Purification method of electronic-grade bis (diethylamino) silane

Abstract

The invention discloses a method for purifying electronic-grade bis (diethylamino) silane, which is characterized in that a bis (diethylamino) silane crude product is treated through rectification-adsorption combination, and some low-boiling-point substances can be removed through reduced-pressure rectification light component removal treatment; a polymer or macromolecular structure formed in the reaction process can be removed through vacuum distillation heavy component removal treatment; however, in the rectification process, phosphorus-containing impurities and metal impurities in a bis (diethylamino) silane crude product cannot be separated from bis (diethylamino) silane all the time, the residual phosphorus-containing impurities and metal impurities in the bis (diethylamino) silane are adsorbed and separated by adopting an adsorption treatment method, so that the electronic-grade bis (diethylamino) silane is obtained, and the purity of the electronic-grade bis (diethylamino) silane is improved. And the product purity can reach 99.99% or above.

Description

Technical Field

[0001] The invention relates to the technical field of bis(diethylamino)silane purification, and in particular to a method for purifying electronic-grade bis(diethylamino)silane. Background Art

[0002] As an important raw material in semiconductor technology, high-purity bis(diethylamino)silane (HDEAS) has been increasingly used in low-temperature atomic layer deposition (ALD) technology in recent years. This material is not only an ideal organic source for the preparation of high-quality silicon oxide, but is also widely used in the preparation of silicon-based high-K thin films, providing strong support for the performance improvement of semiconductor devices.

[0003] The main advantage of high-purity bis(diethylamino)silane is its high volatility, which enables it to achieve self-limiting growth at lower temperatures during the ALD process. The self-limiting growth property means that during the deposition process of the material, as the reactants continue to adsorb and react, the growth rate of the film will gradually slow down and eventually stop, thereby ensuring the uniformity and consistency of the film. This property is crucial in semiconductor manufacturing because it can effectively avoid film defects caused by over-deposition.

[0004] In terms of film composition and properties, high-purity bis(diethylamino)silane can form films with constant composition and stable performance. This is crucial for the manufacture of high-performance semiconductor devices, because the performance of devices often depends on the uniformity and consistency of film materials. The use of HDEAS not only improves the quality of the film, but also reduces the consumption of materials, which is of great significance for reducing production costs and improving production efficiency.

[0005] With the rapid advancement of semiconductor technology, especially in the field of integrated circuits and microelectronic devices, the demand for high-purity bis(diethylamino)silane and other products is increasing. The ALD process has strict control requirements on the metal impurity content of raw materials. Therefore, the use of high-purity bis(diethylamino)silane with a purity of 99.99% can effectively ensure that the conductivity efficiency of the grown material meets the technical requirements. This high purity can not only improve the performance of the device, but also extend its service life and improve overall reliability.

[0006] In order to obtain bis(diethylamino)silane, different synthetic methods can be selected to obtain crude high-purity bis(diethylamino)silane, which is then purified by distillation to obtain a high-purity bis(diethylamino)silane product.

[0007] The purification of bis(diethylamino)silane (BDEAS) used in existing patents and literature technologies mostly uses distillation, and the purity of bis(diethylamino)silane is difficult to exceed 99.99%. Summary of the invention

[0008] In view of the deficiencies of the prior art, the object of the present invention is to provide a method for purifying electronic grade bis(diethylamino)silane.

[0009] In order to achieve the above object, the present invention adopts the following technical scheme:

[0010] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0011] S1. Lightweight treatment

[0012] The crude bis(diethylamino)silane is added to the first distillation tower, and subjected to vacuum distillation to remove light substances, and the product after removal of light substances is drawn out from the bottom of the tower.

[0013] In this step, the pressure of the vacuum distillation is 30-40 mmHg. In some embodiments of the present invention, for example, 30 mmHg, 31 mmHg, 32 mmHg, 33 mmHg, 34 mmHg, 35 mmHg, 36 mmHg, 37 mmHg, 38 mmHg, 39 mmHg, and 40 mmHg can be selected; the temperature of the vacuum distillation is 60-65°C, for example, 60°C, 61°C, 62°C, 63°C, 64°C, and 65°C can be selected; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] S2. Weight removal

[0015] The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy gases, and the product after heavy removal is drawn out from the top of the tower.

