A solar-grade silicon wafer purification control method

Abstract

The present application provides a kind of solar-grade silicon wafer purification control method, steps include: the silicon wafer is placed in the closed storage cavity;Control the particle size in the storage cavity reaches the set standard and makes its inside air pressure reaches positive pressure state;Control the storage cavity carrying the silicon wafer moves to target position.The present application control method, can make the silicon wafer long time storage in the thousand level clean closed space, to ensure the surface cleanliness of silicon wafer in special working environment, to improve the surface quality of silicon wafer, can make the silicon wafer good yield can make the silicon wafer good yield from the existing 92.5% to 92.8%.

Description

Technical Field

[0001] This invention belongs to the field of solar silicon wafer purification technology, and in particular relates to a solar-grade silicon wafer purification control method. Background Technology

[0002] In the existing battery module manufacturing process, the surface quality requirements of silicon wafers are extremely high during texturing, diffusion, and coating. Although the production is carried out in a cleanroom, the silicon wafers are still easily contaminated by dust in the air when they are left open during long-distance transportation. This causes small black spots to form on the surface of the silicon wafers, affecting the texturing, diffusion, and coating effects, accelerating the scrapping of silicon wafers, and increasing production costs. Summary of the Invention

[0003] This invention provides a method for purifying and controlling solar-grade silicon wafers, particularly suitable for preservation during transit and transportation in the solar silicon wafer manufacturing process, solving the technical problem in the prior art where silicon wafers are easily contaminated by dust during transportation between adjacent processes.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A method for purifying and controlling solar-grade silicon wafers, comprising the following steps:

[0006] The silicon wafer is placed in a sealed storage cavity;

[0007] Control the particle size in the storage chamber to reach a set standard and ensure that the air pressure inside the chamber reaches a positive pressure state;

[0008] The storage cavity containing the silicon wafer is controlled to move to the target location.

[0009] Furthermore, the step of placing the silicon wafer in a sealed storage cavity includes:

[0010] Open the filtration and exhaust systems within the storage chamber;

[0011] The filtration system is continuously turned on while the exhaust system is turned on intermittently.

[0012] Test the particle size within the storage cavity and ensure that the particle size is not less than the set standard;

[0013] Then control the air pressure inside the storage chamber and make the air pressure inside and outside the storage chamber the same;

[0014] The silicon wafer is placed inside the storage cavity after the air pressure has been adjusted.

[0015] Furthermore, the set standard is that the number of particles per cubic meter does not exceed 1000, and the size of the particles is not greater than 0.5μm.

[0016] Furthermore, the filtration system includes a filter with a fan.

[0017] Furthermore, the steps of controlling the particle size within the storage cavity to reach a set standard and ensuring the internal air pressure reaches a positive pressure state include:

[0018] First, test the particle size within the storage cavity;

[0019] If the set standard is reached, the air pressure in the storage chamber will be adjusted to a positive pressure state.

[0020] Furthermore, if the set standard is not met, the gas in the storage chamber is first discharged, and then the detection continues until the particle size reaches the set standard.

[0021] Furthermore, the step of controlling the storage cavity containing the silicon wafer to move to the target location includes:

[0022] The navigation system controlling the storage cavity scans the area around the storage cavity and automatically avoids obstacles along a set route;

[0023] Based on the navigation system, the movement system of the storage cavity is then controlled to move the storage cavity containing the silicon wafer to the target location. Furthermore, the navigation system includes a navigator configured for laser SLAM;

[0024] The mobility system includes several rollers.

[0025] Furthermore, a particle detector for monitoring the cleanliness of the storage cavity and a temperature and humidity detector for monitoring the temperature and humidity of the storage cavity are installed inside the storage cavity.

[0026] Furthermore, a pressure sensor for measuring the air pressure inside the storage cavity is also provided inside the storage cavity.

[0027] The control method designed in this invention allows silicon wafers to be stored in a Class 1000 cleanroom for extended periods, ensuring the surface cleanliness requirements of the silicon wafers in special working environments and improving the surface quality of the silicon wafers. This can increase the yield of silicon wafers from the current 92.5% to 92.8%. Attached Figure Description

[0028] Figure 1 This is a flowchart of a solar-grade silicon wafer purification and control method according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of a storage cavity according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of a filter screen according to an embodiment of the present invention;

[0031] Figure 4 This is a circuit connection diagram of the storage cavity according to an embodiment of the present invention.

