Processing technology of photovoltaic monocrystalline silicon wafer substrate

Abstract

The invention relates to the field of silicon wafer processing, in particular to a processing technology of a photovoltaic monocrystalline silicon wafer substrate. Comprising the following steps: 1) carrying out single crystal growth, cutting and pretreatment to obtain a sample; 2) grinding and cleaning the sample to obtain a ground sample; 3) polishing the grinding sample to obtain a polished sample; and 4) cleaning, drying and packaging the polished sample to obtain the photovoltaic monocrystalline silicon wafer substrate. A cleaning agent adopted in the cleaning process of the step 2) and the step 4) is prepared by the following steps: weighing an ethanol solution and an adsorption auxiliary agent, homogenizing to obtain a mixed solution A, then weighing water, a titanium lactate ammonium salt chelate and adsorption resin, adding into the mixed solution A, uniformly mixing, and then adding ammonium hydroxide to adjust the pH value to 8-9 to obtain the cleaning agent; the adsorption auxiliary agent is composed of multimerization isomeric alcohol polyoxyethylene butenyl amide, an organic sodium salt active agent and adsorption particles. According to the technical scheme, the better cleaning effect and cleaning uniformity are obtained.

Description

Technical Field

[0001] The present application relates to the field of silicon wafer processing, and more specifically, to a processing technology for photovoltaic-grade single-crystal silicon wafer substrates. Background Art

[0002] As one of the core raw materials for the photovoltaic industry, monocrystalline silicon plays a vital role in the modern energy system. With the growing global demand for renewable energy, the application of photovoltaic-grade monocrystalline silicon is becoming increasingly widespread, and its processing technology has also developed rapidly. To meet the requirements of high-performance solar cells, photovoltaic-grade monocrystalline silicon wafer substrates must possess extremely high surface quality and dimensional accuracy. To this end, the industry continues to optimize processing techniques and technologies to achieve higher production efficiency and product quality.

[0003] In actual production, single crystal silicon wafer processing usually includes multiple steps such as single crystal growth, cutting, grinding, polishing, and cleaning. However, the cleaning process of single crystal silicon wafers usually uses deionized water, alkaline cleaning agents such as sodium silicate and potassium hydroxide, or alkaline peroxide cleaning agents such as hydrogen peroxide and ammonia.

[0004] The above cleaning agents can meet the cleaning requirements of monocrystalline silicon wafers during the cleaning process. However, photovoltaic-grade monocrystalline silicon wafer substrates are generally larger in size to accommodate the silicon wafer area requirements of solar panels. In existing production processes, the following problems are prone to occur: On the one hand, existing cleaning steps cannot completely remove potential minor defects on the entire surface of photovoltaic-grade monocrystalline silicon wafer substrates. In batch production or long-term cleaning processes, problems such as trace metal ion contamination or organic residue are prone to occur, which affects the surface flatness and optical performance of the final product. On the other hand, the use of highly effective decontamination cleaning agents often causes partial excessive erosion, resulting in damage to the wafer surface and weakening its surface flatness and long-term stability. Therefore, further research is urgently needed. Summary of the Invention

[0005] In order to obtain a photovoltaic-grade single-crystal silicon wafer substrate with better cleaning effect stability and cleaning uniformity, the present application provides a processing technology for a photovoltaic-grade single-crystal silicon wafer substrate.

[0006] In a first aspect, the present application provides a process for processing a photovoltaic-grade single-crystal silicon wafer substrate, comprising the following steps: 1) Obtaining a sample by sequentially growing, cutting, and pre-treating a single crystal; 2) Grinding and cleaning the sample to obtain a ground sample; 3) polishing the ground sample to obtain a polished sample; 4) The polished sample is then cleaned, dried, and packaged to obtain a photovoltaic-grade single crystal silicon wafer substrate; The cleaning agent used in the cleaning process of step 2) and step 4) is prepared by the following method: 80-90% of water, 0.2-2% of ammonium lactate chelate, 1-10% of adsorption resin, and 5-10% of adsorption aid are weighed and mixed uniformly according to weight percentage, and then ammonium hydroxide is added to adjust the pH value to 8-9 to obtain a cleaning agent; The adsorption auxiliary agent comprises polymerized isomeric alcohol polyoxyethylene butylamide, organic sodium salt active agent and adsorption particles in a weight ratio of 1: (2-3): (5-8).

