Phosphorus diffusion tail gas treatment system

Abstract

The embodiment of the utility model provides a phosphorus diffusion tail gas treatment system, which relates to the technical field of environmental protection and comprises a mixed cooling box, an exhaust pipe, a spraying mechanism and a water storage tank. The mixed cooling box is provided with a first air inlet, a second air inlet and a first air outlet. The first air inlet is used for communicating with an exhaust port of the diffusion furnace, the second air inlet is used for guiding external air into the mixed cooling box, and the first air outlet is communicated with the exhaust pipe. The spraying mechanism is installed on the exhaust pipe, and a water outlet of the spraying mechanism is located above the position, communicated with the first air outlet, of the exhaust pipe. The water storage tank communicates with the bottom end of the exhaust pipe. The treatment system can effectively treat tail gas containing phosphorus oxychloride generated in the phosphorus diffusion process, the discharged gas is not prone to polluting the environment or corroding diffusion furnace equipment, and the production efficiency and the product quality are not prone to being affected.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of environmental protection, specifically, a kind of phosphorus diffusion tail gas treatment system. BACKGROUND

[0002] In the semiconductor integrated circuit manufacturing process, phosphorus diffusion is one of the key process steps. The process usually uses phosphorus oxychloride (POCL) as phosphorus source, and phosphorus oxychloride (POCL) is pyrolyzed into phosphorus atoms under high temperature conditions, which diffuses to the surface of the silicon wafer to form the required doped layer. A portion of chlorine gas is generated in the reaction and enters the tail gas. At the same time, during the entire phosphorus diffusion process, tail gas containing phosphorus oxychloride is generated. If this tail gas is not properly treated, it will not only pollute the environment, but also corrode the diffusion furnace equipment, affecting production efficiency and product quality.

[0003] The inventors found in their research that the prior art semiconductor integrated circuit manufacturing at least has the following disadvantages:

[0004] During the phosphorus diffusion process, tail gas containing phosphorus oxychloride is generated. The prior art does not effectively treat this portion of tail gas, which is directly discharged and pollutes the environment, and is prone to damage the equipment. SUMMARY

[0005] The purpose of the utility model includes, for example, providing a phosphorus diffusion tail gas treatment system that can effectively treat the tail gas containing phosphorus oxychloride generated during the phosphorus diffusion process. The discharged gas is less likely to pollute the environment and less likely to corrode the diffusion furnace equipment, which is less likely to affect production efficiency and product quality.

[0006] Embodiments of the utility model can be implemented as follows:

[0007] In a first aspect, the utility model provides a phosphorus diffusion tail gas treatment system, comprising:

[0008] a mixing cooling box, an exhaust pipe, a spraying mechanism and a water storage tank; the mixing cooling box is provided with a first air inlet, a second air inlet and a first air outlet, the first air inlet is used to communicate with the exhaust port of the diffusion furnace, the second air inlet is used to introduce external air into the mixing cooling box, and the first air outlet communicates with the exhaust pipe; the spraying mechanism is installed on the exhaust pipe, and the water outlet of the spraying mechanism is located above the position of the exhaust pipe communicating with the first air outlet; the water storage tank communicates with the bottom end of the exhaust pipe.

[0009] In an optional embodiment, the mixing cooling box is provided with an air inlet side wall, the first air inlet is provided on the air inlet side wall, and the air inlet direction of the second air inlet is arranged towards the air inlet side wall.

[0010] Based on the above scheme, the first air inlet and the second air inlet are not arranged on one side wall, and installation interference does not easily exist between the two, the space around the mixed cooling box is reasonably utilized, the processing and manufacturing difficulty is reduced, and the assembly efficiency is improved. At the same time, the air inlet direction of the second air inlet is towards the air inlet side wall, which plays a role in hindering the tail gas entering from the first air inlet, can prolong the time of the tail gas staying in the mixed cooling box, and the externally introduced air can be fully mixed with the tail gas, thereby improving the mixed cooling effect.

[0011] In an optional embodiment, the second air inlet is located below the first air inlet.

[0012] Based on the above scheme, the external air entering from the second air inlet is low-temperature air, which enters from the lower part, mixes with the high-temperature tail gas during upward flow, and part of the low-temperature air also descends under the action of gravity after moving to the upper part, thereby participating in mixed cooling again, improving the mixed cooling effect, and having higher cooling efficiency.

