Method for monitoring cleanliness of photovoltaic wet process equipment

Abstract

The invention relates to the technical field of photovoltaic cell manufacturing, in particular to a photovoltaic wet process equipment cleanliness monitoring method. The monitoring method comprises the following steps: providing a texturing silicon wafer; when the target wet process machine is a texturing machine, the texturing silicon wafer is a monitoring test sample; when the target wet process machine table is not a texturing machine table, the texturing machine table is in a clean state, and the texturing silicon wafer is processed by the corresponding target wet process machine table to obtain a monitoring test sample wafer; the method comprises the following steps: carrying out passive film layer treatment on two sides of a monitoring test sample, carrying out heat treatment, testing implicit open-circuit voltage iVoc monitoring, and comparing an iVoc monitoring value with a reference iVoc reference value to judge the cleanliness state of a target wet process machine. The monitoring method provided by the invention is short in test period and can quickly position a defective machine.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and more specifically to a method for monitoring the cleanliness of photovoltaic wet process equipment. Background Technology

[0002] With the continuous development of the photovoltaic industry, companies are demanding increasingly higher efficiency from photovoltaic cell manufacturers. Therefore, in each stage of high-efficiency photovoltaic cell production, it is necessary to regularly monitor the cleanliness of the silicon wafer contact equipment and its surrounding environment to prevent process contamination from affecting cell passivation and further impacting efficiency.

[0003] Currently, most production lines focus more on the passivation effect and cleanliness of passivation-related processes such as boron diffusion, poly, and ALD, and have corresponding testing procedures and methods. However, continuous monitoring of the cleanliness of photovoltaic wet process equipment is rarely conducted. Current methods for monitoring the cleanliness of wet process equipment include elemental analysis, which involves collecting the chemical solution in the tank and testing the impurity concentration using particle or elemental analysis equipment such as ICP-MS to determine the tank contamination level. This method requires collecting a large number of chemical samples, has a long testing cycle, poor timeliness, and a cumbersome operation process, making it difficult to use for continuous daily monitoring. Furthermore, the above monitoring methods also pose high operational safety risks.

[0004] Therefore, there is currently no convenient and effective monitoring method to monitor the cleanliness of photovoltaic wet process equipment. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of poor timeliness and cumbersome operation procedures in existing monitoring methods for photovoltaic wet process equipment, and to provide a method for monitoring the cleanliness of photovoltaic wet process equipment. This monitoring method can shorten the monitoring cycle, significantly improve the efficiency of monitoring, and reduce the impact of the monitoring process on the utilization rate of production equipment.

[0006] Photovoltaic silicon wafers refer to thin sheets made of high-purity polycrystalline silicon raw materials, specifically used to manufacture solar cells. They act as the carrier for photoelectric conversion, and their quality and performance directly determine the efficiency and reliability of the final solar cell module.

[0007] For photovoltaic cells, the implied open-circuit voltage (iVoc) is a crucial indicator of passivated silicon wafer performance, reflecting the upper limit of the open-circuit voltage under ideal conditions. Contamination of the passivated silicon wafer creates recombination centers, leading to an increased surface recombination rate and a shortened minority carrier lifetime, thus reducing the iVoc value. For example, sodium contamination can significantly decrease the open-circuit voltage (Voc) of a photovoltaic cell, consequently reducing the iVoc. Through in-depth research, the inventors of this invention discovered that during periods of high and stable electrical performance in the production line (i.e., when the corresponding wet processing equipment has excellent cleanliness), after several consecutive days of sintering tests on passivated monitoring wafers from various wet processing equipment, the average of the recorded implied open-circuit voltage values ​​is used to obtain the benchmark implied open-circuit voltage (iVoc) for the production line. 基准 Furthermore, the texturized silicon wafer, after undergoing a texturing process, is used as a monitoring wafer, or the texturized wafer is further processed in subsequent wet processing equipment to become a monitoring wafer. The monitoring wafer undergoes passivation coating treatment to obtain passivated monitoring wafers processed by different wet processing equipment. After sintering the obtained passivated monitoring wafers, the implicit open-circuit voltage of the passivated monitoring wafers is tested. If the test data of the passivated monitoring wafer shows an implicit open-circuit voltage (iVoc)... 监控 Significantly lower than the benchmark open voltage iVoc 基准 If the passivation monitoring chip test equipment fails, there may be a cleanliness issue, requiring it to be locked down for further investigation.

