

The invention discloses a preparation and purification method of high-purity tris (dimethylamino) silane. The preparation and purification method comprises the steps of reactive distillation, crude product separation, product purification, desolvation recovery and neutralization recovery. Through aprotic solvent solubility and hydrodynamic design, the problem of blockage is radically solved; the T3 tower high vacuum is adopted to guarantee the purity of a thermosensitive substance, and the T4 high vacuum is adopted to realize near zero loss of a solvent; by adopting triple material circulation, the raw material utilization rate is greater than or equal to 98%, the solvent recovery rate is greater than or equal to 99.8%, and the industrial cost can be reduced by 32%.

Description

Technical Field

[0001] This invention belongs to the field of silicon-based precursor technology, specifically relating to a method for preparing and purifying high-purity tris(dimethylamino)silane. Background Technology

[0002] With the rapid development of the semiconductor and integrated circuit industries, the demand for high dielectric constant K materials in atomic layer deposition (ALD) processes is increasing. Tris(dimethylamino)silane (3DMAS), as an important silicon precursor, has become a core raw material for depositing silica thin films due to its high reactivity, excellent vapor pressure, and thermal stability. The reaction of chlorosilanes with amines is the most common method for preparing amino-substituted silanes. The amine itself or the added bases such as Et3N and Py can be used as absorbers for the HX released during the reaction. The steric hindrance of the substituents on the amine and silicon has a significant impact on the ease of the reaction and the product distribution. Halogen atoms on polyhalosilanes can be successively replaced by amine groups to generate polyamine-substituted silanes. A typical route for the synthesis and purification of tris(dimethylamino)silanes uses stoichiometric trichlorosilane and excess dimethylamine as raw materials, benzene or n-hexane as solvent, and dimethylamine hydrochloride as a byproduct. The target product is then purified by distillation: SiHCl3 + 6(CH3)2NH → SiH((CH3)2N)3 + 3(CH3)2NH·HCl. However, existing preparation and purification processes generally suffer from the following technical bottlenecks:

[0003] (1) The core challenge of reaction control

[0004] In existing technologies, the stringent requirements of low-temperature reaction conditions are particularly prominent. Traditional processes require reactions to be carried out at extremely low temperatures of -78°C to achieve the reaction between trichlorosilane and dimethylamine. This low-temperature environment not only significantly increases energy consumption costs but also makes temperature control extremely difficult due to the highly exothermic nature of the reaction, easily leading to localized overheating, which in turn triggers side reactions and reduces product selectivity and yield. Another technical approach uses metal reducing agents (such as magnesium powder), which raises the reaction temperature to 5–85°C, but faces the risk of hydrogen generation (Mg + 2HCl → MgCl2 + H2), posing serious safety hazards. In addition, the dimethylamine hydrochloride byproduct generated in batch reactor reactions is prone to crystallization and deposition in reactor walls and pipelines, causing equipment blockage and making it difficult to exceed 50 hours in production cycle, becoming a major obstacle to continuous production.

[0005] (2) Purification difficulties and impurity control

[0006] Electronic-grade aminosilane precursors require extremely high purity (≥99.999%), especially controlling metal ion impurities (Na⁺, Fe²⁺, etc.) and residual chloride ions. Semiconductor processes require metal impurity content to be below 10 ppb, otherwise it will significantly affect the electrical performance of the gate dielectric. However, traditional distillation techniques are inefficient at separating impurities with similar boiling points (such as BCl3 and tris(dimethylamino)silane, with a boiling point difference <5°C), achieving only 99.95% purity. To improve purity, existing technologies employ adsorbents (such as molecular sieves) or chemical treatments (such as metal complexing agents), but these methods have significant limitations: molecular sieves need frequent replacement, increasing operating costs; and complexing agents may introduce new impurities or cause product decomposition. Of particular note is the problem of ammonium chloride byproduct deposition in exhaust pipes, which not only causes equipment corrosion but also leads to wafer contamination and pump damage, severely impacting the yield of semiconductor devices.

