Method and device for preparing high-purity trichlorosilane

Abstract

The present invention provides a method and device for preparing high-purity trichlorosilane, and electronic-grade trichlorosilane can be obtained by two-stage vacuum distillation. Compared with the prior art for purifying trichlorosilane, the present invention can achieve the effect of three to five levels of distillation at normal pressure by only two-stage vacuum distillation, thereby obtaining electronic-grade trichlorosilane while greatly reducing energy consumption and production costs; through two-stage vacuum distillation, the purity of the components of the trichlorosilane product is significantly improved, and the content of metal trace impurities such as B, P, and Cu is greatly reduced, so as to obtain trichlorosilane suitable for 12-inch silicon wafer epitaxial scenes.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a method and device for preparing high-purity trichlorosilane. Background Art

[0002] High-purity chlorosilane is an important electronic specialty gas raw material that is indispensable to the semiconductor industry. With the rapid development of the semiconductor integrated circuit industry, the demand for high-purity chlorosilane is increasing. The preparation of high-purity chlorosilane has become a battleground for improving the competitiveness of photovoltaic semiconductor manufacturers.

[0003] In the prior art, a trichlorosilane pressure purification device and method (application number CN200510200334.4) is disclosed. By utilizing the characteristics that the liquid viscosity of trichlorosilane and silicon tetrachloride decreases with increasing pressure and the efficiency of the tower plate is improved, a chlorosilane mixture is passed into a sieve plate tower, the tower bottom pressure is controlled to be 0.15-1.5 Mpa, the temperature is 70-200 ° C, and refined trichlorosilane is obtained at the top of the tower. In addition, a chlorosilane purification system (application number: CN201410127032.8) is also disclosed. The system is optimized and expanded on the existing basis, and trichlorosilane is purified by five-tower series distillation, and light and heavy components are removed multiple times to obtain a high-purity trichlorosilane product. However, the above technology still has the following disadvantages: 1) high energy consumption; 2) the existing purification method can only obtain electronic-grade trichlorosilane, and it is difficult to further remove trace impurities of alkali metals such as B and P. Among them, the impurity content of electronic-grade trichlorosilane (ppb): P+As≤0.2; B+AI≤0.1; Fe≤0.5; Cr≤0.5; Ni / ppb≤0.5; and trichlorosilane suitable for 12-inch silicon wafer epitaxial scenarios requires metal impurities such as B, P, and Cu to be higher than the ppb level.

[0004] Therefore, there is an urgent need for a preparation device and method for obtaining ppb-grade trichlorosilane. Summary of the invention

[0005] The object of the present invention is to provide a method and device for preparing high-purity trichlorosilane to solve at least one problem existing in the prior art.

[0006] In order to achieve the above object, the present invention provides a method for preparing high-purity trichlorosilane, the method comprising:

[0007] Pass trichlorosilane raw material with a purity of 99.9%-99.99% and a total impurity of ≤20ppb into a lightness removal tower;

[0008] The trichlorosilane raw material is subjected to light removal treatment by using a light removal tower, and the high boiling products of the light removal tower are obtained as the trichlorosilane intermediate product;

[0009] The intermediate trichlorosilane product is passed into a deweighting tower;

[0010] Using a deweighting tower to deweight the intermediate trichlorosilane product, and obtaining low-boiling substances from the deweighting tower as a purified trichlorosilane product;

[0011] The purified trichlorosilane product is transported to the product tank for storage.

[0012] Furthermore, a preferred method includes collecting the low boiling products of the light removal tower and the high boiling products of the heavy removal tower into high and low boiling product tanks.

[0013] Furthermore, the preferred method includes that the feed flow rate of the lightness removal tower is 100 kg / h, the discharge flow rate of the trichlorosilane intermediate product is 85-90 kg / h, and the extraction flow rate of the low boiling point product is 10 kg / h.