[0008] To achieve the above objectives, the present invention provides a method for monitoring the cleanliness of photovoltaic wet processing equipment, comprising the following steps: Select the target wet processing machine to be monitored; A silicon wafer substrate is provided, and the silicon wafer substrate is subjected to texturing treatment by a texturing machine to obtain a texturized silicon wafer; When the target wet processing equipment is a texturing machine, the texturized silicon wafer itself is the monitoring test sample; when the target wet processing equipment is not a texturing machine, the texturing machine is in a clean state, and the texturized silicon wafer undergoes the processing of the corresponding target wet processing equipment to obtain the monitoring test sample. After passivation film treatment and heat treatment on both sides of the monitoring test sample, the implicit open-circuit voltage iVoc was tested. 监控 ; The measured iVoc 监控 Compared with the preset benchmark iVoc 基准 The values ​​are compared, and the benchmark iVoc 基准 The value is the iVoc value corresponding to the target wet scrubbing machine in a clean state; via iVoc 监控 With iVoc 基准 The comparison results are used to determine the cleanliness status of the target wet cleaning machine.

[0009] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet processing equipment involves repeatedly producing reference test samples for each wet processing machine during a period of stable electrical performance of the photovoltaic cells in the production line. After passivation film treatment and heat treatment on both sides of the reference test samples, the average value of the implicit open-circuit voltage obtained from the tests is used to obtain the reference iVoc for the production line. 基准 .

[0010] According to the present invention, a method for monitoring the cleanliness of a photovoltaic wet process equipment is provided, wherein the method uses iVoc 监控 With iVoc 基准 The comparison results are used to determine the cleanliness status of the target wet scrubbing machine, including: recording the deviation coefficient η = (iVoc 监控 -iVoc 基准 ) / iVoc 基准 ×100%, if η<α, and α is not higher than 0%, then the target wet process machine is determined to have a cleanliness problem; otherwise, the target wet process machine is determined not to have a cleanliness problem.

[0011] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein α is -2% to -0.5%.

[0012] According to the method for monitoring the cleanliness of photovoltaic wet process equipment provided by the present invention, for the TOPCon cell production line, α is set to -1%.

[0013] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the texturing process is an alkaline treatment.

[0014] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the alkaline treatment conditions include: the concentration of alkaline compound is 0.3wt%-0.6wt%, the concentration of texturing additive is 0.2wt%-0.4wt%, the temperature is 80℃-84℃, and the time is 400s-440s.

[0015] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the passivation film layer formed by the passivation film layer treatment includes at least one of silicon nitride film, aluminum oxide film, and amorphous silicon passivation film.

[0016] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the thickness of the passivation film layer formed by the passivation film layer treatment is 2nm-200nm.

[0017] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the passivation film layer treatment is achieved by PECVD deposition of silicon nitride film, ALD deposition of aluminum oxide film, or PECVD deposition of amorphous silicon passivation film.

[0018] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the heat treatment conditions include: sintering in an air atmosphere, preferably at a temperature of 600℃-900℃ and a sintering time of 10min-30min.

[0019] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided, wherein the target wet process equipment includes at least one of a texturing machine, an alkaline polishing machine, and an RCA machine.

[0020] According to the present invention, a method for monitoring the cleanliness of photovoltaic wet process equipment is provided. When the target wet process equipment is an alkaline polishing machine, the process performed by the corresponding target wet process equipment is alkaline polishing; when the target wet process equipment is an RCA machine, the process performed by the corresponding target wet process equipment is decoating and cleaning.

[0021] The present invention, by adopting the above technical solution, has the following beneficial effects: 1. Using texturized silicon wafers as the reference carrier, the complex cleanliness test is transformed into a quantifiable passivation performance test through a full-process monitoring chain of wet processing equipment, passivation film deposition, heat treatment, and iVoc testing. This makes the monitoring method of the present invention have the advantages of short testing cycle and convenient operation, and can be used for daily machine cleanliness monitoring in the production process.