[0007] (3) Solvent management and recycling

[0008] Traditional aminosilane synthesis processes rely on large amounts of organic solvents (such as toluene and n-hexane). These solvents require rigorous dehydration and deoxygenation treatment (sodium wire drying) before use, and subsequent recovery is difficult. The solvent loss rate of traditional batch processes is as high as 15%, increasing production costs and generating large amounts of chlorinated organic wastewater, with treatment costs reaching up to 30% of the total cost. Furthermore, to neutralize the HCl produced in the reaction, current technologies require excessive use of amine feedstocks (dimethylamine consumption reaches 4-6 times the theoretical value). Although some amines can be recovered through distillation, the recovery rate is usually less than 80%, resulting in low feedstock utilization. This high-consumption, high-emission production model not only violates the principles of green chemistry but also significantly weakens the product's market competitiveness. Summary of the Invention

[0009] This invention addresses the shortcomings of existing technologies by providing an efficient, safe, green, and continuously industrially scalable method for the preparation and purification of high-purity tris(dimethylamino)silane. This method solves the problems of low raw material conversion rate, low product yield, and high solvent loss, and meets the high-quality requirements of integrated circuits for tris(dimethylamino)silane.

[0010] To achieve the above objectives, the present invention provides a method for preparing and purifying high-purity tris(dimethylamino)silane, comprising the following steps:

[0011] Reactive distillation

[0012] Dimethylamine feedstock F1 and aprotic amine solvent additive S are mixed in mixer M1 and then fed together with trichlorosilane feedstock F2 into reactive distillation column T1 to react and obtain the top synthesis liquid stream and the bottom synthesis liquid stream, respectively.

[0013] Product Classification

[0014] The top synthesis liquid stream obtained from the top of the reactive distillation column T1 is fed into the coarsening column T2 for coarsening to obtain a top coarse liquid stream and a bottom coarse liquid stream. The top coarse liquid stream obtained from the top of the coarsening column T2 is recycled back to the dimethylamine feedstock F1 and mixed together.

[0015] Product purification

[0016] The bottom coarse liquid stream obtained from the bottom of the coarse separation tower T2 is passed into the purification tower T3 for purification to obtain the top purified liquid stream and the bottom purified liquid stream respectively. The top purified liquid stream obtained from the top of the purification tower T3 is collected to obtain the high-purity tris(dimethylamino)silane product P1.

[0017] Desolvent Recycling

[0018] The bottom synthesis liquid stream obtained from the bottom of the reactive distillation column T1 and the bottom purified liquid stream obtained from the bottom of the purification column T3 are fed together into the desolventizing column T4 for desolventizing to obtain the top solution stream and the bottom desolventizing solution stream respectively. The top desolventizing solution stream obtained from the top of the desolventizing column T4 is recycled back to the solvent auxiliary material S and mixed together.

[0019] Neutralization and Recycling

[0020] The bottom desolventized liquid stream obtained from the bottom of the desolventizing tower T4 is fed together with liquid alkali auxiliary material A into the neutralization tower T5 for neutralization, thereby obtaining a top neutralized liquid stream and a bottom neutralized liquid stream. The top neutralized liquid stream obtained from the top of the neutralization tower T5 is recycled back to the dimethylamine raw material F1 for mixing. The bottom neutralized liquid stream obtained from the bottom of the neutralization tower T5 is fed into the centrifuge X1 and collected to obtain sodium chloride by-product salt P2.

[0021] This invention employs a reaction-separation coupling anti-clogging mechanism: namely, by leveraging the solubility of aprotic solvents and fluid dynamics design, it fundamentally solves the clogging problem; it adopts a vacuum distillation synergistic system: namely, the high vacuum (-95kPaG) of the T3 column ensures the purity of the thermosensitive material, and the high vacuum (-98kPaG) of the T4 column achieves near-zero solvent loss; it adopts a resource full-cycle model: namely, the triple material cycle enables the raw material utilization rate to be ≥98%, the solvent recovery rate to be ≥99.8%, and the industrialization cost can be reduced by 32%.

[0022] Furthermore, in the reactive distillation process, the aprotic amine solvent additive S is one or more of N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, or hexamethylphosphoric triamine.

[0023] Furthermore, in the reactive distillation process, the mass ratio of dimethylamine feedstock F1 to aprotic amine solvent additive S is 1:(1-3).