[0013] In an optional embodiment, the spraying mechanism includes a liquid delivery pipe and a spray head, the liquid delivery pipe is provided with a connecting head, and the spray head is fixedly connected with the connecting head.

[0014] Based on the above scheme, the diluted ammonia water is delivered from the liquid delivery pipe to the spray head and sprayed in a mist form from the spray head, the mist diluted ammonia water sprayed from the spray head has a large coverage area, the liquid can better contact the rising tail gas, the ammonia water reacts with phosphorus oxychloride to generate harmless ammonium chloride (NHCL) and other salts, and the phosphorus oxychloride in the tail gas is rapidly liquefied, thereby having good treatment effect. And by adjusting the layout form of the liquid delivery pipe, the position of the spray head can be reasonably set.

[0015] In an optional embodiment, the angle of the spray head is adjustable.

[0016] Based on the above scheme, by adjusting the angle of the spray head, the coverage area of the mist diluted ammonia water sprayed from the spray head can be improved.

[0017] In an optional embodiment, the liquid delivery pipe is installed on the pipe wall of the air exhaust pipe, the connecting head penetrates the pipe wall of the air exhaust pipe and extends into the lumen of the air exhaust pipe, and the spray head is located in the lumen of the air exhaust pipe.

[0018] Based on the above scheme, the spray head is located in the lumen, the liquid sprayed from the spray head is not easy to leak from the pipe opening, the amount of liquid participating in purification is large, the liquid utilization rate is improved, and the purification effect is improved.

[0019] In an optional embodiment, the number of spray heads is multiple, and the multiple spray heads are located in the lumen of the air exhaust pipe and are arranged at intervals in the circumferential direction of the air exhaust pipe.

[0020] Based on the above scheme, the nozzle distribution position is wide, which can spray misty dilute ammonia water from different positions, has large coverage area, large contact area with tail gas, and good purification effect.

[0021] In an optional embodiment, the phosphorus diffusion tail gas treatment system further comprises a buffer tank, the buffer tank is provided with a third air inlet and a second air outlet, the third air inlet is used for communicating with the exhaust port of the diffusion furnace, and the second air outlet communicates with the first air inlet.

[0022] Based on the above scheme, the tail gas first enters the buffer tank, so as to slow down the flow rate and reduce the influence of the external introduced air on the tail gas flow.

[0023] In an optional embodiment, the height of the second air outlet is higher than the height of the first air inlet.

[0024] Based on the above scheme, the tail gas enters the first air inlet from the second air outlet more smoothly, and gas backflow is not easy to form, so as not to affect the normal exhaust of the tail gas at the exhaust port of the diffusion furnace.

[0025] In an optional embodiment, the phosphorus diffusion tail gas treatment system further comprises a wastewater treatment mechanism, and the wastewater treatment mechanism communicates with the water storage tank.

[0026] Based on the above scheme, after the tail gas rises and contacts with the dilute ammonia water, part of the substances falls with the liquid and is stored in the water storage tank, and then the liquid in the water storage tank is input into the wastewater treatment mechanism for treatment, so that the treated wastewater can be directly discharged, and environmental pollution is not easy to cause.

[0027] The beneficial effects of the embodiments of the utility model include, for example:

[0028] In summary, the phosphorus diffusion tail gas treatment system provided by the embodiment has the following advantages: the exhaust port of the diffusion furnace is in a positive pressure state, and the suction pipe starts to inhale air, so that the tail gas discharged from the exhaust port of the diffusion furnace can enter the mixing cooling tank and the suction pipe in sequence, the tail gas mixes with the external air introduced into the mixing cooling tank, the temperature of the external air is lower than that of the tail gas, and the temperature of the tail gas can be reduced, so that the content of harmful substances in the tail gas is reduced. Moreover, the mixed gas continues to enter the suction pipe and mixes with the dilute ammonia water sprayed by the spraying mechanism, the ammonia water reacts with phosphorus oxychloride to generate harmless ammonium chloride (NHCL) and other salts, and the phosphorus oxychloride in the tail gas is rapidly liquefied. The liquefied position falls with the ammonia water and is stored in the water storage tank. In this way, the phosphorus oxychloride in the tail gas is effectively removed by the combination of natural air cooling and ammonia water neutralization and liquefaction, and the environmental pollution is reduced. The temperature of the tail gas is reduced, the corrosion of the high-temperature tail gas to the inner wall of the suction pipe is avoided, especially the melting of the Teflon coating is prevented, and the service life of the diffusion furnace is prolonged. The whole system has simple and reasonable structure, is easy to implement and maintain, and has low operation cost. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the phosphorus diffusion tail gas treatment system of this application.

