Method for preparing electronic-grade hydrogen bromide by using industrial-grade hydrogen bromide

Abstract

The invention belongs to the technical field of semiconductor materials, and discloses a method for preparing electronic-grade hydrogen bromide from industrial-grade hydrogen bromide, which comprises the following steps: (1) heating an industrial-grade hydrogen bromide raw material with the HBr content of 0.95-0.999 to 18-20.3 DEG C and the pressure of 20-25 kg, and feeding the industrial-grade hydrogen bromide raw material into a dehydrating tower kettle at the flow rate of 10 kg / h; (2) the temperature of the tower kettle of the dehydrating tower is 70-80 DEG C, the pressure in the tower is 20-25 kg, the industrial-grade hydrogen bromide generates rising steam under the action of a tower kettle reboiler, the rising steam is condensed into a liquid phase at the tower top, one part of the liquid phase flows back to the dehydrating tower, and the other part of the liquid phase is extracted from the tower top of the dehydrating tower as a dehydrated product; hydrogen bromide containing concentrated water and heavy components is extracted from the tower kettle; (3) enabling a dehydrated product extracted from the top of the dehydrating tower to enter a middle section of a light component removal tower, discharging non-condensable gas from the top of the light component removal tower, and discharging hydrogen bromide from a tower kettle of the light component removal tower at an average flow rate of 8.5-9.5 kg / h / h; the tower top temperature of the light component removal tower is 15-20 DEG C, and the tower kettle temperature is 19-25 DEG C; (4) hydrogen bromide discharged from the tower kettle of the light component removal tower automatically enters a refining tower through pressure difference, and the temperature of the tower top of the refining tower is 18-22 DEG C; the electronic-grade hydrogen bromide is extracted from the top of the refining tower at the rate of 8kg / h.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor materials, and in particular relates to a method for preparing electronic-grade hydrogen bromide by utilizing industrial-grade hydrogen bromide. Background Art

[0002] With the rapid development of the semiconductor industry, electronic chemicals used in semiconductor etching have become an important factor affecting etching accuracy. Plasma etching technology using hydrogen bromide as etching gas can achieve precise etching accuracy by controlling the temperature of the etched material. Therefore, high-purity hydrogen bromide is often used for etching semiconductor phosphorus-doped N-type polysilicon, phosphorus-doped single crystal silicon or two-dimensional semiconductors, and is one of the core gases for the advanced process of the new generation of chips.

[0003] Electronic-grade hydrogen bromide can be made from hydrogen bromide synthesis or from industrial-grade hydrogen bromide purification. The main hydrogen bromide synthesis processes include: combustion method, red phosphorus method, sulfur method, ammonia method, and chloroform-bromine synthesis method. After synthesis, it is purified and refined to obtain electronic-grade hydrogen bromide. This project uses industrial-grade hydrogen bromide as raw material for purification. The main impurities contained in industrial-grade hydrogen bromide are hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, hydrogen chloride, dichloromethane and water, as well as trace amounts of metal ion impurities. Purification includes two aspects: dehydration and refining. The separation methods used include physical adsorption, chemical dehumidification, freezing and venting, distillation, and a combination of various methods.

[0004] However, there are defects in the dehydration of existing hydrogen bromide refining technology. The water content has a great influence on the corrosiveness of hydrogen bromide. Experimental results show that when the water content is less than 1ppm, hydrogen bromide is non-corrosive, and when the water content is greater than 2ppm, hydrogen bromide shows strong corrosiveness. Therefore, in order to ensure the quality and long-term stability of electronic-grade hydrogen bromide, the water content of hydrogen bromide needs to be strictly controlled below 1ppm. The current dehydration methods include adsorption materials such as molecular sieves, silica gel, alumina, activated carbon, calcium chloride, and phosphorus pentoxide. Physical adsorption dehydration must keep the water content low, otherwise the adsorbent will release heat. In addition, physical dehydration has the problem of frequent adsorbent replacement. Hydrogen bromide containing water can easily destroy the pore structure of adsorbents such as molecular sieves, thereby causing the adsorption capacity of the adsorbent to decay and deactivate rapidly. In addition, the adsorption bed requires a certain pressure, and the fluid conveying equipment (pump or fan) of hydrogen bromide is pressurized. The equipment material needs to be made of corrosion-resistant precious metals, which is relatively expensive. The most important issue is the equilibrium concentration of adsorbent dehydration. The maximum dehydration of general adsorbents is about 100ppm, and it is difficult to achieve a dehydration effect of less than 1ppm. Summary of the invention

[0005] In order to obtain electronic-grade hydrogen bromide with a water content below 1 ppm, the present application provides a method for preparing electronic-grade hydrogen bromide using industrial-grade hydrogen bromide.