[0032] In the picture:

[0033] 10. Storage chamber; 20. Filter; 30. Filter screen

[0034] 40. Exhaust fan; 50. Exhaust port; 60. Particle detector

[0035] 70. Pressure sensor; 80. Navigation device; 90. Temperature and humidity detector. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0037] This embodiment proposes a method for purifying and controlling solar-grade silicon wafers, such as... Figure 1 As shown, the steps include:

[0038] The silicon wafer is placed in a sealed storage cavity.

[0039] In this embodiment, the storage cavity 10 can be used as a cavity for placing a silicon wafer, and its structure is as follows: Figure 2 As shown, there are automatically opening roller shutter doors at the front and back. A filtration system is installed at the top and an exhaust system is installed at the bottom. The airflow entering from the filtration system is filtered and then flows through the storage chamber 10 before being discharged from the exhaust system, thus forming an airflow circulation channel. At the same time, the filtered gas can dry and preserve the silicon wafer to a purity of thousands after entering the storage chamber 10.

[0040] The filtration system includes a two-layer filtration structure: a filter screen 30 placed at the top and a filter 20 placed below the filter screen. The filter screen 20 has a conical structure that is higher in the middle and lower at the edges, as shown in the diagram. Figure 3 As shown, a groove for collecting dust is provided around the filter screen 20. Large dust particles filtered by the filter screen 20 fall down the inclined surface of the filter screen 20 into the groove. At the same time, the filter 20 is also a filter for the FFU fan, which can directly draw air from the outside into the storage chamber 10 and perform thousand-level filtration on the air, so that the particle size entering the storage chamber 10 is no greater than 0.5μm, providing quality assurance for the storage of silicon wafers.

[0041] The exhaust system includes several exhaust ports 50 and exhaust fans 40, wherein the number of exhaust fans 40 is less than the number of exhaust ports 50, and the exhaust fans 40 and exhaust ports 50 are staggered. The exhaust fans 40 can also serve as exhaust holes for venting. When the air pressure in the storage chamber 10 is high, it needs to be completely vented within a set time. Based on the pressure difference and time, the system can automatically calculate the ventilation area that needs to be opened, thereby calculating how many exhaust ports 50 need to be opened. Several exhaust ports 50 are randomly selected from the several exhaust ports 50 to vent the airflow; the extra exhaust ports 50 can also serve as backup holes for auxiliary use in emergencies.

[0042] To ensure the airtightness of the storage chamber 10, a one-way control valve is provided in each exhaust port 50 to create a slightly positive pressure state in the entire storage chamber 10. This creates a dry air pressure difference inside the storage chamber 10 that is slightly higher than the atmospheric pressure outside the storage chamber 10, preventing moisture, dust, and other particles from entering the storage chamber 10. This keeps the environment inside the storage chamber 10 for storing silicon wafers clean and dry, avoiding air leakage, protecting the surface quality of the silicon wafers, and ensuring the airtightness and safety of silicon wafer storage.

[0043] Inside the storage chamber 10, there is also a particle detector 60 for monitoring the cleanliness of the storage chamber 10, a temperature and humidity detector for monitoring the temperature and humidity of the storage chamber 10, and a pressure sensor 70 for measuring the air pressure inside the storage chamber 10. The particle detector 60 can be a MET ONEHHPC2+, which is a thousand-class air particle counter; the pressure sensor 70 is a conventional pressure tester.

[0044] A navigation system consisting of several laser SLAM navigators is installed around the four sides of the storage cavity 10 to identify the surrounding environment during the movement and loading of the storage cavity 10. A touchscreen control unit is installed on the outer wall of the storage cavity 10. This control unit is connected to the cleanroom unit, exhaust unit, roller shutter door, navigation unit, particle detector 60, pressure sensor 70, temperature and humidity detector 90, and movement unit, respectively. The circuit connections are as follows: Figure 4 As shown. By setting the laser SLAM navigation system, the precise location of the storage cavity 10 can be further determined, and it can flexibly and agilely plan its own path, avoid obstacles, and detour autonomously. It can also achieve one-time positioning without the need for mechanical secondary positioning; the touch screen control unit can further improve the intelligence of the system.

[0045] Specifically, during operation, the filter 20 and exhaust fan 40 inside the storage chamber 10 are opened first, while the roller shutter door is closed, allowing only the air inside the storage chamber 10 to circulate. During this process, the filtration system needs to be continuously opened and the exhaust system needs to be opened intermittently to ensure that the air inside the storage chamber 10 reaches the set standard.

[0046] The particle size in the storage chamber 10 is then tested using a particle detector 60 to ensure that the number of particles per cubic meter in the storage chamber 10 does not exceed 1000 and the particle size is not greater than 0.5μm.

[0047] Once the particle size in the storage chamber 10 reaches the standard, the air pressure in the storage chamber 10 is controlled and the air pressure inside and outside the storage chamber 10 is made the same.