[0031] icon:

[0032] 001-Diffusion furnace; 100-Mixing and cooling box; 101-First air inlet; 102-Second air inlet; 103-First air outlet; 110-Air inlet side wall; 120-Air outlet side wall; 200-Exhaust pipe; 300-Spraying mechanism; 400-Water storage tank; 500-Buffer tank; 501-Third air inlet; 502-Second air outlet; 600-Wastewater treatment mechanism. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of the utility model, it is necessary to explain that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship of the product of the application when it is used, it is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.

[0037] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0038] It should be noted that the features in the embodiments of the utility model can be combined with each other without conflict.

[0039] Please refer to Figure 1 The embodiment provides a phosphorus diffusion tail gas treatment system, which comprises a mixed cooling box 100, an air extraction pipe 200, a spraying mechanism 300 and a water storage tank 400. The mixed cooling box 100 is provided with a first air inlet 101, a second air inlet 102 and a first air outlet 103. The first air inlet 101 is used for being communicated with an exhaust port of a diffusion furnace 001, the second air inlet 102 is used for guiding external air into the mixed cooling box 100, and the first air outlet 103 is communicated with the air extraction pipe 200. The spraying mechanism 300 is installed on the air extraction pipe 200, and a water outlet of the spraying mechanism 300 is located above a position of the air extraction pipe 200, which is communicated with the first air outlet 103. The water storage tank 400 is communicated with the bottom end of the air extraction pipe 200.

[0040] As described above, the working process of the phosphorus diffusion tail gas treatment system provided by the embodiment is as follows:

[0041] The exhaust port of the diffusion furnace 001 is in a positive pressure state, and the suction tube 200 is started to perform a suction action, and the two cooperate to enable the exhaust gas discharged from the exhaust port of the diffusion furnace 001 to enter the mixed cooling box 100 and the suction tube 200 in turn. The exhaust gas mixes with the external air introduced into the mixed cooling box 100 in the mixed cooling box 100. The temperature of the external air is lower than the temperature of the exhaust gas, which can reduce the temperature of the exhaust gas, thereby reducing the content of harmful substances in the exhaust gas. Moreover, the mixed gas continues to enter the suction tube 200 and mixes with the diluted ammonia water sprayed by the spraying mechanism 300. The ammonia water and phosphorus oxychloride neutralize to generate harmless ammonium chloride (NHCL) and other salts, and promote the rapid liquefaction of phosphorus oxychloride in the exhaust gas. The liquefied position falls with the ammonia water and is stored in the water storage tank 400. In this way, by combining natural air cooling and ammonia water neutralization and liquefaction, the phosphorus oxychloride in the exhaust gas is effectively removed, and environmental pollution is reduced. The temperature of the exhaust gas is reduced, which avoids the corrosion of the high-temperature exhaust gas to the inner wall of the suction tube 200, especially prevents the melting of the Teflon coating, and prolongs the service life of the diffusion furnace 001. The whole system has simple and reasonable structure, is easy to implement and maintain, and has low operation cost.

[0042] The following embodiments illustrate the details of the phosphorus diffusion exhaust gas treatment system of the present application by way of example.

[0043] Please refer to Figure 1 In the present embodiment, the mixed cooling box 100 is provided with opposite air inlet side wall 110 and air outlet side wall 120. The first air inlet 101 is arranged on the air inlet side wall 110, and the air inlet direction of the second air inlet 102 is arranged towards the air inlet side wall 110. The first air outlet 103 is arranged on the air outlet side wall 120, and the second air inlet 102 can be located between the air inlet side wall 110 and the air outlet side wall 120.

[0044] It should be understood that the first air inlet 101 and the second air inlet 102 are not arranged on one side wall, and there is no installation interference between the two. The space around the mixed cooling box 100 is reasonably utilized, the processing and manufacturing difficulty is reduced, and the assembly efficiency is improved. At the same time, the air inlet direction of the second air inlet 102 is towards the air inlet side wall 110, which hinders the exhaust gas entering from the first air inlet 101, prolongs the time of the exhaust gas staying in the mixed cooling box 100, and the external introduced air can be fully mixed with the exhaust gas, thereby improving the mixing cooling effect.

