Annealing system and annealing method for light absorption layer of thin-film solar cell

Abstract

A thin film solar cell light absorption layer annealing system disclosed by the present invention comprises a slide holder, a heating member, a transportation member, a vacuum assembly and a working chamber, the working chamber comprises a sheet inlet chamber, a preheating chamber, a process chamber, a cooling chamber and a sheet outlet chamber which are connected in sequence, the vacuum assembly controls the vacuum degree of the working chamber, the heating member controls the temperature of the working chamber, and the transportation member controls the temperature of the working chamber. A transportation part transports a slide glass table to sequentially enter a slide inlet chamber, a preheating chamber, a process chamber, a cooling chamber and a slide outlet chamber, and a to-be-processed part on the slide glass table is preheated step by step in the slide inlet chamber and the preheating chamber, stays for a preset time in the process chamber and enters the cooling chamber and the slide outlet chamber to be cooled step by step. By means of the arrangement, fracture caused by rapid heating and cooling of the to-be-machined workpieces can be prevented, repeated rising and falling of the temperature of the cavity can be avoided, energy is saved, continuous annealing treatment of the multiple to-be-machined workpieces can be achieved in cooperation with the conveying part, and therefore the production efficiency of a thin film battery production line is improved. The invention further discloses an annealing method.

Description

Technical Field

[0001] The present invention relates to the technical field of annealing equipment for the light absorption layer of thin-film solar cells, and particularly to an annealing system and an annealing method for the light absorption layer of thin-film solar cells. Background Art

[0002] The energy crisis is a fundamental problem faced by the world today. Solar energy is inexhaustible and is an important way to solve the energy crisis. Copper indium gallium selenide (CIGS) thin-film solar cells have become one of the most promising photovoltaic materials due to their adjustable optical bandgap, strong radiation resistance, stable performance, and good low-light performance.

[0003] Using binary, ternary, or quaternary target magnetron sputtering to deposit a preformed film layer and then selenization annealing is the main technical route for preparing CIGS thin-film solar cells. Among them, the selenization annealing process of the CIGS light absorption layer is a key process in thin-film battery preparation, which directly affects the performance of the CIGS light absorption layer, and thus determines the conversion efficiency and yield of the battery. At the same time, the annealing process is often the bottleneck stage of the production process.

[0004] Currently, when producing large-area CIGS thin-film solar cells by the method of selenization annealing after sputtering, all use the method of single furnace body and multi-piece batch annealing. The problems of this method are: since the chamber needs to be heated to a relatively high temperature of about 550°C during annealing, for the single furnace body annealing method, the energy consumption of the chamber temperature rising and falling repeatedly is large, and the heating and cooling processes are very time-consuming, seriously affecting the production rhythm.

[0005] Therefore, how to improve the production efficiency of the thin-film battery production line is a technical problem that needs to be solved by those skilled in the art at present. Summary of the Invention

[0006] In view of this, the first object of the present invention is to provide an annealing system for the light absorption layer of thin-film solar cells to improve the heating and cooling efficiency of the annealing system for the light absorption layer of thin-film solar cells;

[0007] The second object of the present invention is to provide an annealing method.

[0008] To achieve the above first object, the present invention provides the following technical solutions:

[0009] An annealing system for the light absorption layer of thin-film solar cells, including a wafer stage, a heating element, a transportation element, a vacuum component, and a working chamber, wherein:

[0010] The wafer stage is arranged on the top of the transportation element and is used for carrying the workpiece to be processed;

[0011] The transportation element is arranged at the bottom of the working chamber and is used for transporting the wafer stage;

[0012] The vacuum assembly is connected to the working chamber and is used to control the working chamber to be in a vacuum state;

[0013] The heating element is arranged inside the working chamber and is used to heat the working chamber. The working chamber includes a wafer loading chamber, a preheating chamber, a process chamber, a cooling chamber, and a wafer unloading chamber that are connected in sequence. The heating element is used to control the first temperature of the wafer loading chamber, the second temperature of the preheating chamber, the third temperature of the process chamber, the fourth temperature of the cooling chamber, and the fifth temperature of the wafer unloading chamber. Among them, the first temperature is less than the second temperature, the second temperature is less than the third temperature, the fourth temperature is less than the third temperature, and the fifth temperature is less than the fourth temperature;

[0014] When the thin-film solar cell optical absorption layer annealing system is in a working state, at least one wafer carrier is arranged on the transport member, and at least one workpiece to be processed is arranged on the wafer carrier. The transport member transports the wafer carrier into the wafer loading chamber, the preheating chamber, the process chamber, the cooling chamber, and the wafer unloading chamber in sequence.

[0015] Optionally, in the above-mentioned thin-film solar cell optical absorption layer annealing system, the vacuum assembly includes a vacuum pump group, a vacuum gauge, a vacuum pipeline, a vacuum valve, and an automatic pressure regulator, where:

[0016] The first end of the vacuum pipeline is connected to the vacuum pump group, and its second end is connected to the working chamber;

[0017] The vacuum valve is arranged on the vacuum pipeline and is used to control the on-off of the vacuum pipeline;

[0018] The vacuum gauge is connected to the process chamber and is electrically connected to the automatic pressure regulator, and is used to obtain the air pressure data of the process chamber and transmit the air pressure data to the automatic pressure regulator;

[0019] The vacuum maintenance pump group is connected to the process chamber, and the automatic pressure regulator is electrically connected to the vacuum maintenance pump group and is used to control the vacuum degree of the process chamber.

