Purification device for electronic-grade dimethyldimethoxysilane

Abstract

The utility model discloses an electronic-grade dimethyldimethoxysilane purifying device which is characterized in that an industrial-grade raw material tank is connected with a primary dehydrating tower, the primary dehydrating tower is connected with a buffer tank, the buffer tank is connected with a primary rectifying tower, the top of the primary rectifying tower is connected with a secondary rectifying tower, the bottom of the secondary rectifying tower is connected with the buffer tank, and the buffer tank is connected with a resin tower; the resin tower is connected with the secondary dehydrating tower, the secondary dehydrating tower is connected with the filter, and the filter is connected with the electronic-grade product tank. According to the utility model, the good yield of electronic-grade products can be ensured, in addition, on-line organic component analysis is carried out on the materials after two times of rectification, the organic purity of the materials can be fully ensured to be maintained above 99.99%, and finally electronic-grade qualified products are obtained.

Description

Technical Field

[0001] The utility model relates to the purification and refining of electronic-grade dimethyldimethoxysilane, in particular to a device used in the production process of dimethyldimethoxysilane. Background Art

[0002] Dimethyldimethoxysilane ((CH3O)2Si(CH3)2) is usually a low-viscosity liquid with high volatility and certain solubility. It is soluble in a variety of organic solvents. It is widely used in the fields of chemical industry, materials, semiconductor manufacturing, etc., especially in thin film deposition and surface treatment. Its unique chemical properties make it an important precursor and intermediate. In the semiconductor field, dimethyldimethoxysilane is mainly used as a precursor or intermediate in the manufacturing and processing process. The specific uses are as follows: (1) Used as an insulating layer in semiconductor devices to reduce the capacitance effect and improve the speed and performance of the device. (2) Used as a silicon source material in the chemical vapor deposition (CVD) process to form thin films or nanostructures. These silicon-based films or structures can be used as insulating layers, passivation layers or other functional layers in chip manufacturing. (3) Used for surface treatment in electronic packaging to improve the adhesion and stability of packaging materials and improve the durability and reliability of packaging. (4) Can be used as an additive in photoresist to optimize the performance of photoresist and enhance the accuracy of pattern transfer.

[0003] Currently, dimethyldimethoxysilane is primarily produced at industrial-grade purity. Due to the special properties of the synthetic raw materials, dimethyldimethoxysilane is only 30-40% pure during synthesis. Therefore, even industrial-grade purity requires purification. Chinese patents CN101712691B, CN109251221A, CN116444557A, and CN214346486U disclose methods for preparing dimethyldimethoxysilane and reaction apparatus, which also include methods for purifying industrial-grade dimethyldimethoxysilane. However, these methods fall far short of electronic-grade standards. Not only does the organic purity not meet the standards, but the impurity content, such as anions, cations, moisture, and particles, is too high, making it unsuitable for use in chip manufacturing processes.

[0004] Currently, no literature has reported on electronic-grade dimethyldimethoxysilane purification equipment or process systems. This utility model patent describes a process starting with industrial-grade dimethyldimethoxysilane, including the removal of water, light and heavy components, anions and cations, secondary dehydration, and particle removal. The patent details the relevant process parameters and allows for partial recovery of dimethyldimethoxysilane, ensuring product yield. After a series of purification steps, qualified electronic-grade dimethyldimethoxysilane is ultimately obtained. Summary of the Invention

[0005] In order to obtain electronic-grade dimethyldimethoxysilane, the utility model provides a purification device for electronic-grade dimethyldimethoxysilane, which realizes the purification of electronic-grade dimethyldimethoxysilane by organically combining the processes of removing water, removing light and heavy components, removing anions and cations, secondary dehydration, and removing particles.

[0006] Dimethyldimethoxysilane purification device, including industrial-grade raw material tank, primary dehydration tower A, primary dehydration tower B, buffer tank 1, primary distillation tower, heavy component flash tank, secondary distillation tower, light component flash tank, temporary storage tank, gas chromatograph, buffer tank 2, resin tower A, resin tower B, secondary dehydration tower A, secondary dehydration tower B, filter A, filter B, electronic-grade product tank;

[0007] The industrial-grade raw material tank is connected to the first-level dehydration tower, the first-level dehydration tower is connected to the buffer tank, the buffer tank 1 is connected to the first-level distillation tower, the top of the first-level distillation tower is connected to the second-level distillation tower, the bottom of the second-level distillation tower is connected to the buffer tank, the buffer tank 2 is connected to the resin tower, the resin tower is connected to the second-level dehydration tower, the second-level dehydration tower is connected to the filter, and the filter is connected to the electronic-grade product tank.