[0022] 2. In this invention, various passivation film treatment methods can be adopted according to different process requirements, which can be adapted to the actual situation of multiple types of production lines, with high flexibility. Furthermore, for a large number of machines, this method can quickly locate the problematic machine. Attached Figure Description

[0023] Figure 1 The diagram shows a process flow chart of a method for monitoring the cleanliness of photovoltaic wet process equipment in some examples of the present invention. Detailed Implementation

[0024] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] Unless otherwise defined, all scientific and technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0027] The first aspect of this invention provides a method for monitoring the cleanliness of a photovoltaic wet process equipment, comprising the following steps: Select the target wet processing machine to be monitored; A silicon wafer substrate is provided, and the silicon wafer substrate is subjected to texturing treatment by a texturing machine to obtain a texturized silicon wafer; When the target wet processing equipment is a texturing machine, the texturized silicon wafer itself is the monitoring test sample; when the target wet processing equipment is not a texturing machine, the texturing machine is in a clean state, and the texturized silicon wafer undergoes the processing of the corresponding target wet processing equipment to obtain the monitoring test sample. After passivation film treatment and heat treatment on both sides of the monitoring test sample, the implicit open-circuit voltage iVoc was tested. 监控 ; The measured iVoc 监控 Compared with the preset benchmark iVoc 基准 The values ​​are compared, and the benchmark iVoc 基准 The value is the iVoc value corresponding to the target wet scrubbing machine in a clean state; via iVoc 监控 With iVoc 基准 The comparison results are used to determine the cleanliness status of the target wet cleaning machine.

[0028] The method in this invention has a short testing cycle, is easy to operate, can be used to monitor the cleanliness of wet processing equipment on the same production line, can quickly locate wet processing machines with cleanliness problems, and can be adapted to the actual conditions of various types of production lines, with high flexibility.

[0029] In the photovoltaic cell manufacturing process, silicon wafers undergo multiple wet processing steps, including polishing, cleaning, and texturing. If any wet processing machine becomes contaminated, it can shorten the minority carrier lifetime of the final photovoltaic cell. Furthermore, since raw silicon wafers typically contain a significant amount of dirt and defects, texturing can remove these contaminants and defects to some extent, preventing subsequent testing from being affected by the wafer source. However, when directly performing alkaline polishing on raw silicon wafers, the contaminants on the wafer have a greater impact on the passivation results than the cleanliness of the machine itself. Therefore, testing alkaline polishing machines without prior alkaline texturing cannot determine the cleanliness of the alkaline polishing machine. The monitoring method in this invention uses the texturing wafer, after a texturing process, as a texturing monitoring sheet. Texturing removes dirt and damage from the silicon wafer, preventing any impact on the cleanliness assessment of the equipment. The texturing monitoring sheets are then processed by corresponding target wet processing equipment to obtain monitoring test samples for different devices. After passivation and heat treatment, the implicit open-circuit voltage iVoc is measured from the obtained monitoring test samples. 监控Furthermore, in some embodiments, during the period when the electrical performance of the photovoltaic cells on the production line is stable (especially with high efficiency and stability), reference test samples for each wet processing machine are produced multiple times consecutively (the specific number is not specifically limited, but generally not less than 5 times). After the reference test samples undergo passivation film treatment and heat treatment on both sides, the average value of the implicit open-circuit voltage obtained from the tests is used to obtain the reference iVoc for the production line. 基准 The implicit open-circuit voltage iVoc was subsequently obtained by testing the passivated sheet produced during routine monitoring. 监控 According to iVoc 监控 With iVoc 基准 The comparison results determine the cleanliness status of the target wet scrubbing machine. This allows the method of the present invention to better monitor the cleanliness of each wet scrubbing device.

[0030] Furthermore, the iVoc mentioned above in this invention 基准 The data is derived from historical data statistics during stable production line operation, which makes the monitoring method of the present invention more standardized and closely linked to actual production, thus making the monitoring method of the present invention highly reliable and highly operable.

[0031] The implicit open-circuit voltage iVoc involved in this invention can be obtained through the conventional Sinton test in the art. The specific operation method of the Sinton test is a conventional operation method in the art, and this invention will not elaborate on it further.

[0032] In this invention, if iVoc 监控 Higher than iVoc 基准 If the target wet process machine has no cleanliness issues, then it is considered that there are no cleanliness problems. 监控 Significantly lower than iVoc 基准 That is, the deviation coefficient η=(iVoc) 监控 -iVoc 基准 ) / iVoc 基准 If ×100% < α, where α represents the deviation from the baseline, then the target wet scrubbing machine is considered to have a cleanliness issue and needs to be locked down for further investigation. That is, in some embodiments, the step of using iVoc... 监控 With iVoc 基准 The comparison results are used to determine the cleanliness status of the target wet scrubbing machine, including: recording the deviation coefficient η = (iVoc 监控 -iVoc 基准 ) / iVoc 基准 ×100%, if η<α, and α is not higher than 0%, then the target wet process machine is determined to have a cleanliness problem; otherwise, the target wet process machine is determined not to have a cleanliness problem.