[0006] Based on the above purpose, the present invention adopts the following technical solution: A method for preparing electronic grade hydrogen bromide using industrial grade hydrogen bromide comprises the following steps: (1) The industrial-grade hydrogen bromide raw material with an HBr content of 0.95-0.999 is heated to 18-20.3°C and a pressure of 20-25 kg, and then enters the dehydration tower kettle at a flow rate of 10 kg / h; (2) The temperature of the dehydration tower kettle is 70-80°C, and the pressure in the tower is above 20-25 kg. Industrial-grade hydrogen bromide generates rising steam under the action of the tower kettle reboiler. The rising steam is condensed into liquid phase at the top of the tower. Part of the liquid phase flows back to the dehydration tower, and part of it is extracted from the top of the dehydration tower as the dehydrated product; hydrogen bromide containing concentrated water and heavy components is extracted from the tower kettle; (3) The dehydrated product taken out from the top of the dehydration tower enters the middle section of the dehydration tower, and the non-condensable gas is discharged from the top of the dehydration tower. The bottom of the dehydration tower discharges hydrogen bromide at an average flow rate of 8.5-9.5 kg / h; the top temperature of the dehydration tower is 15-20°C, and the bottom temperature is 19-25°C; (4) The hydrogen bromide discharged from the light-removal tower automatically enters the refining tower through the pressure difference. The temperature at the top of the refining tower is 18-22°C; electronic grade hydrogen bromide is produced from the top of the refining tower at a rate of 7-9 kg / h.

[0007] Furthermore, the electronic grade hydrogen bromide is of 4N-5N grade.

[0008] Furthermore, the pressure in the dehydration tower is preferably 22-25 kg.

[0009] Furthermore, the reflux ratio of the top of the dehydration tower is 1-3, the reflux ratio of the top of the light-removal tower is 3-5, and the reflux ratio of the top of the heavy-removal tower is 3-5.

[0010] Furthermore, the top pressure of the lightness removal tower is higher than the top pressure of the refining tower.

[0011] Furthermore, the top pressure of the lightness removal tower is 20-22 kg, and the top pressure of the refining tower is 18-20 kg.

[0012] Furthermore, the industrial-grade hydrogen bromide raw material is stored in a steel cylinder, and the steel cylinder is heated by an electric heating belt.

[0013] Furthermore, electronic grade hydrogen bromide is extracted from the top of the refining tower and transported to the filling system after passing through a reflux tank.

[0014] Furthermore, the dehydration tower bottom discharges hydrogen bromide containing concentrated water and heavy components at a rate of 0.1-1.0 kg / h, wherein the heavy components include water, dichloromethane, etc.

[0015] Furthermore, the non-condensable gas at the top of the lightness removal tower is condensed twice in a lightness removal tower top condenser and a lightness removal tower cryogenic cooler before being discharged from the lightness removal tower.

[0016] Furthermore, the non-condensable gas at the top of the lightness removal tower is discharged at a rate of 0.1-0.5 kg / h.

[0017] Preferably, the dehydration tower is made of nickel-based material, and the lightness removal tower and refining tower are made of 304 stainless steel.

[0018] Compared with the prior art, the present invention has the following advantages: The method provided by the present invention can produce 4N-5N electronic grade hydrogen bromide, especially 5N electronic grade hydrogen bromide with a hydrogen bromide content greater than >99.999% and a water content less than 0.1-0.5ppm, and the recovery rate of hydrogen bromide reaches 75-90%.

