Monocrystalline silicon wafer cleaning system and method

Abstract

The invention provides a monocrystalline silicon wafer cleaning system and method. The cleaning system comprises a first cleaning tank; a second washing tank; a third cleaning tank; a fourth cleaning tank; a high-pressure conveying device; the fourth cleaning tank comprises a first tank body used for containing a first cleaning solution containing a hydrogen peroxide aqueous solution, a second tank body used for containing a second cleaning solution containing the hydrogen peroxide aqueous solution and a third tank body used for containing a third cleaning solution containing the hydrogen peroxide aqueous solution. The at least one first light source is used for providing light for the first tank body, the at least one second light source is used for providing light for the third tank body, the first tank body is communicated with the second tank body through a first free radical oxidation resistant reverse osmosis membrane, and the second tank body is communicated with the third tank body through a second free radical oxidation resistant reverse osmosis membrane; at least one composite plate is arranged in each of the first groove body and the second groove body; and each composite plate comprises doped graphene, so that the problems of high cleaning cost of the monocrystalline silicon wafer and complex wastewater treatment are solved.

Description

Technical Field

[0001] The present invention relates to the field of silicon wafer cleaning, and more particularly, to a single crystal silicon wafer cleaning system and method. Background Art

[0002] As a core material in the preparation process of solar cells, the surface state of silicon wafers and the degree of removal of pollutants directly affect the yield and power generation efficiency of finished solar cells. The sources of silicon wafer pollutants mainly include the following aspects: process, reagents, human body, environment, water, etc. The main pollution forms of silicon wafers include: organic residue dirt (including cleaning agent residue, fingerprints, glue dirt, etc.), metal ion residue, silicon powder dirt, watermark dirt, etc.

[0003] In the prior art, cleaning agents containing a large amount of macromolecular organic reagents are usually used for cleaning. However, these reagents are severely consumed during the cleaning process and cannot be reused after being contaminated by silicon powder, increasing the complexity and cost of wastewater treatment. In the prior art, an alkaline solution prepared by potassium hydroxide (KOH) or sodium hydroxide (NaOH) and H2O2 (hydrogen peroxide) is also used as a cleaning solution, and its strong oxidizing property is used to remove pollutants on the surface of silicon wafers at a certain temperature. However, the cleaning ability of this method is limited, the stability of hydrogen peroxide is poor, and continuous supplementation is required, resulting in extremely high consumption of alkali and hydrogen peroxide, high cost and difficult control of process stability. Summary of the Invention

[0004] The main object of the present invention is to provide a single crystal silicon wafer cleaning system and method to solve the problems of high cleaning cost and complex wastewater treatment of single crystal silicon wafers in the prior art.

[0005] To achieve the above object, the present invention provides a single crystal silicon wafer cleaning system, comprising:

[0006] A first cleaning tank for holding pure water;

[0007] A second cleaning tank for holding a cleaning solution containing an alkaline substance and a surfactant; the alkaline substance includes at least one of sodium hydroxide and potassium hydroxide, and the surfactant includes alkyl polyglycoside;

[0008] A third cleaning tank for holding pure water;

[0009] Fourth cleaning tank, the fourth cleaning tank includes a first tank body for containing a first cleaning liquid of an aqueous hydrogen peroxide solution, a second tank body for containing a second cleaning liquid of an aqueous hydrogen peroxide solution, a third tank body for containing a third cleaning liquid of an aqueous hydrogen peroxide solution, at least one first light source for providing light to the first tank body, and at least one second light source for providing light to the third tank body; the first tank body and the second tank body are communicated through a first anti-free radical oxidation reverse osmosis membrane, and the second tank body and the third tank body are communicated through a second anti-free radical oxidation reverse osmosis membrane; at least one composite plate is respectively arranged in the first tank body and the second tank body; each composite plate respectively includes doped graphene.

[0010] High-pressure delivery device, used to deliver the first cleaning liquid of the aqueous hydrogen peroxide solution to the first tank body, and drive the water molecules in the first cleaning liquid of the aqueous hydrogen peroxide solution to pass through the first anti-free radical oxidation reverse osmosis membrane, and, used to deliver the third cleaning liquid of the aqueous hydrogen peroxide solution to the third tank body, and drive the water molecules in the third cleaning liquid of the aqueous hydrogen peroxide solution to pass through the second anti-free radical oxidation reverse osmosis membrane.

[0011] Further, at least one air bubbling device is respectively arranged in the first tank body, the second tank body and the third tank body.

[0012] Further, a first cover plate is arranged at the upper end of the first tank body and a first liquid adding port is arranged on the first cover plate; a second cover plate is arranged at the upper end of the third tank body and a second liquid adding port is arranged on the second cover plate; the high-pressure delivery device includes a first high-pressure pump and a second high-pressure pump, the first liquid adding port is connected to the liquid outlet of the first high-pressure pump, and the second liquid adding port is connected to the liquid outlet of the second high-pressure pump.

[0013] Preferably, each air bubbling device is respectively arranged at the bottom of the first tank body, the second tank body and the third tank body.

[0014] Further, each first light source and each second light source are respectively independently selected from one of incandescent lamps or xenon lamps.

[0015] Further, each first light source is arranged at the upper part of the first tank body, and each second light source is arranged at the upper part of the third tank body.

[0016] Preferably, each composite plate located in the first tank body is arranged perpendicular to the bottom of the first tank body, and each composite plate located in the third tank body is arranged perpendicular to the bottom of the third tank body.

[0017] More preferably, each composite plate located in the first tank body is located below each first light source, and each composite plate located in the third tank body is located below each second light source.

[0018] Further, the alkyl polyglycoside is selected from at least one of APG-1214 and dodecyl glucoside.

[0019] Furthermore, the doped graphene includes at least one of nitrogen-doped graphene and phosphorus-doped graphene.

[0020] Furthermore, each composite plate further includes a polymer matrix, the polymer matrix includes at least one of polystyrene and polypropylene, and the doped graphene is distributed on the surface of the polymer matrix.

[0021] Furthermore, the first free radical oxidation-resistant reverse osmosis membrane and the second free radical oxidation-resistant reverse osmosis membrane are respectively antioxidant polyamide reverse osmosis membranes.

[0022] Furthermore, the single-crystalline silicon wafer cleaning system further includes a turbidity automatic monitoring system, and the turbidity automatic monitoring system includes a yellow target, a CCD vision detection probe, an image processing device, a first control device, a drainage device, and a water adding device;

[0023] The yellow target is arranged at the bottom of the first cleaning tank;

[0024] The CCD vision detection probe is used to acquire an image of the yellow target and send it to the image processing device;

[0025] The image processing device is used to receive the image of the yellow target, process the image of the yellow target to obtain the brightness value and clarity value of the yellow target, and send them to the first control device;

[0026] The first control device is used to receive the brightness value and clarity value of the yellow target, and when the brightness value and / or clarity value of the yellow target is lower than a preset value, control the drainage device to drain the first cleaning tank, and after the drainage device finishes draining, control the water adding device to add water to the first cleaning tank.