[0008] The primary dehydration tower includes a primary dehydration tower A and a primary dehydration tower B, one of which is in standby mode and the other in use. During operation, one of the towers uses high-temperature nitrogen to dehydrate and restore performance.

[0009] The bottom of the first-stage distillation tower is connected to the heavy component flash tank, and the top of the second-stage distillation tower is connected to the light component flash tank; the heavy component flash tank and the light component flash tank are respectively connected to the temporary storage tank, and the temporary storage tank is connected to the buffer tank.

[0010] The bottom of the secondary distillation tower is connected to the gas chromatograph and then to the buffer tank 2, and the gas chromatograph is connected to the buffer tank 1.

[0011] The resin tower includes resin tower A and resin tower B, one for backup and the other for use; the materials with anions and cations removed from the resin tower continue to enter the dehydration tower.

[0012] The secondary dehydration tower is divided into secondary dehydration tower A and secondary dehydration tower B, one for backup and the other for use.

[0013] The filter is divided into filter A and filter B, one for backup and the other for use.

[0014] The dimethyldimethoxysilane purification system includes a primary dehydration tower dehydration process, a primary distillation process, a secondary distillation process, a secondary flash evaporation process, an anion and cation removal process, a secondary dehydration process, and a particle removal process. The specific process is as follows: the industrial-grade raw material tank is nitrogen-pressed, and after flowing out from the bottom of the industrial-grade raw material tank, it is pumped to the primary dehydration tower A and the primary dehydration tower B. After dehydration, the material enters the buffer tank and continues to enter the primary distillation tower. The material at the top of the distillation tower enters the secondary distillation tower. The material at the bottom of the primary distillation tower and the material at the top of the secondary distillation tower are flashed and then enter the temporary storage tank together, and enter the buffer tank one at the appropriate time; the material coming out of the bottom of the secondary distillation tower is tested by gas chromatography and then enters the buffer tank two after passing the test, and then goes to the resin tower A and the resin tower B in turn to remove anions and cations, enter the secondary dehydration tower A, the secondary dehydration tower B to remove moisture, enter the filter A, the filter B to remove particulate impurities, and finally the qualified electronic-grade dimethyldimethoxysilane enters the electronic-grade product tank. This process system not only purifies the industrial-grade dimethyldimethoxysilane into electronic-grade products by removing moisture, anions and cations, and particulate impurities. In addition, a post-distillation flash material recovery system is designed, because the light and heavy components of the first and second distillation towers still contain a large amount of dimethyldimethoxysilane, which can still be used as an industrial-grade raw material for distillation and purification after flash evaporation.

[0015] In the dehydration process, the primary dehydration tower is divided into two sets of equipment, A and B, one for use and one for standby. While one set is in use, the other performs high-temperature nitrogen dehydration to restore performance. Each dehydration tower is composed of three layers, filled from top to bottom with three types of fillers: 3A, silica gel, and polyacrylamide absorbent resin. By filling with specific fillers and using a certain amount, moisture can be removed at different levels. Ultimately, after adsorption by the three layers of fillers, the moisture content of the material can be reduced to 40 ppm. This initial dehydration of the material not only prevents corrosion of the material on the pipeline but also minimizes the impact of moisture on subsequent processes.

[0016] In some preferred embodiments, the volume ratio of each filler is 4:2:1 from top to bottom, and the diameter ratio of each section of filler is 1:1:1.

[0017] The first-stage distillation process is characterized in that: the feed pressure of the first-stage distillation tower is 1-5 bar, the feed temperature is 40-50°C, the feed position is the 18th tower plate, the feed gas-liquid state is liquid phase, the theoretical number of plates of the distillation tower is 42, the packing type is theta ring packing, the reflux ratio is 3-5, the tower top pressure is 1.5-3.5 bar, the tower top extraction ratio is 0.90-0.950, the first-stage distillation equipment and the material contact parts are all made of stainless steel, and the stainless steel material is mechanically or electrolytically polished with a roughness of ≤0.2um, and the pipelines and instruments are made of fluorine-lined material.

[0018] The secondary distillation process involves a second-stage distillation tower feed pressure of 10-12 bar, a feed temperature of 100-110°C, a feed position of the 55th tray, a liquid phase feed, 63 theoretical trays, theta ring packing, a reflux ratio of 10-15, a top pressure of 8-10 bar, and a bottom extraction ratio of 0.926-0.955. All parts of the second-stage distillation equipment that come into contact with the material are made of stainless steel, which is mechanically or electrolytically polished to a roughness of ≤0.2 μm. Fluorine-lined piping and instrumentation are used. After secondary distillation, the dimethyldimethoxysilane content reaches 99.99%, with anion concentrations below 10 ppb and individual cation concentrations below 30 ppt.

