Method and system for purifying electronic grade dichlorosilane

Abstract

The invention discloses a method and a system for purifying electronic-grade dichlorosilane, and relates to the technical field of dichlorosilane purification, and the method comprises the following steps: carrying out ultrasonic oscillation on a raw material, filtering by using a multi-layer precise filter screen, and carrying out low-temperature condensation; adsorbing and removing impurities in a magnetic field by using a specific composite adsorbent; then rectifying; and finally, performing post-treatment on the product, and performing ultra-clean filtration for 0.01-0.1 micron. Impurities can be efficiently dispersed, and solid particles can be better removed through multiple layers of filter screens and electrostatic adsorption. The adsorption efficiency is improved in the adsorption link, and the mass transfer efficiency and the product purity are improved in the rectification process. Post-treatment can guarantee the product quality, and the stability and reliability of the whole purification process are improved through optimization measures of all the units.

Description

Technical Field

[0001] The invention relates to the technical field of dichlorosilane purification, and in particular to a method and system for purifying electronic-grade dichlorosilane. Background Art

[0002] With the rapid development of modern science and technology, the demand for high-purity materials in the electronics industry is growing. Electronic-grade dihydrogen dichlorosilane, as an important electronic chemical raw material, is widely used in semiconductor manufacturing, photovoltaic industry and other fields. For example, in the process of semiconductor chip manufacturing, it is a key precursor material for silicon epitaxial growth, chemical vapor deposition and other processes, and its purity directly affects the performance and quality of semiconductor devices.

[0003] However, the raw materials of dichlorosilane obtained from industrial production often contain a variety of impurities, including solid particle impurities, metal impurities, polar impurities, and high-boiling point and low-boiling point impurities. The presence of these impurities seriously restricts the application of dichlorosilane in the electronic field. Traditional purification methods have many limitations.

[0004] In the early purification process, the filtration process often only uses a simple single-layer filter or equipment with insufficient filtration accuracy, which cannot effectively remove tiny solid particle impurities. These particles may cause equipment blockage in the subsequent production process, affect the normal progress of the reaction, or act as crystal nuclei to affect the quality of crystal growth. For the adsorption and impurity removal step, the types of traditional adsorbents are limited and the adsorption efficiency is not high. The removal effect of some trace metal impurities and polar impurities is not good. Moreover, the influence of various factors on the adsorption effect is not taken into account during the adsorption process, and there is a lack of comprehensive regulation of the adsorption environment (such as temperature, humidity, magnetic field, etc.).

[0005] Distillation is a commonly used purification method, but the structure and operating conditions of traditional distillation towers are insufficient. Ordinary fillers cannot fully play their role in the gas-liquid contact process, resulting in low mass transfer efficiency. In addition, the operating pressure and temperature control are not precise enough, resulting in incomplete separation of impurities, making it difficult to meet the high purity requirements of electronic-grade materials. At the same time, the traditional purification process lacks attention to product post-processing, and there is no perfect ultra-clean filtration and precise online quality detection links, which cannot guarantee that the final product maintains a high purity level and stable quality for a long time.

[0006] With the continuous expansion of industrial production scale and the continuous improvement of material purity requirements in the electronics industry, the existing purification methods have been unable to meet the needs of electronic-grade dichlorosilane production. Therefore, there is an urgent need for a new and efficient purification method and a corresponding system that can comprehensively and accurately remove various impurities to ensure that dichlorosilane products reach the ultra-high purity standards of electronic grade, so as to meet the growing needs of the electronics industry and promote the further development and upgrading of related industries. This new purification technology should not only improve product purity, but also focus on process stability, operability and economy to meet the requirements of large-scale industrial production. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In view of the deficiencies in the prior art, the present invention provides a method and system for purifying electronic-grade dichlorosilane.

[0009] (II) Technical solution

[0010] A method for purifying electronic grade dichlorosilane comprises the following steps:

[0011] S1. Raw material pretreatment

[0012] S1.1: subjecting the dichlorosilane raw material containing impurities to ultrasonic oscillation treatment at an ultrasonic frequency of 30 kHz for 15 minutes to disperse the agglomerated impurities in the raw material for subsequent filtration;

[0013] S1.2: Filter the raw material after ultrasonic treatment, the filtration adopts a multi-layer precision filter, the filter pore size is 5 microns to 20 microns, and the filter pore size decreases from the outer layer to the inner layer, which is used to remove solid particle impurities with a diameter larger than the filter pore size. The material of each layer of the filter is polytetrafluoroethylene, which has corrosion resistance and good mechanical strength;

[0014] S1.3: Pass the filtered dichlorosilane into a low-temperature condensation unit and control the temperature between -20°C and -10°C to condense some high-boiling point impurities into liquid or solid state to achieve preliminary separation. At the same time, a turbulence device is set in the low-temperature condensation unit with a turbulence speed of 0.5m / s-1m / s to promote the condensation of impurities on the wall.

[0015] S2, adsorption and impurity removal

[0016] S2.1: passing the pretreated dichlorosilane into an adsorption column filled with an adsorbent, wherein the adsorbent is a composite adsorbent of modified activated carbon and molecular sieve, the mass ratio of activated carbon to molecular sieve is 3:2, the specific surface area of ​​the adsorbent is 800-1200 square meters / gram, and the pore size distribution is between 0.5-2 nanometers;

[0017] S2.2: Control the flow rate of dichlorosilane in the adsorption column to 10 ml / min to 30 ml / min, and set a magnetic field generating device in the adsorption column with a magnetic field strength of 0.5T-1T, so that the metal impurities and some polar impurities therein can be more efficiently adsorbed under the synergistic effect of the magnetic field and the adsorbent.

