A photovoltaic cell manufacturing process parameter self-adaptive regulation system and method

Abstract

The present application relates to the technical field of photovoltaic cell manufacturing, and particularly relates to a photovoltaic cell manufacturing process parameter self-adaptive regulation and control system and method, which comprises a diffusion module for diffusing a textured silicon wafer to obtain a diffusion wafer; a coating module for coating a silicon wafer after etching with a preset radio frequency power and a preset process cavity pressure to obtain a coated silicon wafer; a data acquisition module; a control module for judging whether the diffusion treatment of the diffusion wafer conforms to a preset standard according to a minority carrier lifetime distribution characteristic value of the diffusion wafer and for judging whether the coating treatment of the coated silicon wafer conforms to a preset standard according to a film layer distribution characteristic value of the coated silicon wafer; an adjustment module; and an optimization module for determining an optimization strategy of the coated silicon wafer under a condition that the coating treatment of the coated silicon wafer does not conform to the preset standard according to a defect grid cell proportion of the coated silicon wafer. The present application improves the manufacturing efficiency of photovoltaic cells.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and in particular to an adaptive control system and method for photovoltaic cell manufacturing process parameters. Background Technology

[0002] Crystalline silicon photovoltaic cells are the core components of modern photovoltaic power generation, and their fabrication is a complex process involving multiple precision steps. Typical fabrication steps mainly include: texturing, diffusion junction formation, etching, anti-reflective coating deposition, electrode printing, and sintering. Among these, the diffusion process directly forms the "heart" of the cell, the PN junction, and its uniformity determines the cell's basic electrical performance. The coating process (usually referring to PECVD deposition of silicon nitride film) combines two key functions: anti-reflection and surface passivation, which are crucial for improving cell efficiency.

[0003] Each production piece of equipment typically operates independently, and process parameters are preset and fixed by engineers based on experience. There is a lack of effective data linkage between processes, and quality fluctuations in the preceding process cannot be perceived and compensated for in real time by the subsequent process, leading to the accumulation and amplification of quality risks along the production line.

[0004] Chinese Patent Application Publication No. CN112993079A discloses a method for fabricating photovoltaic cells and the photovoltaic cells themselves. The method includes: fabricating textured surfaces on two sides of a silicon wafer: a first textured surface and a second textured surface; sequentially depositing an alumina film and a silicon nitride film on the first textured surface to form a first alumina film and a first silicon nitride film distributed sequentially from the inside out; cleaning the surface around the deposited surfaces to obtain a first coated surface; diffusing and fabricating a back PN junction on the first coated surface; dry etching to remove the back PN junction at the edge of the first coated surface; removing the PSG from the first coated surface; depositing a second silicon nitride film on the second textured surface to form a second coated surface; and performing laser processing, screen printing, and sintering on the first coated surface to finally fabricate a back electrode and a front electrode. This method protects the textured back surface of the silicon wafer, thereby improving the power generation efficiency of the back side of the fabricated photovoltaic cell, saving manufacturing costs, and reducing the environmental impact of the original etching process.

[0005] It can be seen that the above technical solutions do not consider the influence of the thermal field distribution of the diffusion process on the PN junction quality of different regions of the silicon wafer during the photovoltaic cell manufacturing process, nor do they consider the influence of the plasma state in the reaction chamber on the uniformity of the thin film distribution during the coating process, thus leading to the problem of poor manufacturing efficiency of photovoltaic cells. Summary of the Invention

[0006] To address this, the present invention provides an adaptive control system and method for photovoltaic cell manufacturing process parameters, which overcomes the problems of poor manufacturing efficiency in existing technologies that do not consider the influence of the thermal field distribution of the diffusion process on the PN junction quality of different regions of the silicon wafer, nor the influence of the plasma state in the reaction chamber on the uniformity of the thin film distribution during the coating process.

[0007] To achieve the above objectives, in one aspect, the present invention provides an adaptive control system for photovoltaic cell manufacturing process parameters, comprising:

[0008] A diffusion module is used to perform diffusion treatment on a textured silicon wafer to obtain a diffused wafer, wherein the diffusion treatment includes heating the textured silicon wafer at a preset temperature in the edge temperature zone of a diffusion furnace.

[0009] The coating module is used to coat the etched silicon wafer with a preset radio frequency power and a preset process chamber pressure to obtain a coated silicon wafer.

[0010] The data acquisition module includes a first acquisition unit for acquiring minority carrier lifetime values ​​at several detection points on the surface of the diffuser, a second acquisition unit for acquiring the reflectivity of several grid cells on the surface of the coated silicon wafer at a preset wavelength, and a third acquisition unit for acquiring the surface recombination rate of the coated silicon wafer.