[0016] In this step, the pressure of the vacuum distillation is 30-40 mmHg. In some embodiments of the present invention, for example, 30 mmHg, 31 mmHg, 32 mmHg, 33 mmHg, 34 mmHg, 35 mmHg, 36 mmHg, 37 mmHg, 38 mmHg, 39 mmHg, and 40 mmHg can be selected; the temperature of the vacuum distillation is 70-75°C, for example, 70°C, 71°C, 72°C, 73°C, 74°C, and 75°C can be selected, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] S3. Impurity adsorption

[0018] The deweighted product is introduced into an adsorption tank, which is filled with a composite modified adsorbent to adsorb impurities.

[0019] In this step, the preparation method of the composite modified adsorbent is as follows:

[0020] (1) adding a soluble zinc salt and terephthalic acid to an organic solvent, mixing them evenly, then adding activated carbon, dispersing them evenly and heating them for reaction, and after the reaction is completed, filtering, washing and drying to obtain a composite material;

[0021] (2) dispersing the composite material in an ethanol aqueous solution, then adding vinyl trimethoxysilane thereto, stirring for 1-3 hours, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0022] (3) dispersing the vinyl composite material in an organic solvent, then adding 2-vinylpyridine, 4-imidazole acrylic acid and azobisisobutyronitrile thereto, heating and stirring to react, and after the reaction is completed, filtering, washing and drying to obtain a composite modified adsorbent.

[0023] Specifically, in step (1), the mass ratio of soluble zinc salt, terephthalic acid and activated carbon is 5-10:4-8:15-20, for example, 5:4:15, 5:4:20, 5:4:15, 5:6:20, 8:6:15, 8:6:20, 10:8:15, 10:8:20 can be selected, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0024] Specifically, the soluble zinc salt is selected from zinc chloride, zinc nitrate or zinc sulfate.

[0025] Specifically, in step (1), the temperature of the heating reaction is 120-150°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C; the time of the heating reaction is 4-8h, for example, 4h, 5h, 6h, 7h, 8h can be selected, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Specifically, in step (2), the mass ratio of the composite material to vinyltrimethoxysilane is 8-12:1-3, for example, 8:1, 8:2, 8:3, 10:1, 10:2, 10:3, 12:1, 12:2, 12:3 can be selected, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0027] Specifically, in step (3), the mass ratio of the vinyl composite material, 2-vinylpyridine, 4-imidazole acrylic acid and azobisisobutyronitrile is 10-15:4-6:3-5:0.5-1.

[0028] Specifically, in step (3), the temperature of the heating and stirring reaction is 70-90°C, for example, 70°C, 75°C, 80°C, 85°C, 90°C can be selected; the time of the heating and stirring reaction is 3-5h, for example, 3h, 3.5h, 4h, 4.5h, 5h can be selected; but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] S4, purify to obtain electronic grade bis(diethylamino)silane

[0030] The product after adsorption is subjected to rectification and purification treatment, and fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0031] In this step, during the distillation and purification process, the internal pressure of the distillation purifier is 30 mmHg and the fraction collection temperature is 70°C.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention provides a method for purifying electronic-grade bis(diethylamino)silane, which treats crude bis(diethylamino)silane by combined distillation and adsorption, wherein some low-boiling-point substances can be removed by vacuum distillation and light removal treatment; and polymers or macromolecular structures formed during the reaction can be removed by vacuum distillation and heavy removal treatment; however, during the distillation process, phosphorus-containing impurities and metal impurities in the crude bis(diethylamino)silane cannot be separated from the bis(diethylamino)silane. The present invention adopts an adsorption treatment method to adsorb and separate the phosphorus-containing impurities and metal impurities remaining in the bis(diethylamino)silane, thereby obtaining electronic-grade bis(diethylamino)silane, and the product purity can reach more than 99.99%.