[0020] Optionally, in the above-mentioned thin-film solar cell optical absorption layer annealing system, it further includes a loading platform and an unloading platform. The loading platform is connected to the wafer loading chamber, the unloading platform is connected to the wafer unloading chamber, and a first gate valve is arranged between the loading platform and the wafer loading chamber, a second gate valve is arranged between the wafer loading chamber and the preheating chamber, a third gate valve is arranged between the preheating chamber and the process chamber, a fourth gate valve is arranged between the process chamber and the cooling chamber, a fifth gate valve is arranged between the cooling chamber and the wafer unloading chamber, and a sixth gate valve is arranged between the wafer unloading chamber and the unloading platform.

[0021] Optionally, in the above-mentioned thin-film solar cell optical absorption layer annealing system, the workpiece to be processed includes a substrate prepared with an optical absorption layer, and the substrate is horizontally placed on the wafer carrier;

[0022] When there are two or more substrates arranged on a carrier stage, the substrates are placed horizontally side by side on the carrier stage.

[0023] Optionally, in the above-mentioned thin-film solar cell light absorption layer annealing system, the substrate of the substrate is glass with a thickness of 50 μm to 4 mm or a stainless steel foil with a thickness of 30 μm to 200 μm.

[0024] Optionally, in the above-mentioned thin-film solar cell light absorption layer annealing system, the first temperature is from room temperature to 200 °C, the second temperature is 300 to 450 °C, the third temperature is 500 to 600 °C, the fourth temperature is 300 to 450 °C, and the fifth temperature is from room temperature to 200 °C.

[0025] When the thin-film solar cell light absorption layer annealing system provided by the present invention is in a working state, the vacuum assembly controls the vacuum degree of the working chamber, the heating element controls the temperature of the working chamber, the transportation element transports the carrier stage into the loading chamber, the preheating chamber, the process chamber, the cooling chamber and the unloading chamber in sequence. The workpiece to be processed on the carrier stage is preheated step by step inside the loading chamber and the preheating chamber, and undergoes an annealing process inside the process chamber, and then enters the cooling chamber and the unloading chamber for step-by-step cooling. Such an arrangement can, on the one hand, prevent the workpiece to be processed from cracking due to rapid heating and cooling, on the other hand, avoid repeated temperature rise and fall in the chamber, save energy, and on the other hand, cooperate with the transportation element to realize continuous annealing treatment of multiple workpieces to be processed. Among them, the transportation element can transport multiple carrier stages at the same time, so that at least one of the loading chamber, the preheating chamber, the process chamber, the cooling chamber and the unloading chamber is in a working state. The transportation element transports multiple carrier stages to move unidirectionally simultaneously between the working chambers to realize continuous annealing, thereby improving the production efficiency of the thin-film battery production line.

[0026] In order to achieve the above second object, the present invention provides the following technical solutions:

[0027] An annealing method, applying the above-mentioned thin-film solar cell light absorption layer annealing system, includes:

[0028] Step S1: The vacuum assembly evacuates the working chamber to preset parameters, the heating element heats the working chamber to a preset temperature, arranges the workpiece to be processed on the carrier stage, and arranges the carrier stage on the transportation element;

[0029] Step S2: The vacuum assembly controls the internal air pressure of the loading chamber to 1 atm, the transportation element transports the carrier stage to the loading chamber, and the workpiece to be processed is preheated preliminarily inside the loading chamber;

[0030] Step S3: The transportation element transports the carrier stage to the preheating chamber, and the workpiece to be processed is preheated again inside the preheating chamber;

[0031] Step S4: The transporter conveys the wafer stage to the process chamber and keeps it staying inside the process chamber for a preset time;

[0032] Step S5: The transporter conveys the wafer stage to the cooling chamber, and the workpiece to be processed is preliminarily cooled inside the cooling chamber;

[0033] Step S6: The transporter conveys the wafer stage to the wafer unloading chamber, and the workpiece to be processed is cooled again inside the wafer unloading chamber;

[0034] Step S7: The transporter conveys the wafer stage out of the wafer unloading chamber.

[0035] Optionally, in the above annealing method, the annealing treatment in step S4 includes: the substrate on the wafer stage reaches the annealing temperature inside the process chamber, a protective gas is introduced into the process chamber, the vacuum pumps of the vacuum assembly are at a preset pumping speed, the vacuum gauge obtains the air pressure data of the process chamber and transmits the air pressure data to the automatic pressure regulating valve, and the automatic pressure regulating valve controls the internal air pressure of the process chamber to 0.01 - 0.9 atm, and the annealing time is set to 10 - 60 min.

[0036] Optionally, in the above annealing method, between step S6 and step S7, there is also step S8: evacuate the wafer unloading chamber to the background vacuum, fill it with an inert gas to 0.01 - 0.9 atm, and then evacuate the wafer unloading chamber to the background vacuum again.

[0037] Optionally, in the above annealing method, between step S1 and step S2, there is also step S9: the wafer stage is arranged on the loading table, the first gate valve is opened, the wafer stage enters the wafer loading chamber, and the first gate valve is closed;

[0038] After step S7, there is also step S10: the sixth gate valve is opened, the wafer stage leaves the wafer unloading chamber, reaches the unloading table, and the sixth gate valve is closed;

[0039] After step 10, there is also step S11: the transporter transports the wafer stage from the unloading table to the loading table.