[0007] By adopting the above technical solution, high-precision processing of photovoltaic-grade single-crystal silicon wafer substrates is achieved, and the flatness of the entire surface is improved. Specifically, during the processing, single crystal growth, cutting, and pretreatment are completed in sequence. The pretreatment includes outer diameter rolling, flat edge or V-groove processing, slicing, and chamfering operations to ensure that the entire surface of the sample is neat and defect-free. Subsequently, the surface smoothness is further improved through grinding and cleaning processes to ensure product quality. The polishing process in the step can effectively remove the surface oxide film and uneven areas, and reduce the impact of residual substances. And after polishing, cleaning treatment is performed to further reduce the impurities adhering to the surface of the photovoltaic-grade single-crystal silicon wafer substrate, and further improve the stability and uniformity of the cleaning effect of the photovoltaic-grade single-crystal silicon wafer substrate.

[0008] Furthermore, the process of this application adopts two cleaning steps, and the special cleaning agent used in the two cleaning steps contains water, ammonium lactate titanium salt chelate, adsorption resin and adsorption aid, and a suitable alkaline environment is achieved by adjusting the ammonium hydroxide. It can not only completely remove surface impurities and particles, but also has a slight etching effect to optimize the surface state, further improving the stability and uniformity of the cleaning effect of photovoltaic-grade single-crystal silicon wafer substrates.

[0009] Furthermore, the adsorption aid, composed of polymerized isomeric alcohol polyoxyethylene butylamide, an organic sodium salt surfactant, and adsorption particles, synergizes with the adsorption resin and ammonium titanium lactate chelate to further enhance cleaning effectiveness and promote uniform dispersion of the raw material system, ensuring the cleanliness of the entire surface of photovoltaic-grade monocrystalline silicon wafer substrates. Furthermore, it maintains excellent adsorption over long-term use, fully guaranteeing cleaning effectiveness while also balancing cleaning uniformity requirements. Ultimately, photovoltaic-grade monocrystalline silicon wafer substrates with excellent surface quality and stable performance are achieved.

[0010] Furthermore, the cleaning process in this application specifically includes the following steps: The polished sample is immersed in a cleaning solution at a temperature of 40-50°C for 10-120s, and then sprayed with pure water to rinse its surface clean.

[0011] Preferably, the volume flow rate of the cleaning liquid is 1-3 L / min.

[0012] By adopting this technical solution, the cleaning fluid, at a volume flow rate of 1-3 L / min, can fully contact the surface of photovoltaic-grade monocrystalline silicon wafer substrates, ensuring uniform distribution of the adsorbed resin and other components during the cleaning process. This effectively removes surface impurities and contaminants, improving cleaning results while ensuring overall cleaning efficiency. This flow rate setting helps maintain the dynamic balance of the cleaning fluid, avoiding problems such as incomplete cleaning due to excessively fast flow rates or prolonged cleaning time due to excessively slow flow rates.

[0013] Preferably, the density of the adsorption resin is less than the density of the cleaning liquid.

[0014] By adopting this technical solution, the adsorbent resin, with its lower density than the cleaning liquid, floats on the surface of the cleaning liquid, effectively preventing the adsorbent resin from settling to the bottom during the cleaning process, causing blockage or uneven distribution. This characteristic helps ensure uniformity and stability of the cleaning agent throughout the cleaning process, thereby improving the removal of impurities and particles from the surface of single-crystal silicon wafer substrates while reducing potential damage to the wafer surface.

[0015] Preferably, the alkalinity of the cleaning solution in the cleaning process of step 2) is greater than the alkalinity of the cleaning solution in the cleaning process of step 4).

[0016] By employing this technical solution, a higher alkalinity level in the cleaning process (step 2) effectively removes more impurities and contaminants from the sample surface, ensuring a higher-quality surface finish for the polished standard sample. Appropriately lowering the alkalinity of the cleaning solution in the cleaning process (step 4) prevents excessive corrosion of the polished standard sample surface, thereby ensuring cleanliness while maximally protecting the integrity and optical performance of the photovoltaic-grade monocrystalline silicon wafer substrate. Specifically, this design not only improves cleaning efficiency but also optimizes the final product quality.