[0014] Furthermore, the preferred method includes that the discharge flow rate of the trichlorosilane purification product from the deweighting tower is 70-75 kg / h, and the withdrawal flow rate of the high boiling products is 10-15 kg / h.

[0015] Further, the preferred method includes that the top pressure of the lightness removal tower is -50 kPa, the top temperature is 13°C, and the reflux ratio is 20:1;

[0016] The top pressure of the deweighting tower is -50 kPa, the top temperature is 12-13 °C, and the reflux ratio is 10:1.

[0017] Further, the preferred method includes, before the trichlorosilane raw material enters the lightness removal tower, it is transported to a precision filter by a delivery pump;

[0018] The trichlorosilane raw material is filtered through a precision filter, and the filtered trichlorosilane raw material passes through a flow meter and a pressure reducing valve to reach a lightness removal tower.

[0019] Furthermore, the preferred method includes providing a heat source for the light-removal tower and the heavy-removal tower through a high and low temperature integrated machine, and providing a cold source for the light-removal tower and the heavy-removal tower through a refrigerator; the heat source temperature is -10°C-50°C; the cold source temperature is -25°C-25°C.

[0020] The present invention also includes a high-purity trichlorosilane preparation device, which implements the above-mentioned high-purity trichlorosilane preparation method; the device includes a light removal tower, a heavy removal tower and a product tank which are arranged in sequence;

[0021] The light-removal tower comprises a light-removal tower feed port, a light-removal tower discharge port and a low-boiling-point outlet located at the top of the tower;

[0022] The deweighting tower comprises a deweighting tower feed port, a deweighting tower discharge port and a high boiling point outlet located in the tower kettle;

[0023] The discharge port of the light removal tower is connected with the feed port of the heavy removal tower, the discharge port of the heavy removal tower is connected with the product tank, and the low-boiling substance outlet and the high-boiling substance outlet are connected with the high-low boiling substance tanks.

[0024] Furthermore, the preferred structure includes that both the light-removal tower and the heavy-removal tower are 5-stage distillation towers, the height of each stage of the distillation tower is 1500 mm, and the total effective packing height is 6000 mm.

[0025] Furthermore, a preferred structure includes that both the light-removal tower and the heavy-removal tower are provided with tail gas outlets, and the tail gas outlets are connected to the vacuum pump.

[0026] As described above, the method and device for preparing high-purity trichlorosilane of the present invention can obtain electronic-grade trichlorosilane through two-stage vacuum distillation. The beneficial effects are as follows:

[0027] 1) Compared with the prior art for purifying trichlorosilane, the present invention can achieve the effect of three to five levels of distillation at normal pressure by only two levels of vacuum distillation, thereby obtaining electronic grade trichlorosilane and greatly reducing energy consumption and production costs;

[0028] 2) Through two-stage vacuum distillation, the component purity of trichlorosilane products is significantly improved, and the content of metal trace impurities such as B, P, and Cu is greatly reduced, obtaining trichlorosilane suitable for 12-inch silicon wafer epitaxial scenarios.

[0029] In order to achieve the above and related purposes, one or more aspects of the present invention include the features that will be described in detail later and are particularly pointed out in the claims. The following description describes some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all of these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the process flow of a device for preparing high-purity trichlorosilane according to an embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram of the process principle of the method for preparing high-purity trichlorosilane according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in the field or the product instructions are used. If the manufacturers of the reagents or instruments used are not specified, they can be purchased from regular channels.

[0033] It should be understood that terms such as "upper", "lower", "front", "bottom", "top", "side", "width", "inside" and "outside" indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0034] Various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Figure 1 The process flow of the high-purity trichlorosilane preparation device of the embodiment of the present invention is described in detail. Specifically, Figure 1 It is a schematic diagram of the process flow of a device for preparing high-purity trichlorosilane according to an embodiment of the present invention.

