System for drying electronic-grade polycrystalline silicon

Abstract

The utility model relates to the technical field of polycrystalline silicon drying, in particular to a system for drying electronic-grade polycrystalline silicon, which comprises a sealing cavity and a silicon material storage area communicated with the sealing cavity, a gas buffer area is arranged below the silicon material storage area, a vortex cooler, a water absorption module, a mixer, a heater and a fan are sequentially connected with the silicon material storage area through a gas conveying pipe, and gas blown out by the fan is introduced into the sealing cavity. The novel drying system has the advantages that the sealing cavity, the vortex cooler and the water absorption module are used in cooperation, the novel drying system in the acid pickling process of the electronic-grade polycrystalline silicon is provided, process pollution is reduced, and the product percent of pass is increased.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon drying, in particular to a system for drying electronic-grade polysilicon. Background Art

[0002] Silicon is currently the main raw material for manufacturing integrated circuits. The surface of silicon needs to go through etching, cleaning and other steps during the processing, which consumes a lot of chemicals. In particular, the etching step requires cleaning with a high-concentration hydrofluoric acid and nitric acid mixture. After the etching solution has undergone multiple pickling reactions, it needs to be rinsed with high-purity water multiple times to remove the residual liquid on the surface. After the rinsing is completed, hot nitrogen is used to evaporate the water on the surface of the silicon material to fully remove the residual liquid on the surface and ensure the qualified rate of surface ion removal of electronic-grade polysilicon.

[0003] Thermal nitrogen evaporation is widely used in the drying system of electronic-grade polysilicon. However, due to the problem of nitrogen purity, there is still a risk of external contamination source for silicon materials, and the use of nitrogen itself also greatly increases the cost of the entire pickling process. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a system for drying electronic-grade polysilicon, which effectively solves the problems in the background technology.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a system for drying electronic-grade polysilicon, comprising: a sealed cavity, and a silicon material storage area connected to the sealed cavity; a gas buffer area is provided below the silicon material storage area, and a vortex cooler, a water absorption module, a mixer, a heater, and a fan are sequentially connected to the silicon material storage area through a gas delivery pipe, and the gas blown out by the fan is passed into the sealed cavity.

[0006] Furthermore, the silicon material storage area and the gas buffer area are isolated by a porous partition.

[0007] Furthermore, through holes are evenly distributed on the porous partition.

[0008] Furthermore, the gas buffer zone adopts an elastic structure.

[0009] Furthermore, nitrogen in the gas buffer zone is extracted so that the gas buffer zone is compressed.

[0010] Furthermore, the vortex cooler divides the gas into two parts, a high-temperature section and a low-temperature section, through the vortex effect.

[0011] Furthermore, the low temperature section removes residual moisture in the gas through a water absorption module.

[0012] Furthermore, an air supply pipe and a flow meter are provided on one side of the gas buffer zone, and a vent pipe is provided between the air supply pipe and the gas buffer zone.

[0013] Furthermore, two vent pipes are provided on the gas delivery pipe communicating between the silicon material storage area and the vortex cooler.

[0014] The beneficial effect of the utility model is that a new drying system for the pickling process of electronic-grade polysilicon is provided through the coordinated use of a sealed chamber, a vortex cooler, and a water absorption module. With the help of an elastic buffer zone and a fan, the gas in the system is circulated, the product qualification rate is improved, and the risk of non-compliant impurities on the surface of the silicon material due to pollution from external air sources is reduced. Inert gases such as nitrogen, argon, etc. are fully utilized through the vortex cooler and the sealed chamber to reduce the cost investment of the drying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a schematic structural diagram of a system for drying electronic-grade polysilicon in an embodiment of the utility model;

[0017] Figure 2 It is a schematic diagram of a porous partition in an embodiment of the utility model.

[0018] Figure numerals: 1. Sealed chamber; 2. Silicon material storage area; 21. Porous isolation plate; 3. Gas buffer zone; 4. Gas delivery pipe; 5. Vortex cooler; 51. High temperature section; 52. Low temperature section; 6. Water absorption module; 7. Mixer; 8. Heater; 9. Fan; 10. Air supply pipe; 11. Flow meter; 12. Vent pipe. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0022] like Figure 1 to Figure 2 The system for drying electronic-grade polysilicon shown in the figure comprises: a sealed chamber 1, and a silicon material storage area 2 connected to the sealed chamber 1; a gas buffer area 3 is provided below the silicon material storage area 2, and a vortex cooler 5, a water absorption module 6, a mixer 7, a heater 8, and a fan 9 are sequentially connected to the silicon material storage area through a gas delivery pipe 4, and the gas blown out by the fan 9 is passed into the sealed chamber 1.