[0019] The present invention adopts distillation dehydration, and the dehydration tower operates continuously with high stability; and the distillation dehydration does not require the use of fluid conveying equipment, and adopts the liquid phase heating and pressurization method for operation; the equipment cost is low and the operating cost is low. Like the adsorption method, the distillation dehydration requires the use of a nickel-based tower, but compared with the adsorption tower system using three towers in a row, the distillation dehydration only requires one device to achieve the purpose of dehydration. The dehydration tower can achieve continuous operation by using 70-80℃ hot water and circulating water (refrigerant). The hydrogen bromide treated by the dehydration tower can be refined by using ordinary 304 stainless steel for light and heavy dehydration, and the equipment investment is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the process flow chart of Example 1.

[0021] Among them, there are dehydration tower 1, de-lightness tower 2, refining tower 3, steel cylinder 4, de-lightness tower deep cooler 5, and reflux tank 6. DETAILED DESCRIPTION

[0022] The following examples are only for further explanation of the present invention. It should be noted that all technical and scientific terms used in the present invention have the same meanings as in the technical field to which the present invention belongs unless otherwise specified. The experimental methods in the following examples without specifying specific conditions are all based on conventional techniques in the technical field; the reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0023] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0024] A device for preparing electronic grade hydrogen bromide using industrial grade hydrogen bromide, the structure of which is as follows Figure 1As shown, it includes a dehydration tower 1 made of nickel-based material and a light-removal tower 2 and a refining tower 3 made of ordinary 304 stainless steel, which are connected in sequence, wherein the dehydration tower 1, the light-removal tower 2 and the refining tower 3 are provided with condensers and reflux pipes at the tops, and jacketed reboilers are provided at the bottoms.

[0025] The industrial-grade hydrogen bromide raw material pipeline is connected to the middle of the dehydration tower 1, and the hydrogen bromide containing water and heavy components is discharged from the bottom of the dehydration tower 1. The condensate at the top of the dehydration tower 1 is connected to the middle section of the light removal tower 2 through a pipeline. The condenser at the top of the light removal tower 2 is connected to the light removal tower cryogenic freezer 5. After the light components are condensed by the condenser and the light removal tower cryogenic freezer 5, the non-condensable gas (light boiling products) is discharged from the system. The bottom of the light removal tower 2 is connected to the middle section of the refining tower 3. After the light components at the top of the refining tower 3 are condensed by the condenser, they enter the reflux tank 6 of the refining tower to obtain high-purity electronic-grade hydrogen bromide (5N grade) with a content greater than 99.999% and go to the filling system. The heavy boiling product discharge system of the bottom of the refining tower 3.

[0026] The industrial-grade hydrogen bromide feed pipe of the dehydration tower 1 is connected to a steel cylinder 4, and an electric heating belt is arranged outside the steel cylinder 4.

[0027] The method for preparing electronic grade hydrogen bromide by using the above-mentioned equipment and industrial grade hydrogen bromide comprises the following steps: (1) The industrial-grade hydrogen bromide raw material having a molar composition of 0.9962 HBr, 0.0001 HCl, 0.0035 H2O, 0.0001 O2, 0.00005 CO, and 0.00005 CO is heated in cylinder 4 by an electric heating belt so that the cylinder pressure is greater than 22 kg and the temperature of the liquid hydrogen bromide is 20.3°C.

[0028] (2) The raw material industrial-grade hydrogen bromide is preheated and pressurized and enters the kettle of dehydration tower 1 at a flow rate of 10 kg / h. The temperature of the kettle of dehydration tower 1 is 75°C, and the pressure in the tower is above 22 kg. The pressure of the dehydration tower gradually increases to above 22 kg, and the top condenser is started to generate liquid reflux; the jacket reboiler of the kettle is started to generate rising steam, which is condensed into liquid by the refrigerant. A part of the rising steam returns to the tower, and most of it is extracted as the product after dehydration. The reflux ratio is 1.5; hydrogen bromide containing water and heavy components is discharged from the kettle of dehydration tower 1 at an average of 0.5 kg / h, and the heavy components are water and dichloromethane.

[0029] (3) The dehydrated product extracted from the top of dehydration tower 1 enters the middle section of dehydration tower 2. The top pressure of dehydration tower 2 is 21 kg, the top temperature is 18.4 °C, the bottom temperature is 20.1 °C, and the reflux ratio is 4.2. The non-condensable gas is discharged through the top condenser of dehydration tower 2, and is condensed again in the deep freezer of dehydration tower and discharged from the system. The flow rate of non-condensable gas is 0.3 kg / h. The average flow rate of hydrogen bromide discharged from the bottom of dehydration tower 2 is 9.2 kg / h, and it automatically enters refining tower 3 through the pressure difference.