[0027] Furthermore, the pH value of the cleaning solution containing an alkaline substance and a surfactant is 11 - 12, and in terms of weight percentage, the concentration of alkyl polyglycoside in the cleaning solution containing an alkaline substance and a surfactant is 0.1% - 1%.

[0028] Preferably, the single-crystalline silicon wafer cleaning system further includes a pH value automatic monitoring system, and the pH value automatic monitoring system includes a pH sensor, a second control device, and an alarm device;

[0029] The pH value sensor is arranged in the second cleaning tank, and is used to acquire the pH value of the cleaning solution containing an alkaline substance and a surfactant and send it to the second control device;

[0030] The second control device is used to receive the pH value of the cleaning solution containing an alkaline substance and a surfactant, and when it exceeds the preset range, control the alarm device to give an alarm.

[0031] Further, by weight percentage, the content of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution is 1% to 4%, the content of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution is 1% to 4%, and the content of hydrogen peroxide in the second cleaning solution containing an aqueous hydrogen peroxide solution is 1% to 4%.

[0032] Further, the single-crystal silicon wafer cleaning system further includes an automatic hydrogen peroxide concentration monitoring system, which includes a first online hydrogen peroxide concentration analyzer, a second online hydrogen peroxide concentration analyzer, a third control device, a first hydrogen peroxide feeding device, and a second hydrogen peroxide feeding device;

[0033] The first online hydrogen peroxide concentration analyzer is disposed in the first tank and is used to obtain the concentration of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution and send it to the third control device;

[0034] The second online hydrogen peroxide concentration analyzer is disposed in the third tank and is used to obtain the concentration of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution and send it to the third control device;

[0035] The third control device is used to obtain the concentration of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution and control the first hydrogen peroxide feeding device to add hydrogen peroxide into the first tank when the concentration is lower than a preset value; and is used to obtain the concentration of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution and control the second hydrogen peroxide feeding device to add hydrogen peroxide into the third tank when the concentration is lower than a preset value.

[0036] According to another aspect of the present invention, there is provided a method for cleaning a single-crystal silicon wafer using the above single-crystal silicon wafer cleaning system, including the following steps:

[0037] Step S1, placing the single-crystal silicon wafer in the first cleaning tank for the first cleaning;

[0038] Step S2, placing the single-crystal silicon wafer that has been first cleaned in the second cleaning tank for the second cleaning;

[0039] Step S3, placing the single-crystal silicon wafer that has been second cleaned in the third cleaning tank for the third cleaning;

[0040] Step S4, placing the single-crystal silicon wafer that has been third cleaned in the second tank for the fourth cleaning.

[0041] Further, the time for the first cleaning is 150s to 200s, the time for the second cleaning is 150s to 200s, the time for the third cleaning is 150s to 200s, and the time for the fourth cleaning is 100s to 250s.

[0042] Further, step S1, step S2, the above-mentioned step S3, and step S4 are all carried out at 20°C to 30°C.

[0043] Further, during the fourth cleaning process, air is respectively introduced into the first tank, the second tank, and the third tank, and the air flow rates of introducing air into the first tank, the second tank, and the third tank are 0.4 L / min to 0.6 L / min respectively.

[0044] Applying the technical solution of the present invention, the monocrystalline silicon wafer is first preliminarily cleaned with pure water in the first cleaning tank to remove large particle impurities and some soluble pollutants. After being cleaned in the first cleaning tank, the monocrystalline silicon wafer can then enter the second cleaning tank for a second cleaning. The second cleaning tank contains a cleaning solution comprising an alkaline substance and a surfactant. Since oil-based impurities are molecular organic impurities, the adsorption force between them and the surface of the monocrystalline silicon wafer is weak, and they have the characteristic of hydrophobicity, masking the removal of ionic impurities. Alkyl polyglycoside is a non-ionic surfactant. Using the super strong detergency of alkyl polyglycoside for molecular organic impurities can remove most of the oil-based organic substances on the surface of the silicon wafer. At the same time, using the strong alkalinity of sodium hydroxide to react with some organic substances or hydrolyze ester-based oily sewage to generate substances easily soluble in water, so as to effectively remove some molecular organic impurities for subsequent removal of ionic impurities. In addition, sodium hydroxide can also effectively remove the residual silicon powder on the surface of the monocrystalline silicon wafer or remove metal ion impurities such as residual iron ions and copper ions on the surface of the monocrystalline silicon wafer through precipitation or complexation reactions. Moreover, alkyl polyglycoside is biodegradable and basically has no pollution to the environment. After being cleaned in the second cleaning tank, the silicon wafer can be rinsed again with pure water in the third cleaning tank to remove the residual cleaning reagents and impurities such as sodium silicate on the surface of the monocrystalline silicon wafer, preparing for the subsequent deep cleaning (deep oxidation of ionic impurities).In the fourth cleaning tank for deep cleaning, the first tank body, the second tank body, and the third tank body are respectively filled with cleaning liquids containing hydrogen peroxide aqueous solution. Under light conditions, the doped graphene on the composite board in the first tank body reacts with hydrogen peroxide in an oxidation-reduction reaction to generate hydroxyl radicals (·OH). Hydroxyl radicals are a kind of highly efficient oxidant that can react with ionic impurities on the surface of the silicon wafer and convert them into soluble substances, thus achieving deep cleaning. At the same time, the generated hydroxyl radicals (·OH) can oxidize heavy metal ions on the surface of the monocrystalline silicon wafer into precipitates or more easily treatable forms, and then remove the treated metal ions from the silicon wafer surface through a cleaning operation. In addition, the design of the first free-radical oxidation reverse osmosis membrane, the second free-radical oxidation reverse osmosis membrane, and the high-pressure delivery device ensures that the generated high-concentration hydroxyl radicals can be transferred from the first tank body and the third tank body to the second tank body along with water molecules to deeply purify the silicon wafer, while preventing substances in the middle tank body from flowing back into the first tank body and the second tank body, avoiding secondary pollution in the first tank body and the third tank body. Therefore, the cleaning liquids in the first tank body and the third tank body can be continuously used, and only the cleaning liquid in the second tank body needs to be replaced when necessary, reducing the consumption of sodium hydroxide and hydrogen peroxide and lowering the cleaning cost. Furthermore, by adopting the design of the first free-radical oxidation reverse osmosis membrane and the second free-radical oxidation reverse osmosis membrane, the cleaning efficiency of the monocrystalline silicon wafer in the second tank body can be controlled by adjusting the hydrogen peroxide concentration in the first tank body and the third tank body, and the cleaning process has high controllability and stability. Finally, in the fourth cleaning tank, the synergistic effect of hydrogen peroxide and hydroxyl radicals catalyzed by the composite board with doped graphene significantly improves the cleanliness of the surface of the monocrystalline silicon wafer, which is particularly suitable for the cleaning of silicon wafers in semiconductor manufacturing and solar panel production, and helps to improve the performance and yield of products.