[0040] The annealing method provided by the present invention has the beneficial effects of the above thin - film solar cell light - absorption layer annealing system because it applies the above thin - film solar cell light - absorption layer annealing system, and details are not repeated here. Description of the Drawings

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0042] Figure 1 Overall structure diagram of the annealing system disclosed in the embodiments of the present invention;

[0043] Figure 2 Overall structure diagram of the vacuum assembly disclosed in the embodiments of the present invention;

[0044] Wherein:

[0045] 1. Substrate; 2. Carrier stage; 3. Loading stage; 4. Loading chamber; 5. Preheating chamber; 6. Process chamber; 7. Cooling chamber; 8. Unloading chamber; 9. Unloading stage; 10. First valve; 11. Second valve; 12. Third valve; 13. Fourth valve; 14. Fifth valve; 15. Sixth valve; 16. Vacuum pump group; 17. Vacuum gauge; 18. Vacuum valve; 19. Vacuum pipeline; 20. Automatic pressure regulating valve; 21. Vacuum maintenance pump group. Specific embodiments

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "top surface", "bottom surface", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated position or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0048] Such as Figure 1 And Figure 2As shown in the figure, the annealing system for the light absorption layer of the thin-film solar cell disclosed by the present invention includes a wafer stage 2, a heating element, a transport member, a vacuum assembly, and a working chamber. Among them, the wafer stage 2 is arranged on the top of the transport member and is used to carry the workpiece to be processed. The transport member is arranged at the bottom of the working chamber and is used to transport the wafer stage 2. The vacuum assembly is connected to the working chamber and is used to control the working chamber to be in a vacuum state. The heating element is arranged inside the working chamber and is used to heat the working chamber. The working chamber includes a wafer loading chamber 4, a preheating chamber 5, a process chamber 6, a cooling chamber 7, and a wafer unloading chamber 8 that are connected in sequence. The heating element is used to control the wafer loading chamber 4 to be at a first temperature, the preheating chamber 5 to be at a second temperature, the process chamber 6 to be at a third temperature, the cooling chamber 7 to be at a fourth temperature, and the wafer unloading chamber 8 to be at a fifth temperature. Among them, the first temperature is less than the second temperature, the second temperature is less than the third temperature, the fourth temperature is less than the third temperature, and the fifth temperature is less than the fourth temperature. When the annealing system for the light absorption layer of the thin-film solar cell is in a working state, at least one wafer stage 2 is arranged on the transport member, and at least one workpiece to be processed is arranged on the wafer stage 2. The transport member transports the wafer stage 2 into the wafer loading chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the wafer unloading chamber 8 in sequence.

[0049] Through the multi-temperature zone continuous annealing design, this system realizes the gradient treatment of the workpiece to be processed from low temperature to high temperature and then to low temperature. Compared with the energy consumption mode of the traditional single furnace annealing that needs to repeatedly raise and lower the temperature, this system maintains a constant temperature in each temperature zone, avoiding energy waste. The design of the transport member continuously transporting the wafer stage 2 enables multiple workpieces to be processed to be in different processing stages simultaneously, forming a pipeline operation mode, significantly improving the production efficiency. The step-by-step heating / cooling mechanism effectively reduces the thermal stress, prevents the substrate 1 from cracking or warping due to thermal expansion and contraction, and improves the yield. It should be noted that in the above process, the modular temperature zone design is realized by using the heating element, and each chamber is independently temperature-controlled to ensure the stability of the temperature field. The coordinated control of the vacuum assembly and the heating element realizes the precise matching of the thermal field and the gas environment, providing ideal conditions for the selenization reaction.

[0050] Specifically, the heating element needs to meet core requirements such as temperature uniformity, precise temperature control, and process compatibility. The heating element can be a resistance wire heating system, which uses graphite rods or metal resistance wires (such as tungsten, molybdenum) to be evenly wound on a ceramic / quartz tube to form a radiation heating unit. The heating element can also be a light annealing device, which uses a halogen tungsten lamp array or a laser to be transmitted to the working chamber through an optical fiber.

[0051] In some embodiments of the present invention, the heaters in the film feeding chamber 4 and the film discharging chamber 8 are sheathed heaters. One reason is that the heating temperatures of the film feeding chamber 4 and the film discharging chamber 8 are relatively low. Another reason is that the film feeding chamber 4 and the film discharging chamber 8 often come into contact with air. The outer shell of the sheathed heater is made of stainless steel and can withstand oxidation. The heaters in the preheating chamber 5, the process chamber 6, and the cooling chamber 7 are high-purity graphite rods. One reason is that the heating temperatures of the preheating chamber 5, the process chamber 6, and the cooling chamber 7 are relatively high. Another reason is that the preheating chamber 5, the process chamber 6, and the cooling chamber 7 will come into contact with selenium-containing and sulfur-containing atmospheres, and the high-purity graphite rods will not be corroded.

[0052] It should be noted that the heating elements in all chambers are grouped and controlled according to the chamber size. Each group of heating elements uses a thermocouple to measure the temperature and feeds back to the temperature controller in real time to adjust the heating power. Generally, the heating power is higher at the cold ends on both sides of the chamber and lower in the middle of the chamber, so as to maintain a uniform and constant temperature field at the position of the substrate 1.

[0053] The structural forms of the heating elements include, but are not limited to, the above structural forms. Other devices capable of realizing chamber heating are also within the protection scope of the present invention and will not be elaborated here.

[0054] During use, the transport member runs at the bottom of the working chamber, carrying the carrier stage 2 to move unidirectionally between each chamber, successively completing the preheating, annealing, and cooling processes. By changing the number of carrier stages 2 transported by the transport member, the overall working efficiency of the annealing system can be changed. When there are carrier stages 2 in the film feeding chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the film discharging chamber 8, the annealing system is in a full-load operation state.

[0055] When the thin-film solar cell light absorption layer annealing system provided by the present invention is in a working state, the vacuum assembly controls the vacuum degree of the working chamber, the heating element controls the temperature of the working chamber, the transport member transports the carrier stage 2 to successively enter the film feeding chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the film discharging chamber 8. The workpiece to be processed on the carrier stage 2 is gradually preheated inside the film feeding chamber 4 and the preheating chamber 5, and undergoes an annealing process inside the process chamber 6, and then enters the cooling chamber 7 and the film discharging chamber 8 for gradual cooling. Such an arrangement can, on the one hand, prevent the workpiece to be processed from cracking due to rapid temperature rise and fall, on the other hand, avoid repeated temperature rise and fall in the chamber, save energy, and on the other hand, cooperate with the transport member to realize continuous annealing treatment of multiple workpieces to be processed. Among them, the transport member can transport multiple carrier stages 2 at the same time, so that at least one of the film feeding chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the film discharging chamber 8 is in a working state. The transport member transports multiple carrier stages 2 to move unidirectionally between the working chambers at the same time to realize continuous annealing, thereby improving the production efficiency of the thin-film battery production line.