[0034] (2) The composite modified adsorbent provided by the present invention uses activated carbon as an adsorption carrier. Activated carbon has a high specific surface area and porosity and is a commonly used adsorption material, but its adsorption performance for phosphorus-containing impurities and metal impurities is poor. The present invention first loads the zinc-based MOF material on the surface of the activated carbon through a heating synthesis method. On the one hand, the specific surface area of ​​the activated carbon is increased, and on the other hand, the zinc-based MOF material has a good adsorption effect on phosphorus-containing impurities, thereby improving the adsorption performance of the activated carbon for phosphorus-containing impurities; then, the composite material is treated with vinyltrimethoxysilane to introduce double bonds on the surface of the composite material, and then 2-vinylpyridine and 4-imidazole acrylic acid are grafted on the composite material through the addition effect of the double bonds, thereby improving the adsorption performance of the adsorbent for phosphorus-containing impurities; at the same time, 4-imidazole acrylic acid contains a carboxyl functional group, which can form a coordination bond with metal impurities, thereby improving the adsorption performance of the adsorbent for metal impurities, thereby improving the purity of bis(diethylamino)silane to reach electronic grade. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0036] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention were purchased through commercial channels.

[0037] The purity of the crude bis(diethylamino)silane used in the present invention is 99.2%; the activated carbon is coconut shell activated carbon with a mesh size of 400 meshes.

[0038] Example 1

[0039] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0040] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 60°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0041] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 70°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0042] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0043] The preparation method of the composite modified adsorbent is as follows:

[0044] (1) 5 g of zinc nitrate and 4 g of terephthalic acid were added to 150 mL of an organic solvent, DMF, and mixed evenly. Then, 15 g of activated carbon was added and dispersed evenly, and then heated at 120° C. for reaction for 8 h. After the reaction was completed, the composite material was filtered, washed, and dried to obtain a composite material.

[0045] (2) dispersing 8 g of the composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 2 h, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0046] (3) Disperse 10 g of the vinyl composite material in 150 mL of an organic solvent, DMF, and then add 4 g of 2-vinylpyridine, 3 g of 4-imidazole acrylic acid, and 0.5 g of azobisisobutyronitrile. Heat and stir the mixture at 70 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain a composite modified adsorbent.

[0047] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0048] Example 2

[0049] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0050] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 40 mmHg, the vacuum distillation temperature is 65°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0051] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 40 mmHg, the vacuum distillation temperature is 75°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0052] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0053] The preparation method of the composite modified adsorbent is as follows:

[0054] (1) 10 g of zinc nitrate and 8 g of terephthalic acid were added to 150 mL of an organic solvent, DMF, and mixed evenly. Then, 20 g of activated carbon was added and dispersed evenly, and then heated at 150° C. for reaction for 4 h. After the reaction was completed, the composite material was obtained by filtering, washing, and drying.

[0055] (2) dispersing 12 g of the composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 3 g of vinyltrimethoxysilane thereto, stirring for 3 h, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0056] (3) Disperse 15 g of the vinyl composite material in 150 mL of an organic solvent, DMF, and then add 6 g of 2-vinylpyridine, 5 g of 4-imidazole acrylic acid, and 1 g of azobisisobutyronitrile. Heat and stir the mixture at 90 °C for 3 h. After the reaction is completed, filter, wash, and dry to obtain a composite modified adsorbent.

[0057] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0058] Example 3

[0059] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0060] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 35 mmHg, the vacuum distillation temperature is 63°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0061] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 35 mmHg, the vacuum distillation temperature is 73°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0062] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0063] The preparation method of the composite modified adsorbent is as follows:

[0064] (1) 8 g of zinc nitrate and 6 g of terephthalic acid were added to 150 mL of an organic solvent, DMF, and mixed evenly. Then, 16 g of activated carbon was added and dispersed evenly, and then heated at 130° C. for reaction for 6 h. After the reaction was completed, the composite material was obtained by filtering, washing, and drying.

[0065] (2) dispersing 10 g of the composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 2 g of vinyltrimethoxysilane thereto, stirring for 3 h, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0066] (3) 12 g of the vinyl composite material was dispersed in 150 mL of an organic solvent, DMF, and then 5 g of 2-vinylpyridine, 4 g of 4-imidazole acrylic acid and 0.8 g of azobisisobutyronitrile were added thereto. The mixture was heated and stirred at 80 °C for 4 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain a composite modified adsorbent.