[0024] Furthermore, in the reactive distillation process, the molar ratio of trichlorosilane feedstock F2 to dimethylamine feedstock F1 is 1:(3-5).

[0025] Furthermore, the operating pressure at the top of the reactive distillation column T1 is 10–50 kPaG, the operating temperature at the top is 90–150°C, the reflux ratio is 3–5, and the number of theoretical plates is 30–50.

[0026] Furthermore, the operating pressure at the top of the coarse separator T2 is 50–150 kPaG, the operating temperature at the top is 20–30°C, the reflux ratio is 1–3, and the number of theoretical plates is 10–30.

[0027] Furthermore, the purification tower T3 has an operating pressure of -95 to -85 kPaG at the top, an operating temperature of 60 to 90°C at the top, a reflux ratio of 10 to 20, and a theoretical plate number of 40 to 60.

[0028] Furthermore, the T4 desolventizing tower has an operating pressure of -98 to -90 kPaG, an operating temperature of 100 to 130°C, a reflux ratio of 0.5 to 1.5, and a theoretical plate number of 20 to 30.

[0029] Furthermore, the neutralization tower T5 has an operating pressure of 50–150 kPaG at the top, an operating temperature of 20–30°C at the top, a reflux ratio of 1.5–3.5, and a theoretical number of trays of 10–20.

[0030] The principle of this invention is as follows:

[0031] 1) Mechanism of reaction anti-blocking and conversion rate improvement

[0032] Using a nonprotic amine solvent (NMP / DMAC), the solubility of dimethylamine hydrochloride reaches 25 g / 100 g. Combined with the turbulent shear force generated by the high Reynolds number flow field (Re>5000) in column T1, salt crystallization is completely suppressed. Low-pressure operation of the distillation column (10–50 kPaG) lowers the boiling point to 90–150 °C and shortens the residence time to <15 min (compared to >60 min in traditional batch distillation), reducing side reactions by approximately 80%.

[0033] 2) High purity guarantee mechanism

[0034] The high vacuum (-95~-85kPaG) of the T3 column lowers the boiling point of 3DMAS to below 80℃, avoiding thermal decomposition (activation energy >120kJ / mol); the high reflux ratio (10-20) and multiple trays (40-60) work together to achieve impurity separation with a boiling point difference of only 3℃ (BCl3 separation factor α>5.2).

[0035] 3) The principle of multi-cycle coordination and synergy

[0036] The top circulation of the coarse fractionation tower T2 reduces F1 consumption, resulting in a total dimethylamine utilization rate of ≥98% (compared to 80% in the traditional process); the top circulation of the desolventizing tower T4 can recover ≥99% of solvent S, reducing solvent loss to ≤5%; the top circulation of the neutralization tower T5 can reuse the released free dimethylamine (99.2% purity), achieving a complete closed loop of amine resources.

[0037] The key process parameters and the principle of synergistic effect are as follows:

[0038]

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1) High product purity: The continuous production process of reactive distillation is adopted to ensure that the reaction is complete and efficient. Combined with multi-stage distillation and purification units, impurities and by-products are effectively removed, and finally high-purity tris(dimethylamino)silane products are obtained, which meet the strict purity requirements of integrated circuit materials.

[0041] 2) High production efficiency: The continuous production process using a nonprotic amine that is highly soluble in dimethylamine hydrochloride as a solvent avoids the equipment blockage and frequent start-up and shutdown problems of the traditional batch process, significantly shortens the production cycle, improves equipment utilization, and is suitable for large-scale industrial production.

[0042] 3) High raw material conversion rate: Through multi-stage recovery and recycling (such as dimethylamine and solvent recycling), the utilization rate of raw materials is maximized, solvent loss is effectively reduced, production costs are reduced, and resource waste is reduced.

[0043] 4) Good environmental performance: The residual liquid is treated by neutralization tower and centrifuge, and the waste is converted into recyclable by-products (such as sodium chloride), reducing waste emissions, reducing environmental pollution, and achieving green production.

[0044] 5) Strong industrial adaptability: The operating parameters of each distillation column (such as pressure, temperature, reflux ratio, etc.) have been optimized to adapt to the production needs of different scales, and have good industrial adaptability and scalability.