[0056] To optimize the above technical solution, the vacuum assembly includes a vacuum pump group 16, a vacuum gauge 17, a vacuum pipeline 19, a vacuum valve 18, and an automatic pressure regulating valve 20. Among them, the first end of the vacuum pipeline 19 is connected to the vacuum pump group 16, and its second end is connected to the working chamber. The vacuum valve 18 is arranged on the vacuum pipeline 19 to control the on / off of the vacuum pipeline 19. The vacuum gauge 17 is connected to the process chamber 6 and electrically connected to the automatic pressure regulating valve 20, used to obtain the air pressure data of the process chamber 6 and transmit the air pressure data to the automatic pressure regulating valve 20. The vacuum maintenance pump group 21 is connected to the process chamber 6, and the automatic pressure regulating valve 20 is electrically connected to the vacuum maintenance pump group 21 to control the vacuum degree of the process chamber 6.

[0057] Specifically, the number of vacuum gauges 17 is one or more, and at least one vacuum gauge 17 is connected to the process chamber 6. Five vacuum gauges 17 can be arranged, which are respectively connected to the wafer loading chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the wafer unloading chamber 8 to monitor the air pressure of the working chamber in real time.

[0058] Specifically, the vacuum pipeline 19 can include multiple sub-pipelines and a main pipeline. The main pipeline is connected to the vacuum pump group 16, and the sub-pipelines are respectively connected to the wafer loading chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the wafer unloading chamber 8 and the main pipeline. And a vacuum valve 18 is installed in each sub-pipeline to complete the individual switching of the vacuum pumping operation of each chamber, realizing the vacuum pumping and air pressure data monitoring of the working chamber.

[0059] Specifically, the vacuum pump group 16 is used to realize the vacuum pumping operation of the working chamber. When the annealing system is in the working state, the vacuum pump group 16 performs the vacuum pumping operation on each chamber simultaneously or separately to facilitate the preheating, annealing, and cooling of the substrate 1.

[0060] Specifically, the vacuum maintenance pump group 21 is used to adjust and stabilize the vacuum pressure of the process chamber 6. When the process chamber 6 is in the working state, the vacuum maintenance pump group 21 connected to the process chamber 6 will maintain a certain pumping speed. The vacuum gauge 17 connected to the process chamber 6 will monitor the air pressure of the process chamber 6 and transmit the air pressure data to the automatic pressure regulating valve 20. The automatic pressure regulating valve 20 automatically adjusts the opening and closing degree, thereby maintaining the air pressure of the process chamber 6 at the required value.

[0061] The vacuum assembly of the present invention realizes an integrated design. By using the vacuum gauge 17 to monitor the air pressure of the process chamber 6 in real time and combining with the automatic pressure regulating valve 20 to form a closed-loop control system. When gas by-products are generated during the selenization annealing process, the system can dynamically adjust the pumping speed to maintain a constant pressure, which not only ensures the full progress of the reaction but also avoids the influence of pressure fluctuations on the yield. The optimized layout of the vacuum pump group 16 and the pipeline can improve the pumping efficiency and shorten the process preparation time, thereby further improving the production efficiency of the thin-film battery production line.

[0062] To optimize the above technical solution, the annealing system for the light absorption layer of the thin-film solar cell further includes a loading table 3 and an unloading table 9. The loading table 3 is connected to the film inlet chamber 4, and the unloading table 9 is connected to the film outlet chamber 8. A first gate valve 10 is provided between the loading table 3 and the film inlet chamber 4, a second gate valve 11 is provided between the film inlet chamber 4 and the preheating chamber 5, a third gate valve 12 is provided between the preheating chamber 5 and the process chamber 6, a fourth gate valve 13 is provided between the process chamber 6 and the cooling chamber 7, a fifth gate valve 14 is provided between the cooling chamber 7 and the film outlet chamber 8, and a sixth gate valve 15 is provided between the film outlet chamber 8 and the unloading table 9.

[0063] Specifically, on the moving path of the wafer stage 2, the loading table 3 is located upstream of the moving path. After successively entering the film inlet chamber 4, the preheating chamber 5, the process chamber 6, the cooling chamber 7, and the film outlet chamber 8, it reaches the unloading table 9, and the unloading table 9 is located downstream of the moving path.

[0064] It should be noted that the transport member includes but is not limited to a conveyor belt, an orbital trolley, a linear motor drive system, etc. Taking the conveyor belt as an example, when the conveyor belt is started, loading is performed at the loading table 3, and the wafer stage 2 moves along with the conveyor belt. As the number of wafer stages 2 increases, the working chambers can be in a full-load working state, and the workpieces to be annealed and cooled leave the annealing system from the unloading table 9. Further, considering the coherence of the assembly line production, a loop conveyor belt can be set, with part of it placed under the working chambers. The wafer stage 2 at the unloading table 9 is directly conveyed to the loading table 3 through the loop conveyor belt to form a closed transmission chain, further improving the production efficiency of the thin-film battery production line.