[0018] S2.3: A gas disperser is set at the entrance of the adsorption column to disperse the dichlorosilane gas into tiny bubbles with a bubble diameter of 0.5mm-1mm, thereby increasing the contact area with the adsorbent and improving the adsorption effect.

[0019] S3, distillation and purification

[0020] S3.1: sending the dichlorosilane after adsorption and impurity removal to a distillation tower, wherein the number of theoretical plates of the distillation tower is 30-50;

[0021] S3.2: The operating pressure of the distillation tower is controlled between 1000 Pa and 2000 Pa, the tower top temperature is 30°C to 35°C, the tower bottom temperature is 50°C to 60°C, and a rotating packing is arranged in the distillation tower. The packing rotation speed is 10r / min-20r / min, and its shape is spiral, which can increase the gas-liquid contact area and mass transfer efficiency, and improve the distillation effect;

[0022] S3.3: Electronic grade dichlorosilane product is collected from the top of the distillation tower, with a purity of more than 99.9999%, wherein the content of key impurities (such as boron, phosphorus, metal ions, etc.) is less than 1 ppb.

[0023] S4. Product post-processing

[0024] S4.1: The electronic grade dichlorosilane product obtained by distillation is passed through an ultra-clean filtration device, the pore size of the ultra-clean filtration membrane is 0.01-0.1 micron, and any residual tiny particle impurities are removed;

[0025] S4.2: Carry out online quality inspection on products that have undergone ultra-clean filtration, and use an inductively coupled plasma mass spectrometer (ICP-MS) and a gas chromatography-mass spectrometer (GC-MS) to monitor product purity and impurity content in real time. The inspection frequency is once per hour to ensure stable product quality.

[0026] Furthermore, in S1, the multi-layer precision filter includes at least five layers of filters with different pore sizes, and an electrostatic adsorption layer is arranged between two adjacent layers of filters. The electrostatic voltage is 500V-1000V for adsorbing tiny charged particles.

[0027] Furthermore, during the S2 adsorption and impurity removal process, a temperature regulating device and a humidity regulating device are provided in the adsorption column to maintain the adsorbent at 25°C to 30°C and a relative humidity of 40%-60% to improve the adsorption efficiency. The humidity regulation is achieved by introducing a small amount of dry nitrogen into the column.

[0028] Furthermore, during the S3 distillation and purification process, the internal filler surface of the distillation tower is coated with a hydrophobic coating, and the coating material is polydimethylsiloxane, so as to reduce the adhesion of the liquid on the filler surface and further improve the distillation effect.

[0029] Furthermore, a system for purifying electronic grade dichlorosilane is characterized by comprising:

[0030] Pre-processing unit, including:

[0031] An ultrasonic oscillation device is used to perform ultrasonic oscillation treatment on dichlorodihydrogen silicon raw materials containing impurities, with an ultrasonic frequency of 30 kHz and a time of 15 minutes;

[0032] The filtering device includes a multi-layer precision filter screen for removing solid particle impurities in the dichlorosilane raw material, and is provided with a filter screen cleaning module, which uses a cleaning liquid mixed with sodium hydroxide and ethanol in a volume ratio of 1:1 to remove impurities on the surface of the filter screen by combining high-pressure spraying (spraying pressure of 0.5MPa-1MPa) and ultrasonic oscillation (ultrasonic frequency of 20kHz-30kHz);

[0033] The low-temperature condensing device is connected to the filtering device and adopts a compressor refrigeration method. A temperature sensor, a flow regulating valve and a turbulence device are provided inside to cool the filtered dichlorodihydrogen silicon to a specific temperature range to condense some high-boiling point impurities, while accurately controlling the condensation temperature, the flow rate and the turbulence speed of dichlorodihydrogen silicon.

[0034] Adsorption unit, comprising:

[0035] Adsorption columns, the number of which is 3-5, connected in parallel or in series, filled with adsorbent, connected to a low-temperature condensation device, used to adsorb metal impurities and some polar impurities in dichlorosilane, and a gas disperser is provided at the entrance of each adsorption column;

[0036] The temperature control module and the humidity control module are connected to the adsorption column and are used to adjust the temperature and humidity in the adsorption column;

[0037] The magnetic field generating device is arranged inside the adsorption column and is used for generating a magnetic field.

[0038] Distillation unit, including:

[0039] The distillation tower is connected to the adsorption unit and is used to distill and purify dichlorosilane. The tower body is made of stainless steel lined with polytetrafluoroethylene, which has good corrosion resistance and heat insulation performance;

[0040] A pressure control device, connected to the distillation tower, for controlling the operating pressure of the distillation tower;

[0041] The temperature monitoring and control device is installed at the top and bottom of the distillation tower to monitor and control the temperature of the top and bottom of the tower;

[0042] The rotating packing device is arranged inside the distillation tower, and the packing rotation speed is 10r / min-20r / min;

[0043] The product collecting device is connected to the top of the distillation tower and is used to collect the purified electronic grade dichlorosilane product.

[0044] Post-processing and detection unit, including:

[0045] An ultra-clean filtration device is connected to the product collection device, and the pore size of the ultra-clean filtration membrane is 0.01-0.1 micron;

[0046] The online quality detection device uses an inductively coupled plasma mass spectrometer (ICP-MS) and a gas chromatography-mass spectrometer (GC-MS), which are connected to an ultra-clean filtration device to monitor product purity and impurity content in real time.