[0036] like Figure 1 As shown, a preparation device of high-purity trichlorosilane comprises a light-removing tower, a heavy-removing tower and a product tank which are arranged in sequence; the light-removing tower comprises a light-removing tower feed port, a light-removing tower discharge port and a low-boiling-substance outlet located at the top of the tower; the heavy-removing tower comprises a heavy-removing tower feed port, a heavy-removing tower discharge port and a high-boiling-substance outlet located at the bottom of the tower; the light-removing tower discharge port is connected with the heavy-removing tower feed port, the heavy-removing tower discharge port is connected with the product tank, and the low-boiling-substance outlet and the high-boiling-substance outlet are connected with the high-and-low-boiling-substance tanks.

[0037] The light-removal tower and the heavy-removal tower are both connected to a high-low temperature integrated machine for providing a heat source, and are both connected to a refrigerator for providing a cold source. The various components in the preparation device of high-purity trichlorosilane are connected by pipe fittings, wherein the pipe fittings are made of EP grade 316L stainless steel pipes, and the pipeline connection method is flange connection, ferrule connection or VCR connection, preferably VCR connection or direct welding.

[0038] Specifically, a delivery pump, a precision filter and a flow meter are provided between the discharge port of the light-removal tower and the feed port of the heavy-removal tower. A delivery pump, a precision filter, a flow meter and a pressure reducing valve are also provided between the feed port of the light-removal tower and the raw material storage tank. The valve of the pressure reducing valve adopts a high-purity membrane valve for degreasing and deoiling.

[0039] Among them, the delivery pump is a magnetic gear pump, the pump head is made of S31603 stainless steel, and the gear is made of PEEK.

[0040] In the specific implementation process, in order to further improve the stability of the system and production and sales volume, a product buffer tank is also set between the discharge port of the deweighting tower and the product tank. After the trichlorosilane purification product is discharged from the discharge port of the deweighting tower, it first enters the product buffer tank, and then is sent to the product tank for storage through a delivery pump.

[0041] In order to further improve the distillation and stripping efficiency, the number of feed inlets of the distillation tower can be set to 3.

[0042] In a specific embodiment, both the light-removing tower and the heavy-removing tower are provided with tail gas outlets, and the tail gas outlets are connected to a vacuum pump. The vacuum pump controls the pressure range of 0kpa to -90kpa. Specifically, the exhaust port is connected to the vacuum pump, and the vacuum pump can be set to pressurize and decompress the environment of the reactor so that the entire distillation system meets the vacuum or pressurized state. Among them, the discharge port of the light-removing tower is connected to the feed port of the heavy-removing tower, the discharge port of the heavy-removing tower is connected to the product tank, and the low-boiling substance outlet and the high-boiling substance outlet are connected to the high-low boiling substance tank to form a closed reaction environment. Moreover, the vacuum pump can be used to evacuate and ventilate the entire distillation tower group. By adopting the above-mentioned closed implementation method, the volatilization of the solution can be effectively avoided, the atmosphere of the reactor is guaranteed, and it is particularly suitable for organic solvents, and the contamination of the solution by external substances is avoided, so as to achieve the effect of improving the reaction efficiency and not polluting the environment. In addition, by adopting a high and low temperature integrated machine, a refrigerator and a vacuum pump, the entire preparation device realizes accurate control of the cold and heat source and the top pressure of the tower, so that the system runs more stably.

[0043] In a specific embodiment, the light-removing tower and the heavy-removing tower are both 5-stage distillation towers, and the material of the distillation tower can be but is not limited to S31603 stainless steel. The height of each distillation tower is 1500mm, and the total effective packing height is 6000mm. Specifically, the light-removing distillation tower and the heavy-removing distillation tower are both provided with wire mesh bulk packing, liquid distributor and packing support ring in the tower. In the specific implementation process, the tower sections of the 5-stage distillation tower are connected by flanges, the tower diameter is DN100, and the distillation tower can be disassembled under normal pressure.