[0067] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0068] Comparative Example 1

[0069] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0070] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 60°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0071] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 70°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0072] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0073] The preparation method of the composite modified adsorbent is as follows:

[0074] (1) 8 g of activated carbon was dispersed in 100 mL of 80 wt% ethanol aqueous solution, and then 1 g of vinyl trimethoxysilane was added thereto and stirred for 2 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain vinyl activated carbon;

[0075] (2) Disperse 10 g of vinyl activated carbon in 150 mL of organic solvent DMF, then add 4 g of 2-vinylpyridine, 3 g of 4-imidazole acrylic acid and 0.5 g of azobisisobutyronitrile, heat and stir at 70 ° C for 5 h, and after the reaction is completed, filter, wash and dry to obtain a composite modified adsorbent.

[0076] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0077] Compared with Example 1, in Comparative Example 1, the activated carbon was not treated with the zinc-based MOF material.

[0078] Comparative Example 2

[0079] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0080] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 60°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0081] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 70°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0082] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0083] The preparation method of the composite modified adsorbent is as follows:

[0084] (1) 5 g of copper nitrate and 4 g of terephthalic acid were added to 150 mL of an organic solvent, DMF, and mixed evenly. Then, 15 g of activated carbon was added and dispersed evenly, and then heated at 120° C. for reaction for 8 h. After the reaction was completed, the composite material was obtained by filtering, washing, and drying.

[0085] (2) dispersing 8 g of the composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 2 h, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0086] (3) Disperse 10 g of the vinyl composite material in 150 mL of an organic solvent, DMF, and then add 4 g of 2-vinylpyridine, 3 g of 4-imidazole acrylic acid, and 0.5 g of azobisisobutyronitrile. Heat and stir the mixture at 70 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain a composite modified adsorbent.

[0087] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0088] Compared with Example 1, in Comparative Example 2, the activated carbon-supported zinc-based MOF material is replaced with an activated carbon-supported copper-based MOF material.

[0089] Comparative Example 3

[0090] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0091] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 60°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0092] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 70°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0093] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0094] The preparation method of the composite modified adsorbent is as follows:

[0095] (1) 5 g of zinc nitrate and 4 g of terephthalic acid were added to 150 mL of an organic solvent, DMF, and mixed evenly. Then, 15 g of activated carbon was added and dispersed evenly, and then heated at 120° C. for reaction for 8 h. After the reaction was completed, the composite material was filtered, washed, and dried to obtain a composite material.

[0096] (2) dispersing 8 g of the composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 2 h, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0097] (3) Disperse 10 g of the vinyl composite material in 150 mL of an organic solvent, DMF, and then add 3 g of 4-imidazole acrylic acid and 0.5 g of azobisisobutyronitrile. Heat and stir the mixture at 70 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain a composite modified adsorbent.

[0098] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0099] Compared with Example 1, in Comparative Example 3, no 2-vinylpyridine was added to the composite modified adsorbent.

[0100] Comparative Example 4

[0101] A method for purifying electronic grade bis(diethylamino)silane comprises the following steps:

[0102] S1. Add the crude bis(diethylamino)silane into the first distillation tower, and perform vacuum distillation to remove light substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 60°C, the theoretical plate number is 55, and the product after light removal is drawn out from the bottom of the tower.

[0103] S2. The product after light removal is introduced into the second distillation tower for vacuum distillation to remove heavy substances. The vacuum distillation pressure is 30 mmHg, the vacuum distillation temperature is 70°C, the theoretical plate number is 55, and the product after heavy removal is drawn out from the top of the tower.

[0104] S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent at room temperature to adsorb impurities;

[0105] The preparation method of the composite modified adsorbent is as follows:

[0106] (1) 5 g of zinc nitrate and 4 g of terephthalic acid were added to 150 mL of an organic solvent, DMF, and mixed evenly. Then, 15 g of activated carbon was added and dispersed evenly, and then heated at 120° C. for reaction for 8 h. After the reaction was completed, the composite material was filtered, washed, and dried to obtain a composite material.