[0011] The control module is used to determine whether the diffusion treatment of the diffusion sheet meets the preset standard based on the minority carrier lifetime distribution characterization value of the diffusion sheet, and to determine whether the coating treatment of the coated silicon wafer meets the preset standard based on the film layer distribution characterization value of the coated silicon wafer.

[0012] The adjustment module is used to increase the preset temperature of the diffusion furnace edge temperature zone based on the minority carrier lifetime distribution characterization value of the diffuser being greater than or equal to a first preset minority carrier lifetime distribution characterization value and less than a second preset minority carrier lifetime distribution characterization value, and to increase the preset radio frequency power based on the surface recombination rate being greater than or equal to a preset surface recombination rate.

[0013] An optimization module is used to determine, based on the proportion of defect grid cells in the coated silicon wafer, whether to trigger cleaning and maintenance of the process chamber of the coating module or to reduce the preset process chamber pressure.

[0014] Furthermore, the control module determines that the diffusion process of the diffusion sheet does not meet the preset standard based on the comparison result that the minority carrier lifetime distribution characterization value of the diffusion sheet is greater than or equal to the first preset minority carrier lifetime distribution characterization value and less than the second preset minority carrier lifetime distribution characterization value.

[0015] Wherein, the first preset minority carrier lifetime distribution characterization value is less than the second preset minority carrier lifetime distribution characterization value.

[0016] Furthermore, the adjustment module has several temperature adjustment methods for increasing the preset temperature of the edge temperature zone of the diffusion furnace, and each temperature adjustment method increases the preset temperature of the edge temperature zone of the diffusion furnace by a different amount.

[0017] Furthermore, the minority carrier lifetime distribution characterization value of the diffuser is determined based on the minority carrier lifetime values ​​of several detection points on the surface of the diffuser, wherein the detection point is the center point of the surface grid cell of the diffuser.

[0018] Furthermore, in response to the fact that the film distribution characterization value of the coated silicon wafer is greater than or equal to the first preset film distribution characterization value and less than the second preset film distribution characterization value, the control module determines that the coating process of the coated silicon wafer has a risk of not meeting the preset standard, and makes a second determination on whether the coating of the silicon wafer meets the preset standard based on the surface recombination rate of the coated silicon wafer, wherein the first preset film distribution characterization value is less than the second preset film distribution characterization value.

[0019] Furthermore, the film distribution characterization value is determined based on the reflectance of several grid units on the surface of the coated silicon wafer at a preset wavelength, which is collected by the data acquisition module.

[0020] Furthermore, in response to the control module determining that the coating process of the coated silicon wafer does not meet the preset standard when the film distribution characterization value of the coated silicon wafer is greater than or equal to the second preset film distribution characterization value, the optimization module determines the optimization strategy under the condition that the coating process of the coated silicon wafer does not meet the preset standard based on the proportion of defect grid cells of the coated silicon wafer.

[0021] Furthermore, the control module makes a secondary determination based on the surface recombination rate of the coated silicon wafer to determine whether the coating process of the coated silicon wafer meets the preset standard, wherein,

[0022] If the surface recombination rate is less than the preset surface recombination rate, then the coating process of the coated silicon wafer is determined to meet the preset standard.

[0023] If the surface recombination rate is greater than or equal to the preset surface recombination rate, it is determined that the coating process of the coated silicon wafer does not meet the preset standard, and the adjustment module is controlled to increase the preset RF power according to the difference between the surface recombination rate and the preset surface recombination rate.

[0024] Furthermore, the optimization module determines an optimization strategy for situations where the coating process of the silicon wafer does not meet a preset standard based on the proportion of defective grid cells in the coated silicon wafer.

[0025] If the proportion of defective mesh cells is less than the preset proportion of defective mesh cells, an alarm is triggered to clean and maintain the process chamber of the coating module.

[0026] If the proportion of the defective mesh cells is greater than or equal to the preset proportion of the defective mesh cells, the preset process chamber pressure is reduced according to the difference between the proportion of the defective mesh cells and the preset proportion of the defective mesh cells.

[0027] The defect mesh cell ratio is the ratio of the number of surface mesh cells of the coated silicon wafer whose reflectance value at a preset wavelength is less than a preset reflectance value to the total number of surface mesh cells.