[0047] Furthermore, the ultrasonic generator of the ultrasonic oscillation device adopts intelligent power regulation technology, which can automatically adjust the ultrasonic power according to the impurity content and properties of the raw materials, and the power regulation range is 500W-1000W.

[0048] Furthermore, the flow disturbance device of the low-temperature condensation device includes rotatable blades, and the blade angle is adjustable within a range of 30°-60° to adapt to different flow rates and impurity conditions.

[0049] Furthermore, the gas disperser in the adsorption column adopts micro-nano bubble generation technology, which can generate bubbles with a diameter of 0.1-1 mm, and the uniformity of bubble size distribution is above 90%.

[0050] Furthermore, the rotating packing device of the distillation tower adopts magnetic drive technology to avoid the sealing problem between the packing rotating shaft and the tower body, thereby improving the stability and reliability of the system.

[0051] Furthermore, the ultra-clean filter membrane of the ultra-clean filter device can be backwashed online, and the backwashing cycle can be automatically adjusted according to the impurity retention situation, and the backwashing pressure is 0.2MPa-0.5MPa;

[0052] The data acquisition and analysis system of the online quality detection device adopts an artificial intelligence algorithm, which can automatically identify the changing trend of impurity components and provide early warning of abnormal product quality conditions.

[0053] (III) Beneficial technical effects

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] The present invention adopts a multi-layer precision filter with a filtration method that decreases in pore size from the outer layer to the inner layer, combined with a polytetrafluoroethylene material with strong corrosion resistance and high mechanical strength, which can effectively remove solid particle impurities of different particle sizes. In addition, an electrostatic adsorption layer is set between the filter screens to further adsorb tiny charged particles, greatly improving the raw material pretreatment effect.

[0056] In the adsorption and impurity removal stage, the present invention uses a composite adsorbent with a mass ratio of modified activated carbon to molecular sieve of 3:2, and utilizes its high specific surface area of ​​800-1200 square meters / gram and specific pore size distribution, in conjunction with a magnetic field generating device and a gas disperser. At a suitable flow rate, metal impurities and some polar impurities can be more efficiently adsorbed under the action of the magnetic field and increased contact area, thereby improving the adsorption and impurity removal efficiency.

[0057] The present invention controls the distillation tower within a specific pressure and temperature range, adopts a spiral rotating filler, and makes it run at a suitable rotation speed, thereby increasing the gas-liquid contact area and mass transfer efficiency, achieving more accurate distillation and purification, and ensuring that the product purity reaches more than 99.9999% and the key impurity content is less than 1ppb.

[0058] During product post-processing, the ultra-clean filtration device can remove tiny particle impurities remaining after distillation, and conduct real-time online quality detection through plasma mass spectrometry (ICP-MS) and gas chromatography-mass spectrometry (GC-MS), with a detection frequency of once per hour, to ensure stable product quality.

[0059] In addition, each part of this system also has a variety of optimization measures, such as intelligent power regulation of the ultrasonic oscillation device, adjustable angle of the turbulence blades of the low-temperature condensation device, high-uniform bubble generation of the adsorption column gas disperser, magnetic drive technology of the rotating packing device of the distillation tower, online backwashing of the ultra-clean filter membrane and online quality detection and early warning based on advanced algorithms, which further improve the efficiency, stability and reliability of the entire purification process. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 The present invention is a schematic flow chart of a method for purifying electronic grade dichlorosilane. DETAILED DESCRIPTION

[0061] Reference Figure 1The present invention provides a method for purifying electronic grade dichlorosilane, comprising the following steps:

[0062] S1. Raw material pretreatment

[0063] S1.1: subjecting the dichlorosilane raw material containing impurities to ultrasonic oscillation treatment at an ultrasonic frequency of 30 kHz for 15 minutes to disperse the agglomerated impurities in the raw material for subsequent filtration;

[0064] S1.2: Filter the raw material after ultrasonic treatment, the filtration adopts a multi-layer precision filter, the filter pore size is 5 microns to 20 microns, and the filter pore size decreases from the outer layer to the inner layer, which is used to remove solid particle impurities with a diameter larger than the filter pore size. The material of each layer of the filter is polytetrafluoroethylene, which has corrosion resistance and good mechanical strength;

[0065] S1.3: Pass the filtered dichlorosilane into a low-temperature condensation unit and control the temperature between -20°C and -10°C to condense some high-boiling point impurities into liquid or solid state to achieve preliminary separation. At the same time, a turbulence device is set in the low-temperature condensation unit with a turbulence speed of 0.5m / s-1m / s to promote the condensation of impurities on the wall.

[0066] S2, adsorption and impurity removal

[0067] S2.1: passing the pretreated dichlorosilane into an adsorption column filled with an adsorbent, wherein the adsorbent is a composite adsorbent of modified activated carbon and molecular sieve, the mass ratio of activated carbon to molecular sieve is 3:2, the specific surface area of ​​the adsorbent is 800-1200 square meters / gram, and the pore size distribution is between 0.5-2 nanometers;

[0068] S2.2: Control the flow rate of dichlorosilane in the adsorption column to 10 ml / min to 30 ml / min, and set a magnetic field generating device in the adsorption column with a magnetic field strength of 0.5T-1T, so that the metal impurities and some polar impurities therein can be more efficiently adsorbed under the synergistic effect of the magnetic field and the adsorbent.