[0023] The implementation process of the utility model is that the silicon material after being washed with high-purity water is sent to the silicon material storage area 2 through a conveyor belt. The silicon material storage area 2 and the gas buffer zone 3 are isolated by a porous partition plate 21. A part of the residual high-purity water flows into the gas buffer zone 3 below by gravity. At the same time, since the supporting structure of the gas buffer zone 3 adopts an elastic structure, the gas in the gas buffer zone 3 is compressed and enters the vortex cooler 5 through the gas delivery pipe 4. The vortex cooler 5 divides the gas into a high temperature section 51 and a low temperature section 52 through the vortex effect. The water is enriched in the low temperature section 52. The low temperature section 52 carrying water removes the residual water in the gas through the water absorption module 6. After removal, the two streams of gas are mixed and enter the mixer 7. The gas temperature is increased by the heater 8. The gas pressure is increased after passing through the fan 9. At this time, the gas pressure is increased and released instantly after entering the sealed cavity 1, which improves the gas purge power and is more conducive to the removal of residual water on the surface. At the same time, the loss of gas can be input with inert gas such as nitrogen, argon, etc. through the gas supply pipe 10. The gas supply pipe 10 is mainly used to replenish the system with gas when the drying system is first operated.

[0024] In order to isolate most of the moisture from the silicon material, a porous partition 21 is used to isolate the silicon material storage area 2 and the gas buffer area 3. Through holes 211 are evenly distributed on the porous partition 21. As a structural design, the porous partition has a large number of tiny pores, which allow gas molecules to pass through while blocking the passage of solid particles and macromolecules.

[0025] In the utility model, in order to better compress the inert gas such as nitrogen, argon, etc. in the gas buffer zone 3, the gas buffer zone 3 adopts an elastic structure, and the gas buffer zone 3 with an elastic structure can also manage the gas supply more effectively. Due to the deformable characteristics of the wall, it can expand the capacity as needed to adapt to the sudden increase in pressure, or shrink to cope with the situation of reduced demand. This self-regulating ability makes the gas supply more stable and reliable. At the same time, because the elastic structure can absorb and release pressure, it reduces the repetitive stress caused to the fixed structure, which reduces the possibility of material fatigue and extends the service life of the buffer zone.

[0026] In this solution, the gas buffer zone 3 is compressed by extracting nitrogen from the gas buffer zone 3, thereby improving the gas transmission efficiency. At the same time, the inert gases such as nitrogen and argon in the gas buffer zone 3 are compressed into the vortex cooler 5 under the action of high pressure.

[0027] In the embodiment of the utility model, the vortex cooler 5 divides the gas into two parts, a high-temperature section 51 and a low-temperature section 52, through the vortex effect. The low-temperature section 52 removes residual moisture in the gas through the water absorption module 6. In the low-temperature section 52, the speed of the gas slows down and the pressure increases, which is conducive to the condensation of water vapor. By setting the water absorption module 6, the water vapor content in the gas can be further reduced.

[0028] In order to ensure the stability of the gas pressure in the whole system, an air supply pipe 10 and a flow meter 11 are provided on one side of the gas buffer zone 3. The flow meter 11 is used to measure the pressure of the gas to be supplemented. In order to improve the safety redundancy of the pipeline system, a vent pipe 12 is provided between the air supply pipe 10 and the gas buffer zone 3. Two vent pipes 12 are provided on the gas delivery pipe 4 connected between the silicon material storage area 2 and the vortex cooler 5. At the same time, in order to better ensure the removal of residual moisture in the gas, the high-pressure gas after the gas pressure is increased by the fan 7 is introduced into the sealed cavity 1 to form a circulation system. After multiple cycles and multiple passes through the water absorption module 6, the residual water in the gas is continuously removed, and the gas in the gas buffer zone is simultaneously continuously purified, thereby reducing the increase of impurity ions on the surface of the silicon material due to gas pollution.

[0029] Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the description are only for explaining the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which are within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A system for drying electronic grade polysilicon, characterized in that: include: A sealed cavity (1) and a silicon material storage area (2) connected to the sealed cavity (1); a gas buffer area (3) is provided below the silicon material storage area (2), and is sequentially connected to the silicon material storage area via a gas delivery pipe (4) with a vortex cooler (5), a water absorption module (6), a mixer (7), a heater (8), and a fan (9), and the gas blown out by the fan (9) is passed into the sealed cavity (1).

2. The system for drying electronic grade polysilicon according to claim 1, characterized in that: The silicon material storage area (2) and the gas buffer area (3) are isolated by a porous partition (21).

3. The system for drying electronic grade polysilicon according to claim 2, characterized in that: The porous partition plate (21) is evenly provided with through holes (211).

4. The system for drying electronic grade polysilicon according to claim 1, characterized in that: The gas buffer zone (3) adopts an elastic structure.

5. The system for drying electronic grade polysilicon according to claim 1, characterized in that: The nitrogen in the gas buffer zone (3) is extracted, so that the gas buffer zone (3) is compressed.

6. The system for drying electronic grade polysilicon according to claim 1, characterized in that: The vortex cooler (5) divides the gas into two parts, a high-temperature section (51) and a low-temperature section (52), through the vortex effect.

7. The system for drying electronic grade polysilicon according to claim 6, characterized in that: The low-temperature section (52) removes residual moisture in the gas through a water absorption module (6).

8. The system for drying electronic grade polysilicon according to claim 1, characterized in that: A gas supply pipe (10) and a flow meter (11) are provided on one side of the gas buffer zone (3), and a vent pipe (12) is provided between the gas supply pipe (10) and the gas buffer zone (3).

9. The system for drying electronic grade polysilicon according to claim 1, characterized in that: Two vent pipes (12) are provided on the gas delivery pipe (4) communicating between the silicon material storage area (2) and the vortex cooler (5).

Images