[0028] On the other hand, the present invention provides a control method applicable to an adaptive control system for parameters in photovoltaic cell manufacturing processes, comprising:

[0029] A diffusion furnace diffuses a textured silicon wafer through the edge temperature zone of the diffusion furnace at a preset temperature to obtain a diffusion sheet. The minority carrier lifetime distribution characterization value of the diffusion sheet is obtained based on the minority carrier lifetime values ​​of several grid cells on the surface of the diffusion sheet.

[0030] The diffusion treatment of the diffusion sheet is determined based on the minority carrier lifetime distribution characterization value of the diffusion sheet to determine whether it meets the preset standard.

[0031] The diffusion wafer that meets the preset standard is etched to obtain an etched silicon wafer.

[0032] The etched silicon wafer is coated with a film using the preset radio frequency power and preset process cavity pressure to obtain a coated silicon wafer. The film distribution characterization value of the coated silicon wafer is obtained based on the reflectivity of the coated silicon wafer at a preset wavelength.

[0033] When it is determined that the coating process of the coated silicon wafer is at risk of not meeting the preset standard based on the film distribution characterization value, the coating of the silicon wafer is further determined based on the surface recombination rate of the coated silicon wafer to determine whether the coating meets the preset standard.

[0034] When the coating process of the coated silicon wafer does not meet the preset standard based on the film distribution characterization value, the optimization strategy under the condition that the coating process of the coated silicon wafer does not meet the preset standard is determined based on the proportion of defect grid cells of the coated silicon wafer. The optimization strategy is to trigger an alarm to clean and maintain the process chamber of the coating module or reduce the preset process chamber pressure.

[0035] The coated silicon wafers that meet the preset standards are sequentially subjected to electrode printing and sintering processes to obtain photovoltaic cells.

[0036] Compared with existing technologies, the beneficial effects of this invention are that it integrates an adaptive control system for the two core processes of diffusion and coating in photovoltaic cell manufacturing. The system acquires parameter values ​​reflecting the essence of the process through a data acquisition module, which are then judged by the control module. This drives the adjustment and optimization modules to perform differentiated actions, from parameter fine-tuning to maintenance strategies. This effectively solves the problem that traditional fixed-parameter production modes cannot cope with equipment status fluctuations and changes in process conditions. Without human intervention, it improves the inherent stability of the production process and the consistency of product performance, thereby increasing the manufacturing efficiency of photovoltaic cells.

[0037] Furthermore, by setting minority carrier lifetime distribution characterization values ​​and two judgment thresholds, this invention performs graded processing of diffusion unevenness, realizing automatic compensation and adjustment for slight unevenness and production intervention for severe anomalies. This avoids efficiency loss caused by excessive downtime and prevents defective cells from continuously flowing into subsequent processes, thereby improving production continuity while ensuring the efficiency of photovoltaic cells.

[0038] Furthermore, this invention introduces a risk warning status and a secondary judgment mechanism for the coating process. When the film uniformity is initially judged to be in the risk range, the system does not directly determine failure, but initiates a secondary judgment based on the surface recombination rate. This effectively distinguishes between two fundamentally different situations: one where the appearance is only slightly uneven but the function is intact, and the other where both the appearance and function are damaged. The former can be released to avoid accidental rejection, while the latter is confirmed as unqualified, reducing the loss of qualified products caused by fluctuations in appearance inspection. At the same time, it ensures that any functional defects can be captured, thereby achieving an effective balance between strict quality control and smooth production.

[0039] Furthermore, this invention introduces surface recombination rate to achieve a leap from appearance evaluation to functional inspection of the coating process quality. When the surface recombination rate is below a preset threshold, it indicates that the coating has a good passivation effect on the silicon wafer and can effectively suppress the loss of charge carriers on the surface. At this time, even if there is a slight risk to the appearance uniformity, the coating is judged to be functionally qualified. When the surface recombination rate reaches or exceeds the preset threshold, it is diagnosed that the passivation function of the coating has been substantially deteriorated. Increasing the preset radio frequency power of the coating module can fundamentally repair or improve the passivation characteristics of the thin film to reduce the surface recombination rate, thereby improving the reliability of the judgment.

[0040] Furthermore, by differentiating the root causes of coating defects and implementing differentiated treatment, the system does not take a single measure for all defects. Instead, it intelligently determines whether the problem originates from localized accidental contamination or a global systemic process imbalance by quantifying and statistically analyzing the distribution range of defects. This provides a key decision-making basis for subsequent corrective measures, thereby improving optimization efficiency. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the module connection of the photovoltaic cell manufacturing process parameter adaptive control system according to an embodiment of the present invention;

[0042] Figure 2 This is a flowchart illustrating how to determine whether the diffusion treatment of a diffusion sheet meets a preset standard, according to an embodiment of the present invention.