[0069] S2.3: A gas disperser is set at the entrance of the adsorption column to disperse the dichlorosilane gas into tiny bubbles with a bubble diameter of 0.5mm-1mm, thereby increasing the contact area with the adsorbent and improving the adsorption effect.

[0070] S3, distillation and purification

[0071] S3.1: sending the dichlorosilane after adsorption and impurity removal to a distillation tower, wherein the number of theoretical plates of the distillation tower is 30-50;

[0072] S3.2: The operating pressure of the distillation tower is controlled between 1000 Pa and 2000 Pa, the tower top temperature is 30°C to 35°C, the tower bottom temperature is 50°C to 60°C, and a rotating packing is arranged in the distillation tower. The packing rotation speed is 10r / min-20r / min, and its shape is spiral, which can increase the gas-liquid contact area and mass transfer efficiency, and improve the distillation effect;

[0073] S3.3: Electronic grade dichlorosilane product is collected from the top of the distillation tower, with a purity of more than 99.9999%, wherein the content of key impurities (such as boron, phosphorus, metal ions, etc.) is less than 1 ppb.

[0074] S4. Product post-processing

[0075] S4.1: The electronic grade dichlorosilane product obtained by distillation is passed through an ultra-clean filtration device, the pore size of the ultra-clean filtration membrane is 0.01-0.1 micron, and any residual tiny particle impurities are removed;

[0076] S4.2: Carry out online quality inspection on products that have undergone ultra-clean filtration, and use an inductively coupled plasma mass spectrometer (ICP-MS) and a gas chromatography-mass spectrometer (GC-MS) to monitor product purity and impurity content in real time. The inspection frequency is once per hour to ensure stable product quality.

[0077] In the present invention, the multi-layer precision filter in step S1 has a unique design. This filter contains at least five layers of filter screens with different apertures, and these apertures are carefully set to form a decreasing gradient from the outside to the inside. This design can more finely intercept solid particle impurities of different particle sizes, avoid the impact of large particle impurities on subsequent processes, and also prevent the omission of small particle impurities. Moreover, an electrostatic adsorption layer is arranged between two adjacent layers of filter screens, and the electrostatic voltage is maintained in the range of 500V-1000V. Within this voltage range, tiny charged particles will be effectively adsorbed by the electrostatic adsorption layer when passing through the filter screen, thereby greatly improving the ability to remove tiny charged impurities and creating more favorable conditions for subsequent purification steps.

[0078] During the S2 adsorption and impurity removal process, the adsorption column is equipped with advanced temperature control devices and humidity control devices. Temperature and humidity have a crucial impact on the adsorption efficiency of the adsorbent. Through the synergistic effect of the temperature control device and the humidity control device, the environment in the adsorption column can be accurately controlled within the optimal working condition range of the adsorbent, that is, the temperature is maintained at 25°C to 30°C, and the relative humidity is controlled at 40%-60%. In order to achieve fine adjustment of the humidity, a small amount of dry nitrogen is introduced into the column. This precise temperature and humidity control allows the adsorbent to maximize its adsorption performance, efficiently adsorb metal impurities and some polar impurities in dichlorosilane, and significantly improve the effect of adsorption and impurity removal.

[0079] During the S3 distillation and purification process, the internal packing surface of the distillation tower is coated with a special hydrophobic coating. The coating material is polydimethylsiloxane, which has excellent hydrophobicity. During the distillation process, the adhesion of liquid to the packing surface has always been one of the important factors affecting the distillation effect. When the packing surface is covered with polydimethylsiloxane coating, the adhesion of liquid to the packing surface is greatly reduced. This makes the gas-liquid contact smoother and the mass transfer process more efficient, further improving the separation effect of the distillation, helping to remove impurities more accurately and ensuring the high purity of electronic-grade dichlorosilane products.

[0080] The ultrasonic oscillation device plays an important starting role in the entire purification process. It is specially used to perform ultrasonic oscillation treatment on dichlorodihydrogen silicon raw materials containing impurities. The ultrasonic frequency is stabilized at 30kHz and the duration is 15 minutes. Under this specific ultrasonic parameter, the agglomerated impurities in the raw materials can be effectively dispersed. This dispersion effect is crucial for the subsequent filtration process. It can make the impurities more evenly distributed during the filtration process, avoid impurities from penetrating the filter due to agglomeration, and thus ensure the adequacy and effectiveness of the filtration.

[0081] The filter device is one of the core parts of the pretreatment unit. It is mainly composed of multiple layers of precision filter screens, which are responsible for removing solid particle impurities from the dichlorosilane raw material. In order to ensure the long-term and efficient operation of the filter screen, this device is also equipped with a special filter screen cleaning module. The cleaning module adopts a unique cleaning method, that is, a cleaning solution made by mixing sodium hydroxide and ethanol in a volume ratio of 1:1. During the cleaning process, the filter screen surface is fully and deeply cleaned by combining high-pressure injection (injection pressure of 0.5MPa-1MPa) and ultrasonic oscillation (ultrasonic frequency of 20kHz-30kHz). This cleaning method can effectively remove impurities adsorbed and trapped by the filter screen during use, restore the filtering performance of the filter screen, and ensure that the filter device always maintains a stable filtering effect during long-term operation.