[0017] Preferably, the adsorption resin is composed of one or more of an amide-based adsorption resin, a phenolic hydroxyl-based adsorption resin, and a sulfone-containing adsorption resin.

[0018] By adopting the above technical solution, the adsorption resin in the cleaning agent can be selected from one or more combinations of amide-based adsorption resins, phenolic hydroxyl-based adsorption resins, and sulfone-based adsorption resins. This design gives the cleaning agent a stronger adsorption capacity, effectively removing different types of contaminants from the entire surface of photovoltaic-grade single-crystal silicon wafer substrates. Specifically: Amide-based adsorption resin, due to its hydrophilicity and certain lipophilicity, can adsorb and remove a variety of organic and inorganic salt impurities in water, thereby improving the cleaning effect.

[0019] Phenolic hydroxyl adsorption resin effectively removes organic pollutants such as phenols and aniline by forming hydrogen bonds or other chemical reactions with specific pollutants, showing high selectivity and adsorption efficiency.

[0020] Sulfone-containing adsorption resins have a strong adsorption capacity for polar pollutants due to the high polarity of the sulfone group, which can further improve the cleaning quality.

[0021] In summary, by rationally selecting different types of adsorption resins and their combinations, the overall adsorption capacity and selectivity of the cleaning agent can be significantly enhanced, achieving a more efficient cleaning effect, while protecting the overall surface of the photovoltaic-grade monocrystalline silicon wafer substrate from damage, and maintaining better cleaning effect stability and cleaning uniformity during mass production or long-term use.

[0022] Preferably, the organic sodium salt active agent is one or more of sodium glutamate, dioctyl sulfosuccinate sodium salt, disodium lauryl polyethylene oxide sulfosuccinate, and 1-ethyl-3-methylimidazole acetate.

[0023] By adopting the above technical solution, sodium glutamate can significantly reduce the surface tension of the cleaning liquid, enhance the wettability of the cleaning liquid on the entire surface of the photovoltaic-grade monocrystalline silicon wafer substrate, and have a certain buffering capacity to adjust the pH value of the cleaning liquid; sodium salt of dioctyl sulfosuccinate has excellent emulsifying properties, which can emulsify grease and particulate pollutants into small droplets and disperse them in the cleaning liquid, while improving the stability of the cleaning agent; disodium lauryl polyethylene oxide sulfosuccinate has good penetration and solubility, which can destroy the chemical bonds between dirt molecules and peel them off the entire surface of the photovoltaic-grade monocrystalline silicon wafer substrate, reducing chemical corrosion; 1-ethyl-3-methylimidazole acetate can remove metal ions through chelation, further improving the cleaning effect and adjusting the pH value of the cleaning liquid, protecting the entire surface of the photovoltaic-grade monocrystalline silicon wafer substrate from chemical corrosion.

[0024] Preferably, the organic sodium salt active agent is composed of sodium glutamate, dioctyl sulfosuccinate sodium salt, disodium polyethylene oxide lauryl sulfosuccinate, and 1-ethyl-3-methylimidazole acetate.

[0025] By adopting the above technical solution, the organic sodium salt active agent is composed of sodium glutamate, sodium salt of dioctyl sulfosuccinate, disodium lauryl polyethylene oxide sulfosuccinate, and 1-ethyl-3-methylimidazole acetate, which can significantly reduce the surface tension of the cleaning liquid, improve wettability and penetration ability, and make it easier for the cleaning agent to cover and penetrate into the tiny gaps on the overall surface of the photovoltaic-grade single-crystalline silicon wafer substrate. At the same time, the composition has excellent emulsification and dispersibility, which can effectively remove pollutants such as grease and particles on the overall surface of the photovoltaic-grade single-crystalline silicon wafer substrate, and remove metal ions through chelation to prevent them from corroding or contaminating the overall surface of the photovoltaic-grade single-crystalline silicon wafer substrate. In addition, the formula also has good stability, which can prevent the cleaning agent from stratification or precipitation during storage and use, ensuring the consistency and reliability of the cleaning effect.

[0026] When the organic sodium salt active agent is composed of sodium glutamate, sodium salt of dioctyl sulfosuccinate, disodium lauryl polyethylene oxide sulfosuccinate, and 1-ethyl-3-methylimidazole acetate in a weight ratio of 1:(1-2):(0.5-1):(1-3), it plays a synergistic role and plays a synergistic role with the polymerized isomeric alcohol polyoxyethylene butylamide and adsorption particles, further improving the cleaning effect and cleaning uniformity of the cleaning agent, thereby improving the flatness, neatness and optical properties of the entire surface of the photovoltaic-grade single-crystal silicon wafer substrate.