[0065] Further, when the wafer stage 2 of the unloading table 9 needs to return to the loading table 3, the wafer stage 2 needs to be removed from the unloading table 9 and sent back to the loading table 3 through an external path without interfering with other wafer stages 2 being processed. Therefore, the transport member can be designed as an external closed-loop track system connecting the unloading table 9 and the loading table 3, and an electric trolley or a belt conveyor mechanism is used to return the wafer stage 2 externally. At the same time, a linear motor or a track system is used inside the working chambers to move the wafer stage 2 between the chambers. To ensure the smooth connection between the external transport and the internal transport, the wafer stage 2 can be transferred from the unloading table 9 to the external track through a manipulator or a lifting mechanism, and then moved back to the internal transport path from the external track of the loading table 3.

[0066] In summary, an embodiment of the transport member is as follows: a double-layer closed-loop track system is adopted, a ceramic roller conveyor belt capable of withstanding high temperature and corrosion is used as the internal transmission path, passing through the working chambers, and the barrier-free transmission of the wafer stage 2 is realized by coordinating with the sequential switching of the first gate valve 10 to the sixth gate valve 15. A rigid guide rail is used to cooperate with a servo-driven trolley to connect the unloading table 9 and the loading table 3 to complete the return transmission of the wafer stage 2. At the same time, lifting docking platforms can be designed at the loading table 3 and the unloading table 9 to facilitate the transportation of the wafer stage 2 and complete the connection of the double-layer closed-loop track.

[0067] Transportation components in other structural forms are also within the protection scope of the present invention and will not be elaborated herein.

[0068] Specifically, the first valve 10, the second valve 11, the third valve 12, the fourth valve 13, the fifth valve 14 and the sixth valve 15 are sequentially opened during the transportation of the wafer stage 2. Among them, the third valve 12 and the fourth valve 13 can be equipped with a double-layer sealing structure to further ensure sealing, prevent the unannealed substrate 1 from contacting the high-temperature environment, and improve the yield.

[0069] The addition of the loading station 3 and the unloading station 9 can form a closed-loop logistics system, cooperate with the first valve 10 to the sixth valve 15 to realize fully automated production. The first valve 10 to the sixth valve 15 have a sequential opening and closing mechanism to ensure air pressure isolation between chambers and prevent the unannealed substrate 1 from contacting the high-temperature environment. This design enables the system to support multi-batch continuous loading, and the transportation component can achieve seamless handover of the wafer stage 2 without stopping, eliminating the production pause time, thereby further improving the production efficiency of the thin-film battery production line.

[0070] To optimize the above technical solution, the workpiece to be processed includes the substrate 1 prepared with a light absorption layer. The substrate 1 is horizontally placed on the wafer stage 2. When two or more substrates 1 are arranged on a wafer stage 2, the substrates 1 are horizontally placed side by side on the wafer stage 2.

[0071] It should be noted that in the prior art, the single furnace annealing method usually adopts multi-piece vertical placement, which makes it difficult to control the uniformity of the gas field and temperature field of a single piece. Especially for rigid glass substrate batteries, the battery chips are very easy to warp or even break. When multi-piece flat placement is adopted during single furnace annealing, due to mutual overlap and occlusion, there is also a problem that it is difficult to keep the gas field and temperature of each layer of substrate 1 uniform in a vacuum state. According to the size of the working chamber and the wafer stage 2, the substrate 1 can be a single battery chip or multiple battery chips placed side by side, which can realize the horizontal placement of multiple substrates 1 without overlap, maximize the utilization area of the wafer stage 2, improve the single processing volume, and is relatively easy to control in terms of temperature uniformity and gas field distribution, etc., and realize simultaneous annealing, thereby improving the production rhythm and production capacity.

[0072] To optimize the above technical solution, the substrate of the substrate 1 is glass with a thickness of 50 μm to 4 mm or stainless steel foil with a thickness of 30 μm to 200 μm. Specifically, the substrate material of the substrate 1 is selected as glass or stainless steel foil, where the glass substrate is used to prepare a rigid thin film component, and the stainless steel foil substrate is used to prepare a flexible thin film component. The limitation of the thickness range not only ensures the mechanical strength but also avoids the thermal hysteresis effect caused by being too thick. Specifically, the substrate of the substrate 1 can be glass or stainless steel foil. By preparing multiple layers of thin films including a light absorption layer on the substrate, a coated substrate is formed. Specifically, when the thickness of the stainless steel foil is less than or equal to 100 μm, a tooling needs to be made to press the four sides of the stainless steel foil onto the carrier table 2 to avoid curling during annealing heating.

[0073] To optimize the above technical solution, the first temperature is from room temperature to 200 °C, the second temperature is 300 to 450 °C, the third temperature is 500 to 600 °C, the fourth temperature is 300 to 450 °C, and the fifth temperature is from room temperature to 200 °C. Such a setting enables the temperature of the substrate 1 to rise or fall gradually, thereby avoiding the film layer peeling due to excessive thermal stress, and when the substrate is glass, preventing the substrate 1 from cracking due to rapid temperature changes.

[0074] The annealing method disclosed in the present invention, which applies the above thin film solar cell light absorption layer annealing system, includes:

[0075] Step S1: The vacuum component evacuates the working chamber to a preset parameter, the heating element heats the working chamber to a preset temperature, arranges the workpiece to be processed on the carrier table 2, and arranges the carrier table 2 on the transport member;

[0076] Step S2: The vacuum component controls the internal air pressure of the loading chamber 4 to 1 atm, the transport member transports the carrier table 2 to the loading chamber 4, and the workpiece to be processed is preheated inside the loading chamber 4;

[0077] Step S3: The transport member transports the carrier table 2 to the preheating chamber 5, and the workpiece to be processed is preheated again inside the preheating chamber 5;

[0078] Step S4: The transport member transports the carrier table 2 to the process chamber 6 and stays inside the process chamber 6 for a preset time;

[0079] Step S5: The transport member transports the carrier table 2 to the cooling chamber 7, and the workpiece to be processed is preliminarily cooled inside the cooling chamber 7;

[0080] Step S6: The transport member transports the carrier table 2 to the unloading chamber 8, and the workpiece to be processed is cooled again inside the unloading chamber 8;

[0081] Step S7: The transport member transports the carrier table 2 out of the unloading chamber 8.