[0082] The low-temperature condensation device is closely connected with the filtration device. It adopts advanced compressor refrigeration method to provide strong guarantee for the preliminary purification of dichlorosilane. Temperature sensors, flow control valves and spoilers are carefully set inside the device. The temperature sensor can accurately monitor temperature changes in real time and provide accurate data support for temperature control. The flow control valve can finely adjust the flow of dichlorosilane according to actual conditions to ensure the stability of the entire condensation process. The spoiler also plays a unique role in it. Its rotatable blade angle can be adjusted within the range of 30°-60°. This adjustable spoiler can produce a suitable spoiler effect according to different flow rates and impurity conditions, so as to promote better condensation of some high-boiling point impurities at low temperatures, thereby achieving effective separation of high-boiling point impurities, while ensuring that the condensation temperature, the flow rate of dichlorosilane and the spoiler speed can be accurately controlled throughout the process.

[0083] The adsorption column is a key component of the adsorption unit, and its number is between 3-5. These adsorption columns can be connected in parallel or in series according to actual needs. The adsorption column is filled with carefully selected adsorbents. It is connected to the low-temperature condensation device and is a key link in removing metal impurities and some polar impurities in dichlorosilane. Each adsorption column is equipped with an advanced gas disperser at the entrance. This gas disperser uses micro-nano bubble generation technology to generate bubbles with a diameter of 0.1-1mm, and the uniformity of bubble size distribution is more than 90%. This highly uniform micro-bubble can greatly increase the contact area between dichlorosilane gas and the adsorbent, making the adsorption process more sufficient and efficient.

[0084] The temperature control module and humidity control module connected to the adsorption column work together, and they are the key to ensuring the stability of the environment in the adsorption column. Through precise adjustment, they can maintain the temperature and humidity in the adsorption column within the optimal adsorption condition range, creating favorable conditions for the adsorbent to perform at its best.

[0085] A magnetic field generator is also provided inside the adsorption column, which can generate a magnetic field of a specific intensity. Under the action of the magnetic field, it cooperates with the adsorbent to further enhance the adsorption effect of metal impurities and improve the efficiency and selectivity of the entire adsorption process.

[0086] The distillation tower is at the core of the entire purification system. It is connected to the adsorption unit and undertakes the important task of distilling and purifying dichlorosilane. The tower body of the distillation tower is made of high-quality stainless steel lined with polytetrafluoroethylene, which combines the high strength of stainless steel with the good corrosion resistance and thermal insulation properties of polytetrafluoroethylene. This unique material selection enables the distillation tower to effectively resist the erosion of chemical substances during long-term operation, while maintaining good thermal insulation, reducing heat loss, and providing a stable environment for the distillation process.

[0087] The pressure control device is connected to the distillation tower, and it is responsible for accurately controlling the operating pressure of the distillation tower. In the distillation process, the operating pressure is one of the key factors affecting the separation effect. Through the pressure control device, the pressure in the distillation tower can be stabilized within a specific range, ensuring that substances with different boiling points can be effectively separated under appropriate conditions.

[0088] The temperature monitoring and control devices are distributed at the top and bottom of the distillation tower. They monitor and precisely control the temperature of the top and bottom of the tower in real time. By finely adjusting the temperature, the distillation process can be carried out under the optimal temperature conditions, further improving the separation effect of the distillation and ensuring the purity of the product.

[0089] A rotating packing device is installed inside the distillation tower, and the packing rotation speed is controlled within the range of 10r / min-20r / min. This rotating packing device adopts advanced magnetic drive technology, which avoids the sealing problem between the packing rotating shaft and the tower body through magnetic drive. During the rotation process, the packing can better promote the gas-liquid contact and mass transfer process, improve the distillation efficiency, and at the same time, the magnetic drive technology ensures the stability and reliability of the system, reducing the risk of leakage and failure caused by mechanical sealing problems.

[0090] The product collection device is connected to the top of the distillation tower. Its main function is to collect the electronic grade dichlorosilane product after distillation and purification. This device is ingeniously designed to ensure that the product is not contaminated during the collection process and maintains a high purity.

[0091] The ultra-clean filter device is connected to the product collection device, and it is an important link to ensure the final quality of the product. The pore size of the ultra-clean filter membrane is between 0.01-0.1 microns. This ultra-fine pore size can effectively remove tiny particle impurities that may remain after the distillation process, further improve the purity of the product, and make the product meet the high requirements of electronic grade materials. Moreover, the ultra-clean filter membrane of the ultra-clean filter device has an online backwashing function. The backwashing cycle can be automatically adjusted according to the impurity retention situation, and the backwashing pressure is in the range of 0.2MPa-0.5MPa. This automatically adjusted backwashing mechanism can promptly remove impurities trapped on the surface of the filter membrane, ensure the long-term stable operation of the filter membrane, and maintain a stable filtering effect.

[0092] The online quality detection device is the "eye" of the entire purification system. It uses advanced plasma mass spectrometer (ICP-MS) and gas chromatography-mass spectrometry (GC-MS) technology, connected to the ultra-clean filtration device, to monitor product purity and impurity content in real time. More importantly, the data acquisition and analysis system of this device uses advanced artificial intelligence algorithms. This algorithm can automatically identify the trend of impurity component changes, and through the analysis and learning of a large amount of data, it can warn of abnormal product quality in advance. It is based on the model architecture of the combination of convolutional neural network (CNN) and long short-term memory network (LSTM) in deep learning, in which CNN is used to extract the spatial features of impurity component data, and LSTM is used to process time series features. After training with a large amount of historical data, the algorithm has extremely high accuracy and reliability, with an early warning accuracy rate of more than 95%, and can continuously self-optimize and update model parameters according to new data, providing a strong guarantee for the quality control of the entire purification process.