[0048] Once the air pressure inside and outside the storage chamber 10 is consistent, stop the exhaust fan 40 and continue the filter 20; then open one end of the roller shutter door in the storage chamber 10 and place the silicon wafer inside the storage chamber 10 after the air pressure has been adjusted.

[0049] Furthermore, the particle size within the storage chamber 10 is controlled to meet a set standard, and the air pressure within it is brought to a positive pressure state.

[0050] Specifically, closing the roller shutter door seals the storage chamber 10. Since opening the roller shutter door allows some external airflow to enter the storage chamber 10, affecting the particle size within the chamber, the particle size must first be detected by the ion detector 60.

[0051] If the set standard is reached, the air pressure inside the storage chamber 10 is adjusted to a positive pressure state. This creates a dry air pressure difference inside the storage chamber 10 that is slightly higher than the atmospheric pressure outside, preventing moisture, dust, and other particles from entering the storage chamber 10. This keeps the environment inside the storage chamber 10 clean and dry, preventing air leakage and protecting the surface quality of the silicon wafers. It also ensures the airtightness and safety of the silicon wafer storage.

[0052] If the set standard is not met, the gas in the storage chamber 10 is first discharged through the exhaust fan 40, and then the particle size in the storage chamber 10 is tested. The exhaust-testing process is repeated until the particle size in the storage chamber 10 reaches the set standard. Then the operation of the exhaust fan 40 is stopped.

[0053] Furthermore, the storage cavity 10 containing the silicon wafer is controlled to move to the target position.

[0054] Specifically, the navigation device 80 outside the storage cavity 10 is first controlled to scan the surroundings of the storage cavity 10 and then automatically avoid obstacles and proceed along the set route.

[0055] Based on the set path and image capture results of the navigator 80, the moving system consisting of several rollers located at the bottom of the storage cavity 10 is controlled to move the storage cavity 10 containing the silicon wafers until it reaches the target position. Using the control method designed in this invention, silicon wafers can be stored for extended periods in a Class 1000 clean, sealed space, ensuring the surface cleanliness requirements of the silicon wafers in special working environments, thereby improving the surface quality of the silicon wafers and increasing the yield rate from the current 92.5% to 92.8%.

[0056] The embodiments of the present invention have been described in detail above. These descriptions are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for purifying and controlling solar-grade silicon wafers, characterized in that the steps include... include: The silicon wafer is placed in a sealed storage cavity; Control the particle size in the storage chamber to reach a set standard and ensure that the air pressure inside the chamber reaches a positive pressure state; The navigation system controlling the storage cavity scans the area around the storage cavity and automatically avoids obstacles along a set route; Based on the navigation system, the movement system of the storage cavity is then controlled to move the storage cavity containing the silicon wafer to the target location; The step of placing the silicon wafer in a sealed storage cavity includes: Open the filtration and exhaust systems within the storage chamber; The filtration system is continuously turned on while the exhaust system is turned on intermittently. Test the particle size within the storage cavity and ensure that the particle size is not less than the set standard; Then control the air pressure inside the storage chamber and make the air pressure inside and outside the storage chamber the same; The silicon wafer is placed inside the storage cavity after the air pressure has been adjusted; The set standard is that the number of particles of the specified size in each cubic meter does not exceed 1000, and the size of the particles is not greater than 0.5μm; The steps of controlling the particle size in the storage cavity to reach a set standard and ensuring that the air pressure inside reaches a positive pressure state include: First, test the particle size within the storage cavity; If the set standard is reached, the air pressure in the storage chamber will be adjusted to a positive pressure state.

2. The solar-grade silicon wafer purification and control method according to claim 1, characterized in that, The filtration system includes a filter with a fan.

3. A method for purifying and controlling solar-grade silicon wafers according to claim 1 or 2, characterized in that, If the set standard is not met, the gas in the storage chamber is first discharged, and then the detection continues until the particle size reaches the set standard.

4. The solar-grade silicon wafer purification and control method according to claim 1, characterized in that, The navigation system includes a navigator configured with laser SLAM; The mobility system includes several rollers.

5. A method for purifying and controlling solar-grade silicon wafers according to any one of claims 1-2 and 4, characterized in that, A particle detector for monitoring the cleanliness of the storage cavity and a temperature and humidity detector for monitoring the temperature and humidity of the storage cavity are installed inside the storage cavity.

6. The solar-grade silicon wafer purification and control method according to claim 5, characterized in that, A pressure sensor for measuring the air pressure inside the storage cavity is also installed inside the storage cavity.

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