[0082] Specifically, the above-mentioned vacuum assembly evacuates the working chamber to a preset parameter below the background vacuum in the preset parameters, and the background vacuum is ≤ 0.1 Pa.

[0083] Specifically, a CIGS light absorption layer is deposited on the above-mentioned substrate 1.

[0084] Specifically, the above-mentioned preset time is the annealing time.

[0085] To optimize the above technical solution, the annealing treatment in step S4 includes: the substrate 1 on the carrier stage 2 reaches the annealing temperature inside the process chamber 6, a protective gas is introduced into the inside of the process chamber 6, the vacuum pump group 16 of the vacuum assembly is at a preset pumping speed, the vacuum gauge 17 obtains the air pressure data of the process chamber 6, and transmits the air pressure data to the automatic pressure regulating valve 20. The automatic pressure regulating valve 20 controls the internal air pressure of the process chamber 6 to 0.01 - 0.9 atm, and sets the annealing time to 10 - 60 min.

[0086] Specifically, the protective gas introduced during the annealing treatment is an inert gas such as argon or nitrogen, or a selenium-containing gas such as hydrogen selenide or solid selenium vapor, or a sulfur-containing gas such as hydrogen sulfide or solid sulfur vapor, as well as a mixed gas of the above gases.

[0087] To optimize the above technical solution, between step S6 and step S7, there is also step S8: evacuate the outfeed chamber 8 to the background vacuum, fill it with an inert gas to 0.01 - 0.9 atm, and then evacuate the outfeed chamber 8 to the background vacuum again.

[0088] To optimize the above technical solution, between step S1 and step S2, there is also step S9: the carrier stage 2 is arranged on the loading table 3, the first gate valve 10 is opened, the carrier stage 2 enters the loading chamber 4, and the first gate valve 10 is closed;

[0089] After step S7, there is also step S10: the sixth gate valve 15 is opened, the carrier stage 2 leaves the outfeed chamber 8, reaches the unloading table 9, and the sixth gate valve 15 is closed;

[0090] After step 10, there is also step S11: the transport member transports the carrier stage 2 from the unloading table 9 to the loading table 3.

[0091] Specifically, the carrier stage 2 flows in a cyclic and reciprocating manner. During the process, the substrate 1 moves with the carrier stage 2 from the low-temperature chamber to the high-temperature chamber, and then from the high-temperature chamber to the low-temperature chamber. The temperature of the substrate 1 changes accordingly, but the temperature inside the chamber remains constant all the time, reducing the power consumption caused by repeated heating and cooling. When the carrier stage 2 reaches the loading table 3 from the unloading table 9, another substrate 1 can be placed on the carrier stage 2 again to start a new round of annealing process.

[0092] Specifically, during the transportation process of the transport piece, it should also include: the carrier stage 2 reaches the loading stage 3, the first valve 10 opens, the carrier stage 2 enters the film loading chamber 4, the first valve 10 closes, the film loading chamber 4 is pumped to the base vacuum, after the preliminary preheating is completed, the second valve 11 opens, the carrier stage 2 enters the preheating chamber 5, the second valve 11 closes, the preheating chamber 5 is pumped to the base vacuum, after the preheating is completed, the third valve 12 opens, the carrier stage 2 enters the process chamber 6, the third valve 12 closes, a protective gas is introduced to the required air pressure, and at the same time the substrate 1 is heated to the annealing temperature, the fourth valve 13 opens, the carrier stage 2 enters the cooling chamber 7, the fourth valve 13 closes, the cooling chamber 7 is pumped to the base vacuum to remove the protective gas, after the preliminary cooling is completed, the fifth valve 14 opens, the carrier stage 2 enters the film unloading chamber 8, the fifth valve 14 closes, the film unloading chamber 8 is pumped to the base vacuum to completely remove the residual protective gas, after the cooling is completed, the sixth valve 15 opens, the carrier stage 2 reaches the unloading stage 9, and the sixth valve 15 closes.

[0093] The workpiece to be processed uses a glass substrate and has the following embodiments:

[0094] (1) The working chamber is evacuated to a base vacuum of less than 0.1 Pa;

[0095] (2) The working chamber is heated to the required temperatures, which are: the film loading chamber 4 is 80 °C, the preheating chamber 5 is 350 °C, the process chamber 6 is 550 °C, the cooling chamber 7 is 350 °C, and the film unloading chamber 8 is 80 °C;

[0096] (3) The 3-mm-thick glass substrate wafer 1 deposited with a CIGS light absorption layer is horizontally placed on the carrier stage 2, and then the carrier stage 2 is placed on the loading stage 3;

[0097] (4) The film loading chamber 4 is filled with air to 1 atm pressure, the first valve 10 is opened, the carrier stage 2 carrying the substrate 1 is transferred to the film loading chamber 4, the first valve 10 is closed, the substrate 1 is initially preheated to 80 °C, and at the same time the film loading chamber 4 is pumped to the base vacuum;

[0098] (5) The second valve 11 is opened, the carrier stage 2 carrying the substrate 1 is transferred to the preheating chamber 5, the second valve 11 is closed, and preheating is carried out to 350 °C, and at the same time the preheating chamber 5 is pumped to the base vacuum;

[0099] (6) The third valve 12 is opened, the carrier stage 2 carrying the substrate 1 is transferred to the process chamber 6, the third valve 12 is closed, a mixed gas of argon and hydrogen selenide is introduced, the chamber air pressure reaches 0.5 atm, and at the same time the substrate 1 is heated to 550 °C and then annealed, and the annealing time is 30 min;