[0043] Figure 3 This is a flowchart illustrating how an embodiment of the present invention determines whether the coating process of a coated silicon wafer meets a preset standard based on the film layer distribution characterization value of the coated silicon wafer.

[0044] Figure 4 This is a flowchart of an adaptive control method for photovoltaic cell manufacturing process parameters according to an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0046] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] It should be noted that the data in this embodiment are all derived from a comprehensive analysis and evaluation of historical test data and corresponding historical test results from the three months prior to this test. Those skilled in the art will understand that the method described in this invention can determine the above-mentioned parameters in the following ways: selecting the value with the highest proportion based on the data distribution as the preset standard parameter; using weighted summation to obtain the value as the preset standard parameter; substituting each historical data point into a specific formula and using the value obtained by that formula as the preset standard parameter; or other selection methods, as long as the method described in this invention can clearly define different specific situations in the single-item judgment process through the obtained values.

[0048] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 The diagrams shown are: a schematic diagram of the module connection of the photovoltaic cell manufacturing process parameter adaptive control system according to an embodiment of the present invention; a flowchart of the present invention for determining whether the diffusion treatment of the diffusion sheet meets the preset standard; a flowchart of the present invention for determining whether the coating treatment of the coated silicon wafer meets the preset standard based on the film layer distribution characterization value of the coated silicon wafer; and a flowchart of the photovoltaic cell manufacturing process parameter adaptive control method according to an embodiment of the present invention.

[0049] On one hand, embodiments of the present invention provide an adaptive control system and method for photovoltaic cell manufacturing process parameters, including:

[0050] A diffusion module is used to perform diffusion treatment on a textured silicon wafer to obtain a diffused wafer, wherein the diffusion furnace of the diffusion module heats the textured silicon wafer at a preset temperature of 820°C through its edge temperature zone.

[0051] The coating module is used to coat the etched silicon wafer with a preset RF power of 4500W and a preset process chamber pressure of 1200mTorr to obtain a coated silicon wafer.

[0052] The data acquisition module, which is connected to the diffusion module and the coating module respectively, includes a first acquisition unit for acquiring minority carrier lifetime values ​​at several detection points on the surface of the diffusion sheet, a second acquisition unit for acquiring the reflectance of several grid units on the surface of the coated silicon wafer at a preset wavelength, and a third acquisition unit for acquiring the surface recombination rate of the coated silicon wafer. In this embodiment, the first acquisition unit is a microwave photoconductivity attenuation scanner, the second acquisition unit is a spectral reflectance scanner, and the third acquisition unit is a quasi-steady-state photoconductivity tester.

[0053] The control module is connected to the data acquisition module and the diffusion module respectively, and is used to determine whether the diffusion treatment of the diffusion sheet meets the preset standard based on the minority carrier lifetime distribution characterization value of the diffusion sheet, and to determine whether the coating treatment of the coated silicon wafer meets the preset standard based on the film layer distribution characterization value of the coated silicon wafer.

[0054] An adjustment module, which is connected to the diffusion module, the coating module and the control module respectively, is used to increase the preset temperature of the diffusion furnace edge temperature zone under the condition that the minority carrier lifetime distribution characterization value of the diffusion sheet is greater than or equal to the first preset minority carrier lifetime distribution characterization value and less than the second preset minority carrier lifetime distribution characterization value, and to increase the preset radio frequency power under the condition that the surface recombination rate is greater than or equal to the preset surface recombination rate.

[0055] An optimization module, connected to the control module and the coating module, is used to determine an optimization strategy for the coating process of the silicon wafer that does not meet a preset standard based on the proportion of defect grid cells in the coated silicon wafer. The optimization strategy is to trigger an alarm to clean and maintain the process chamber of the coating module or to reduce the preset process chamber pressure.

[0056] Specifically, there are no restrictions on the specific structure of the control module, adjustment module, and optimization module. They themselves and their units can be composed of logic components, including field-programmable components, computers, or microprocessors in computers.

[0057] Specifically, the control module determines whether the diffusion process of the diffusion sheet meets a preset standard based on the minority carrier lifetime distribution characterization value of the diffusion sheet, wherein,

[0058] If the minority carrier lifetime distribution characterization value is less than the first preset minority carrier lifetime distribution characterization value of 0.06, then the diffusion treatment of the diffusion sheet is determined to meet the preset standard.