[0045] By using the monocrystalline silicon wafer cleaning system of the present invention, the device is simple and easy to operate, the components of each cleaning liquid are simple, and the waste liquid treatment cost is low. While effectively cleaning the surface of the monocrystalline silicon wafer, it has a low cleaning cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The schematic diagrams of the drawings forming a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0047] Figure 1 shows a schematic external three-dimensional structure diagram of the fourth cleaning tank in the monocrystalline silicon wafer cleaning system according to an embodiment of the present invention; and

[0048] Figure 2 shows a schematic internal three-dimensional structure diagram of the fourth cleaning tank in the monocrystalline silicon wafer cleaning system according to an embodiment of the present invention. Among them, the above-mentioned drawings include the following reference numerals:

[0049] 1. Fourth cleaning tank; 11. First tank body; 111. First cover plate; 112. First liquid addition port; 12. Second tank body; 13. Third tank body; 131. Second cover plate; 132. Second liquid addition port;

[0050] 2. First anti-free radical oxidation reverse osmosis membrane;

[0051] 3. Second anti-free radical oxidation reverse osmosis membrane;

[0052] 4. Composite board;

[0053] 5. Air bubbling device;

[0054] 6. First light source;

[0055] 7. Second light source. Detailed implementation manners

[0056] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0057] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0058] As described in the background art, there are problems of high cleaning cost of single crystal silicon wafers and complex wastewater treatment in the prior art. To solve the above problems, as Figure 1 and Figure 2 shown, the present invention provides a single crystal silicon wafer cleaning system, including a first cleaning tank for holding pure water;

[0059] a second cleaning tank for holding a cleaning solution containing an alkaline substance and a surfactant; the alkaline substance includes at least one of sodium hydroxide and potassium hydroxide, and the surfactant includes alkyl polyglycoside;

[0060] a third cleaning tank for holding pure water;

[0061] Fourth cleaning tank 1, the fourth cleaning tank 1 includes a first tank body 11 for containing a first cleaning liquid of an aqueous hydrogen peroxide solution, a second tank body 12 for containing a second cleaning liquid of an aqueous hydrogen peroxide solution, a third tank body 13 for containing a third cleaning liquid of an aqueous hydrogen peroxide solution, at least one first light source 6 for providing light to the first tank body 11, and at least one second light source 7 for providing light to the third tank body 13. The first tank body 11 and the second tank body 12 are connected through a first anti-free radical oxidation reverse osmosis membrane 2, and the second tank body 12 and the third tank body 13 are connected through a second anti-free radical oxidation reverse osmosis membrane 3. At least one composite plate 4 is respectively arranged in the first tank body 11 and the second tank body 12. Each composite plate 4 includes doped graphene;

[0062] And a high-pressure delivery device for delivering the first cleaning liquid of the aqueous hydrogen peroxide solution into the first tank body 11 and driving the water molecules in the first cleaning liquid of the aqueous hydrogen peroxide solution to pass through the first anti-free radical oxidation reverse osmosis membrane, and for delivering the third cleaning liquid of the aqueous hydrogen peroxide solution into the third tank body 13 and driving the water molecules in the third cleaning liquid of the aqueous hydrogen peroxide solution to pass through the second anti-free radical oxidation reverse osmosis membrane 3.

[0063] In order to obtain better cleaning effects and reduce the cleaning cost, the present invention provides a single-crystalline silicon wafer cleaning system. The single-crystalline silicon wafer is first preliminarily cleaned with pure water in a first cleaning tank to remove large-particle impurities and some soluble pollutants. After being cleaned in the first cleaning tank, the single-crystalline silicon wafer can then enter a second cleaning tank for a second cleaning. The second cleaning tank contains a cleaning solution comprising an alkaline substance and a surfactant. Since oil-based impurities are molecular organic impurities, the adsorption force between them and the surface of the single-crystalline silicon wafer is weak, and they have a hydrophobic property and a masking effect on the removal of ionic impurities. Alkyl polyglycoside is a non-ionic surfactant. By using the super strong detergency of alkyl polyglycoside on molecular organic impurities, most of the oil-based organic substances on the surface of the silicon wafer can be removed. At the same time, by using the strong alkalinity of sodium hydroxide to react with some organic substances (as shown in Formula I) or hydrolyze ester-based oily sewage, substances that are easily soluble in water are generated, thereby effectively removing some molecular organic impurities to facilitate the subsequent removal of ionic impurities. In addition, sodium hydroxide can also effectively remove the residual silicon powder on the surface of the single-crystalline silicon wafer (as shown in Formula II) or remove metal ions such as residual iron ions and copper ions on the surface of the single-crystalline silicon wafer through precipitation or complexation reactions. Moreover, alkyl polyglycoside is biodegradable and basically has no pollution to the environment. After being cleaned in the second cleaning tank, the silicon wafer can be rinsed again with pure water in a third cleaning tank to remove the residual cleaning reagents and impurities such as sodium silicate on the surface of the single-crystalline silicon wafer, preparing for the subsequent deep cleaning (deep oxidation of ionic impurities).In the fourth cleaning tank 1 for deep cleaning, the cleaning liquids containing hydrogen peroxide aqueous solution are respectively placed in the first tank body 11, the second tank body 12 and the third tank body 13. Under the illumination condition, the doped graphene on the composite plate 4 in the first tank body 11 undergoes an oxidation-reduction reaction with hydrogen peroxide to generate hydroxyl radicals (·OH). Hydroxyl radicals are a kind of highly efficient oxidants, which can react with the ionic impurities on the surface of the silicon wafer and convert them into soluble substances, thus achieving deep cleaning. At the same time, the generated hydroxyl radicals (·OH) can oxidize the heavy metal ions on the surface of the monocrystalline silicon wafer into precipitates or more easily treatable forms, and then the treated metal ions are removed from the surface of the silicon wafer through cleaning (combined with bubbling, etc.) operations. In addition, the designs of the first anti-free radical oxidation reverse osmosis membrane, the second anti-free radical oxidation reverse osmosis membrane and the high-pressure delivery device ensure that the generated high-concentration hydroxyl radicals can be transferred from the first tank body 11 and the third tank body 13 to the second tank body 12 along with water molecules to deeply purify the silicon wafer, while preventing the substances in the middle tank body from flowing back into the first tank body and the second tank body, avoiding secondary pollution in the first tank body 11 and the third tank body 13. Therefore, the cleaning liquids in the first tank body 11 and the third tank body 13 can be continuously used, and only the cleaning liquid in the second tank body 12 needs to be replaced when necessary, reducing the consumption of sodium hydroxide and hydrogen peroxide and lowering the cleaning cost. Moreover, with the designs of the first anti-free radical oxidation reverse osmosis membrane 2 and the second anti-free radical oxidation reverse osmosis membrane 3, the cleaning efficiency of the monocrystalline silicon wafer in the second tank body 12 can be controlled by adjusting the hydrogen peroxide concentration in the first tank body 11 and the third tank body 13, and the cleaning process has high controllability and stability. Finally, in the fourth cleaning tank 1, the synergistic effect of hydrogen peroxide and the hydroxyl radicals catalytically generated by the composite plate with doped graphene significantly improves the cleanliness of the surface of the monocrystalline silicon wafer, which is particularly suitable for the cleaning of silicon wafers in semiconductor manufacturing and solar panel production, and helps to improve the performance and yield of products. By using the monocrystalline silicon wafer cleaning system of the present invention, the device is simple and easy to operate, the components of each cleaning liquid are simple, and the waste liquid treatment cost is low. While effectively cleaning the surface of the monocrystalline silicon wafer, it has a low cleaning cost.