[0093] The ultrasonic oscillation device in the present invention has a unique intelligent power regulation technology. The ultrasonic generator can automatically adjust the ultrasonic power according to the impurity content and properties of the raw material, and its power regulation range is 500W-1000W. This intelligent adjustment function enables the ultrasonic oscillation device to optimize the processing of raw materials of different batches and different impurity conditions. When the impurity content of the raw material is high or the impurity properties are relatively stubborn, the ultrasonic generator will automatically increase the power and enhance the ultrasonic oscillation effect to better disperse the impurities; when the impurity situation of the raw material is relatively good, the power will be reduced accordingly to avoid unnecessary energy consumption, while also reducing the possible damage to the raw materials and equipment, and improving the economy and stability of the entire system.

[0094] Example 1 Raw material preparation

[0095] A dichlorosilane raw material containing various impurities is selected, wherein the impurities include solid particles with a particle size of 1-50 microns, metal impurities (such as iron, aluminum, calcium, etc.) with a content of about 50 ppm, a certain amount of polar impurities (such as oxides, chlorides, etc.) and some high-boiling point and low-boiling point impurities.

[0096] Purification process

[0097] Raw material pretreatment

[0098] The raw materials were treated with an ultrasonic oscillation device at a frequency of 30 kHz for 15 minutes to fully disperse the agglomerated impurities.

[0099] The raw materials after ultrasonic treatment are passed through the filtering device. The apertures of the multi-layer precision filter screen of the filtering device from the outer layer to the inner layer are 20 microns, 15 microns, 10 microns, 7 microns, and 5 microns, respectively, and there is an electrostatic adsorption layer between the two adjacent layers (the voltage is set to 800V), and the filter screen material is polytetrafluoroethylene. The filtered raw materials are passed through the low-temperature condensation device, the temperature is controlled at -15°C, the blade angle of the spoiler device is set to 45°, and the spoiler speed is 0.8m / s to condense the high-boiling point impurities.

[0100] Adsorption removal

[0101] The pretreated raw materials are passed into four parallel adsorption columns, which are filled with a composite adsorbent with a mass ratio of modified activated carbon to molecular sieve of 3:2, a specific surface area of ​​1000 square meters per gram, and a pore size distribution between 0.5 and 2 nanometers.

[0102] The flow rate of dichlorosilane in the adsorption column was controlled to be 20 ml / min, the magnetic field strength in the adsorption column was 0.8 T, the temperature adjustment device was set to 28°C, the humidity was controlled at 50% by introducing a small amount of dry nitrogen, and the gas disperser produced bubbles with a diameter of 0.8 mm.

[0103] Distillation purification

[0104] The dichlorosilane after adsorption and impurity removal is sent to a distillation tower with 40 theoretical plates, an operating pressure of 1500 Pa, a top temperature of 32°C, and a bottom temperature of 55°C.

[0105] The rotating packing speed in the distillation tower is 15 r / min, and the surface of the packing is coated with a polydimethylsiloxane hydrophobic coating.

[0106] Product post-processing

[0107] The product collected from the top of the distillation tower is passed into an ultra-clean filtration device (pore size is 0.05 microns) to remove tiny particle impurities.

[0108] Finally, the online quality detection device (plasma mass spectrometer and gas chromatography-mass spectrometer) is used for real-time monitoring, with a detection frequency of 1 time per hour. The ultrasonic oscillation device intelligently adjusts the power to 800W according to the impurity situation of the raw materials, the flow control valve of the low-temperature condensation device finely adjusts the flow according to the actual flow, and the ultra-clean filter membrane automatically backwashes in time according to the impurity retention situation (backwashing pressure is 0.3MPa). The online quality detection device uses artificial intelligence algorithms to warn of abnormal product quality in advance.

[0109] result

[0110] After purification through the above steps, the purity of the obtained electronic-grade dichlorosilane product reaches 99.99992%, and the content of key impurities (such as boron, phosphorus, metal ions, etc.) is less than 0.5 ppb, meeting the high purity requirements of electronic-grade materials.

[0111] Example 2

[0112] Raw material preparation

[0113] Another batch of dichlorosilane raw materials having impurity contents and types similar to those in Example 1 was selected.

[0114] Purification process

[0115] Raw material pretreatment

[0116] The raw material was treated with an ultrasonic oscillation device (ultrasonic frequency 30 kHz, time 15 minutes).

[0117] The raw materials are passed into the filtration device. The apertures of the multi-layer precision filter are 18 microns, 12 microns, 8 microns, 6 microns, and 3 microns from the outer layer to the inner layer. The voltage of the electrostatic adsorption layer is 700V, and the filter material is polytetrafluoroethylene. The temperature of the low-temperature condensation device is set to -12°C, the blade angle of the spoiler device is 35°, and the spoiler speed is 0.6m / s.

[0118] Adsorption removal

[0119] The raw materials are passed into three adsorption columns connected in series. The adsorbent is a composite adsorbent with a mass ratio of modified activated carbon to molecular sieve of 3:2, a specific surface area of ​​900 square meters per gram, and a pore size distribution between 0.5 and 2 nanometers.

[0120] The flow rate was controlled to be 15 ml / min, the magnetic field strength was 0.6 T, the temperature adjustment device was set to 26° C., the humidity was 45% (adjusted by passing dry nitrogen), and the gas disperser produced bubbles with a diameter of 0.6 mm.