[0033] In this invention, the above-mentioned deviation coefficient η and threshold are introduced after research to establish a state threshold model, which enables the monitoring results to be further quantified, thereby reducing the error of subjective judgment and realizing accurate early warning of the cleanliness of wet equipment.

[0034] In this invention, α represents the deviation from the baseline, which can be determined based on the reference open voltage iVoc. 基准 The fluctuation range during testing is obtained and then adjusted according to the actual situation of the production line. In some embodiments, α is -2% to -0.5%, for example, -2%, -1.5%, -1%, -0.5%, and the specific value is not limited.

[0035] The monitoring method of this invention controls α within the above-mentioned suitable range, which can balance the sensitivity of the monitoring method and the stability of production, and avoid monitoring errors caused by normal fluctuations.

[0036] The monitoring method in this invention has good adaptability and adjustability in photovoltaic cell production lines. As an example, for the TOPCon cell production line, setting α to -1% is sufficient to meet the equipment cleanliness requirements.

[0037] Texturing is a method of creating a microscopic "textured" surface on a silicon wafer. In some embodiments, the texturing process is an alkaline treatment.

[0038] The aforementioned "alkali treatment" refers to texturing using an alkaline solution. The solvent in this alkaline solution is generally water. In some embodiments, the conditions for the alkali treatment include: the concentration of the alkaline compound is 0.3wt%-0.6wt%, for example, 0.3wt%, 0.4wt%, 0.45wt%, 0.5wt%, or 0.6wt%, with no specific limitation. The specific selection of the aforementioned alkaline compound is not particularly limited in this invention, and includes, but is not limited to, sodium hydroxide and / or potassium hydroxide.

[0039] In the texturing process, texturing additives are generally added. In some embodiments, the alkaline treatment conditions include a texturing additive concentration of 0.2wt%-0.4wt%. Texturing additives can have functions such as reducing surface tension, controlling texturing rate, and complexing metal ions. The texturing additives used in this invention can be any known texturing additive in the art, and this invention has no special limitations on them, and they will not be listed one by one.

[0040] In some embodiments, the conditions for alkali treatment include: a temperature of 80°C-84°C (e.g., 80°C, 81°C, 82°C, 83°C, 84°C, etc., which are not specifically limited), and a time of 400s-440s (e.g., 400s, 410s, 420s, 430s, 440s, etc., which are not specifically limited).

[0041] Passivation film treatment refers to the formation of one or more passivated thin films on both sides of a monitoring test sample. Its core purpose is to "passivate" the silicon wafer surface. As long as the objective of this invention is achieved, the specific type of passivation film formed by the passivation film treatment is not particularly limited. In some embodiments, the passivation film formed by the passivation film treatment includes silicon nitride (SiN) films. x ), alumina film (AlO) x At least one of the following: ) and amorphous silicon passivation film.

[0042] In some embodiments, the passivation film treatment can be achieved by depositing a silicon nitride film using PECVD; in some embodiments, the passivation film treatment can be achieved by depositing an alumina film using ALD; and in some embodiments, the passivation film treatment can be achieved by depositing an amorphous silicon passivation film using PECVD. That is, the passivation film treatment is achieved by depositing a silicon nitride film using PECVD, an alumina film using ALD, or an amorphous silicon passivation film using PECVD.

[0043] Therefore, the monitoring method of the present invention can be used to prepare monitoring samples directly on existing mass production equipment (such as PECVD, ALD), thereby making the monitoring method of the present invention more compatible and universal.

[0044] The specific thickness of the passivation film formed by the passivation film layer treatment in this invention is not particularly limited, as long as the purpose of this invention can be achieved. In some embodiments, the thickness of the passivation film formed by the passivation film layer treatment is 2nm-200nm. As an example, the thickness of the silicon nitride film is 60nm-100nm; as an example, the thickness of the aluminum oxide film is 3nm-5nm. As an example, the thickness of the amorphous silicon passivation film is 100nm-150nm.

[0045] In some embodiments, the heat treatment conditions include sintering in an air atmosphere, preferably at a temperature of 600°C-900°C (e.g., 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, or 900°C, without specific limitation), and a sintering time of 10 min-30 min (e.g., 10 min, 15 min, 20 min, 25 min, or 30 min, without specific limitation).

[0046] In the manufacturing process of some photovoltaic cells, after the antireflection film and passivation film are deposited, there is usually a sintering step in air to optimize the contact between the film layer and the electrode. The monitoring method in this invention replicates this key step and can better realize the closed loop of monitoring and production.

