A method and apparatus for purifying boron trichloride

Abstract

The application provides a purification method of boron trichloride, which comprises the following steps: removing the size particles in raw material boron trichloride through a filter, removing water through a first adsorption tower, removing phosgene through a second adsorption tower, collecting the boron trichloride after pressure boosting through a crude product tank, removing light components through a first rectification tower, removing heavy components through a second rectification tower, finally detecting the boron trichloride, collecting the boron trichloride to a product storage tank when the detection is qualified, and returning the unqualified product to the first adsorption tower for further purification; and the application also provides a purification device of boron trichloride, which removes water and phosgene in crude boron trichloride through an adsorption tower containing 4A molecular sieve and MOF-74 series fillers, and then purifies the boron trichloride through a second rectification, so that the process flow is simple, and the purity of the product can reach 6N level.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a method and apparatus for purifying boron trichloride. Background Technology

[0002] In semiconductor integrated circuit manufacturing, electronic gases are indispensable core support gases. Boron trichloride, as an important electronic gas, can be deposited into thin films via chemical vapor deposition and is a fundamental material for manufacturing optical fibers and BPG materials for integrated circuits. In plasma etching processes, boron trichloride is a crucial gas for etching aluminum metals and can also be used in doping and ion implantation processes in IC manufacturing.

[0003] With the development of the semiconductor industry, the control of semiconductor process conditions has become increasingly refined, placing higher demands on the purity of boron trichloride. Only by using high-purity boron trichloride can the controllability of chip manufacturing processes be guaranteed. The key to achieving sufficient purity in boron trichloride is to remove harmful and most difficult-to-remove impurities.

[0004] Impurities in crude boron trichloride typically include: water, phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen. Phosgene, in particular, is difficult to remove due to its boiling point being very close to that of boron trichloride. Therefore, a simple process is urgently needed to purify crude boron trichloride to obtain high-quality boron trichloride. Summary of the Invention

[0005] The purpose of this invention is to provide a purification method and apparatus for high-purity boron trichloride, which is simple in process and easy to operate.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A method for purifying boron trichloride includes the following steps:

[0008] S1. Boron trichloride raw material in the raw material tank is filtered and then pressed into the first-stage adsorption tower. The filter removes particles from the raw material, and the first-stage adsorption tower removes moisture from the boron trichloride raw material.

[0009] S2. Boron trichloride treated by S1 is passed into a secondary adsorption tower to remove phosgene from the boron trichloride.

[0010] S3. Pass the boron trichloride treated in S2 into the crude product tank for collection. After collecting to 3 / 4 of the liquid level, pressurize the crude product tank.

[0011] S4. Pass the boron trichloride in the pressurized crude product tank into the first-stage distillation column;

[0012] S5. After the working pressure and operating temperature of the first-stage distillation column have stabilized for at least 3 hours, the boron trichloride treated in S4 is introduced into the second-stage distillation column;

[0013] S6. After the working pressure and operating temperature of the secondary distillation column have stabilized for at least 3 hours, the boron trichloride collected from the secondary distillation column is analyzed. If it is qualified, it is collected into the finished product tank; if it is not qualified, it is returned to the primary adsorption column.

[0014] Preferably, the filter has a diameter of 3-30 nm.

[0015] Preferably, the packing material of the primary adsorption tower is 4A molecular sieve, and the working pressure of the primary adsorption tower is 0.4 MPa; the packing material of the secondary adsorption tower is MOF-74 series, and the working pressure of the secondary adsorption tower is 0.3 MPa.

[0016] Preferably, the MOF-74 series materials are one or any combination of Mg-MOF-74, Zn-MOF-74, Ni-MOF-74, Co-MOF-74, Cu-MOF-74, Mn-MOF-74, and Cr-MOF-74.

[0017] Preferably, the crude product tank is equipped with a refrigerant refrigeration device and a heating device. During collection, refrigerant is introduced to adjust the pressure of the crude product tank to 0.0-0.1MPa. After collecting to a certain liquid level, the crude product tank is heated to a pressure of 0.6-1.0MPa.