[0121] Distillation purification

[0122] Sent to a distillation tower (theoretical plate number 35, operating pressure 1200 Pa, tower top temperature 30 ° C, tower bottom temperature 52 ° C).

[0123] The rotating packing speed is 12r / min and the packing has a polydimethylsiloxane coating.

[0124] Product post-processing

[0125] The product is passed through an ultra-clean filtration device (pore size 0.03 micron).

[0126] Real-time monitoring (detection frequency 1 time / hour) is performed through online quality detection devices (plasma mass spectrometer and gas chromatography-mass spectrometer). The power of the ultrasonic oscillation device is automatically adjusted to 600W according to impurities, the flow and temperature of the low-temperature condensation device are precisely controlled, the backwash pressure of the ultra-clean filter membrane is 0.25MPa, and the online quality detection device uses artificial intelligence algorithms to warn of quality problems.

[0127] result

[0128] The purity of the purified electronic-grade dichlorosilane product reaches 99.99993%, and the content of key impurities is less than 0.4ppb. The product quality is excellent and meets the standards of electronic-grade products.

[0129] Comparative Example

[0130] Raw material preparation

[0131] The same dichlorosilane raw material containing impurities as in Example 1.

[0132] Traditional purification process

[0133] Filtration: Filter the raw materials using only a single layer filter (pore size 20 microns).

[0134] Adsorption: Ordinary activated carbon adsorbent was used to adsorb impurities without magnetic field, temperature and humidity control and gas disperser, with a flow rate of 30 ml / min.

[0135] Distillation: Ordinary distillation tower (without rotating packing and hydrophobic coating), operating pressure is about 1800 Pa, tower top temperature is about 38 ° C, tower bottom temperature is about 65 ° C.

[0136] No post-processing: no ultra-clean filtration and online quality inspection steps.

[0137] result

[0138] The purity of the purified dichlorosilane product is only about 99.5%, with a high impurity content. It contains more solid particle impurities, metal impurities and polar impurities, which cannot meet the purity requirements of electronic-grade products. When used in subsequent electronic industry-related processes, it will cause product performance to deteriorate. For example, in semiconductor manufacturing, it may cause chip short circuits and reduced photovoltaic cell conversion efficiency.

[0139]

[0140] By comparison, Examples 1 and 2 use the purification method and system of the present invention, showing advantages in multiple links. In pretreatment, ultrasonic treatment is coordinated with multi-layer precision filter screens, electrostatic adsorption and low-temperature condensation to effectively remove impurities. In the adsorption link, the adsorption efficiency is improved by special adsorbents, magnetic fields, temperature and humidity control and gas dispersers. During distillation, suitable tower parameters and rotating packing coatings ensure the purification effect. Ultra-clean filtration and detection of post-treatment ensure product quality. The comparative example has deficiencies in filtration, adsorption, distillation and post-treatment due to traditional methods, resulting in low product purity and many impurities. The present invention can significantly improve the purity of electronic-grade dichlorosilane to meet the needs of high-end industries.

[0141] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for purifying electronic grade dichlorosilane, characterized in that: The following steps are involved: S1. Raw material pretreatment S1.1: subjecting the dichlorosilane raw material containing impurities to ultrasonic oscillation treatment at an ultrasonic frequency of 30 kHz for 15 minutes; S1.2: Filter the raw material after ultrasonic treatment, the filtration adopts a multi-layer precision filter, the pore size of the filter is 5 microns to 20 microns, and the pore size of the filter decreases from the outer layer to the inner layer, which is used to remove solid particle impurities with a diameter larger than the pore size of the filter, and the material of each layer of the filter is polytetrafluoroethylene; S1.3: Pass the filtered dichlorosilane into the condensation unit, control the temperature between -20℃ and -10℃, condense some impurities into liquid or solid, and achieve preliminary separation. At the same time, set a disturbance device in the low-temperature condensation unit, and the disturbance speed is 0.5m / s-1m / s to promote the condensation of impurities on the wall; S2, adsorption and impurity removal S2.1: passing the pretreated dichlorosilane into an adsorption column filled with an adsorbent, wherein the adsorbent is a composite adsorbent of modified activated carbon and molecular sieve, the mass ratio of activated carbon to molecular sieve is 3:2, the specific surface area of ​​the adsorbent is 800-1200 square meters / gram, and the pore size distribution is between 0.5-2 nanometers; S2.2: Control the flow rate of dichlorosilane in the adsorption column to be 10 ml / min to 30 ml / min, and set a magnetic field generating device in the adsorption column with a magnetic field strength of 0.5T-1T, so that the metal impurities and some polar impurities therein are more efficiently adsorbed under the synergistic effect of the magnetic field and the adsorbent; S2.3: A gas disperser is set at the entrance of the adsorption column to disperse the dichlorosilane gas into tiny bubbles with a bubble diameter of 0.5mm-1mm; S3, distillation and purification S3.1: sending the dichlorosilane after adsorption and impurity removal to a distillation tower, wherein the number of theoretical plates of the distillation tower is 30-50; S3.2: The operating pressure of the distillation tower is controlled to be between 1000 Pa and 2000 Pa, the tower top temperature is 30°C to 35°C, the tower bottom temperature is 50°C to 60°C, and a rotating packing is arranged in the distillation tower, the packing rotation speed is 10r / min-20r / min, and its shape is spiral; S3.3: Collect electronic grade dichlorosilane product from the top of the distillation tower, the purity of which reaches more than 99.9999%, wherein the impurity content of boron, phosphorus and metal ions is less than 1 ppb; S4. Product post-processing S4.1: The electronic grade dichlorosilane product obtained by distillation is passed through an ultra-clean filtration device, the pore size of the ultra-clean filtration membrane is 0.01-0.1 micron, and the residual tiny particle impurities are removed; S4.2: Carry out online quality inspection on the products after ultra-clean filtration, and use ICP-MS and GC-MS to monitor the purity and impurity content of the products in real time, with a detection frequency of once per hour.