[0047] Furthermore, by controlling the sintering temperature and time within the aforementioned suitable range, the accuracy of monitoring can be improved, while avoiding excessively long monitoring times that could affect production efficiency.

[0048] In this invention, there is no special limitation on the specific selection of the target wet processing equipment. All wet processing equipment used for photovoltaic cells can be used as the target wet processing equipment for testing by the method of this invention. In some embodiments, the target wet processing equipment includes, but is not limited to, at least one of a texturing machine, an alkaline polishing machine, and an RCA machine.

[0049] A texturing machine is a wet process device that creates a microscopic "textured" structure on the surface of a silicon wafer. In this invention, the texturing machine is the starting point for the monitoring method of this invention. All test samples used to monitor other wet processes need to be processed by a "known clean" texturing machine first.

[0050] An alkaline polishing machine is a wet process for alkaline polishing of silicon wafers. It can be understood that when the target wet process is an alkaline polishing machine, the process performed on the target wet process is called alkaline polishing. Alkaline polishing is any known processing method in the art, and the silicon wafers can be processed according to the actual battery production line. This invention does not have any special limitations on this. As an example, the conditions for alkaline polishing include: a concentration of alkaline compound of 0.3wt%-1.6wt%, a concentration of alkaline polishing additive of 0.2wt%-0.4wt%, a temperature of 55℃-65℃, and a time of 160s-240s. The alkaline compound includes, but is not limited to, sodium hydroxide and / or potassium hydroxide; the alkaline polishing additive plays a role in "controlling" and "optimizing" the alkaline polishing process. The alkaline polishing additive can be any alkaline polishing additive in the art, and this invention does not have any special limitations on this, so they are not listed individually.

[0051] RCA (Rich Coating and Cleaning) equipment is a wet process for cleaning silicon wafers. It can be understood that when the target wet process equipment is an RCA equipment, the process of going through the corresponding target wet process equipment is a de-coating cleaning process.

[0052] RCA (Rich Coating Aging) equipment is a wet process for cleaning silicon wafers to remove plating. It can be understood that when the target wet process equipment is an RCA equipment, the process performed on the target wet process equipment constitutes plating removal cleaning. Plating removal cleaning is any known processing method in the art, and can be performed using an alkaline solution. The solvent in this alkaline solution is generally water. The specific processing method can be tailored to the actual battery production line. This invention does not have any particular limitations in this regard. As an example, the conditions for plating removal cleaning include: an alkaline compound concentration of 1.8wt%-2.5wt%, a plating removal additive concentration of 0.5wt%-0.6wt%, a temperature of 65℃-75℃, and a time of 300s-380s. The alkaline compound includes, but is not limited to, sodium hydroxide and / or potassium hydroxide; the plating removal additive can be any plating removal additive in the art, and this invention does not have any particular limitations in this regard, so they are not listed individually.

[0053] As an example, in some embodiments, such as Figure 1 As shown, a method for monitoring the cleanliness of photovoltaic wet processing equipment includes the following monitoring process: When testing a texturing machine, use raw silicon wafers from the production line to perform texturing on the machine to obtain double-sided texturing wafers as monitoring test samples for the machine. When testing an alkaline polishing machine or an RCA machine, use raw silicon wafers from the production line in a clean state on the texturing machine to perform texturing on the machine to obtain double-sided texturing wafers. Polish the double-sided texturing wafers using the alkaline polishing machine to be tested or perform decoupling and cleaning treatment using the RCA machine to be tested to obtain double-sided polished wafers as monitoring test samples. The monitoring test sample was coated to obtain a passivated sheet, which was then subjected to high-temperature treatment in a sintering furnace before the passivation data (iVoc) was tested. 监控 ).

[0054] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0055] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0056] The present invention will now be described in detail with reference to specific embodiments, which are intended to understand rather than limit the invention.

[0057] Example 1 (1) Select the original silicon wafers used in the production line and perform alkaline texturing on the texturing machine to be inspected (NaOH concentration 0.45wt%, texturing additive concentration 0.3wt%, process temperature 82℃, process time 420s) to remove surface damage and dirt of the silicon wafers and obtain double-sided texturing wafers as monitoring test samples for the texturing machine. (2) Use the monitoring test sample obtained in step (1) to perform PECVD double-sided SiN x A coating (80nm thick) is applied to obtain a texturing and passivated monitoring wafer. (3) The texturized passivated monitoring sheet obtained in step (2) is sintered at high temperature (750℃, 20min) in air atmosphere to obtain the sintered passivated monitoring sheet. The iVoc of the sintered passivated monitoring sheet is obtained by Sinton test. 监控 It is 718mV.