[0044] The top of the light removal distillation tower outputs low-boiling substances, which are substances with low boiling points such as silylamine and disilylamine. The bottom of the heavy removal distillation tower outputs high-boiling substances and solid particles, and high-boiling substances are n-hexane with relatively high metal impurity content.

[0045] The following method for preparing high-purity trichlorosilane is performed using the above-mentioned high-purity trichlorosilane preparation device.

[0046] The invention also discloses a method for preparing high-purity trichlorosilane. Figure 2 The process principle of the method for preparing high-purity trichlorosilane in the embodiment of the present invention is described in detail. Specifically, Figure 2 FIG. 1 is a schematic diagram of the process principle of the method for preparing high-purity trichlorosilane according to an embodiment of the present invention. Figure 2 As shown, the method includes steps S110 to S130.

[0047] A method for preparing high-purity trichlorosilane, the method comprising:

[0048] S110, pass the trichlorosilane raw material with a purity of 99.9%-99.99% and a total impurity of ≤20ppb into a lightness removal tower; use the lightness removal tower to remove lightness from the trichlorosilane raw material, and obtain the high-boiling products of the lightness removal tower as the intermediate trichlorosilane product. Among them, the feed flow rate of the lightness removal tower is 100kg / h, the discharge flow rate of the trichlorosilane intermediate product is 85-90kg / h, and the extraction flow rate of the low-boiling products is 10kg / h. The top pressure of the lightness removal tower is -50kpa, the top temperature is 13℃, and the reflux ratio is 20:1.

[0049] It should be noted that before the trichlorosilane raw material enters the light-removal tower, it is transported to a precision filter through a delivery pump; the trichlorosilane raw material is filtered through the precision filter, and the filtered trichlorosilane raw material reaches the light-removal tower through a flow meter and a pressure reducing valve.

[0050] S120, passing the intermediate trichlorosilane product into a deweighting tower; using the deweighting tower to deweight the intermediate trichlorosilane product, and obtaining the low-boiling products from the deweighting tower as the purified trichlorosilane product. The discharge flow rate of the purified trichlorosilane product from the deweighting tower is 70-75 kg / h, and the withdrawal flow rate of the high-boiling products is 10-15 kg / h. The top pressure of the deweighting tower is -50 kpa, the top temperature is 12-13 ° C, and the reflux ratio is 10:1.

[0051] By setting the top pressure and reflux ratio of the two distillation towers, the component purity of the trichlorosilane product can be significantly improved, and the content of metal trace impurities such as B, P, and Cu can be greatly reduced.

[0052] In addition, a high and low temperature integrated machine is used to provide a heat source for the light removal tower and the heavy removal tower, and a refrigerator is used to provide a cold source for the light removal tower and the heavy removal tower; the heat source temperature is -10℃-50℃; the cold source temperature is -25℃-25℃.

[0053] The light removal tower produces not only the intermediate product of trichlorosilane, but also low-boiling substances; the heavy removal tower produces not only the purified product of trichlorosilane, but also high-boiling substances. The low-boiling substances of the light removal tower and the high-boiling substances of the heavy removal tower are collected in high- and low-boiling substance tanks.

[0054] S130, transporting the purified trichlorosilane product to a product tank for storage.

[0055] By adopting the above-mentioned preparation method of high-purity trichlorosilane, the trichlorosilane component reached more than 99.99% after GC-MS detection of hexachlorodisilane. After ICP-MS detection, all impurities in the purified trichlorosilane product were less than 0.01ppb, and the total impurity content of the product was 0.05ppb; the total B / P impurity was less than 0.02ppb; which promoted the improvement of the quality stability and consistency of trichlorosilane products.