[0019] In the secondary flash evaporation process, the flash tank at the bottom of the primary distillation tower is mainly used to collect the dimethyldimethoxysilane in the removed heavy components and collect it into a temporary storage tank. The flash tank pressure is 1.7 bar and the temperature is 100°C. After flash evaporation, its purity can be purified from 0.9600 to 0.9878; the flash tank at the top of the secondary distillation tower is mainly used to collect the dimethyldimethoxysilane in the removed light components and collect it into a temporary storage tank. The flash tank pressure is 10 bar and the temperature is 179°C. After flash evaporation, its purity can be purified from 0.9838 to 0.9869. Because the purity of industrial-grade dimethyldimethoxysilane has reached more than 99%, a large amount of dimethyldimethoxysilane will flow out from the light components and heavy components together during the light and heavy component removal process, so it needs to be recovered. The recovered dimethyldimethoxysilane has a purity of 99.68%.

[0020] In the anion and cation removal process, different resins are used for exchange removal of anions and cations. Specifically, a mixed resin is formed by mixing a cationic resin and an anionic resin, wherein the cationic resin is selected from XO1300-H and XO1310-H; the anionic resin is selected from XO1600-OH resin;

[0021] The resin types filled in the upper and lower packings are cationic resin and anionic resin, respectively, with a filling volume ratio of 3-5:1-2. The working pressure of the resin tower is 2-5 bar, and the working temperature is room temperature. After the resin cation exchange, the anion concentration in dimethyldimethoxysilane is controlled below 50ppb, and the single cation concentration is controlled below 30ppt; however, the water content exceeds 20ppm, and the dehydration process needs to be carried out again.

[0022] In the secondary dehydration process, the types of mixed fillers in the secondary dehydration tower are two types of fillers, silica gel and water-absorbing resin. The above conditions are used to dehydrate dimethyldimethoxysilane. The moisture content of dimethyldimethoxysilane after dehydration can also be controlled at 20ppm through moisture detection.

[0023] In some preferred cases, the volume ratio of the upper and lower packings is 1:1, and the diameter ratio of the upper and lower packing beds is 1:1.

[0024] In the particle removal process, the dimethyldimethoxysilane after resin filtration in the filter is circulated and filtered, and the filtration is carried out in series using microporous folded filter elements with pore sizes of 120-100nm, 50-40nm, and 10-5nm (in some preferred cases, the filtration is carried out using microporous folded filter elements with pore sizes of 100nm, 50nm, and 10nm, respectively). The filter element material is one of polytetrafluoroethylene and polyvinylidene fluoride membrane (PVDF). After filtration, the concentration of particles greater than 0.2 microns in the dimethyldimethoxysilane is less than 50 particles / ml, the concentration of particles greater than 0.1 microns is less than 100 particles / ml, and the concentration of particles greater than 0.05 microns is less than 200 particles / ml. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the process scheme of the embodiment of the utility model, the following is a brief introduction to the drawings required for use in the embodiment of the utility model. The following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a device diagram for the process of purifying electronic-grade dimethyldimethoxysilane in the utility model.

[0027] Description of the marks in the figure:

[0028] Industrial-grade raw material tank 1, primary dehydration tower A 2, primary dehydration tower B 3, buffer tank 1 4, primary distillation tower 5, heavy component flash tank 6, secondary distillation tower 7, light component flash tank 8, temporary storage tank 9, gas chromatograph 10, buffer tank 2 11, resin tower A 12, resin tower B 13, secondary dehydration tower A 14, secondary dehydration tower B 15, filter A 16, filter B 17, electronic-grade product tank 18. DETAILED DESCRIPTION

[0029] The industrial-grade dimethyldimethoxysilane described in the utility model has a main content of ≥99%, a water content of ≤800ppm, a chloride ion content of ≤300ppm, and a total metal ion content of ≤700ppb, and the metal ions mainly include K, Ga, Na, Mg, Al, Zn, Fe, Cr, Mn, Ni, Pb, Cu, etc.

[0030] Example 1

[0031] A purification device for electronic-grade dimethyldimethoxysilane includes an industrial-grade raw material tank 1, a primary dehydration tower A2, a primary dehydration tower B3, a buffer tank 14, a primary distillation tower 5, a heavy component flash tank 6, a secondary distillation tower 7, a light component flash tank 8, a temporary storage tank 9, a gas chromatograph 10, a buffer tank 2 11, a resin tower A 12, a resin tower B 13, a secondary dehydration tower A 14, a secondary dehydration tower B 15, a filter A 16, a filter B 17, and an electronic-grade product tank 18.