[0027] Preferably, the adsorption particles are composed of fiber powder, nano-silica aerogel powder, and maleic anhydride grafted material in a weight ratio of 3: (1-3): (1-1.8).

[0028] By adopting the above technical solution, the adsorption particles are composed of fiber powder, nano-silica aerogel powder, and maleic anhydride grafts in specific proportions, achieving a multi-faceted synergistic effect. The fiber powder provides a large specific surface area and pore structure, enhancing physical adsorption capacity while improving the stability of the cleaning agent and reducing mechanical friction on the overall surface of the photovoltaic-grade monocrystalline silicon wafer substrate. The nano-silica aerogel powder, with its high specific surface area and porosity, effectively adsorbs tiny contaminants and improves the permeability of the cleaning agent. The maleic anhydride grafts have a coating and compatibilizing effect, promoting thorough and uniform mixing of the fiber powder and nano-silica aerogel powder, while also coating them to form structurally stable adsorption particles and reduce alkali corrosion of the fiber powder, thereby maintaining optimal adsorption effects over the long term.

[0029] The three components are compounded in a weight ratio of 3:(1-3):(1-1.8), ensuring the optimal overall performance of the adsorbed particles. They demonstrate excellent targeting and efficiency in removing impurities from the overall surface of photovoltaic-grade monocrystalline silicon wafer substrates, while protecting the overall surface of photovoltaic-grade monocrystalline silicon wafer substrates from damage.

[0030] Preferably, the maleic anhydride grafted product is polyisoprene grafted maleic anhydride and / or PTW.

[0031] By adopting the above technical solution, the introduction of polyisoprene-grafted maleic anhydride and PTW significantly improves the compatibility between the various components in the adsorption particles. Specifically, the introduction of maleic anhydride functional groups in polyisoprene-grafted maleic anhydride and PTW enhances their interaction with fiber powder and nano-silica aerogel powder, thereby improving the stability of the overall blend system and producing adsorption particles with a stable structure and excellent adsorption performance.

[0032] Preferably, the fiber powder is seaweed fiber powder and / or viscose fiber powder.

[0033] By adopting the above technical solution, the fiber powder selected from seaweed fiber powder and / or viscose fiber powder can increase the viscosity and adhesion of the cleaning agent, allowing the cleaning agent to better cover the entire surface of the photovoltaic-grade single-crystalline silicon wafer substrate. Furthermore, this type of fiber powder can form a stable composite material with the nano-silica aerogel powder and maleic anhydride graft, which together can adsorb and remove impurities, thereby improving the cleaning effect and protecting the photovoltaic-grade single-crystalline silicon wafer substrate surface from damage. At the same time, it interacts with the polymerized isomeric alcohol polyoxyethylene butylamide and organic sodium salt surfactant to further improve the cleaning uniformity of the photovoltaic-grade single-crystalline silicon wafer substrate surface.

[0034] In summary, this application includes at least one of the following beneficial technical effects: 1. By using a cleaning agent with a specific ratio for two cleaning treatments, the metal ion contamination and organic residue on the entire surface of the photovoltaic-grade monocrystalline silicon wafer substrate can be effectively removed, significantly improving the surface purity and flatness of the photovoltaic-grade monocrystalline silicon wafer substrate; 2. The raw material composition of the cleaning liquid of the present application, such as the compounding of polymerized isomeric alcohol polyoxyethylene butylamide, organic sodium salt active agent, and adsorption particles, can avoid excessive corrosion during the cleaning process, and can ensure its overall cleaning cleanliness and overall cleaning uniformity. At the same time, it can maintain the adsorption effect during the batch production process, and has achieved better quality stability.

[0035] 3. The design of the cleaning solution in step 2) being more alkaline than that in step 4) reduces additional damage to the wafer surface in the later stage while ensuring sufficient removal of stubborn impurities in the early stage, thereby taking into account both efficient decontamination effect and overall stability of the wafer.