[0056] The various embodiments of the method for preparing high-purity trichlorosilane of the present invention are described in detail below. Example 1

[0057] S110, the trichlorosilane raw material with a purity of 99.9%-99.99% and a total impurity of ≤20ppb is delivered to the light removal tower through a delivery pump, a precision filter, a flow meter and a pressure reducing valve; the light removal tower is used for light removal treatment to obtain the high-boiling products of the light removal tower as the intermediate product of trichlorosilane; the low-boiling products of the light removal tower are transported to the high- and low-boiling product tanks. Among them, the feed flow rate of the light removal tower is 100kg / h, the discharge flow rate of the intermediate product of trichlorosilane is 85kg / h, and the extraction flow rate of the low-boiling products is 10kg / h. The top pressure of the light removal tower is -50kpa, the top temperature is 13℃, and the reflux ratio is 20:1.

[0058] S120, pass the intermediate product of trichlorosilane into the deweighting tower; use the deweighting tower to remove weight, obtain the low-boiling products of the deweighting tower as the purified trichlorosilane product, and transport the high-boiling products of the deweighting tower to the high-low boiling product tank. Among them, the discharge flow rate of the purified trichlorosilane product of the deweighting tower is 70kg / h, and the extraction flow rate of the high-boiling products is 10kg / h. The top pressure of the deweighting tower is -50kpa, the top temperature is 12℃, and the reflux ratio is 10:1.

[0059] S130, transporting the purified trichlorosilane product to a product tank for storage. Example 2

[0060] S110, the trichlorosilane raw material with a purity of 99.9%-99.99% and a total impurity of ≤20ppb is delivered to the light removal tower through a delivery pump, a precision filter, a flow meter and a pressure reducing valve; the light removal tower is used for light removal treatment to obtain the high-boiling products of the light removal tower as the intermediate product of trichlorosilane; the low-boiling products of the light removal tower are transported to the high- and low-boiling product tanks. Among them, the feed flow rate of the light removal tower is 100kg / h, the discharge flow rate of the intermediate product of trichlorosilane is 90kg / h, and the extraction flow rate of the low-boiling products is 10kg / h. The top pressure of the light removal tower is -50kpa, the top temperature is 13℃, and the reflux ratio is 20:1.

[0061] S120, pass the intermediate product of trichlorosilane into the de-weighting tower through a delivery pump, a precision filter and a flowmeter; use the de-weighting tower to remove weight, obtain the low-boiling products of the de-weighting tower as the purified trichlorosilane product, and transport the high-boiling products of the de-weighting tower to the high-low boiling product tank. Among them, the discharge flow rate of the purified trichlorosilane product of the de-weighting tower is 75kg / h, and the extraction flow rate of the high-boiling products is 15kg / h. The top pressure of the de-weighting tower is -50kpa, the top temperature is 13℃, and the reflux ratio is 10:1.

[0062] S130, transporting the purified trichlorosilane product to a product buffer tank, and then transporting it from the product buffer tank to a product tank for storage via a delivery pump. Example 3

[0063] S110, the trichlorosilane raw material with a purity of 99.9%-99.99% and a total impurity of ≤20ppb is delivered to the light removal tower through a delivery pump, a precision filter, a flow meter and a pressure reducing valve; the light removal tower is used for light removal treatment to obtain the high-boiling products of the light removal tower as the intermediate product of trichlorosilane; the low-boiling products of the light removal tower are transported to the high- and low-boiling product tanks. Among them, the feed flow rate of the light removal tower is 100kg / h, the discharge flow rate of the trichlorosilane intermediate product is 88kg / h, and the extraction flow rate of the low-boiling products is 10kg / h. The top pressure of the light removal tower is -50kpa, the top temperature is 13℃, and the reflux ratio is 20:1.

[0064] S120, pass the intermediate product of trichlorosilane into the deweighting tower; use the deweighting tower to remove weight, obtain the low-boiling products of the deweighting tower as the purified trichlorosilane product, and transport the high-boiling products of the deweighting tower to the high-low boiling product tank. Among them, the discharge flow rate of the purified trichlorosilane product of the deweighting tower is 72kg / h, and the extraction flow rate of the high-boiling products is 13kg / h. The top pressure of the deweighting tower is -50kpa, the top temperature is 12℃, and the reflux ratio is 10:1.