[0107] (2) dispersing 8 g of the composite material in 100 mL of 80 wt% ethanol aqueous solution, then adding 1 g of vinyltrimethoxysilane thereto, stirring for 2 h, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material;

[0108] (3) Disperse 10 g of the vinyl composite material in 150 mL of an organic solvent, DMF, and then add 4 g of 2-vinylpyridine and 0.5 g of azobisisobutyronitrile. Heat and stir the mixture at 70 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain a composite modified adsorbent.

[0109] S4. The product after adsorption is subjected to distillation and purification. The internal pressure of the distillation purifier is 30 mmHg, the fraction collection temperature is 70° C., the theoretical plate number is 50, and the fractions are collected to obtain electronic grade bis(diethylamino)silane.

[0110] Compared with Example 1, in Comparative Example 4, no 4-imidazole acrylic acid was added to the composite modified adsorbent.

[0111] The purity of the bis(diethylamino)silane obtained in Examples 1-3 and Comparative Examples 1-4 is shown in the following table:

[0112] Bis(diethylamino)silane purity, volume fraction (%) Example 1 99.999 Example 2 99.998 Example 3 99.999 Comparative Example 1 99.892 Comparative Example 2 99.984 Comparative Example 3 99.991 Comparative Example 4 99.986

[0113] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, some modifications and improvements can be made to the present invention. Therefore, any modification or improvement made without departing from the spirit of the present invention belongs to the scope of protection claimed in the present invention.

Claims

1. A method for purifying electronic grade bis(diethylamino)silane, characterized in that: The steps include: S1, adding the crude bis(diethylamino)silane to the first distillation tower, performing vacuum distillation to remove light, and drawing the product after light removal from the bottom of the tower; S2, introducing the product after light removal into the second distillation tower, performing vacuum distillation to remove heavy substances, and drawing the product after heavy removal from the top of the tower; S3, introducing the deweighted product into an adsorption tank, which is filled with a composite modified adsorbent to adsorb impurities; S4, subjecting the product after adsorption to rectification and purification, collecting fractions, and obtaining electronic grade bis(diethylamino)silane.

2. The purification method according to claim 1, characterized in that In step S1, the pressure of vacuum distillation is 30-40 mmHg, and the temperature of vacuum distillation is 60-65°C.

3. The purification method according to claim 1, characterized in that In step S2, the pressure of vacuum distillation is 30-40 mmHg, and the temperature of vacuum distillation is 70-75°C.

4. The purification method according to claim 1, characterized in that In step S3, the preparation method of the composite modified adsorbent is as follows: (1) adding a soluble zinc salt and terephthalic acid to an organic solvent, mixing them evenly, then adding activated carbon, dispersing them evenly and heating them for reaction, and after the reaction is completed, filtering, washing and drying to obtain a composite material; (2) dispersing the composite material in an ethanol aqueous solution, then adding vinyl trimethoxysilane thereto, stirring for 1-3 hours, and after the reaction is completed, filtering, washing, and drying to obtain a vinyl composite material; (3) dispersing the vinyl composite material in an organic solvent, then adding 2-vinylpyridine, 4-imidazole acrylic acid and azobisisobutyronitrile thereto, heating and stirring to react, and after the reaction is completed, filtering, washing and drying to obtain a composite modified adsorbent.

5. The purification method according to claim 4, characterized in that In step (1), the mass ratio of soluble zinc salt, terephthalic acid and activated carbon is 5-10:4-8:15-20.

6. The purification method according to claim 4, characterized in that: In step (1), the heating reaction temperature is 120-150° C., and the heating reaction time is 4-8 hours.

7. The purification method according to claim 4, characterized in that: In step (2), the mass ratio of the composite material to vinyltrimethoxysilane is 8-12:1-3.

8. The purification method according to claim 4, characterized in that: In step (3), the mass ratio of the vinyl composite material, 2-vinylpyridine, 4-imidazole acrylic acid and azobisisobutyronitrile is 10-15:4-6:3-5:0.5-1.

9. The purification method according to claim 4, characterized in that: In step (3), the temperature of the heating and stirring reaction is 70-90° C., and the time of the heating and stirring reaction is 3-5 h.

10. The purification method according to claim 1, characterized in that: In step S4, during the distillation purification process, the internal pressure of the distillation purifier is 30 mmHg and the fraction collection temperature is 70°C.