[0036] 4. The adsorption particles are composed of fiber powder, nano-silica aerogel powder, and maleic anhydride grafted material in a weight ratio of 3: (1-3): (1-1.8), and the adsorption particles have an adsorption effect and are not easy to scratch the single crystal silicon. Under the action of polymerized isomeric alcohol polyoxyethylene butylamide and organic sodium salt active agent, the impurities on the entire surface of the photovoltaic-grade single crystal silicon wafer substrate can be effectively and evenly removed, thereby improving the surface cleanliness. At the same time, it can maintain a better adsorption effect to ensure cleaning stability and improve product quality. DETAILED DESCRIPTION

[0037] The present application is further described in detail below with reference to the embodiments.

[0038] Grinding fluid: nano titanium dioxide grinding fluid, brand Jiupeng model XH2010YYRNTG; Polishing liquid: nano alumina polishing liquid, brand Jinghe model VK-L30W; Titanium ammonium lactate chelate: di(2-hydroxypropionic acid) diammonium dihydroxide, CAS No. 65104-06-5; Polymeric isomeric alcohol polyoxyethylene butylamide: brand: Tuoxinda, model: 014, pH value: 7, critical micelle concentration (25°C): 42 mol / L, surface tension (25°C): 75 dyn / cm; The scientific name of monosodium glutamate is α-aminoglutarate monosodium; The molecular formula of dioctyl sulfosuccinate sodium salt is C20H36O7SNa; Disodium lauryl polyethylene oxide sulfosuccinate, model PZ51531351, brand Tangyi; 1-Ethyl-3-methylimidazolium acetate CAS No. 143314-17-4; Polyisoprene grafted maleic anhydride CAS No. 139948-75-7; PTW compatibilizer: American DuPont PTW terpolymer; Seaweed fiber powder and viscose fiber powder are sieved through 1000-2000 mesh; Nano-silica aerogel powder, manufactured by Senate (Guangdong) New Materials Technology Co., Ltd., has a thermal conductivity of 0.012W / (m·K) and is an oleophilic and hydrophobic adsorbent. The adsorption resin is an amide-based adsorption resin with a particle size of 0.1 mm. At 25°C, the maximum adsorption capacity for 5-hydroxymethylfurfural is 85 mg / g. Preparation example of adsorption particles Preparation Example 1 A method for preparing adsorption particles comprises the following steps: Fiber powder, nano-silica aerogel powder, and maleic anhydride grafted material were weighed in a weight ratio of 3:1:1 and mixed evenly. The mixture was heated until the maleic anhydride grafted material was completely melted, and then fully mixed and placed in an extruder for melt extrusion. The extruder temperature was set to 80°C, 90°C, 100°C, 110°C, 120°C, 105°C, 100°C, and 100°C in sequence according to the extrusion section. After extrusion, the mixture was cooled to 30°C in a water cooling device and then placed in a granulator for granulation to obtain adsorption particles with a particle size of 0.1 mm.

[0039] Preparation Example 2 Preparation Example 2 differs from Preparation Example 1 in that the weight ratio of the fiber powder, the nano-silica aerogel powder, and the maleic anhydride graft is 3:2:1.5.

[0040] Preparation Example 3 Preparation Example 3 is different from Preparation Example 1 in that the weight ratio of the fiber powder, the nano-silica aerogel powder, and the maleic anhydride graft is 3:3:1.8.

[0041] Preparation Example 4 Preparation Example 4 differs from Preparation Example 1 in that the fiber powder is viscose fiber powder.

[0042] Preparation Example 5 Preparation Example 5 differs from Preparation Example 1 in that the fiber powder is composed of seaweed fiber powder and viscose fiber powder in a weight ratio of 1:3.

[0043] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 1 is that the maleic anhydride grafted product is a PTW compatibilizer.

[0044] Preparation Example 7 Preparation Example 7 is different from Preparation Example 1 in that the maleic anhydride grafted product is composed of polyisoprene grafted maleic anhydride and PTW compatibilizer in a weight ratio of 1:1.

[0045] Preparation Comparative Example Preparation Comparative Example 1 The difference between Preparation Comparative Example 1 and Preparation Example 1 is that an equal amount of fiber powder is replaced by nano-silica aerogel powder.

[0046] Preparation Comparative Example 2 The difference between Preparation Comparative Example 2 and Preparation Example 1 is that an equal amount of nano-silica aerogel powder is replaced by fiber powder.