[0030] (4) The top pressure in the refining tower 3 is 20 kg, the top temperature is 16.3°C, and the reflux ratio is 4.2. 8 kg / h of electronic grade hydrogen bromide of >99.999% (5N grade) with a water content of less than 0.3 ppm is produced from the top of the refining tower, and it goes to the filling system after passing through the reflux tank 6; the average flow rate of hydrogen bromide containing heavy component impurities is 1.2 kg / h, and the total recovery rate of hydrogen bromide is 80%.

Claims

1. A method for preparing electronic grade hydrogen bromide using industrial grade hydrogen bromide, characterized in that: The following steps are involved: The industrial-grade hydrogen bromide raw material with an HBr content of 0.95-0.999 is heated to 18-20.3°C and a pressure of 20-25 kg, and then enters the dehydration tower kettle at a flow rate of 10 kg / h; The temperature of the dehydration tower kettle is 70-80℃, and the pressure in the tower is 20-25 kg. Industrial-grade hydrogen bromide generates rising steam under the action of the tower kettle reboiler. The rising steam is condensed into liquid phase at the top of the tower. Part of the liquid phase flows back to the dehydration tower, and part of it is extracted from the top of the dehydration tower as a dehydrated product; the tower kettle extracts hydrogen bromide containing concentrated water and heavy components; The dehydrated product taken out from the top of the dehydration tower enters the middle section of the dehydration tower, and the non-condensable gas is discharged from the top of the dehydration tower. The bottom of the dehydration tower discharges hydrogen bromide at an average flow rate of 8.5-9.5kg / h / h; the top temperature of the dehydration tower is 15-20℃, and the bottom temperature is 19-25℃; The hydrogen bromide discharged from the kettle of the lightness removal tower automatically enters the refining tower through the pressure difference. The temperature at the top of the refining tower is 18-22°C; electronic grade hydrogen bromide is produced from the top of the refining tower at a rate of 8kg / h.

2. The method for preparing electronic grade hydrogen bromide using industrial grade hydrogen bromide according to claim 1, characterized in that: The reflux ratio of the top of the dehydration tower is 1-3, the reflux ratio of the top of the light removal tower is 3-5, and the reflux ratio of the top of the heavy removal tower is 3-5.

3. The method for preparing electronic grade hydrogen bromide using industrial grade hydrogen bromide according to claim 1 or 2, characterized in that: The top pressure of the lightness removal tower is higher than the top pressure of the refining tower.

4. The method for preparing electronic grade hydrogen bromide using industrial grade hydrogen bromide according to claim 3, characterized in that: The top pressure of the lightness removal tower is 20-22 kg, and the top pressure of the refining tower is 18-20 kg.

5. The method for preparing electronic grade hydrogen bromide by using industrial grade hydrogen bromide according to claim 1, characterized in that: Electronic grade hydrogen bromide is extracted from the top of the refining tower and transported to the filling system after passing through the reflux tank.

6. The method for preparing electronic grade hydrogen bromide by using industrial grade hydrogen bromide according to claim 1, characterized in that: The dehydration tower bottom discharges hydrogen bromide containing concentrated water and heavy components at a rate of 0.1-1.0 kg / h.

7. The method for preparing electronic grade hydrogen bromide by using industrial grade hydrogen bromide according to claim 1, characterized in that: The non-condensable gas at the top of the light-removal tower is discharged from the light-removal tower after being condensed twice.

8. The method for preparing electronic grade hydrogen bromide by using industrial grade hydrogen bromide according to claim 7, characterized in that: The non-condensable gas at the top of the light-removal tower is discharged at a rate of 0.1-0.5 kg / h.

9. The method for preparing electronic grade hydrogen bromide by using industrial grade hydrogen bromide according to any one of claims 4 to 8, characterized in that: The dehydration tower is made of nickel-based material, and the lightness removal tower and refining tower are made of 304 stainless steel.

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