[0032] The industrial-grade raw material tank 1 is connected to the primary dehydration tower, the primary dehydration tower is connected to the buffer tank 1 4, the buffer tank 1 4 is connected to the primary distillation tower 5, the top of the primary distillation tower 5 is connected to the secondary distillation tower 7, the bottom of the secondary distillation tower 7 is connected to the buffer tank 2 11, the buffer tank 2 11 is connected to the resin tower, the resin tower is connected to the secondary dehydration tower, the secondary dehydration tower is connected to the filter, and the filter is connected to the electronic-grade product tank 18.

[0033] The primary dehydration tower includes a primary dehydration tower A2 and a primary dehydration tower B3, one of which is in standby mode and the other in use. During operation, one of the towers uses high-temperature nitrogen to dehydrate and restore performance.

[0034] The bottom of the primary distillation tower 5 is connected to the heavy component flash tank 6, and the top of the secondary distillation tower 7 is connected to the light component flash tank 8; the heavy component flash tank 6 and the light component flash tank 8 are respectively connected to the temporary storage tank 9, and the temporary storage tank 9 is connected to the buffer tank 4.

[0035] The bottom of the secondary distillation tower 7 is connected to the gas chromatograph 10 and then to the buffer tank 11, and the gas chromatograph 10 is connected to the buffer tank 1 4.

[0036] The resin tower includes resin tower A 12 and resin tower B 13, one for standby and the other for use; the material from which anions and cations are removed from the resin tower continues to enter the dehydration tower.

[0037] The secondary dehydration tower is divided into a secondary dehydration tower A 13 and a secondary dehydration tower B 14, one for backup and the other for use.

[0038] The filter is divided into filter A 11 and filter B 12, one for backup and the other for use.

[0039] The industrial-grade raw material tank 1 is pressurized with nitrogen. After flowing out from the bottom of the industrial-grade raw material tank 1, it is pumped to the primary dehydration tower A2 and the primary dehydration tower B3. After dehydration, the material enters the buffer tank 1-4 and continues to enter the primary distillation tower 5. The material at the top of the distillation tower enters the secondary distillation tower 7. The bottom material of the primary distillation tower 5 and the top material of the secondary distillation tower 7 are flashed and then enter the temporary storage tank 9 together, and enter the buffer tank 1-4 at the appropriate time; the material coming out of the bottom of the secondary distillation tower 7 is tested by gas chromatography 10 and passes the test and enters the buffer tank 2 11, and then goes to the resin tower A 12 and the resin tower B 13 in sequence to remove anions and cations, enters the secondary dehydration tower A 14, the secondary dehydration tower B 15 to remove moisture, enters the filter A 16, and the filter B 17 to remove particulate impurities. Finally, the qualified electronic-grade dimethyldimethoxysilane enters the electronic-grade product tank 18.

[0040] Example 2

[0041] The process apparatus of Example 1 was used, and industrial-grade dimethyldimethoxysilane continuously entered the purification system.

[0042] The primary dehydration tower consists of two sets, A and B. Each set is divided into three layers, loaded from top to bottom with three types of fillers: 3A, silica gel, and polyacrylamide absorbent resin. The volume ratio of each filler is 4:2:1 from top to bottom, and the diameter ratio of each filler section is 1:1:1. After adsorption, the moisture content of the material can be reduced to 40ppm.

[0043] The dehydrated material enters the first-stage distillation tower for weight removal, with a feed pressure of 2 bar, a feed temperature of 50°C, a feed position of the 18th tray, a feed state of liquid phase, a theoretical number of 42 plates in the distillation tower, a packing of Theta rings, a reflux ratio of 3, a top pressure of 1.8 bar, and a top extraction ratio of 0.950. The weight-removed material enters the secondary distillation tower with a feed pressure of 12 bar, a feed temperature of 103°C, a feed position of the 55th tray, a feed state of liquid phase, a theoretical number of 63 plates, a packing of Theta rings, a reflux ratio of 10, a top pressure of 10 bar, and a bottom extraction ratio of 0.926. After the secondary distillation, the dimethyldimethoxysilane content reaches 99.99%.