[0064] C x H y O z +NaOH→C x H y-1 O z Na+H2O(I);

[0065] Si + 2NaOH + H2O = Na2SiO3 + 2H2↑(II).

[0066] In some embodiments, at least one air bubbling device 5 is respectively arranged in the first tank body 11, the second tank body 12 and the third tank body 13.

[0067] In the technical solution of the embodiment of the present application, by arranging an air bubbling device 5 in the second tank 12, the turbulence degree of the cleaning liquid can be increased, which is beneficial to the shedding of impurities (ionic impurities) on the surface of the silicon wafer, improves the cleaning efficiency, and is especially suitable for the continuous cleaning of single-crystalline silicon wafers in a large-scale production environment, and can significantly improve the cleaning speed and effect; in addition, by introducing air into the first tank 11 and the third tank 13, the fluidity of the cleaning liquid in the system can be increased, the generation efficiency and diffusion efficiency of hydroxyl radicals can be improved, and the cleaning effect can be improved; preferably, each air bubbling device 5 is respectively arranged at the bottom of the first tank 11, the second tank 12 and the third tank 13, which is beneficial to improving the cleaning effect and efficiency. Specifically, the bubbling device can be a tube-type bubbling device, and the tube-type bubbling device includes a chemically resistant pipeline (such as a PVC or PE pipeline) and a plurality of microporous nozzles installed on the pipeline, which can evenly distribute bubbles along the bottom or side of the tank. The advantage of adopting this device design is that it can be flexibly arranged according to the size and shape of the tank to ensure that the entire tank can be well covered by bubbles, improving the uniformity and efficiency of cleaning; in order to prevent the bubbles blown out by two adjacent bubbling ports from interacting with each other and affecting the flow and rupture of the bubbles, thereby affecting the coverage rate of the bubbles on the liquid surface, the distance between two adjacent nozzles is preferably 10 cm to 12 cm.

[0068] In some embodiments, a first cover plate 111 is arranged at the upper end of the first tank 11, and a first liquid adding port 112 is arranged on the first cover plate 111; a second cover plate 131 is arranged at the upper end of the third tank 13, and a second liquid adding port 132 is arranged on the second cover plate 131; the high-pressure conveying device includes a first high-pressure pump and a second high-pressure pump. The first liquid adding port 112 is connected to the liquid outlet of the first high-pressure pump, and the second liquid adding port 132 is connected to the liquid outlet of the second high-pressure pump. The first high-pressure pump conveys a first cleaning liquid containing an aqueous hydrogen peroxide solution into the first tank 11 and drives the water molecules in the first cleaning liquid containing an aqueous hydrogen peroxide solution to pass through the first anti-free radical oxidation reverse osmosis membrane. The second high-pressure pump conveys a third cleaning liquid containing an aqueous hydrogen peroxide solution into the third tank 13 and drives the water molecules in the third cleaning liquid containing an aqueous hydrogen peroxide solution to pass through the second anti-free radical oxidation reverse osmosis membrane 3; preferably, the first tank 11 and the first cover plate 111 are integrally and hermetically arranged, and the third tank 13 and the second cover plate 131 are integrally and hermetically arranged.

[0069] In some embodiments, each first light source 6 and each second light source 7 are respectively independently selected from one of an incandescent lamp or a xenon lamp. It can be understood that other light sources that can provide visible light that doped graphene can absorb are also applicable to the present invention and will not be listed one by one here.

[0070] In some embodiments, in order to make full use of the energy of the light source for the doped graphene on the composite plate 4, each first light source 6 is arranged at the upper part of the first trough body 11, and each second light source 7 is arranged at the upper part of the third trough body 13; preferably, each composite plate 4 located in the first trough body 11 is arranged perpendicular to the bottom of the first trough body 11, and each composite plate 4 located in the third trough body 13 is arranged perpendicular to the bottom of the third trough body 13; more preferably, each composite plate 4 located in the first trough body 11 is located below each first light source 6, and each composite plate 4 located in the third trough body 13 is located below each second light source 7.

[0071] In some embodiments, the alkyl glycoside is selected from at least one of APG-1214 and dodecyl glucoside. APG-1214 and dodecyl glucoside are both non-ionic surfactants with good emulsification, dispersing and cleaning properties, good biodegradability, and are environmentally friendly.

[0072] Doped graphene has more sufficient electrons and holes to provide more sites for redox reactions, and can generate sufficient hydroxyl radicals to meet the quality and efficiency requirements of single crystal silicon wafer cleaning. In some embodiments, the doped graphene includes at least one of nitrogen-doped graphene and phosphorus-doped graphene, and is doped with N and phosphorus non-metals. The incorporation of nitrogen elements can generate NC bonds, and the C atoms adjacent to the N atoms will have more positive charges, which can effectively enhance the electronegativity of the graphene material, facilitate the redox reaction with hydrogen peroxide, and increase the generation rate of free radicals.

[0073] In some embodiments, each composite plate 4 also includes a polymer matrix, the polymer matrix includes at least one of polystyrene and polypropylene, and the doped graphene is distributed on the surface of the polymer matrix to obtain higher cleaning efficiency and reduce cleaning costs; preferably, a coating or surface modification can be provided on the surface of the polymer matrix so that the doped graphene can be bonded to the composite plate 4; preferably, the doped graphene (for example, nitrogen or phosphorus doped graphene) is chemically bonded to the composite plate by a chemical modification method, so that it is firmly bonded to the composite plate 4. For example, common chemical modification methods such as acylation, hydroxylation and amination can be used.

[0074] In some embodiments, the first anti-free radical oxidation reverse osmosis membrane 2 and the second anti-free radical oxidation reverse osmosis membrane 3 are respectively anti-oxidation polyamide reverse osmosis membranes. Phosphorus-based antioxidants, such as phosphites, can be introduced into the polyamide reverse osmosis membrane to enhance the antioxidant properties of the membrane. These antioxidants reduce the oxidative degradation of the polyamide membrane material by inhibiting the chain reaction of free radicals.