[0047] Preparation Comparative Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that the maleic anhydride grafted material is replaced by PP in equal amounts, and the heating temperature of the extruder is increased by 60° C. in each stage, which can completely dissolve the PP.

[0048] Preparation Comparative Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that: on the basis of Preparation Example 3, the maleic anhydride grafted material is composed of PP and silane coupling agent KH550 in a weight ratio of 10:1. Example

[0049] Example 1 A process for processing a photovoltaic-grade single-crystal silicon wafer substrate comprises the following steps: 1) growing a single crystal by a single crystal growth device, cutting it by a cutting device, and then performing outer diameter rolling, flat edge or V-groove processing, slicing, and chamfering in a grinding device and a chamfering device in sequence to obtain a sample; 2) Grind the sample in a grinder at a pressure of 380 kg, a flow rate of 20 ml / min, and a grinding liquid concentration of 10 wt% until the surface particles are approximately 20 microns. Then, completely immerse the sample in a cleaning solution at 50°C and a pH of 9 for 30 seconds. Then, rinse the sample with pure water at a pressure of 200 kPa, a flow rate of 10 L / min, and a spraying time of 1 minute. Then, dry the sample in an oven at 80°C for 5 minutes to obtain a standard sample. 3) polishing the standard sample at a pressure of 300 kg, a liquid flow rate of 2 L / min, a polishing time of 30 min, a polishing liquid concentration of 5 wt %, and a polishing disk rotation speed of 100 rpm to obtain a polished sample; 4) The polished sample was completely immersed in a cleaning solution at a temperature of 50°C and a pH of 8 for 30 seconds, and then sprayed with pure water at a spray pressure of 200 kPa, a spray flow rate of 10 L / min, and a spray time of 2 minutes. The sample was then placed in an oven at 80°C for drying for 5 minutes and packaged to obtain a photovoltaic-grade single crystal silicon wafer substrate; The cleaning agent used in steps 2) and 4) is prepared by the following method: 15% of a 75% ethanol solution and 10% of an adsorption aid are weighed and mixed uniformly to obtain a mixed solution A; 73.8% of water, 0.2% of ammonium lactate chelate, and 1% of an adsorption resin are then weighed and added to the mixed solution A, mixed uniformly, divided into portions, and ammonium hydroxide is added to adjust the pH to 8 and 9, respectively, to obtain the cleaning agent. The adsorption resin is an amide-based adsorption resin.

[0050] The adsorption aid is composed of polymerized isomeric alcohol polyoxyethylene butylamide, an organic sodium salt active agent, and the adsorption particles obtained in Preparation Example 1 in a weight ratio of 1:2:5. The organic sodium salt active agent is sodium salt of dioctyl sulfosuccinate; and the adsorption resin is an amide-based adsorption resin.

[0051] Example 2 The difference between Example 2 and Example 1 is that the raw materials of the cleaning agent are as follows: The cleaning agent used in the cleaning process of step 2) and step 4) is prepared by the following method: according to the weight percentage, 10% of a 75% ethanol solution and 8% of an adsorption aid are weighed and mixed evenly to obtain a mixed solution A, and then 77% of water, 1% of titanium ammonium lactate chelate, and 4% of an adsorption resin are weighed and added to the mixed solution A, mixed evenly, packaged, and then ammonium hydroxide is added to adjust the pH value to 8 and the pH value to 9, respectively, to obtain a cleaning agent.

[0052] The adsorption auxiliary agent is composed of polymerized isomeric alcohol polyoxyethylene butylamide, organic sodium salt active agent and adsorption particles in a weight ratio of 1:3:6.

[0053] Example 3 The difference between Example 3 and Example 1 is that the raw materials of the cleaning agent are as follows: the cleaning agent used in the cleaning process of step 2) and step 4) is prepared by the following method: according to the weight percentage, 8% of a 75% ethanol solution and 5% of an adsorption aid are weighed and evenly mixed to obtain a mixed solution A, and then 75% of water, 2% of titanium ammonium lactate chelate, and 10% of an adsorption resin are weighed and added to the mixed solution A, mixed evenly, divided into packages, and then ammonium hydroxide is added to adjust the pH value to 8 and the pH value to 9, respectively, to obtain a cleaning agent.