[0018] The finished product tank is equipped with a refrigerant refrigeration device and a heating device. During collection, refrigerant is introduced to adjust the pressure of the finished product tank to 0.0-0.1MPa.

[0019] Preferably, the operating pressure of the primary distillation column is 0.5MPa-0.6MPa, the operating temperature is 50℃-60℃, and the number of trays is 50-70.

[0020] Preferably, the operating pressure of the secondary distillation column is 0.4MPa-0.5MPa, the operating temperature is 40℃-50℃, and the number of trays is 70-100.

[0021] Preferably, the top product of the secondary distillation column that fails the analysis is returned to the primary adsorption column.

[0022] Preferably, the purity of the qualified product is 6N.

[0023] A boron trichloride purification apparatus includes a raw material tank, a filter, a primary adsorption tower, a secondary adsorption tower, a crude product tank, a primary distillation tower, a secondary distillation tower, and a finished product tank connected in sequence.

[0024] The bottom of the first-stage distillation column is connected to a first heater, and the top of the first-stage distillation column is connected to a first condenser. The bottom of the second-stage distillation column is connected to a second heater, and the top of the second-stage distillation column is connected to a second condenser. The temperature inside the distillation column is controlled by the first heater and the second heater, and gaseous boron trichloride is condensed and refluxed by the first condenser and the second condenser.

[0025] The top discharge of the secondary distillation column is connected to the primary adsorption column via a valve. After the valve is opened, the unqualified gas in the finished product tank enters the primary adsorption column for further purification.

[0026] Beneficial effects of this invention:

[0027] The purification method for boron trichloride described in this invention employs a combination of two-stage adsorption and two-stage distillation to remove impurities such as moisture, phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen from boron trichloride. After purification, the impurity content of boron trichloride is less than 1 ppm, and the purity of boron trichloride can reach 6N grade. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the boron trichloride purification apparatus of the present invention:

[0029] Among them, 1-raw material tank, 2-first-stage adsorption tower, 3-second-stage adsorption tower, 4-crude product tank, 5-first-stage distillation tower, 6-second-stage distillation tower, 7-finished product tank, 8-filter. Detailed Implementation

[0030] To better understand the content of this invention, the invention will be further described in detail below through specific embodiments, so that those skilled in the art can implement it based on the description. However, the scope of protection of this invention is not limited to the content described.

[0031] Examples 1-3 all employ a boron trichloride purification device, comprising a raw material tank 1, a filter 8, a primary adsorption tower 2, a secondary adsorption tower 3, a crude product tank 4, a primary distillation tower 5, a secondary distillation tower 6, and a finished product tank 7, which are connected in sequence.

[0032] The bottom of the primary distillation column 5 is connected to a first heater, and the top of the primary distillation column is connected to a first condenser. The bottom of the secondary distillation column 6 is connected to a second heater, and the top of the secondary distillation column 6 is connected to a second condenser. The temperature inside the distillation column is controlled by the first heater and the second heater, and gaseous boron trichloride is condensed and refluxed by the first condenser and the second condenser.

[0033] The top discharge of the secondary distillation column 6 is connected to the primary adsorption column 2 through a valve. After the valve is opened, the unqualified gas in the finished product tank 7 enters the primary adsorption column 2 for further purification.

[0034] Example 1:

[0035] A method for purifying boron trichloride, wherein the boron trichloride raw material has a purity of 90%, and the impurities in the raw material include moisture, phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen. The specific steps are as follows:

[0036] S1. The boron trichloride raw material in the raw material tank 1 is pressed into the primary adsorption tower 2. The particles in the raw material are removed by the filter 8 with a diameter of 30 nm. The moisture in the boron trichloride raw material is removed by the primary adsorption tower 2. The working pressure of the primary adsorption tower is 0.4 MPa. The packing material of the primary adsorption tower 2 is 4A molecular sieve.

[0037] S2. Boron trichloride treated by S1 is introduced into the secondary adsorption tower 3 to remove phosgene from the boron trichloride. The working pressure of the secondary adsorption tower 3 is 0.3 MPa, and the packing material of the secondary adsorption tower 3 is Mg-MOF-74.