[0100] (7) Pump the process chamber 6 to its base vacuum, open the fourth valve 13, transfer the wafer stage 2 carrying the substrate 1 to the cooling chamber 7 for cooling to 350 °C, close the fourth valve 13, and at the same time pump the cooling chamber 7 to its base vacuum to remove the mixed gas of argon and hydrogen selenide;

[0101] (8) Open the fifth valve 14, transfer the wafer stage 2 carrying the substrate 1 to the out - of - wafer chamber 8 for further cooling to 80 °C, close the fifth valve 14, and at the same time pump the out - of - wafer chamber 8 to its base vacuum. Then refill with argon to 0.5 atm, and then pump the out - of - wafer chamber 8 to its base vacuum again to completely remove the residual hydrogen selenide gas;

[0102] (9) Fill the out - of - wafer chamber 8 with air to 1 atm pressure, open the sixth valve 15, transfer the wafer stage 2 carrying the substrate 1 to the unloading stage 9, close the sixth valve 15, pump the out - of - wafer chamber 8 to its base vacuum, and complete the annealing process;

[0103] (10) Remove the substrate 1 from the wafer stage 2, then transfer the wafer stage 2 from outside the chamber back from the unloading stage 9 to the loading stage 3, place another substrate 1 on the wafer stage 2 again, and start a new round of annealing process.

[0104] The workpiece to be processed uses a stainless - steel foil substrate and has the following embodiments:

[0105] (1) Pump the working chamber to a base vacuum below 0.1 Pa;

[0106] (2) Heat the working chamber to the required temperatures, which are: the wafer - loading chamber 4 is at room temperature, the pre - heating chamber 5 is at 300 °C, the process chamber 6 is at 580 °C, the cooling chamber 7 is at 300 °C, and the out - of - wafer chamber 8 is at room temperature;

[0107] (3) Horizontally place the 50 - micron - thick stainless - steel foil - substrate wafer 1 with a deposited CIGS light - absorbing layer on the wafer stage 2, use high - purity graphite pressing blocks to press and attach the four sides of the stainless - steel foil tightly to the wafer stage 2 to prevent the stainless - steel foil from curling during annealing heating, and then place the wafer stage 2 on the loading stage 3;

[0108] (4) Fill the wafer - loading chamber 4 with air to 1 atm pressure, open the first valve 10, transfer the wafer stage 2 carrying the substrate 1 to the wafer - loading chamber 4, close the first valve 10, and pump the wafer - loading chamber 4 to its base vacuum;

[0109] (5) Open the second valve 11, transfer the wafer stage 2 carrying the substrate 1 to the pre - heating chamber 5, close the second valve 11, perform pre - heating to 300 °C, and at the same time pump the pre - heating chamber 5 to its base vacuum;

[0110] (6) Open the third valve 12, transfer the wafer stage 2 carrying the substrate 1 to the process chamber 6, close the third valve 12, introduce a mixed gas of argon and solid selenium vapor, and adjust the chamber pressure to 0.7 atm. At the same time, heat the substrate 1 to 580 °C and then perform an annealing process for 20 minutes;

[0111] (7) Pump the process chamber 6 to its base vacuum, open the fourth valve 13, transfer the wafer stage 2 carrying the substrate 1 to the cooling chamber 7 for cooling to 300 °C, close the fourth valve 13, and at the same time pump the cooling chamber 7 to its base vacuum to remove the mixed gas of argon and solid selenium vapor;

[0112] (8) Open the fifth valve 14, transfer the wafer stage 2 carrying the substrate 1 to the out - of - wafer chamber 8 for further cooling to room temperature, close the fifth valve 14, and at the same time pump the out - of - wafer chamber 8 to its base vacuum. Then, refill it with argon to 0.7 atm, and then pump the out - of - wafer chamber 8 to its base vacuum again to thoroughly remove the gas residue of solid selenium vapor;

[0113] (9) Fill the out - of - wafer chamber 8 with air to 1 atm pressure, open the sixth valve 15, transfer the wafer stage 2 carrying the substrate 1 to the unloading table 9, close the sixth valve 15, pump the out - of - wafer chamber 8 to its base vacuum, and complete the annealing process;

[0114] (10) Remove the substrate 1 from the wafer stage 2, then transfer the wafer stage 2 from outside the chamber back from the unloading table 9 to the loading table 3, place another substrate 1 on the wafer stage 2 again, and start a new round of annealing process.

[0115] The advantages of the present invention are as follows:

[0116] (1) It has a step - by - step pre - heating and cooling function, which can prevent the workpiece from cracking due to rapid temperature rise and fall;

[0117] (2) The chamber temperature is constant, which can avoid repeated temperature rise and fall in the chamber and save energy;

[0118] (3) Through the transport component, continuous annealing treatment of multiple workpieces to be processed is realized, achieving continuous annealing and improving the production efficiency of the thin - film battery production line.

[0119] It should be noted that the annealing system and method for the light - absorption layer of thin - film solar cells provided by the present invention can be used in the technical field of annealing equipment for the light - absorption layer of thin - film solar cells or other fields. The other fields refer to any fields other than the technical field of annealing equipment for the light - absorption layer of thin - film solar cells. The above is only an example and does not limit the application fields of the annealing system and method for the light - absorption layer of thin - film solar cells provided by the present invention.