[0045] Further, the second air inlet 102 is located below the first air inlet 101.

[0046] Thus, the external air entering from the second air inlet 102 is low-temperature air, which enters from the lower portion and flows upward to mix with the high-temperature tail gas. In addition, part of the low-temperature air moves to the upper portion and then falls under the action of gravity to participate in mixing and cooling again, thereby improving the mixing and cooling effect and increasing the cooling efficiency. It should be understood that natural wind can be introduced from the second air inlet 102, and the temperature of the natural wind is generally lower than the temperature of the tail gas, thereby reducing energy consumption. Alternatively, the air can be cooled before being introduced into the mixing and cooling box 100, and the selection can be made as required.

[0047] Please refer to Figure 1 In this embodiment, the spraying mechanism 300 includes a liquid delivery pipe and a spray head. The liquid delivery pipe is provided with a connecting head, and the spray head is fixedly connected to the connecting head. The diluted ammonia water is delivered from the liquid delivery pipe to the spray head and sprayed in the form of mist from the spray head. The mist of the diluted ammonia water sprayed from the spray head has a large coverage area, and the liquid can better contact the rising tail gas. The ammonia water reacts with phosphorus oxychloride to generate harmless ammonium chloride (NHCL) and other salts, and promotes the rapid liquefaction of phosphorus oxychloride in the tail gas, thereby achieving good treatment effect. In addition, by adjusting the layout form of the liquid delivery pipe, the position of the spray head can be reasonably set.

[0048] Optionally, the angle of the spray head is adjustable. For example, the spray head and the connecting head can be connected by a hose. The hose can adaptively adjust the shape and has a wide range of use. In addition, the spray head can be installed on the pipe wall by rotating the support. The position of the spray head is adjusted by rotating the support. At this time, the hose adaptively adjusts the bending shape and does not easily affect the adjustment of the position of the spray head. After adjusting the position of the support, the support is locked, and then the angle of the spray head is locked. The operation is convenient and reliable. It should be understood that the structure of the rotating support is various, and the structure of the existing spray head capable of adjusting the angle can be referred to. This embodiment will not be specifically described.

[0049] It should be noted that by adjusting the angle of the spray head, the coverage area of the mist of the diluted ammonia water sprayed from the spray head can be increased.

[0050] Optionally, the liquid delivery pipe is installed on the pipe wall of the air extraction pipe 200, the connecting head penetrates the pipe wall of the air extraction pipe 200 and extends into the pipe cavity of the air extraction pipe 200, and the spray head is located in the pipe cavity of the air extraction pipe 200. The spray head is located in the pipe cavity, and the liquid sprayed from the spray head is not easy to leak from the pipe opening. The amount of liquid participating in purification is large, the utilization rate of the liquid is improved, and the purification effect is improved.

[0051] In some embodiments, the number of spray heads is multiple, and the multiple spray heads are located in the pipe cavity of the air extraction pipe 200 and are arranged at intervals in the circumferential direction of the air extraction pipe 200. The spray heads are distributed in a wide range, can spray mist of diluted ammonia water from different positions, have a large coverage area, have a large contact area with the tail gas, and have a good purification effect.

[0052] Please refer toFigure 1 In the embodiment, the phosphorus diffusion tail gas treatment system further comprises a buffer tank 500, the buffer tank 500 is provided with a third air inlet 501 and a second air outlet 502, the third air inlet 501 is used to be communicated with the exhaust port of the diffusion furnace 001 through a pipeline, and the second air outlet 502 can be communicated with the first air inlet 101 through a pipeline. A pipeline for introducing external air can be installed at the second air inlet 102. The first air outlet 103 can be communicated with the pipe wall of the exhaust pipe 200 through a pipeline.

[0053] In this way, the tail gas first enters the buffer tank 500, so that the flow rate is slowed down, and the influence of the external introduced air on the tail gas flow is reduced.

[0054] Optionally, the height of the second air outlet 502 is higher than the height of the first air inlet 101, the tail gas entering the first air inlet 101 from the second air outlet 502 is more smooth, and gas backflow is not easy to form, so as not to affect the normal discharge of the tail gas at the exhaust port of the diffusion furnace 001.

[0055] Please refer to Figure 1 In the embodiment, the phosphorus diffusion tail gas treatment system further comprises a wastewater treatment mechanism 600, the wastewater treatment mechanism 600 is communicated with the water storage tank 400. After the tail gas rises and contacts with the diluted ammonia water, part of the substances falls with the liquid and is stored in the water storage tank 400, then the liquid in the water storage tank 400 is input into the wastewater treatment mechanism 600 for treatment, and the treated wastewater can be directly discharged, so as not to cause environmental pollution.