[0038] S3. The boron trichloride treated in S2 is introduced into the crude product tank 4. The crude product tank 4 is equipped with a refrigerant and a heater. During collection, the refrigerant is introduced to adjust the pressure of the crude product tank 4 to 0.05 MPa. After collecting to 3 / 4 of the liquid level, the pressure of the crude product tank 4 is heated to 0.6 MPa.

[0039] S4. The boron trichloride treated in S3 is fed into the first-stage distillation column 5, which has an operating pressure of 0.55 MPa, an operating temperature of 50°C, and 50 trays.

[0040] S5. After the working pressure and operating temperature of the primary distillation column 5 have stabilized for at least 3 hours, the boron trichloride treated in S4 is introduced into the secondary distillation column 6. The working pressure of the secondary distillation column 6 is 0.45 MPa, the operating temperature is 40°C, and the number of trays is 100.

[0041] S6. The boron trichloride collected from the secondary distillation column was analyzed. The impurities in the boron trichloride, including phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen, were 0.62 ppm. The boron trichloride with a purity of 99.99993% was obtained by this device.

[0042] Example 2:

[0043] A method for purifying boron trichloride, wherein the boron trichloride raw material has a purity of 95%, and the impurities in the raw material include moisture, phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen. The specific steps are as follows:

[0044] S1. The boron trichloride raw material in the raw material tank 1 is then pressed into the primary adsorption tower 2. The particles in the raw material are removed by the filter 8 with a diameter of 3 nm, and the moisture in the boron trichloride raw material is removed by the primary adsorption tower 2. The working pressure of the primary adsorption tower is 0.4 MPa, and the packing material of the primary adsorption tower 2 is 4A molecular sieve.

[0045] S2. Boron trichloride treated by S1 is introduced into the secondary adsorption tower 3 to remove phosgene from the boron trichloride. The working pressure of the secondary adsorption tower 3 is 0.3 MPa, and the packing material of the secondary adsorption tower 3 is Zn-MOF-74.

[0046] S3. The boron trichloride treated in S2 is introduced into the crude product tank 4. The crude product tank 4 is equipped with a refrigerant and a heater. During collection, the refrigerant is introduced to adjust the pressure of the crude product tank 4 to 0 MPa. After collecting to 3 / 4 of the liquid level, the pressure of the crude product tank 4 is heated to 0.7 MPa.

[0047] S4. The boron trichloride treated in S3 is fed into the first-stage distillation column 5, which has an operating pressure of 0.55 MPa, an operating temperature of 55°C, and 60 trays.

[0048] S5. After the working pressure and operating temperature of the primary distillation column 5 have stabilized for at least 3 hours, the boron trichloride treated in S4 is introduced into the secondary distillation column 6. The working pressure of the secondary distillation column 6 is 0.4 MPa, the operating temperature is 45°C, and the number of trays is 85.

[0049] S6. The boron trichloride collected from the secondary distillation column was analyzed. The impurities in the boron trichloride, including phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen, were 0.45 ppm. The boron trichloride with a purity of 99.99995% was obtained through this device.

[0050] Example 3:

[0051] A method for purifying boron trichloride, wherein the boron trichloride raw material has a purity of 99%, and the impurities in the raw material include phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen. The specific steps are as follows:

[0052] S1. The boron trichloride raw material in the raw material tank 1 is pressed into the primary adsorption tower 2. The particles in the raw material are removed by the filter 8 with a diameter of 10 nm, and the moisture in the boron trichloride raw material is removed by the primary adsorption tower 2. The working pressure of the primary adsorption tower is 0.4 MPa, and the packing of the primary adsorption tower 2 is 4A molecular sieve.

[0053] S2. Boron trichloride treated by S1 is introduced into the secondary adsorption tower 3 to remove phosgene from the boron trichloride. The working pressure of the secondary adsorption tower 3 is 0.3 MPa, and the packing material of the secondary adsorption tower 3 is 50 wt% Ni-MOF-74 and 50 wt% Co-MOF-74.