[0044] Flash evaporation is mainly used to recover dimethyldimethoxysilane. The pressure of the flash tank at the bottom of the primary distillation tower is 1.7 bar and the temperature is 100°C; the pressure of the flash tank at the top of the secondary distillation tower is 10 bar and the temperature is 179°C; the dimethyldimethoxysilane content in the temporary storage tank reaches 99.68%.

[0045] The material after light removal enters the resin tower for the removal of anions and cations. Experiments show that the types of mixed resins are two of XO1300-H and XO1600-OH resins, and the resin types filled in the upper and lower packings are cation resin and anion resin with a filling volume ratio of 3:2. When the working pressure of the resin tower is 2 bar and the working temperature is 25°C, after the resin cation exchange, the anion concentration in dimethyldimethoxysilane is controlled below 50ppb, and the single cation concentration is controlled below 30ppt.

[0046] The material enters the secondary dehydration tower from the resin tower. The types of mixed fillers are two types of fillers, silica gel and polyacrylamide water-absorbing resin. The volume ratio of the upper and lower fillers is 1:1, and the diameter ratio of the upper and lower filler beds is 1:1. The above conditions are used to dehydrate dimethyldimethoxysilane. The moisture content of dimethyldimethoxysilane after dehydration can also be controlled at 20ppm through moisture detection.

[0047] The material is finally subjected to particle removal. The dimethyldimethoxysilane filtered by the resin in the filter is then circulated and filtered. The filtration is carried out in series using microporous folded filter elements with pore sizes of 100nm, 50nm, and 10nm respectively. The filter element material is one of polytetrafluoroethylene and polyvinylidene fluoride membrane (PVDF). The concentration of particles of dimethyldimethoxysilane greater than 0.2 microns is less than 50 particles / ml, the concentration of particles greater than 0.1 microns is less than 100 particles / ml, and the concentration of particles greater than 0.05 microns is less than 200 particles / ml.

Claims

1. Electronic grade dimethyldimethoxysilane purification device, characterized in that, Including industrial grade raw material tank (1), primary dehydration tower A (2), primary dehydration tower B (3), buffer tank 1 (4), primary distillation tower (5), heavy component flash tank (6), secondary distillation tower (7), light component flash tank (8), temporary storage tank (9), gas chromatograph (10), buffer tank 2 (11), resin tower A (12), resin tower B (13), secondary dehydration tower A (14), secondary dehydration tower B (15), filter A (16), filter B (17), electronic grade product tank (18); The industrial-grade raw material tank (1) is connected to the primary dehydration tower, the primary dehydration tower is connected to the buffer tank 1 (4), the buffer tank 1 (4) is connected to the primary distillation tower (5), the top of the primary distillation tower (5) is connected to the secondary distillation tower (7), the bottom of the secondary distillation tower (7) is connected to the buffer tank 2 (11), the buffer tank 2 (11) is connected to the resin tower, the resin tower is connected to the secondary dehydration tower, the secondary dehydration tower is connected to the filter, and the filter is connected to the electronic-grade product tank (18).

2. The electronic grade dimethyldimethoxysilane purification device according to claim 1, characterized in that: The first-stage dehydration tower includes a first-stage dehydration tower A (2) and a first-stage dehydration tower B (3), one of which is in standby mode and the other in use. During operation, one of the towers uses high-temperature nitrogen to perform dehydration and restore performance.

3. The electronic grade dimethyldimethoxysilane purification device according to claim 1, characterized in that: The bottom of the first-stage distillation tower (5) is connected to the heavy component flash tank (6), and the top of the second-stage distillation tower (7) is connected to the light component flash tank (8); the heavy component flash tank (6) and the light component flash tank (8) are respectively connected to the temporary storage tank (9), and the temporary storage tank (9) is connected to the buffer tank (4).

4. The electronic grade dimethyldimethoxysilane purification device according to claim 1, characterized in that: The bottom of the secondary distillation tower (7) is connected to the gas chromatograph (10) and then to the buffer tank 2 (11), and the gas chromatograph (10) is connected to the buffer tank 1 (4).

5. The electronic grade dimethyldimethoxysilane purification device according to claim 1, characterized in that: The resin tower includes resin tower A (12) and resin tower B (13), one for standby and the other for use; the material from which anions and cations are removed from the resin tower continues to enter the dehydration tower.

6. The electronic grade dimethyldimethoxysilane purification device according to claim 1, characterized in that: The secondary dehydration tower is divided into a secondary dehydration tower A (14) and a secondary dehydration tower B (15), one for backup and the other for use.

7. The dimethyldimethoxysilane purification device according to claim 1, characterized in that: The filter is divided into filter A (16) and filter B (17), one for backup and the other for use.

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