[0059] If the minority carrier lifetime distribution characterization value is greater than or equal to the first preset minority carrier lifetime distribution characterization value and less than the second preset minority carrier lifetime distribution characterization value of 0.17, it is determined that the diffusion treatment of the diffusion sheet does not meet the preset standard, and the adjustment module is controlled to increase the preset temperature of the diffusion furnace edge temperature zone according to the difference between the minority carrier lifetime distribution characterization value and the first preset minority carrier lifetime distribution characterization value.

[0060] If the minority carrier lifetime distribution characterization value is greater than or equal to the second preset minority carrier lifetime distribution characterization value, it is determined that the diffusion process of the diffusion wafer does not meet the preset standard, and the diffusion module is controlled to suspend wafer feeding.

[0061] Wherein, the first preset minority carrier lifetime distribution characterization value is less than the second preset minority carrier lifetime distribution characterization value.

[0062] Specifically, the first preset minority carrier lifetime distribution characterization value ranges from [0.05, 0.10], and the second preset minority carrier lifetime distribution characterization value ranges from [0.15, 0.25]. In this embodiment, the first preset minority carrier lifetime distribution characterization value is 0.06, and the second preset minority carrier lifetime distribution characterization value is 0.17.

[0063] Specifically, when the minority carrier lifetime distribution characterization value indicates a slight non-compliance, the non-uniformity in the diffusion process's edge region is most likely due to insufficient heat or uneven airflow distribution in the edge temperature zone of the diffusion furnace. Therefore, the preset temperature in the edge temperature zone should be increased. When the uniformity deteriorates across the board, the cause may be complex and exceed the capabilities of the preset automatic compensation model. In this case, the most reasonable and safest action is to shut down the system and trigger an alarm, allowing for in-depth manual diagnosis.

[0064] Specifically, the adjustment module has several temperature adjustment methods for increasing the preset temperature of the diffusion furnace edge temperature zone, among which,

[0065] If the minority carrier lifetime distribution deviation is less than the first preset minority carrier lifetime distribution deviation of 0.05, then the preset temperature of the diffusion furnace edge temperature zone is increased to the corresponding value using the first adjustment coefficient of 1.02.

[0066] If the minority carrier lifetime distribution deviation is greater than or equal to the first preset minority carrier lifetime distribution deviation and less than the second preset minority carrier lifetime distribution deviation of 0.09, then the preset temperature of the diffusion furnace edge temperature zone is increased to the corresponding value using the second adjustment coefficient of 1.04.

[0067] If the minority carrier lifetime distribution deviation is greater than or equal to the second preset minority carrier lifetime distribution deviation, then the preset temperature of the diffusion furnace edge temperature zone is increased to the corresponding value using the third adjustment coefficient of 1.06.

[0068] The minority carrier lifetime distribution deviation value is the difference between the minority carrier lifetime distribution characterization value and the first preset minority carrier lifetime distribution characterization value.

[0069] Specifically, the process of obtaining the minority carrier lifetime distribution characterization value of the diffuser sheet includes:

[0070] The surface of the diffuser is divided into several 10mm×10mm grid units. The minority carrier lifetime value at the center point of each sampling unit is located and measured sequentially using the measurement probe of a microwave photoconductivity attenuation scanner.

[0071] The ratio of the standard deviation of all minority carrier lifetime values ​​to the arithmetic mean of all minority carrier lifetime values ​​is denoted as the minority carrier lifetime distribution characterization value of the diffuser.

[0072] Specifically, the control module determines whether the coating process of the coated silicon wafer meets the preset standard based on the film layer distribution characterization value of the coated silicon wafer, wherein,

[0073] If the film distribution characterization value is less than 0.5% of the first preset film distribution characterization value, then the coating process of the coated silicon wafer is determined to meet the preset standard.

[0074] If the film distribution characterization value is greater than or equal to the first preset film distribution characterization value and less than 1.1% of the second preset film distribution characterization value, it is determined that the coating process of the coated silicon wafer has a risk of not meeting the preset standard. The coating of the silicon wafer is then determined a second time based on the surface recombination rate of the coated silicon wafer to determine whether the coating meets the preset standard.

[0075] If the film distribution characterization value is greater than or equal to the second preset film distribution characterization value, it is determined that the coating process of the coated silicon wafer does not meet the preset standard. The optimization module determines the optimization strategy under the condition that the coating process of the coated silicon wafer does not meet the preset standard based on the proportion of defect grid cells of the coated silicon wafer.

[0076] Specifically, the first preset film layer distribution characterization value ranges from [0.4%, 0.6%], and the second preset film layer distribution characterization value ranges from [0.8%, 1.2%]. In this embodiment, the first preset film layer distribution characterization value is 0.5%, and the second preset film layer distribution characterization value is 1.1%.