[0058] The baseline data iVoc obtained from testing the aforementioned flocking machine during a stable production line period. 基准 The value is 705mV (this value is obtained by repeating steps (1)-(3) above 6 times during the period when the production line efficiency is stable, and testing the average value of iVoc).

[0059] The deviation from the bottom line is α = -1%, η 制绒 =(iVoc 监控 -iVoc 基准 ) / iVoc 基准 If ×100%=1.8%>-1%, then it can be considered that the velvet making machine has no cleanliness issues.

[0060] The electrical performance parameters of the battery cells produced by the texturing machine were found to be normal during synchronous testing, which further proves that the texturing machine has no cleanliness issues.

[0061] Example 2 (1) Select the original silicon wafers for production line production and perform alkaline texturing (same as in Example 1) on the texturing machine to remove surface damage and dirt from the silicon wafers and obtain double-sided texturized wafers; (2) Use the double-sided texturing sheet obtained in step (1) to perform alkaline polishing on the alkaline polishing machine to be inspected (NaOH concentration 1wt%, alkaline polishing additive concentration 0.3wt%, process temperature 60℃, process time 200s) to obtain a double-sided polished sheet as a monitoring test sample for the alkaline polishing machine. (3) Use the monitoring test sample obtained in step (2) to perform PECVD double-sided SiN x A coating (80nm thick) was applied to obtain an alkaline polished passivated monitoring wafer. (4) The alkaline passivated monitoring sheet obtained in step (3) is sintered at high temperature (750℃, 20min) in air atmosphere to obtain the sintered passivated monitoring sheet. The iVoc of the sintered passivated monitoring sheet is obtained by Sinton test. 监控 It is 700mV.

[0062] The baseline data iVoc obtained from testing the above-mentioned alkali polishing machine during the stable production line period. 基准 The value is 715mV (this value is obtained by repeating steps (1)-(4) above 6 times during the period when the production line efficiency is stable, and testing the average value of iVoc).

[0063] The deviation from the baseline value α is -1%. Based on Example 1, it was determined that the texturing machine had no cleanliness issues. η was obtained through this example. 碱抛 =(iVoc 监控 -iVoc 基准 ) / iVoc 基准 If ×100% = -2.1% < -1%, then the alkaline polishing machine is considered to have a cleanliness issue and needs to be investigated.

[0064] Simultaneous testing of the electrical performance parameters of the solar cells produced by this alkaline polishing machine revealed a decrease in Voc, further proving that the alkaline polishing machine has a cleanliness issue.

[0065] Example 3 (1) Select the original silicon wafers for production line production and perform alkaline texturing (same as in Example 1) on the texturing machine to remove surface damage and dirt from the silicon wafers and obtain double-sided texturized wafers; (2) The double-sided texturing sheet obtained in step (1) is used to perform de-coating cleaning on the RCA machine to be inspected (NaOH concentration 2.1wt%, de-coating additive concentration 0.55wt%, process temperature 60℃, process time 340s) to obtain a double-sided polished sheet as a monitoring test sample for the RCA machine. (3) Use the monitoring test sample obtained in step (2) to perform PECVD double-sided SiN x A 100nm thick coating was applied to obtain an RCA passivated monitoring chip. (4) The RCA passivated monitoring sheet obtained in step (3) is sintered at high temperature (800℃, 15min) in air atmosphere to obtain the sintered passivated monitoring sheet. The iVoc of the sintered passivated monitoring sheet is obtained by Sinton test. 监控 It is 716mV.

[0066] The benchmark data iVoc obtained from the above RCA machine during the stable production line period 基准The value is 715mV (this value is obtained by repeating steps (1)-(4) above 6 times during the period when the production line efficiency is stable, and testing the average value of iVoc).

[0067] The deviation from the baseline value α is -1%. Based on Example 1, it was determined that the texturing machine had no cleanliness issues. η was obtained through this example. RCA =(iVoc 监控 -iVoc 基准 ) / iVoc 基准 If ×100%=0.14%>-1%, then the RCA machine can be considered to have no cleanliness issues.

[0068] The electrical performance parameters of the solar cells produced by this RCA machine were found to be normal during synchronous testing, further proving that the RCA machine has no cleanliness issues.