[0075] In some embodiments, the single crystal silicon wafer cleaning system further comprises a turbidity automatic monitoring system, the turbidity automatic monitoring system comprises a yellow target object, a CCD visual detection probe and an image processing device, a first control device, a drainage device and a water adding device;

[0076] The yellow object is disposed at the bottom of the first cleaning tank;

[0077] The CCD vision detection probe is used to acquire an image of the yellow object and send it to the image processing device;

[0078] The image processing device is used to receive the image of the yellow object, process the image of the yellow object to obtain the brightness value and the clarity value of the yellow object, and send them to the first control device;

[0079] The first control device is used to receive the brightness value and the clarity value of the yellow object, and when the brightness value and / or the clarity value of the yellow object is lower than the preset value, control the drainage device to drain the first cleaning tank, and control the water adding device to add water to the first cleaning tank after the drainage device finishes draining.

[0080] In the technical solution of the embodiment of the present application, the turbidity automatic monitoring system can monitor the turbidity of the cleaning liquid in real time, automatically control the replacement of pure water in the first cleaning tank, and is applicable to the single-crystalline silicon wafer production line with high automation degree, which can significantly reduce manual intervention and improve production efficiency and cleaning quality. Specifically, in the present application, the yellow target is used as a key reference object in the turbidity automatic monitoring system for real-time monitoring of the water quality condition in the cleaning tank by the CCD (Charge Coupled Device) vision detection probe. To ensure the accuracy of the monitoring results and the stability of the system operation, the yellow target can be made of a specially designed corrosion-resistant ceramic material with a stable yellow glaze or dye applied on its surface to ensure the long-term stability of the color, or it can be made of plastic materials such as high-density polyethylene (HDPE) or polytetrafluoroethylene (PTFE). These materials not only have good chemical stability but also can form a stable yellow surface by adding yellow masterbatch or pigments. Specifically, as one of the key components for implementing the turbidity automatic monitoring system, the CCD vision detection probe is used to obtain the image information of the yellow target at the bottom of the cleaning tank to judge the turbidity of the cleaning liquid. The CCD vision detection probe has a high resolution to ensure that it can clearly capture the details of the yellow target, including the brightness and clarity changes on the surface of the target. The CCD vision detection probe has the signal transmission ability so that the image information can be transmitted to the image processing device. For example, the CCD vision detection probe and the image processing device can be realized by using high-quality data lines and interfaces, such as high-speed data transmission interfaces like USB 3.0 and GigE Vision. For example, cameras of the In-Sight series by Cognex or the ace series by Basler can be used as the preferred types of the CCD vision detection probe in the present application. These cameras have wide applications in the field of industrial vision detection, can not only provide high-precision image acquisition but also have the characteristics of chemical corrosion resistance, waterproof and dustproof, and are very suitable for monitoring the water quality condition in the cleaning tank. In addition, they support multiple data transmission standards, such as GigE Vision, and can quickly and stably send the image information to the image processing device to realize the automatic monitoring and control of turbidity.

[0081] In some embodiments, the pH value of the cleaning liquid containing an alkaline substance and a surfactant is 11 - 12, and the concentration of alkyl polyglycoside in the cleaning liquid containing an alkaline substance and a surfactant is 0.1% - 1% by weight.

[0082] In the technical solution of the embodiment of the present application, the synergistic effect of the alkaline environment with a pH value of 11 - 12 and the alkyl polyglycoside surfactant not only ensures the cleaning effect but also reduces the consumption of chemical reagents and the residue of chemical substances on the single-crystalline silicon wafer, thereby reducing the cleaning cost.

[0083] In some embodiments, the single-crystalline silicon wafer cleaning system further includes a pH automatic monitoring system, which includes a pH sensor, a second control device, and an alarm device;

[0084] The pH sensor is disposed in the second cleaning tank and is configured to obtain the pH value of the cleaning liquid containing an alkaline substance and a surfactant and send it to the second control device;

[0085] The second control device is configured to receive the pH value of the cleaning liquid containing an alkaline substance and a surfactant and control the alarm device to give an alarm when the pH value of the cleaning liquid containing an alkaline substance and a surfactant exceeds a preset range.

[0086] In the technical solution of the embodiments of the present application, when the pH value of the cleaning liquid containing an alkaline substance and a surfactant in the second cleaning tank exceeds the preset range, the automatic alarm system is triggered. After manually adding the reagent and determining that the pH value is within the preset range, the cleaning system can operate. The pH automatic monitoring system ensures the stability of the chemical properties of the cleaning liquid, especially suitable for processes that require precise control of cleaning conditions, such as the manufacture of integrated circuits, and can effectively avoid poor cleaning effects caused by pH value fluctuations, ensuring the stability and high efficiency of the cleaning effect. Specifically, the type of pH sensor in the present application can be a solid-state pH sensor or an electrochemical pH sensor. The above two types can withstand strong alkaline environments, have high stability, and rapid response, and are suitable for use in automatic control systems to monitor the pH value of the cleaning liquid in real time. For example, the pH sensors of HACH Company in the United States or WTW in Germany. These sensors have extensive applications in industrial pH monitoring, can not only provide high-precision measurements, but also have the characteristics of chemical corrosion resistance, rapid response, and easy integration.

[0087] In some embodiments, by weight percentage, the content of hydrogen peroxide in the first cleaning liquid containing an aqueous hydrogen peroxide solution is 1% to 4%, the content of hydrogen peroxide in the third cleaning liquid containing an aqueous hydrogen peroxide solution is 1% to 4%, and the content of hydrogen peroxide in the second cleaning liquid containing an aqueous hydrogen peroxide solution is 1% to 4%.

[0088] In the technical solution of the embodiments of the present application, under the above concentration conditions, hydrogen peroxide can efficiently remove the organic residue on the surface of the silicon wafer by releasing hydroxyl radicals, improving the surface cleanliness of the silicon wafer. And at a concentration of 1% to 4%, the storage and use safety risks of hydrogen peroxide are relatively low, while reducing the consumption of chemical reagents and lowering the overall cleaning cost.

[0089] In some embodiments, the single-crystalline silicon wafer cleaning system further includes an automatic hydrogen peroxide concentration monitoring system, which includes a first hydrogen peroxide on-line concentration analyzer, a second hydrogen peroxide on-line concentration analyzer, a third control device, a first hydrogen peroxide feeding device, and a second hydrogen peroxide feeding device;

[0090] The first hydrogen peroxide on-line concentration analyzer is disposed in the first tank 11 for obtaining the concentration of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution and sending it to the third control device;

[0091] The second hydrogen peroxide on-line concentration analyzer is disposed in the third tank 13 for obtaining the concentration of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution and sending it to the third control device;

[0092] The third control device is configured to obtain the concentration of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution and control the first hydrogen peroxide feeding device to add hydrogen peroxide into the first tank 11 when the concentration is lower than a preset value; and to obtain the concentration of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution and control the second hydrogen peroxide feeding device to add hydrogen peroxide into the third tank 13 when the concentration is lower than a preset value.