[0054] S3. The boron trichloride treated in S2 is introduced into the crude product tank 4. The crude product tank 4 is equipped with a refrigerant and a heater. During collection, the refrigerant is introduced to adjust the pressure of the crude product tank 4 to 0.1 MPa. After collecting to 3 / 4 of the liquid level, the pressure of the crude product tank 4 is heated to 1.0 MPa.

[0055] S4. The boron trichloride treated in S3 is fed into the first-stage distillation column 5, which has an operating pressure of 0.6 MPa, an operating temperature of 60°C, and 70 trays.

[0056] S5. After the working pressure and operating temperature of the first-stage distillation column 5 have stabilized for at least 3 hours, the boron trichloride treated in S4 is introduced into the second-stage distillation column 6. The working pressure of the second-stage distillation column 6 is 0.5 MPa, the operating temperature is 50°C, and the number of trays is 70.

[0057] S6. The boron trichloride collected from the secondary distillation column was analyzed. The impurities in the boron trichloride, including phosgene, chlorine, carbon monoxide, carbon dioxide, hydrogen chloride, dichlorosilane, trichlorosilane, silicon tetrachloride, nitrogen, and oxygen, were 0.31 ppm. The boron trichloride with a purity of 99.99996% was obtained by this device.

[0058] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for purifying boron trichloride, characterized by, Comprise the following steps: S1. The raw material tank (1) of boron trichloride raw material is pressed into the first adsorption tower (2) after the filter (8), the particles in the raw material are removed by the filter (8), and the moisture in the boron trichloride raw material is removed by the first adsorption tower (2); S2. The boron trichloride treated in S1 is introduced into the second adsorption tower (3), and the phosgene in the boron trichloride is removed; S3. The boron trichloride treated in S2 is introduced into the crude product tank (4) for collection, and the crude product tank (4) is pressurized after the liquid level reaches 3 / 4; S4. The boron trichloride in the pressurized crude product tank (4) is introduced into the first rectifying tower (5); S5. After the working pressure and operating temperature of the first rectifying tower (5) are stable for at least 3h, the boron trichloride treated in S4 is introduced into the second rectifying tower (6); S6. After the working pressure and operating temperature of the second rectifying tower (6) are stable for at least 3h, the boron trichloride collected from the second rectifying tower (6) is analyzed, and the qualified product is collected into the finished product tank (7), and the unqualified product is returned to the first adsorption tower (2); The packing of the first adsorption tower (2) is 4A molecular sieve, the working pressure of the first adsorption tower (2) is 0.4 MPa, the packing of the second adsorption tower (3) is MOF-74 series, and the working pressure of the second adsorption tower (3) is 0.3 MPa; The MOF-74 series material is one or any combination of Mg-MOF-74, Zn-MOF-74, Ni-MOF-74, Co-MOF-74, Cu-MOF-74, Mn-MOF-74 and Cr-MOF-74.

2. The method of purifying boron trichloride according to claim 1, wherein The diameter of the filter (8) is 3-30 nm.

3. The method of purifying boron trichloride according to claim 1, wherein The crude product tank (4) is equipped with a refrigerant refrigeration device and a heating device, and the pressure of the crude product tank (4) is adjusted to 0.0-0.1 MPa by introducing refrigerant during collection, and the crude product tank (4) is heated to a pressure of 0.6-1.0 MPa after collecting to a certain liquid level; The finished product tank (7) is equipped with a refrigerant refrigeration device and a heating device, and the pressure of the finished product tank (7) is adjusted to 0.0-0.1 MPa by introducing refrigerant during collection.

4. The method of purifying boron trichloride according to claim 1, wherein The working pressure of the first rectifying tower (5) is 0.5-0.6 MPa, the operating temperature is 50-60℃, and the number of plates is 50-70.

5. The method of purifying boron trichloride according to claim 1, wherein The working pressure of the second rectifying tower (6) is 0.4-0.5 MPa, the operating temperature is 40-50℃, and the number of plates is 70-100.

6. The method of purifying boron trichloride according to claim 1, wherein The overhead of the second rectifying tower (6) is returned to the first adsorption tower (2) after analysis.

7. The method of purifying boron trichloride according to claim 1, wherein The purity of the qualified product is 6N.

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