[0069] Example 4 (1) Select the original silicon wafers used in the production line and perform alkaline texturing (NaOH concentration 0.6wt%, texturing additive concentration 0.2wt%, process temperature 84℃, process time 400s) on the texturing machine to be inspected to remove surface damage and dirt of the silicon wafers and obtain double-sided texturing wafers as monitoring test samples of the texturing machine. (2) Use the monitoring test sample obtained in step (1) to perform ALD on both sides of AlO. x A 4nm thick coating was applied to obtain a texturing and passivated monitoring wafer. (3) The texturized passivated monitoring sheet obtained in step (2) is sintered at high temperature (700℃, 30min) in air atmosphere to obtain the sintered passivated monitoring sheet. The iVoc of the sintered passivated monitoring sheet is obtained by Sinton test. 监控 It is 705mV.

[0070] The baseline data iVoc obtained from testing the aforementioned flocking machine during a stable production line period. 基准 The value is 700mV (this value is obtained by repeating steps (1)-(3) above 6 times during the period when the production line efficiency is stable, and testing the average value of iVoc).

[0071] The deviation from the bottom line is α = -1%, η 制绒 =(iVoc 监控 -iVoc 基准 ) / iVoc 基准 If ×100%=0.7%>-1%, then the cleanliness of the velvet making machine can be considered to be without problems.

[0072] The electrical performance parameters of the battery cells produced by the texturing machine were found to be normal during synchronous testing, which further proves that the texturing machine has no cleanliness issues.

[0073] Comparative Example 1 (1) Select the original silicon wafers used in the production line and perform alkaline texturing on the texturing machine to be tested (NaOH concentration 0.45wt%, texturing additive concentration 0.3wt%, process temperature 82℃, process time 420s) to remove surface damage and dirt from the silicon wafers and obtain double-sided texturing wafers. (2) Use the double-sided texturing sheet obtained in step (1) to perform alkaline polishing on the alkaline polishing machine to be inspected (NaOH concentration 1wt%, alkaline polishing additive concentration 0.3wt%, process temperature 60℃, process time 200s) to obtain a double-sided polished sheet as a monitoring test sample for the alkaline polishing machine. (3) PECVD double-sided SiN fabrication was performed on the double-sided texturing sheet obtained in step (1) and the alkaline polishing test sample obtained in step (2). x A coating (80 nm thick) was applied to obtain texturing passivated monitoring wafers and alkaline polishing passivated monitoring wafers, respectively. (4) The above-mentioned texturing passivation monitoring sheet and alkaline polishing passivation monitoring sheet were sintered at high temperature (750℃, 20min) in air atmosphere to obtain texturing sintered passivation monitoring sheet and alkaline polishing sintered passivation monitoring sheet, respectively. The iVoc of the texturing sintered passivation monitoring sheet and the alkaline polishing sintered passivation monitoring sheet were tested by Sinton test to obtain the iVoc of the texturing sintered passivation monitoring sheet. 制绒监控 The iVoc of the alkaline passivated sheet is 690mV. 碱抛监控 It is 700mV.

[0074] The baseline data iVoc obtained from testing the aforementioned flocking machine during a stable production line period. 制绒基准 705mV, the above-mentioned alkali polishing machine iVoc 碱抛基准 The value is 715mV (both values ​​are obtained during the period when the production line efficiency is stable). Repeat steps (1)-(4) above to test the corresponding average iVoc.

[0075] The deviation from the baseline value α is -1%, and the above η 制绒 =(iVoc 制绒监控 -iVoc 制绒基准 ) / iVoc 制绒基准 ×100% = -2% < -1%. Therefore, it can be considered that the velvet making machine has a cleanliness issue. The deviation from the baseline value α is -1%, and the above η 碱抛 =(iVoc 碱抛监控 -iVoc 碱抛基准 ) / iVoc 碱抛基准 ×100%=-2%<-1%, but it cannot be considered that the alkaline polishing machine has a cleanliness problem. It is necessary to replace it with a velvet machine without a cleanliness problem and repeat step (1).

[0076] Comparative Example 2 (1) Select the original silicon wafers used in the production line without alkaline texturing, and directly perform alkaline polishing on the alkaline polishing machine to be inspected (NaOH concentration 1wt%, alkaline polishing additive concentration 0.3wt%, process temperature 60℃, process time 200s) to obtain double-sided polished wafers as monitoring test samples for the alkaline polishing machine. (2) Use the monitoring test sample obtained in step (1) to perform PECVD double-sided SiN x A coating (80nm thick) was applied to obtain an alkaline polished passivated monitoring wafer. (3) The alkaline passivated monitoring sheet obtained in step (2) is sintered at high temperature (750℃, 20min) in air atmosphere to obtain the sintered passivated monitoring sheet. The iVoc of the sintered passivated monitoring sheet is obtained by Sinton test. 监控 It is 660mV.