[0054] The adsorption auxiliary agent is composed of polymerized isomeric alcohol polyoxyethylene butylamide, organic sodium salt active agent and adsorption particles in a weight ratio of 1:3:8.

[0055] Example 4 The difference between Example 4 and Example 2 is that the organic sodium salt active agent is dioctyl sulfosuccinate sodium salt.

[0056] Example 5 The difference between Example 5 and Example 2 is that the organic sodium salt active agent is composed of sodium salt of dioctyl sulfosuccinate at a weight ratio of 1:2.

[0057] Example 6 The difference between Example 6 and Example 2 is that the organic sodium salt active agent is composed of dioctyl sodium sulfosuccinate, disodium polyethylene oxide lauryl sulfosuccinate, and 1-ethyl-3-methylimidazole acetate in a weight ratio of 1:2:1.

[0058] Example 7 The difference between Example 7 and Example 2 is that the organic sodium salt active agent is composed of sodium glutamate, dioctyl sodium sulfosuccinate, disodium polyethylene oxide lauryl sulfosuccinate, and 1-ethyl-3-methylimidazole acetate in a weight ratio of 2:2:1:1.

[0059] Examples 8-17 The difference between Examples 8-17 and Example 7 is that the sources of adsorbed particles are different, as shown in Table 1; Table 1 The adsorption particles of Examples 8-17 have different sources Example Source of adsorbed particles Example 8 Preparation Example 2 Example 9 Preparation Example 3 Example 10 Preparation Example 4 Example 11 Preparation Example 5 Example 12 Preparation Example 6 Example 13 Preparation Example 7 Example 14 Preparation Comparative Example 1 Example 15 Preparation Comparative Example 2 Example 16 Preparation Comparative Example 3 Example 17 Preparation Comparative Example 4 Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that an equal amount of the polymerized isomeric alcohol polyoxyethylene butylamide is replaced by an organic sodium salt active agent.

[0060] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the adsorption particles are replaced with an equal amount of an organic sodium salt active agent.

[0061] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the adsorption aid is polymerized isomeric alcohol polyoxyethylene butylamide.

[0062] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the adsorption aid is replaced by an adsorption resin in equal amounts.

[0063] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that in the cleaning process in step 2), only pure water spraying is used, and the spraying time is 1.5 minutes.

[0064] Performance testing Detection method / test method Test 1: Cleaning effect 100 photovoltaic-grade single-crystal silicon wafer substrates (300 μm thick, 12-inch size) were batch-produced from Examples 1-17 and Comparative Examples 1-5 and observed for surface stains, flow marks, defects, breakage, etc. The surface particle size obtained by testing was also greater than 50 nm. If any of the above phenomena occurred, it was recorded as unqualified, and the unqualified rate was calculated.

[0065] Test 2: Based on Test 1, produce another 200 photovoltaic-grade monocrystalline silicon wafer substrates (thickness 300μm, size 12 inches), with a total cleaning liquid volume of 20kg, and calculate the pass rate of the last 100 photovoltaic-grade monocrystalline silicon wafer substrates (thickness 300μm, size 12 inches).

[0066] Test 3: Glossiness The photovoltaic-grade monocrystalline silicon wafer substrates (300 μm thick, 12-inch size) obtained in Examples 1-17 and Comparative Examples 1-5 were tested using a glossiness tester with a refraction angle of 60°. Three qualified samples from Test 1 were taken for testing, and the tests were performed on the central axis and the four corners, respectively. The average difference of the five points was taken. The specific data is shown in Table 2.

[0067] Table 2 Experimental data of Examples 1-17 and Comparative Examples 1-3 Combining Example 1 and Comparative Examples 1-5 and Table 2, it can be seen that the average gloss difference of Example 1 is below 4, while the average gloss difference of Comparative Examples 1-5 is above 6, indicating that the present application uses a polymerized isomeric alcohol polyoxyethylene butylene amide, an organic sodium salt active agent, and adsorption particles for compounding, and then through the production process of the present application, it can achieve better cleaning uniformity and cleaning effect, can ensure the surface flatness of photovoltaic-grade single-crystal silicon wafer substrates, and improve its practicality. After batch production of Test 1 and Test 2, the qualified rate 1 in Test 1 of Example 1 is 100%, and the qualified rate 2 in Test 2 is 92%, while the qualified rate 1 in Test 1 of Comparative Examples 1-5 is below 95%, and the qualified rate 2 in Test 2 is below 85%, indicating that the use of the polymerized isomeric alcohol polyoxyethylene butylene amide, an organic sodium salt active agent, and adsorption particles of the present application for compounding has a synergistic effect, can maintain a better cleaning effect for a long time, and ensure the quality stability of the batch production process.