[0077] Specifically, the film distribution characterization value assesses the uniformity of reflectivity after coating and is a key appearance indicator for evaluating the quality of silicon nitride antireflective films. When it is judged to be in the risk range, it indicates that there are appearance defects, but it is uncertain whether it will affect the core function. The system initiates a secondary judgment, measuring the surface recombination rate to determine: when the judgment fails to meet the standard, it indicates that the appearance is severely uneven. The defect pattern is analyzed based on the proportion of defect mesh cells, and corresponding optimization strategies are implemented.

[0078] Specifically, the process of obtaining the film layer distribution characterization values ​​includes:

[0079] The reflectance of several grid cells on the surface of several coated silicon wafers was measured using a spectral reflectance scanner under narrow-band light illumination with a center wavelength of 650 nm.

[0080] The standard deviation of all reflectance measurements is denoted as the film layer distribution characterization value.

[0081] Specifically, the control module makes a secondary determination based on the surface recombination rate of the coated silicon wafer to determine whether the coating process of the coated silicon wafer meets the preset standard, wherein,

[0082] If the surface recombination rate is less than the preset surface recombination rate of 100 cm / s, then the coating process of the coated silicon wafer is determined to meet the preset standard.

[0083] If the surface recombination rate is greater than or equal to the preset surface recombination rate, it is determined that the coating process of the coated silicon wafer does not meet the preset standard, and the adjustment module is controlled to increase the preset RF power according to the difference between the surface recombination rate and the preset surface recombination rate.

[0084] Specifically, the surface recombination rate directly quantifies the passivation effect of the coating on the silicon wafer surface and is a key intrinsic parameter that determines the final open-circuit voltage and conversion efficiency of the battery. In this embodiment, the preset surface recombination rate is 100 cm / s.

[0085] Specifically, if the surface recombination rate is less than the preset surface recombination rate, it indicates that although there may be slight defects in appearance, the core passivation function of the coating is intact and the electrical performance of the battery is guaranteed, so it is judged to meet the preset standard; if the surface recombination rate is greater than or equal to the preset surface recombination rate, it indicates that the passivation function of the coating has failed. At this time, the system automatically triggers the compensation mechanism, increases the radio frequency power according to the difference exceeding the standard, and improves the film quality by increasing the plasma energy.

[0086] Specifically, the optimization module determines an optimization strategy for situations where the coating process of the silicon wafer does not meet a preset standard based on the proportion of defective grid cells in the coated silicon wafer.

[0087] If the proportion of defective mesh cells is less than the preset proportion of defective mesh cells of 0.14, an alarm is triggered to clean and maintain the process cavity of the coating module.

[0088] If the proportion of the defective mesh cells is greater than or equal to the preset proportion of the defective mesh cells, the preset process chamber pressure is reduced according to the difference between the proportion of the defective mesh cells and the preset proportion of the defective mesh cells.

[0089] The defect mesh cell ratio is the ratio of the number of surface mesh cells of the coated silicon wafer whose reflectance value at a preset wavelength is less than 7.5% of the preset reflectance value to the total number of surface mesh cells.

[0090] In this embodiment, the preset defect mesh cell ratio is 0.14, but the above value is not limited to this. Specifically, when the proportion of unqualified mesh cells is less than the preset defect mesh cell ratio, the defects are usually scattered in a point or small area. This is caused by accidental factors such as local contamination of components in the process chamber, particle falling, or blockage of individual spray heads. When the proportion of unqualified cells is greater than or equal to the preset defect mesh cell ratio, it indicates that the defects have become continuous or widely distributed. This is due to improper setting of the process chamber pressure, resulting in an overall non-uniformity of the reaction gas flow field or plasma density. At this time, the system automatically lowers the chamber pressure according to the difference to improve the film thickness uniformity.

[0091] On the other hand, embodiments of the present invention provide a control method applicable to an adaptive control system for parameters in photovoltaic cell manufacturing processes, including:

[0092] Step S1: The textured silicon wafer is sent into a diffusion furnace. The diffusion furnace diffuses phosphorus onto the textured silicon wafer in a diffusion atmosphere of POCL3 at a preset temperature of 820°C through the edge temperature zone of the diffusion furnace to form a PN junction and obtain a diffusion sheet. A microwave photoconductivity attenuation scanner is used to perform a surface scan on the entire diffusion sheet, and the minority carrier lifetime value of the center point of each 10mm×10mm grid unit on the silicon wafer surface is measured and recorded to obtain the minority carrier lifetime distribution characterization value of the diffusion sheet.