2. The method for purifying electronic grade dichlorosilane according to claim 1, characterized in that: In S1, the multi-layer precision filter includes at least five layers of filters with different pore sizes, and an electrostatic adsorption layer is arranged between two adjacent layers of filters. The electrostatic voltage is 500V-1000V for adsorbing tiny charged particles.

3. The method for purifying electronic grade dichlorosilane according to claim 1, characterized in that: During the S2 adsorption and impurity removal process, the adsorption column is provided with a temperature regulating device and a humidity regulating device for maintaining the adsorbent at 25°C to 30°C and a relative humidity of 40%-60%. The humidity regulation is achieved by introducing a small amount of dry nitrogen into the column.

4. The method for purifying electronic grade dichlorosilane according to claim 1, characterized in that: In the S3 distillation and purification process, the internal filler surface of the distillation tower is coated with a hydrophobic coating, and the coating material is polydimethylsiloxane.

5. A system for implementing the method for purifying electronic grade dichlorosilane according to any one of claims 1 to 4, characterized in that: include: Pre-processing unit, including: An ultrasonic oscillation device is used to perform ultrasonic oscillation treatment on dichlorodihydrogen silicon raw materials containing impurities, with an ultrasonic frequency of 30 kHz and a time of 15 minutes; The filtering device includes a multi-layer precision filter screen for removing solid particle impurities in the dichlorosilane raw material, and is provided with a filter screen cleaning module, which uses a cleaning solution of sodium hydroxide and ethanol mixed in a volume ratio of 1:1, and removes impurities on the filter screen surface by combining high-pressure spraying with a spray pressure of 0.5MPa-1MPa and ultrasonic oscillation with an ultrasonic frequency of 20kHz-30kHz; The low-temperature condensation device is connected to the filtering device and adopts a compressor refrigeration method. A temperature sensor, a flow regulating valve and a disturbance device are provided inside the device to cool the filtered dichlorodihydrogen silicon to a specific temperature range, condense some high-boiling point impurities, and precisely control the condensation temperature, the flow rate and the disturbance speed of dichlorodihydrogen silicon; Adsorption unit, comprising: Adsorption columns, the number of which is 3-5, connected in parallel or in series, filled with adsorbent, connected to a low-temperature condensation device, used to adsorb metal impurities and some polar impurities in dichlorosilane, and a gas disperser is provided at the entrance of each adsorption column; The temperature control module and the humidity control module are connected to the adsorption column and are used to adjust the temperature and humidity in the adsorption column; A magnetic field generating device is arranged inside the adsorption column and is used to generate a magnetic field; Distillation unit, including: The distillation tower is connected to the adsorption unit and is used to distill and purify dichlorosilane. The tower body is made of stainless steel lined with polytetrafluoroethylene, which has good corrosion resistance and heat insulation performance; A pressure control device, connected to the distillation tower, for controlling the operating pressure of the distillation tower; The temperature monitoring and control device is installed at the top and bottom of the distillation tower to monitor and control the temperature of the top and bottom of the tower; The rotating packing device is arranged inside the distillation tower, and the packing rotation speed is 10r / min-20r / min; A product collecting device, connected to the top of the distillation tower, for collecting the purified electronic grade dichlorosilane product; Post-processing and detection unit, including: An ultra-clean filtration device is connected to the product collection device, and the pore size of the ultra-clean filtration membrane is 0.01-0.1 micron; The online quality detection device uses an ICP-MS and a GC-MS, which are connected to an ultra-clean filtration device to monitor product purity and impurity content in real time.

6. The system of the method for purifying electronic grade dichlorosilane according to claim 5, characterized in that: The ultrasonic generator of the ultrasonic oscillation device adopts intelligent power regulation technology to automatically adjust the ultrasonic power according to the impurity content and properties of the raw materials, and the power regulation range is 500W-1000W.

7. The system of the method for purifying electronic grade dichlorosilane according to claim 5, characterized in that: The flow disturbance device of the low-temperature condensation device comprises rotatable blades, the blade angle is adjustable, and the angle adjustment range is 30°-60°.

8. The system of the method for purifying electronic grade dichlorosilane according to claim 5, characterized in that: The gas disperser in the adsorption column adopts micro-nano bubble generation technology, which can generate bubbles with a diameter of 0.1-1 mm, and the uniformity of bubble size distribution is above 90%.

9. The system of the method for purifying electronic grade dichlorosilane according to claim 5, characterized in that: The rotating packing device of the distillation tower adopts magnetic driving technology to avoid the sealing problem between the packing rotating shaft and the tower body.

10. The system according to claim 5, characterized in that: The ultra-clean filter membrane of the ultra-clean filter device is backwashed online, and the backwashing cycle can be automatically adjusted according to the impurity interception situation, and the backwashing pressure is 0.2MPa-0.5MPa; The data acquisition and analysis system of the online quality detection device adopts an artificial intelligence algorithm to automatically identify the change trend of impurity components.

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