[0068] Combining Example 2, Examples 4-7 and Table 2, it can be seen that the average gloss difference of Example 7 is as low as 1.5, while the average gloss difference of Examples 2 and Examples 4-6 are all within the range of 3.4-3.7, and the pass rate 2 of Examples 2 and Examples 4-6 is less than the pass rate of Example 7, which further illustrates that the use of an organic sodium salt active agent composed of sodium glutamate, sodium salt of dioctyl sulfosuccinate, disodium polyethylene oxide sulfosuccinate, and 1-ethyl-3-methylimidazole acetate plays a synergistic role in further improving the surface uniformity of photovoltaic-grade single crystal silicon wafer substrates during the production process.

[0069] From Examples 14-17, Example 7 and Table 2, it can be seen that the average gloss difference of Examples 14-17 is greater than the average gloss difference of Example 7, and the qualified rate of Examples 14-17 in Test 2 is below 98%, while the qualified rate of Example 7 in Test 2 is 100%, indicating that the adsorption particles obtained by using fiber powder, nano-silica aerogel powder and maleic anhydride grafts have better adsorption stability, and when combined with other additives, maintain better adsorption effect, further improving the surface uniformity and cleaning effect of photovoltaic-grade single crystal silicon wafer substrates in the production process.

[0070] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A process for processing photovoltaic-grade single-crystal silicon wafer substrates, characterized in that: The following steps are involved: 1) Obtaining samples through single crystal growth, cutting, and pretreatment; 2) Grinding and cleaning the sample to obtain a ground sample; 3) polishing the ground sample to obtain a polished sample; 4) The polished sample is then cleaned, dried, and packaged to obtain a photovoltaic-grade single crystal silicon wafer substrate; The cleaning agent used in the cleaning process of step 2) and step 4) is prepared by the following method: 8-15% of ethanol solution and 5-10% of adsorption aid are weighed and mixed uniformly to obtain a mixed solution A, 60-80% of water, 0.2-2% of titanium ammonium lactate chelate, and 1-10% of adsorption resin are weighed and added to the mixed solution A, mixed uniformly, and then ammonium hydroxide is added to adjust the pH value to 8-9 to obtain a cleaning agent; The adsorption auxiliary agent is composed of polymerized isomeric alcohol polyoxyethylene butylamide, organic sodium salt active agent and adsorption particles in a weight ratio of 1: (2-3): (5-8).

2. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 1, wherein: The volume flow rate of the cleaning liquid is 1-3 L / min.

3. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 1, wherein: The density of the adsorption resin is less than the density of the cleaning liquid.

4. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 1, wherein: The pH value of the cleaning solution in the cleaning process of step 2) is greater than the pH value of the cleaning solution in the cleaning process of step 4).

5. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 1, wherein: The adsorption resin is composed of one or more of an amide-based adsorption resin, a phenolic hydroxyl-based adsorption resin, and a sulfone-containing adsorption resin.

6. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 1, wherein: The organic sodium salt active agent is one or more of sodium glutamate, sodium salt of dioctyl sulfosuccinate, disodium lauryl polyethylene oxide sulfosuccinate, and 1-ethyl-3-methylimidazole acetate.

7. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 6, characterized in that: The organic sodium salt active agent consists of sodium glutamate, dioctyl sulfosuccinate sodium salt, disodium lauryl polyethylene oxide sulfosuccinate and 1-ethyl-3-methylimidazole acetate.

8. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 1, wherein: The adsorption particles are composed of fiber powder, nano silicon dioxide aerogel powder and maleic anhydride grafted material in a weight ratio of 3: (1-3): (1-1.8).

9. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 8, characterized in that: The maleic anhydride grafted product is polyisoprene grafted with maleic anhydride and / or PTW compatibilizer.

10. The process for processing a photovoltaic-grade single-crystal silicon wafer substrate according to claim 8, characterized in that: The fiber powder is seaweed fiber powder and / or viscose fiber powder.

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