[0065] S130, transporting the purified trichlorosilane product to a product tank for storage.

[0066] After GC-MS detection of the high-purity trichlorosilane obtained in the above embodiments 1 to 3, the component reached 99.99%; after ICP-MS detection, the impurities in the high-purity trichlorosilane obtained in embodiments 1 to 3 were all less than 0.01 ppb, and the total impurity amount of the product was 0.05 ppb; the total B / P impurity was less than 0.02 ppb, which was suitable for 12-inch silicon wafer epitaxial scene.

[0067] The preparation method and device of high-purity trichlorosilane of the present invention can obtain electronic-grade trichlorosilane through two-stage vacuum distillation. Compared with the prior art of purifying trichlorosilane, the present invention can achieve the effect of three to five levels of distillation at normal pressure by only two stages of vacuum distillation, and obtain electronic-grade trichlorosilane while greatly reducing energy consumption and production costs; through two-stage vacuum distillation, the purity of the components of the trichlorosilane product is significantly improved, and the content of metal trace impurities such as B, P, and Cu is greatly reduced, so as to obtain trichlorosilane suitable for 12-inch silicon wafer epitaxial scenes.

[0068] However, those skilled in the art should understand that various improvements can be made to the method and device for preparing high-purity trichlorosilane provided by the present invention without departing from the content of the present invention. Therefore, the protection scope of the present invention should be determined by the content of the attached claims.

Claims

1. A method for preparing high-purity trichlorosilane, characterized in that: include: Pass trichlorosilane raw material with a purity of 99.9%-99.99% and a total impurity of ≤20ppb into a light-removal tower; wherein the top pressure of the light-removal tower is -50kpa, the top temperature is 13°C, and the reflux ratio is 20:1; The trichlorosilane raw material is subjected to a light removal treatment by using the light removal tower to obtain a high boiling product of the light removal tower as a trichlorosilane intermediate product; Passing the trichlorosilane intermediate product into a deweighting tower; wherein the top pressure of the deweighting tower is -50 kPa, the top temperature is 12-13° C., and the reflux ratio is 10:1; Using the deweighting tower to deweight the intermediate trichlorosilane product, and obtaining low-boiling substances from the deweighting tower as a purified trichlorosilane product; The purified trichlorosilane product is transported to a product tank for storage.

2. The method for preparing high-purity trichlorosilane according to claim 1, characterized in that: The low boiling products of the light removal tower and the high boiling products of the heavy removal tower are collected in high and low boiling product tanks.

3. The method for preparing high-purity trichlorosilane according to claim 2, characterized in that: The feed flow rate of the light-removal tower is 100 kg / h, the discharge flow rate of the trichlorosilane intermediate product is 85-90 kg / h, and the extraction flow rate of the low-boiling substances is 10 kg / h.

4. The method for preparing high-purity trichlorosilane according to claim 2, characterized in that: The discharge flow rate of the trichlorosilane purification product of the deweighting tower is 70-75 kg / h, and the withdrawal flow rate of the high boiling point is 10-15 kg / h.

5. The method for preparing high-purity trichlorosilane according to claim 1, characterized in that: Before the trichlorosilane raw material enters the lightness removal tower, Delivered to the precision filter through a delivery pump; Filtering the trichlorosilane raw material through the precision filter; The filtered trichlorosilane raw material passes through a flow meter and a pressure reducing valve to reach the lightness removal tower.

6. The method for preparing high-purity trichlorosilane according to claim 1, characterized in that: A high and low temperature integrated machine is used to provide a heat source for the light-removal tower and the heavy-removal tower, and a refrigerator is used to provide a cold source for the light-removal tower and the heavy-removal tower; the temperature of the heat source is -10°C-50°C; the temperature of the cold source is -25°C-25°C.

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