[0093] In the technical solution of the embodiment of the present application, by using the automatic hydrogen peroxide concentration monitoring system to monitor the hydrogen peroxide concentration in real time, the stability of the oxidant concentration can be ensured, and the cleaning effect and production yield can be effectively improved; specifically, the first hydrogen peroxide on-line concentration analyzer and the second hydrogen peroxide on-line concentration analyzer can be independently selected from an electro-chemical type on-line concentration analyzer or an optical type on-line concentration analyzer, which can provide high-precision real-time concentration measurement and have strong adaptability to environmental factors. For example, the Orion Star A329 / MD hydrogen peroxide on-line concentration analyzer and the MPR E-Scan hydrogen peroxide on-line concentration analyzer of Orion in the United States can not only meet the requirements of real-time monitoring, but also have high stability and low maintenance cost, ensuring the controllability and efficiency of the cleaning process.

[0094] According to another aspect of the present invention, there is also provided a method for cleaning a single-crystalline silicon wafer using the above single-crystalline silicon wafer cleaning system, including the following steps:

[0095] Step S1, placing the single-crystalline silicon wafer in the first cleaning tank for the first cleaning to remove particulate impurities on the single-crystalline silicon wafer;

[0096] Step S2, placing the single-crystalline silicon wafer that has been first cleaned in the second cleaning tank for the second cleaning to remove oil-based organic substances on the single-crystalline silicon wafer;

[0097] Step S3: Place the single-crystalline silicon wafer after the second cleaning into the third cleaning tank for the third cleaning to remove impurities such as sodium silicate on the single-crystalline silicon wafer;

[0098] Step S4: Place the single-crystalline silicon wafer after the third cleaning into the second tank for the fourth cleaning.

[0099] In the technical solution of the embodiment of the present application, the single-crystalline silicon wafer is first preliminarily cleaned with pure water in the first cleaning tank to remove large particle impurities and some soluble pollutants; then it enters the second cleaning tank for the second cleaning to remove most of the oil-based organic substances on the silicon wafer surface, and at the same time, some organic substances are decomposed by the strong alkalinity of sodium hydroxide; subsequently, it is rinsed again with pure water in the third cleaning tank to remove the residual cleaning reagents and impurities such as sodium silicate on the single-crystalline silicon wafer surface; finally, it enters the fourth cleaning tank to clean and remove the ionic impurities on the single-crystalline silicon wafer surface, improve the cleanliness of the single-crystalline silicon wafer surface, help improve the performance and yield of the product, and the process is simple, with high controllability and stability.

[0100] In order to obtain a good cleaning effect and improve the cleaning efficiency at the same time, in some embodiments, the time for the first cleaning is 150s - 200s, the time for the second cleaning is 150s - 200s, the time for the third cleaning is 150s - 200s, and the time for the fourth cleaning is 100s - 250s.

[0101] In some embodiments, steps S1, S2, S3, and S4 are all carried out at 20°C - 30°C. At this temperature, there is a good cleaning effect, and it can effectively reduce the damage to the silicon wafer surface caused by high temperature and strong chemical reactions, improving the yield and performance of the product; preferably carried out at room temperature, with low cleaning costs.

[0102] In some embodiments, during the fourth cleaning process, air is respectively introduced into the first tank, the second tank, and the third tank to form bubbles in the first tank, the second tank, and the third tank. The air flow rates of introducing air into the first tank, the second tank, and the third tank are 0.4 / min - 0.6L / min respectively. At this air flow rate, a relatively high bubble density can be obtained to increase the fluidity of the cleaning liquid in the system, improve the generation efficiency and diffusion efficiency of hydroxyl radicals, and improve the cleaning effect.

[0103] Example 1

[0104] As Figure 1 shown, a single-crystalline silicon wafer cleaning system includes:

[0105] A first cleaning tank for holding pure water; a second cleaning tank for holding a cleaning solution containing an alkaline substance and a surfactant; the alkaline substance is sodium hydroxide, and the surfactant is dodecyl glucoside; a third cleaning tank for holding pure water; a fourth cleaning tank 1, the fourth cleaning tank 1 includes a first tank body 11 for holding a first cleaning solution containing an aqueous hydrogen peroxide solution, a second tank body 12 for holding a second cleaning solution containing an aqueous hydrogen peroxide solution, a third tank body 13 for holding a third cleaning solution containing an aqueous hydrogen peroxide solution, six first light sources 6 for providing light to the first tank body 11, and six second light sources 7 for providing light to the third tank body 13. The first tank body 11 and the second tank body 12 are connected through a first anti-free radical oxidation reverse osmosis membrane 2, and the second tank body 12 and the third tank body 13 are connected through a second anti-free radical oxidation reverse osmosis membrane 3; at least one composite plate 4 is respectively arranged in the first tank body 11 and the second tank body 12; each composite plate 4 respectively includes doped graphene; and a high-pressure conveying device for conveying the first cleaning solution containing an aqueous hydrogen peroxide solution into the first tank body 11 and driving the water molecules in the first cleaning solution containing an aqueous hydrogen peroxide solution to pass through the first anti-free radical oxidation reverse osmosis membrane, and for conveying the third cleaning solution containing an aqueous hydrogen peroxide solution into the third tank body 13 and driving the water molecules in the third cleaning solution containing an aqueous hydrogen peroxide solution to pass through the second anti-free radical oxidation reverse osmosis membrane 3;

[0106] Wherein, at least one air bubbling device 5 is respectively arranged in the first tank body 11, the second tank body 12 and the third tank body 13; each air bubbling device 5 is respectively arranged at the bottom of the first tank body 11, the second tank body 12 and the third tank body 13; a first cover plate 111 is arranged at the upper end of the first tank body 11, and a first liquid adding port 112 is arranged on the first cover plate 111; a second cover plate 131 is arranged at the upper end of the third tank body 13, and a second liquid adding port 132 is arranged on the second cover plate 131; the high-pressure conveying device includes a first high-pressure pump and a second high-pressure pump, the first liquid adding port 112 is connected to the liquid outlet of the first high-pressure pump, and the second liquid adding port 132 is connected to the liquid outlet of the second high-pressure pump; each first light source 6 is arranged at the upper part of the first tank body 11, and each second light source 7 is arranged at the upper part of the third tank body 13; each composite plate 4 located in the first tank body 11 is arranged perpendicular to the bottom of the first tank body 11, and each composite plate 4 located in the third tank body 13 is arranged perpendicular to the bottom of the third tank body 13; each composite plate 4 located in the first tank body 11 is located below each first light source 6, and each composite plate 4 located in the third tank body 13 is located below each second light source 7; each first light source 6 and each second light source 7 are both incandescent lamps; each composite plate 4 further includes a polymer matrix, the polymer matrix material is polystyrene, and the doped graphene is distributed on the surface of the polymer matrix; the first anti-free radical oxidation reverse osmosis membrane and the second anti-free radical oxidation reverse osmosis membrane 3 are respectively polyamide reverse osmosis membranes modified with phosphite antioxidants.