[0045] 6) High safety: Avoids the use of flammable organic lithium reagents, reducing operational risks. Simultaneously, continuous production reduces the residence time of materials within the equipment, lowering safety risks caused by material accumulation.

[0046] 7) Significant economic benefits: By improving raw material conversion rate, reducing solvent loss and waste disposal costs, production costs are significantly reduced, economic benefits are improved, and market competitiveness is enhanced.

[0047] In summary, the method of the present invention has significant advantages in improving product quality, reducing production costs, enhancing production safety, and reducing environmental pollution, and has broad potential for industrial mass production. Attached Figure Description

[0048] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] Combination Figure 1 The specific process is as follows:

[0052] Reactive distillation

[0053] Dimethylamine feedstock F1 (99.9% purity) and N,N-dimethylacetamide (i.e., solvent excipient S, 99.9% purity) are uniformly mixed in a mass ratio of 1:2 through mixer M1. Then, the mixture is fed together with trichlorosilane feedstock F2 (molar ratio F2:F1=1:4) with a purity of 99.9% into the reaction section of reactive distillation column T1 for a substitution reaction. The operating parameters of reactive distillation column T1 are: top pressure 30 kPaG, top temperature 120℃, reflux ratio 4, and theoretical plate number 40. At the top of reactive distillation column T1, a synthesis liquid rich in tris(dimethylamino)silane product, unreacted dimethylamine feedstock, and a small amount of solvent excipient S is collected. At the bottom of the column, a synthesis liquid rich in dimethylamine hydrochloride byproduct and solvent excipient S is discharged.

[0054] Product Classification

[0055] The synthesis liquid obtained from the top of the reactive distillation column T1 is fed into the coarse separation column T2 for coarse separation. The operating parameters of the coarse separation column T2 are: top pressure 100 kPaG, top temperature 25℃, reflux ratio 2, and theoretical plate number 20. The coarse separation liquid with qualified dimethylamine feedstock collected from the top of the coarse separation column T2 is recycled back to the dimethylamine feedstock F1 and mixed together in the mixer M1. The coarse separation liquid rich in tris(dimethylamino)silane product and a small amount of solvent excipient S is discharged from the bottom of the column.

[0056] Product purification

[0057] The crude fraction obtained from the bottom of the coarse fractionation column T2, rich in tris(dimethylamino)silane and containing a small amount of solvent excipient S, is passed into the purification column T3 for purification. The operating parameters of the purification column T3 are: top pressure -90 kPaG, top temperature 80℃, reflux ratio 15, and theoretical plate number 50. The purified liquid of high-purity tris(dimethylamino)silane product P1 with a purity of 99.998% and a yield of 88% is collected from the top of the purification column T3. The concentrated purified liquid containing solvent excipient S is discharged from the bottom of the column.

[0058] Desolvent Recycling

[0059] The synthesis liquid rich in dimethylamine hydrochloride by-product and solvent additive S, obtained from the bottom of reactive distillation column T1, is fed together with the concentrated purified solvent additive S obtained from the bottom of purification column T3 into desolventizing column T4 for desolventizing treatment. The operating parameters of desolventizing column T4 are: top pressure -95 kPaG, top temperature 115℃, reflux ratio 1.0, and theoretical plate number 25. The desolventized solution with qualified solvent additives collected from the top of desolventizing column T4 is recycled back to solvent additive S and mixed together in mixer M1. The desolventized solution rich in dimethylamine hydrochloride by-product and a small amount of solvent additive S is discharged from the bottom of the column.

[0060] Neutralization and Recycling

[0061] The desolvated solution, rich in dimethylamine hydrochloride byproduct and a small amount of solvent additive S, obtained from the bottom of the desolvation tower T4, is fed together with liquid alkali additive A (30% NaOH solution) into the neutralization tower T5 for neutralization treatment. The operating parameters of the neutralization tower T5 are: top pressure 100 kPaG, top temperature 25℃, reflux ratio 2.5, and theoretical plate number 15. The neutralized solution of qualified dimethylamine raw material collected from the top of the neutralization tower T5 is recycled back to the dimethylamine raw material F1 and mixed together in the mixer M1. The neutralized solution rich in sodium chloride, discharged from the bottom of the tower, is fed into the centrifuge X1 to collect sodium chloride byproduct salt P2 (purity 99.5%).