[0077] According to Example 2, the baseline data iVoc obtained by testing the alkali polishing machine during a stable production line period was... 基准 It is 715mV.

[0078] The deviation from the bottom line is α = -1%, η 制绒 =(iVoc 监控 -iVoc 基准 ) / iVoc 基准 ×100% = -7.6% < -1%, indicating a cleanliness issue with the texturing machine. However, simultaneous testing of the electrical performance parameters of the battery cells produced by this machine showed no abnormalities, suggesting that the alkaline polishing machine should not have a cleanliness problem.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring the cleanliness of photovoltaic wet processing equipment, characterized in that, Includes the following steps: Select the target wet processing machine to be monitored; A silicon wafer substrate is provided, and the silicon wafer substrate is subjected to texturing treatment by a texturing machine to obtain a texturized silicon wafer; When the target wet processing equipment is a texturing machine, the texturized silicon wafer itself is the monitoring test sample; when the target wet processing equipment is not a texturing machine, the texturing machine is in a clean state, and the texturized silicon wafer undergoes the processing of the corresponding target wet processing equipment to obtain the monitoring test sample. After passivation film treatment and heat treatment on both sides of the monitoring test sample, the implicit open-circuit voltage iVoc was tested. 监控 ; The measured iVoc 监控 Compared with the preset benchmark iVoc 基准 The values ​​are compared, and the benchmark iVoc 基准 The value is the iVoc value corresponding to the target wet scrubbing machine in a clean state; via iVoc 监控 With iVoc 基准 The comparison results are used to determine the cleanliness status of the target wet cleaning machine.

2. The monitoring method according to claim 1, characterized in that, During the period when the electrical performance of photovoltaic cells on the production line is stable, benchmark test samples are continuously produced for each wet processing machine. After passivation film treatment and heat treatment on both sides of the benchmark test samples, the average value of the implicit open-circuit voltage obtained from the tests is used to obtain the benchmark iVoc for the production line. 基准 .

3. The monitoring method according to claim 1, characterized in that, The via iVoc 监控 With iVoc 基准 The comparison results are used to determine the cleanliness status of the target wet scrubbing machine, including: recording the deviation coefficient η = (iVoc 监控 -iVoc 基准 ) / iVoc 基准 ×100%, if η<α, and α is not higher than 0%, then the target wet process machine is determined to have a cleanliness problem; otherwise, the target wet process machine is determined not to have a cleanliness problem.

4. The monitoring method according to claim 3, characterized in that, The value of α is -2% to -0.5%; Alternatively, for the TOPCon battery production line, α is set to -1%.

5. The monitoring method according to any one of claims 1-4, characterized in that, The texturing process is an alkaline treatment; The conditions for the alkali treatment include: a concentration of 0.3wt%-0.6wt% for the alkali compound, a concentration of 0.2wt%-0.4wt% for the texturing additive, a temperature of 80℃-84℃, and a time of 400s-440s.

6. The monitoring method according to any one of claims 1-4, characterized in that, The passivation film layer formed by the passivation film layer treatment includes at least one of silicon nitride film, aluminum oxide film, and amorphous silicon passivation film; And / or, the thickness of the passivation film formed by the passivation film treatment is 2nm-200nm.

7. The monitoring method according to claim 6, characterized in that, The passivation film treatment is achieved by PECVD deposition of silicon nitride film, ALD deposition of aluminum oxide film, or PECVD deposition of amorphous silicon passivation film.

8. The monitoring method according to any one of claims 1-4, characterized in that, The heat treatment conditions include: sintering in an air atmosphere at a temperature of 600℃-900℃ for a time of 10min-30min.

9. The monitoring method according to any one of claims 1-4, characterized in that, The target wet processing equipment includes at least one of a texturing machine, an alkaline polishing machine, and an RCA machine.

10. The monitoring method according to claim 9, characterized in that, When the target wet process machine is an alkaline polishing machine, the corresponding processing step on the target wet process machine is alkaline polishing. When the target wet process machine is an RCA machine, the process performed by the corresponding target wet process machine is a de-coating cleaning process.

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