[0107] Among them, the pH value of the cleaning solution containing an alkaline substance and a surfactant is 11.5. By weight percentage, the concentration of dodecyl glucoside in the cleaning solution containing an alkaline substance and a surfactant is 5%; by weight percentage, the content of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution is 3%, the content of hydrogen peroxide in the second cleaning solution containing an aqueous hydrogen peroxide solution is 3%, and the content of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution is 3%.

[0108] The specific steps for cleaning a single-crystalline silicon wafer using a single-crystalline silicon wafer cleaning system are as follows:

[0109] In the first step, place the single-crystalline silicon wafer in the first cleaning tank for the first cleaning, and the cleaning time is 180 s;

[0110] In the second step, place the single-crystalline silicon wafer that has undergone the first cleaning in the second cleaning tank for the second cleaning, and the cleaning time is 180 s;

[0111] In the third step, place the single-crystalline silicon wafer that has undergone the second cleaning in the third cleaning tank for the third cleaning, and the cleaning time is 180 s;

[0112] In the fourth step, place the single-crystalline silicon wafer that has undergone the third cleaning in the second tank body 12 for the fourth cleaning, and the cleaning time is 180 s.

[0113] Among them, the above cleaning steps are all carried out at room temperature; during the fourth cleaning process, air is respectively introduced into the first tank body, the second tank body, and the third tank body to form bubbles in the first tank body, the second tank body, and the third tank body. The air flow rates of introducing air into the first tank body, the second tank body, and the third tank body are 0.5 L / min respectively.

[0114] Example 2

[0115] The difference from Example 1 is only that the pH value of the cleaning solution containing an alkaline substance and a surfactant is 11. By weight percentage, the concentration of dodecyl glucoside in the cleaning solution containing an alkaline substance and a surfactant is 0.1%; by weight percentage, the content of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution is 1%, the content of hydrogen peroxide in the second cleaning solution containing an aqueous hydrogen peroxide solution is 1%, and the content of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution is 1%.

[0116] Example 3

[0117] The only difference from Example 1 is that the pH value of the cleaning solution containing the alkaline substance and the surfactant is 12, and the concentration of dodecyl glucoside in the cleaning solution containing the alkaline substance and the surfactant is 1% by weight; the content of hydrogen peroxide in the first cleaning solution containing the hydrogen peroxide aqueous solution is 4% by weight, the content of hydrogen peroxide in the second cleaning solution containing the hydrogen peroxide aqueous solution is 4% by weight, and the content of hydrogen peroxide in the third cleaning solution containing the hydrogen peroxide aqueous solution is 4% by weight.

[0118] Comparative Example 1

[0119] The only difference from Example 1 is that the second cleaning step is not performed.

[0120] Comparative Example 2

[0121] The only difference from Example 1 is that the fourth cleaning step is not performed.

[0122] Cleaning effect test

[0123] (1) Carbon residue amount test: Take the cleaned monocrystalline silicon wafer and place it in pure water for ultrasonic cleaning, then use COD (chemical oxygen demand) to test the carbon content C1 in the pure water after cleaning. At the same time, use the same batch of monocrystalline silicon wafers without any cleaning operation as the object, perform ultrasonic cleaning under the same conditions and test the carbon content C2 in the pure water, and then calculate the carbon residue amount n (n=(C1 / C2×100%)) on the surface of the cleaned monocrystalline silicon wafer. The specific results are shown in Table 1.

[0124] (2) Metal residue amount test: Use ICP-MS to test the content of metal ions on the surface of the cleaned monocrystalline silicon wafer. At the same time, use the same batch of monocrystalline silicon wafers without any cleaning operation as the object to test the content of surface metal ions, and obtain the content of metal ions on the surface of the monocrystalline silicon wafer before cleaning. The content of metal ions on the surface of the monocrystalline silicon wafer before cleaning and the content of metal ions on the surface of the cleaned monocrystalline silicon wafer are shown in Table 1 respectively.

[0125] (3) Turbidity test: Take the cleaned monocrystalline silicon wafer and place it in pure water for ultrasonic cleaning, then test the turbidity T1 of the pure water after cleaning. See Table 1 for details. At the same time, use the same batch of monocrystalline silicon wafers without any cleaning operation as the object, perform ultrasonic cleaning under the same conditions and test the turbidity of the pure water after cleaning to be 8 NTU.

[0126] Table 1

[0127]

[0128] As can be seen from Table 1, for the single-crystalline silicon wafer cleaning system based on the present invention, the carbon residue amount on the surface of the single-crystalline silicon wafer and the content of metal ion impurities on the surface of the single-crystalline silicon wafer after cleaning have excellent cleaning effects, are applicable to the cleaning of silicon wafers in semiconductor manufacturing and solar panel production, help to improve the performance and yield of products, and have low consumption of alkaline substances such as sodium hydroxide, surfactant dodecyl glucoside, and hydrogen peroxide, reducing the cleaning cost.

[0129] The foregoing are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A single crystal silicon wafer cleaning system, characterized in that: include: a first cleaning tank for holding pure water; a second cleaning tank for holding a cleaning solution containing an alkaline substance and a surfactant; the alkaline substance comprises at least one of sodium hydroxide and potassium hydroxide, and the surfactant comprises an alkyl polyglycoside; a third cleaning tank for holding pure water; A fourth cleaning tank (1), the fourth cleaning tank (1) comprising a first tank body (11) for holding a first cleaning liquid containing an aqueous hydrogen peroxide solution, a second tank body (12) for holding a second cleaning liquid containing an aqueous hydrogen peroxide solution, a third tank body (13) for holding a third cleaning liquid containing an aqueous hydrogen peroxide solution, at least one first light source (6) for providing light to the first tank body (11), and at least one second light source (7) for providing light to the third tank body (13); the first tank body (11) and the second tank body (12) are connected via a first anti-free radical oxidation reverse osmosis membrane (2), and the second tank body (12) and the third tank body (13) are connected via a second anti-free radical oxidation reverse osmosis membrane (3); at least one composite plate (4) is respectively arranged in the first tank body (11) and the second tank body (12); each of the composite plates (4) comprises doped graphene; A high-pressure delivery device is used to deliver the first cleaning liquid containing an aqueous hydrogen peroxide solution into the first tank body (11) and drive water molecules in the first cleaning liquid containing an aqueous hydrogen peroxide solution to pass through the first anti-free radical oxidation reverse osmosis membrane, and to deliver the third cleaning liquid containing an aqueous hydrogen peroxide solution into the third tank body (13) and drive water molecules in the third cleaning liquid containing an aqueous hydrogen peroxide solution to pass through the second anti-free radical oxidation reverse osmosis membrane (3).