[0093] Step S2: Determine whether the diffusion treatment of the diffusion sheet meets the preset standard based on the minority carrier lifetime distribution characterization value of the diffusion sheet;

[0094] Step S3: The diffusion wafer that meets the preset standard is subjected to wet chemical etching to remove the phosphorus silicon glass coating formed on the edge and back during the diffusion process, so as to achieve electrical isolation and obtain the etched silicon wafer.

[0095] Step S4: The etched silicon wafer is fed into a PECVD equipment, and a silicon nitride antireflection film is deposited on the etched silicon wafer with the preset RF power of 4500W and the preset process chamber pressure of 1200mTorr to obtain a coated silicon wafer. The film layer distribution characterization value of the coated silicon wafer is obtained based on the reflectivity at a preset wavelength of 650nm.

[0096] Step S5: When it is determined that the coating process of the coated silicon wafer is at risk of not meeting the preset standard based on the film distribution characterization value, the coating of the silicon wafer is determined a second time based on the surface recombination rate of the coated silicon wafer to determine whether the coating meets the preset standard.

[0097] Step S6: When it is determined that the coating process of the coated silicon wafer does not meet the preset standard based on the film distribution characterization value, an optimization strategy is determined under the condition that the coating process of the coated silicon wafer does not meet the preset standard based on the proportion of defect grid cells of the coated silicon wafer. The optimization strategy is to trigger an alarm to clean and maintain the process chamber of the coating module or reduce the preset process chamber pressure.

[0098] Step S7: Using screen printing technology, fine grid lines and main grid silver paste are printed on the front side of the silicon wafer that meets the preset standards, and back electric field aluminum paste and back electrode silver paste are printed on the back side. Then, in a sintering furnace, sintering is carried out at a peak temperature of 800°C, so that the organic solvent in the paste evaporates, the glass material melts, and low-resistance ohmic contacts are formed, and finally photovoltaic cells are made.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photovoltaic cell manufacturing process parameter adaptive regulation system, characterized in that, include: A diffusion module is used to perform diffusion treatment on a textured silicon wafer to obtain a diffused wafer, wherein the diffusion treatment includes heating the textured silicon wafer at a preset temperature in the edge temperature zone of a diffusion furnace; The coating module is used to coat the etched silicon wafer with a preset radio frequency power and a preset process chamber pressure to obtain a coated silicon wafer. The data acquisition module is connected to the diffusion module and the coating module respectively, and includes a first acquisition unit for acquiring minority carrier lifetime values ​​at several detection points on the surface of the diffusion sheet, a second acquisition unit for acquiring the reflectivity of several grid units on the surface of the coated silicon wafer at a preset wavelength, and a third acquisition unit for acquiring the surface recombination rate of the coated silicon wafer. The control module is connected to the data acquisition module and the diffusion module respectively, and is used to determine whether the diffusion treatment of the diffusion sheet meets the preset standard based on the minority carrier lifetime distribution characterization value of the diffusion sheet, and to determine whether the coating treatment of the coated silicon wafer meets the preset standard based on the film layer distribution characterization value of the coated silicon wafer. An adjustment module, which is connected to the diffusion module, the coating module and the control module respectively, is used to increase the preset temperature of the diffusion furnace edge temperature zone based on the minority carrier lifetime distribution characterization value of the diffusion sheet being greater than or equal to the first preset minority carrier lifetime distribution characterization value and less than the second preset minority carrier lifetime distribution characterization value, and to increase the preset radio frequency power based on the surface recombination rate being greater than or equal to the preset surface recombination rate. An optimization module, which is connected to the control module and the coating module, is used to determine, based on the proportion of defect grid cells in the coated silicon wafer, whether to trigger an alarm to clean and maintain the process chamber of the coating module or to reduce the preset process chamber pressure. The minority carrier lifetime distribution characterization value of the diffuser is determined based on the minority carrier lifetime values ​​of several detection points on the surface of the diffuser, wherein the detection point is the center point of the surface grid cell of the diffuser. The film distribution characterization value is determined based on the reflectance of several grid units on the surface of the coated silicon wafer at a preset wavelength, which is collected by the data acquisition module. The defect mesh cell ratio is the ratio of the number of surface mesh cells of the coated silicon wafer whose reflectance value at a preset wavelength is less than a preset reflectance value to the total number of surface mesh cells.