[0062] The boundary parameter verification results are as follows: when the pressure of column T3 is > -85 kPaG, the top temperature of the column is > 95℃, and the BCl3 impurity in the product reaches 52 ppb (SEMI standard limit of 5 ppb); when a vacuum of -90 kPaG is used, the BCl3 content drops to 5 ppb (ICP-MS detection); when the operating pressure of column T4 is -95 kPaG, the solvent residue is <0.1%, and when the pressure is > -90 kPaG, the residue is >1.2%.

[0063] Example 2

[0064] Reactive distillation

[0065] Dimethylamine feedstock F1 (purity 99.8%) and N-methylpyrrolidone (solvent excipient S, purity 99.9%) were mixed at a mass ratio of 1:1.5, and then fed into reactive distillation column T1 with trichlorosilane feedstock F2 (molar ratio F2:F1=1:3). The column top pressure was 20 kPaG, the column top temperature was 100℃, the reflux ratio was 3, and the theoretical plate number was 35. The synthesis liquid collected at the top of the column contained the target product and unreacted dimethylamine, and the by-product and solvent mixture was discharged from the bottom of the column.

[0066] Product Classification

[0067] Operating parameters of coarse separator T2: top pressure 80 kPaG, top temperature 22℃, reflux ratio 1.5, theoretical plate number 15; dimethylamine at the top is recycled back to the feed, and the coarse liquid at the bottom contains tris(dimethylamino)silane and a small amount of solvent.

[0068] Product purification

[0069] Purification tower T3 parameters: top pressure -88 kPaG, top temperature 70℃, reflux ratio 12, theoretical plate number 45; the top product P1 has a purity of 99.995% and a yield of 85%, and the bottom solvent concentrate enters the desolventizing tower.

[0070] Desolvent Recycling

[0071] Parameters of the solvent stripping tower T4: top pressure -92 kPaG, top temperature 105℃, reflux ratio 0.8, theoretical plate number 22; the solvent at the top of the tower is recycled, and the by-products at the bottom of the tower enter the neutralization tower.

[0072] Neutralization and Recycling

[0073] Neutralization tower T5 parameters: top pressure 80 kPaG, top temperature 22℃, reflux ratio 2.0, theoretical plate number 12; dimethylamine is circulated at the top of the tower, and sodium chloride by-product salt P2 (purity 96.0%) is obtained after centrifugation at the bottom of the tower.

[0074] Example 3

[0075] Compared with Example 1, Example 3 changed solvent excipient S to hexamethylphosphoric triamine, the mass ratio of dimethylamine to solvent was 1:3, and the molar ratio of trichlorosilane to dimethylamine was 1:5; the reactive distillation column T1 had a top pressure of 40 kPaG, a temperature of 140℃, a reflux ratio of 5, and a theoretical plate number of 45; the purity of product P1 reached 99.997%, the yield was 90%, and the solvent recovery rate was increased to 98%.

[0076] Comparative Example 1 (Traditional batch reactor process)

[0077] The batch process described in Chinese invention patent application CN 103172653A was adopted: trichlorosilane reacts with excess dimethylamine (6 equivalents) in toluene at a reaction temperature of -10°C for 8 hours. Dimethylamine hydrochloride is removed by filtration, and the solvent is recovered by vacuum distillation. The crude product is treated with an adsorbent and then distilled to obtain the final product. Results: Product purity 99.95%, yield 75%, solvent loss 15%, long reaction cycle (12 hours), and frequent equipment blockage.

[0078] Comparative Example 2 (solvent-free cycling)

[0079] The recycling steps in the desolventizing tower T4 and the neutralization tower T5 were omitted, and the waste liquid was directly discharged. The parameters of the reactive distillation tower T1 were the same as in Example 1. The solvent auxiliary material S was used only once and was not recovered. Results: The product purity was 99.996%, but solvent loss increased by 40%, raw material utilization decreased to 70%, and waste liquid treatment costs increased by 3 times.