2. The single crystal silicon wafer cleaning system according to claim 1, characterized in that: At least one air bubbling device (5) is respectively disposed in the first tank body (11), the second tank body (12) and the third tank body (13); and / or, A first cover plate (111) is disposed at the upper end of the first tank body (11), and a first liquid filling port (112) is disposed on the first cover plate (111); a second cover plate (131) is disposed at the upper end of the third tank body (13), and a second liquid filling port (132) is disposed on the second cover plate (131); the high-pressure delivery device comprises a first high-pressure pump and a second high-pressure pump, the first liquid filling port (112) is connected to a liquid outlet of the first high-pressure pump, and the second liquid filling port (132) is connected to a liquid outlet of the second high-pressure pump; Preferably, each of the air bubbling devices (5) is respectively arranged at the bottom of the first tank body (11), the second tank body (12) and the third tank body (13).

3. The single crystal silicon wafer cleaning system according to claim 1, characterized in that: Each of the first light sources (6) and each of the second light sources (7) are independently selected from one of an incandescent lamp and a xenon lamp.

4. The single crystal silicon wafer cleaning system according to claim 1, characterized in that: Each of the first light sources (6) is arranged on the upper part of the first slot body (11), and each of the second light sources (7) is arranged on the upper part of the third slot body (13); Preferably, each of the composite plates (4) located in the first trough body (11) is arranged perpendicularly to the bottom of the first trough body (11), and each of the composite plates (4) located in the third trough body (13) is arranged perpendicularly to the bottom of the third trough body (13); More preferably, each of the composite panels (4) located in the first trough body (11) is located below each of the first light sources (6), and each of the composite panels (4) located in the third trough body (13) is located below each of the second light sources (7).

5. The single crystal silicon wafer cleaning system according to claim 1, characterized in that: The alkyl glycoside is selected from at least one of APG-1214 and dodecyl glucoside; and / or, The doped graphene includes at least one of nitrogen-doped graphene and phosphorus-doped graphene; and / or, Each of the composite plates (4) further comprises a polymer matrix, wherein the polymer matrix comprises at least one of polystyrene and polypropylene, and the doped graphene is distributed on the surface of the polymer matrix; and / or, The first anti-free radical oxidation reverse osmosis membrane (2) and the second anti-free radical oxidation reverse osmosis membrane (3) are respectively anti-oxidation polyamide reverse osmosis membranes.

6. The single crystal silicon wafer cleaning system according to any one of claims 1 to 5, characterized in that: The single crystal silicon wafer cleaning system also includes a turbidity automatic monitoring system, which includes a yellow target, a CCD visual detection probe and an image processing device, a first control device, a drainage device and a water adding device; The yellow label is disposed at the bottom of the first cleaning tank; The CCD visual detection probe is used to obtain the image of the yellow target and send it to the image processing device; The image processing device is used to receive the image of the yellow target object and process the image of the yellow target object to obtain the brightness value of the yellow target object and the clarity value of the yellow target object and send them to the first control device; The first control device is used to receive the brightness value of the yellow label and the clarity value of the yellow label and control the drainage device to drain the first cleaning tank when the brightness value of the yellow label and / or the clarity value of the yellow label is lower than a preset value, and control the water adding device to add water to the first cleaning tank after the drainage system device completes the drainage.

7. The single crystal silicon wafer cleaning system according to any one of claims 1 to 5, characterized in that: The pH value of the cleaning solution containing the alkaline substance and the surfactant is 11 to 12, and the concentration of the alkyl polyglycoside in the cleaning solution containing the alkaline substance and the surfactant is 0.1% to 1% by weight; Preferably, the single crystal silicon wafer cleaning system further comprises a pH value automatic monitoring system, and the pH value automatic monitoring system comprises a pH sensor, a second control device and an alarm device; The pH sensor is disposed in the second cleaning tank, and is used to obtain the pH value of the cleaning solution containing the alkaline substance and the surfactant and send it to the second control device; The second control device is used to receive the pH value of the cleaning solution containing alkaline substances and surfactants and control the alarm device to sound an alarm when the pH value exceeds a preset range.

8. The single crystal silicon wafer cleaning system according to any one of claims 1 to 5, characterized in that: In percentage by weight, the content of hydrogen peroxide in the first cleaning solution containing an aqueous hydrogen peroxide solution is 1% to 4%, the content of hydrogen peroxide in the third cleaning solution containing an aqueous hydrogen peroxide solution is 1% to 4%, and the content of hydrogen peroxide in the second cleaning solution containing an aqueous hydrogen peroxide solution is 1% to 4%; and / or, The single crystal silicon wafer cleaning system also includes a hydrogen peroxide concentration automatic monitoring system, which includes a first hydrogen peroxide online concentration analyzer, a second hydrogen peroxide online concentration analyzer, a third control device, a first hydrogen peroxide feeding device, and a second hydrogen peroxide feeding device; The first hydrogen peroxide online concentration analyzer is disposed in the first tank body, and is used to obtain the concentration of hydrogen peroxide in the first cleaning liquid containing the hydrogen peroxide aqueous solution and send it to the third control device; The second hydrogen peroxide online concentration analyzer is disposed in the third tank body, and is used to obtain the concentration of hydrogen peroxide in the third cleaning solution containing hydrogen peroxide aqueous solution and send it to the third control device; The third control device is used to obtain the concentration of hydrogen peroxide in the first cleaning liquid containing the hydrogen peroxide aqueous solution and control the first hydrogen peroxide feeding device to add hydrogen peroxide into the first tank body when the concentration of hydrogen peroxide is lower than a preset value; and is used to obtain the concentration of hydrogen peroxide in the third cleaning liquid containing the hydrogen peroxide aqueous solution and control the second hydrogen peroxide feeding device to add hydrogen peroxide into the third tank body when the concentration of hydrogen peroxide is lower than a preset value.

9. A method for cleaning a single crystal silicon wafer using the single crystal silicon wafer cleaning system according to any one of claims 1 to 8, characterized in that: The steps include: Step S1, placing the single crystal silicon wafer in a first cleaning tank for first cleaning; Step S2, placing the single crystal silicon wafer that has undergone the first cleaning in a second cleaning tank for a second cleaning; Step S3, placing the single crystal silicon wafer that has undergone the second cleaning in a third cleaning tank for a third cleaning; Step S4, placing the single crystal silicon wafer that has been cleaned for the third time in a second tank body for a fourth cleaning.

10. The method for cleaning a single crystal silicon wafer according to claim 9, characterized in that: The first cleaning time is 150s to 200s, the second cleaning time is 150s to 200s, the third cleaning time is 150s to 200s, and the fourth cleaning time is 100s to 250s; The step S1, the step S2, the step S3 and the step S4 are all performed at 20° C. to 30° C.; and / or, During the fourth cleaning process, air is blown into the first tank body, the second tank body and the third tank body respectively, and the air flow rate of the air blown into the first tank body, the air flow rate of the air blown into the second tank body and the air flow rate of the air blown into the third tank body are 0.4 / min to 0.6L / min respectively.

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