2. The photovoltaic cell manufacturing process parameter self-adaptive regulating system according to claim 1, wherein, The control module determines that the diffusion process of the diffusion sheet does not meet the preset standard based on the comparison result that the minority carrier lifetime distribution characterization value of the diffusion sheet is greater than or equal to the first preset minority carrier lifetime distribution characterization value and less than the second preset minority carrier lifetime distribution characterization value. Wherein, the first preset minority carrier lifetime distribution characterization value is less than the second preset minority carrier lifetime distribution characterization value.

3. The photovoltaic cell manufacturing process parameter self-adaptive regulating system according to claim 2, characterized in that, The adjustment module has several temperature adjustment methods for increasing the preset temperature of the edge temperature zone of the diffusion furnace, and each temperature adjustment method increases the preset temperature of the edge temperature zone of the diffusion furnace by a different amount.

4. The photovoltaic cell manufacturing process parameter self-adaptive regulating system according to claim 1, wherein, The control module determines that the coating process of the coated silicon wafer is at risk of not meeting the preset standard if the film distribution characterization value of the coated silicon wafer is greater than or equal to the first preset film distribution characterization value and less than the second preset film distribution characterization value. It then determines whether the coating of the silicon wafer meets the preset standard based on the surface recombination rate of the coated silicon wafer, wherein the first preset film distribution characterization value is less than the second preset film distribution characterization value.

5. The photovoltaic cell manufacturing process parameter self-adaptive regulating system according to claim 1, wherein, The control module determines that the coating process of the coated silicon wafer does not meet the preset standard when the film distribution characterization value of the coated silicon wafer is greater than or equal to the second preset film distribution characterization value. The optimization module determines the optimization strategy under the condition that the coating process of the coated silicon wafer does not meet the preset standard based on the proportion of defect grid cells of the coated silicon wafer.

6. The photovoltaic cell manufacturing process parameter self-adaptive regulating system according to claim 4, wherein, The control module makes a secondary determination based on the surface recombination rate of the coated silicon wafer to determine whether the coating process of the coated silicon wafer meets the preset standard. If the surface recombination rate is less than the preset surface recombination rate, then the coating process of the coated silicon wafer is determined to meet the preset standard. If the surface recombination rate is greater than or equal to the preset surface recombination rate, it is determined that the coating process of the coated silicon wafer does not meet the preset standard, and the adjustment module is controlled to increase the preset RF power according to the difference between the surface recombination rate and the preset surface recombination rate.

7. The photovoltaic cell manufacturing process parameter self-adaptive regulating system according to claim 5, wherein, The optimization module determines an optimization strategy for situations where the coating process of the silicon wafer does not meet a preset standard based on the proportion of defective grid cells in the coated silicon wafer. If the proportion of defective mesh cells is less than the preset proportion of defective mesh cells, an alarm is triggered to clean and maintain the process chamber of the coating module. If the proportion of the defective mesh cells is greater than or equal to the preset proportion of the defective mesh cells, the preset process chamber pressure is reduced based on the difference between the proportion of the defective mesh cells and the preset proportion of the defective mesh cells.

8. A method for regulating the process parameter adaptive regulating system for the photovoltaic cell manufacturing process according to any one of claims 1-7, characterized in that, include: A diffusion furnace diffuses a textured silicon wafer through the edge temperature zone of the diffusion furnace at a preset temperature to obtain a diffusion sheet. The minority carrier lifetime distribution characterization value of the diffusion sheet is obtained based on the minority carrier lifetime values ​​of several grid cells on the surface of the diffusion sheet. The diffusion treatment of the diffusion sheet is determined based on the minority carrier lifetime distribution characterization value of the diffusion sheet to determine whether it meets the preset standard. The diffusion wafer that meets the preset standard is etched to obtain an etched silicon wafer. The etched silicon wafer is coated with a film using the preset radio frequency power and preset process cavity pressure to obtain a coated silicon wafer. The film distribution characterization value of the coated silicon wafer is obtained based on the reflectivity of the coated silicon wafer at a preset wavelength. When it is determined that the coating process of the coated silicon wafer is at risk of not meeting the preset standard based on the film distribution characterization value, the coating of the silicon wafer is further determined based on the surface recombination rate of the coated silicon wafer to determine whether the coating meets the preset standard. When the coating process of the coated silicon wafer does not meet the preset standard based on the film distribution characterization value, the optimization strategy under the condition that the coating process of the coated silicon wafer does not meet the preset standard is determined based on the proportion of defect grid cells of the coated silicon wafer. The optimization strategy is to trigger an alarm to clean and maintain the process chamber of the coating module or reduce the preset process chamber pressure. The coated silicon wafer meeting the preset standard is subjected to electrode printing treatment and sintering treatment in sequence to obtain a photovoltaic cell wafer.

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