[0056] It should be understood that the wastewater treatment mechanism 600 can adopt a known structure, for example, the wastewater treatment mechanism 600 comprises a grid pool, an adjusting pool, a chemical treatment pool and a deep treatment pool arranged in sequence. The wastewater is discharged into the grid pool, and the larger particulate impurities in the wastewater are removed by using the grid to prevent these impurities from damaging the subsequent treatment equipment. The adjusting pool is used to adjust the flow and water quality of the wastewater to ensure the stable operation of the subsequent treatment units. The adjusted wastewater enters the chemical treatment pool, mainly by adding chemical agents to precipitate heavy metal ions in the wastewater; for example, by adding lye to make the heavy metals form hydroxide precipitates, which can be removed by a sedimentation separation device. The wastewater after the above treatment may still contain some pollutants that are difficult to remove and need to be treated deeply. By using reverse osmosis membrane separation technology, small molecule organic matter and salt in the wastewater can be effectively removed. Then, the treated wastewater is monitored and recovered, that is, the treated wastewater needs to undergo strict water quality monitoring to ensure that it meets the discharge standards. Part of the water after deep treatment can be used for production links with low water quality requirements, such as cooling tower water replenishment, which helps to save water resources.

[0057] The phosphorus diffusion tail gas treatment system provided by the embodiment combines natural air cooling with ammonia water neutralization and liquefaction, so that phosphorus oxychloride generates harmless ammonium chloride (NHCL) and other salts, and the phosphorus oxychloride in the tail gas is rapidly liquefied, and the phosphorus oxychloride in the tail gas is effectively removed.

[0058] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A phosphorus diffusion off-gas treatment system characterized by, The system comprises a mixing cooling box (100), an air exhaust pipe (200), a spraying mechanism (300) and a water storage box (400); the mixing cooling box (100) is provided with a first air inlet (101), a second air inlet (102) and a first air outlet (103), the first air inlet (101) is used for connecting the exhaust port of a diffusion furnace (001), the second air inlet (102) is used for introducing external air into the mixing cooling box (100), and the first air outlet (103) is connected with the air exhaust pipe (200); the spraying mechanism (300) is installed on the air exhaust pipe (200), the water outlet of the spraying mechanism (300) is located above the position of the air exhaust pipe (200) connected with the first air outlet (103); and the water storage box (400) is connected with the bottom end of the air exhaust pipe (200).

2. The system according to claim 1, wherein: the mixing cooling box (100) is provided with an air inlet side wall (110), the first air inlet (101) is arranged on the air inlet side wall (110), and the air inlet direction of the second air inlet (102) is arranged towards the air inlet side wall (110).

3. The system according to claim 2, wherein: the second air inlet (102) is located below the first air inlet (101).

4. The system according to claim 1, wherein: the spraying mechanism (300) comprises a liquid delivery pipe and a spray head, the liquid delivery pipe is provided with a connecting head, and the spray head is fixedly connected with the connecting head.

5. The system according to claim 4, wherein: the angle of the spray head is adjustable.

6. The system according to claim 4, wherein: the liquid delivery pipe is installed on the pipe wall of the air exhaust pipe (200), the connecting head penetrates through the pipe wall of the air exhaust pipe (200) and extends into the pipe cavity of the air exhaust pipe (200), and the spray head is located in the pipe cavity of the air exhaust pipe (200).

7. The system according to claim 4, wherein: the number of the spray heads is multiple, and the multiple spray heads are arranged in the pipe cavity of the air exhaust pipe (200) and are spaced apart in the circumferential direction of the air exhaust pipe (200).

8. The system according to claim 1, wherein: the system further comprises a buffer box (500), the buffer box (500) is provided with a third air inlet (501) and a second air outlet (502), the third air inlet (501) is used for connecting the exhaust port of the diffusion furnace (001), and the second air outlet (502) is connected with the first air inlet (101).

9. The system according to claim 8, wherein: the height of the second air outlet (502) is higher than the height of the first air inlet (101).

10. The system according to claim 1, wherein: ​ The phosphorus diffusion tail gas treatment system further comprises a wastewater treatment mechanism (600) in communication with the water storage tank (400).

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