[0080] Comparative Example 3 (Low reflux ratio operation)

[0081] The reflux ratio of purification column T3 was reduced to 5 (15 in Example 1), while other parameters remained the same as in Example 1. The purity of product P1 decreased to 99.92%, the yield was 80%, and the impurity content increased significantly.

[0082] Effect Comparison

[0083]

[0084] The continuous process of this invention significantly improves product purity and yield, reduces solvent loss and production costs by optimizing solvent selection, operating parameters and circulation system, while avoiding the clogging problem of traditional processes, and has significant advantages in terms of industrial mass production prospects.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing and purifying high-purity tris(dimethylamino)silane, characterized in that, Includes the following steps: Reactive distillation Dimethylamine feedstock F1 and aprotic amine solvent additive S are mixed in mixer M1 and then fed together with trichlorosilane feedstock F2 into reactive distillation column T1 to react and obtain the top synthesis liquid stream and the bottom synthesis liquid stream, respectively. Product Classification The top synthesis liquid stream obtained from the top of the reactive distillation column T1 is fed into the coarsening column T2 for coarsening to obtain a top coarse liquid stream and a bottom coarse liquid stream. The top coarse liquid stream obtained from the top of the coarsening column T2 is recycled back to the dimethylamine feedstock F1 and mixed together. Product purification The bottom coarse liquid stream obtained from the bottom of the coarse separation tower T2 is passed into the purification tower T3 for purification to obtain the top purified liquid stream and the bottom purified liquid stream respectively. The top purified liquid stream obtained from the top of the purification tower T3 is collected to obtain the high-purity tris(dimethylamino)silane product P1. Desolvent Recycling The bottom synthesis liquid stream obtained from the bottom of the reactive distillation column T1 and the bottom purified liquid stream obtained from the bottom of the purification column T3 are fed together into the desolventizing column T4 for desolventizing to obtain the top solution stream and the bottom desolventizing solution stream respectively. The top desolventizing solution stream obtained from the top of the desolventizing column T4 is recycled back to the solvent auxiliary material S and mixed together. Neutralization and Recycling The bottom desolventized liquid stream obtained from the bottom of the desolventizing tower T4 is fed together with liquid alkali auxiliary material A into the neutralization tower T5 for neutralization, thereby obtaining a top neutralized liquid stream and a bottom neutralized liquid stream. The top neutralized liquid stream obtained from the top of the neutralization tower T5 is recycled back to the dimethylamine raw material F1 for mixing. The bottom neutralized liquid stream obtained from the bottom of the neutralization tower T5 is fed into the centrifuge X1 and collected to obtain sodium chloride by-product salt P2.

2. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, In the reactive distillation process, the aprotic amine solvent additive S is one or more of N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, or hexamethylphosphoric triamine.

3. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, In the reactive distillation process, the mass ratio of dimethylamine feedstock F1 to aprotic amine solvent additive S is 1:(1-3).

4. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, In the reactive distillation process, the molar ratio of trichlorosilane feedstock F2 to dimethylamine feedstock F1 is 1:(3-5).

5. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, The reactive distillation column T1 has an operating pressure of 10–50 kPaG at the top, an operating temperature of 90–150°C at the top, a reflux ratio of 3–5, and a theoretical plate number of 30–50.

6. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, The coarse separator T2 has an operating pressure of 50–150 kPaG at the top, an operating temperature of 20–30°C at the top, a reflux ratio of 1–3, and a theoretical plate number of 10–30.

7. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, The purification tower T3 has an operating pressure of -95 to -85 kPaG at the top, an operating temperature of 60 to 90°C at the top, a reflux ratio of 10 to 20, and a theoretical plate number of 40 to 60.

8. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, The T4 desolventizing tower has an operating pressure of -98 to -90 kPaG, an operating temperature of 100 to 130°C, a reflux ratio of 0.5 to 1.5, and a theoretical plate number of 20 to 30.

9. The method for preparing and purifying high-purity tris(dimethylamino)silane according to claim 1, characterized in that, The neutralization tower T5 has an operating pressure of 50–150 kPaG at the top, an operating temperature of 20–30°C at the top, a reflux ratio of 1.5–3.5, and a theoretical plate number of 10–20.

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