[0120] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0121] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0122] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0123] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the present invention to the specific implementation manners. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A thin-film solar cell light absorption layer annealing system, characterized in that, It includes a wafer stage, a heating element, a transport member, a vacuum assembly and a working chamber, wherein: The wafer stage is arranged on the top of the transport member and is used for carrying the workpiece to be processed; The transport member is arranged at the bottom of the working chamber and is used for transporting the wafer stage; The vacuum assembly is connected to the working chamber and is used for controlling the working chamber to be in a vacuum state; The heating element is arranged inside the working chamber and is used for heating the working chamber. The working chamber includes a wafer inlet chamber, a preheating chamber, a processing chamber, a cooling chamber and a wafer outlet chamber which are connected in sequence. The heating element is used for controlling the wafer inlet chamber to be at a first temperature, the preheating chamber to be at a second temperature, the processing chamber to be at a third temperature, the cooling chamber to be at a fourth temperature, and the wafer outlet chamber to be at a fifth temperature. Among them, the first temperature is less than the second temperature, the second temperature is less than the third temperature, the fourth temperature is less than the third temperature, and the fifth temperature is less than the fourth temperature; When the thin film solar cell photoabsorber layer annealing system is in a working state, at least one wafer stage is arranged on the transport member, at least one workpiece to be processed is arranged on the wafer stage, and the transport member transports the wafer stage to sequentially enter the wafer inlet chamber, the preheating chamber, the processing chamber, the cooling chamber and the wafer outlet chamber.

2. The annealing system for the light absorption layer of a thin-film solar cell according to claim 1, characterized in that, The vacuum assembly includes a vacuum pump group, a vacuum gauge, a vacuum pipeline, a vacuum valve, a vacuum maintenance pump group and an automatic pressure regulating valve, wherein: The first end of the vacuum pipeline is connected to the vacuum pump group, and its second end is connected to the working chamber; The vacuum valve is arranged on the vacuum pipeline and is used for controlling the on-off of the vacuum pipeline; The vacuum gauge is connected to the processing chamber and is electrically connected to the automatic pressure regulating valve, and is used for obtaining the air pressure data of the processing chamber and transmitting the air pressure data to the automatic pressure regulating valve; The vacuum maintenance pump group is connected to the processing chamber, and the automatic pressure regulating valve is electrically connected to the vacuum maintenance pump group and is used for controlling the vacuum degree of the processing chamber.

3. The annealing system for the light absorption layer of a thin-film solar cell according to claim 1, characterized in that, It further includes a loading table and an unloading table. The loading table is connected to the wafer inlet chamber, the unloading table is connected to the wafer outlet chamber, and a first gate valve is arranged between the loading table and the wafer inlet chamber, a second gate valve is arranged between the wafer inlet chamber and the preheating chamber, a third gate valve is arranged between the preheating chamber and the processing chamber, a fourth gate valve is arranged between the processing chamber and the cooling chamber, a fifth gate valve is arranged between the cooling chamber and the wafer outlet chamber, and a sixth gate valve is arranged between the wafer outlet chamber and the unloading table.

4. The annealing system for the light absorption layer of the thin-film solar cell according to claim 1, wherein, The workpiece to be processed includes a substrate prepared with a photoabsorber layer, and the substrate is horizontally placed on the wafer stage; When two or more substrates are arranged on one wafer stage, the substrates are horizontally placed side by side on the wafer stage.

5. The annealing system for the light absorption layer of a thin film solar cell according to claim 4, characterized in that, The substrate of the substrate is glass with a thickness of 50μm to 4mm or stainless steel foil with a thickness of 30μm to 200μm.

6. The annealing system for the light absorption layer of a thin-film solar cell according to claim 1, wherein The first temperature is from room temperature to 200°C, the second temperature is 300 to 450°C, the third temperature is 500 to 600°C, the fourth temperature is 300 to 450°C, and the fifth temperature is from room temperature to 200°C.

7. An annealing method, characterized in that, Applying the annealing system for the light absorption layer of a thin-film solar cell according to any one of claims 1 to 6, comprising: Step S1: The vacuum assembly evacuates the working chamber to a preset parameter, the heating element heats the working chamber to a preset temperature, arranges the workpiece to be processed on the wafer stage, and arranges the wafer stage on the transport member; Step S2: The vacuum assembly controls the internal air pressure of the loading chamber to 1 atm, the transport member transports the wafer stage to the loading chamber, and the workpiece to be processed is preheated preliminarily inside the loading chamber; Step S3: The transport member transports the wafer stage to the preheating chamber, and the workpiece to be processed is preheated again inside the preheating chamber; Step S4: The transport member transports the wafer stage to the process chamber and stays inside the process chamber for a preset time; Step S5: The transport member transports the wafer stage to the cooling chamber, and the workpiece to be processed is cooled preliminarily inside the cooling chamber; Step S6: The transport member transports the wafer stage to the unloading chamber, and the workpiece to be processed is cooled again inside the unloading chamber; Step S7: The transport member transports the wafer stage out of the unloading chamber.

8. The annealing method according to claim 7, characterized in that, The annealing treatment in step S4 includes: the substrate of the wafer stage reaches the annealing temperature inside the process chamber, a protective gas is introduced into the process chamber, the vacuum pump set of the vacuum assembly is at a preset pumping speed, the vacuum gauge obtains the air pressure data of the process chamber and transmits the air pressure data to the automatic pressure regulating valve, and the automatic pressure regulating valve controls the internal air pressure of the process chamber to 0.01 - 0.9 atm, and sets the annealing time to 10 - 60 min.

9. The annealing method according to claim 7, wherein Between step S6 and step S7, there is also step S8: evacuate the unloading chamber to the base vacuum, fill it with an inert gas to 0.01 - 0.9 atm, and then evacuate the unloading chamber to the base vacuum again.

10. The annealing method according to claim 7, characterized in that, Between step S1 and step S2, there is also step S9: arrange the wafer stage on the loading table, open the first gate valve, the wafer stage enters the loading chamber, and the first gate valve closes; After step S7, there is also step S10: open the sixth gate valve, the wafer stage leaves the unloading chamber, reaches the unloading table, and the sixth gate valve closes; After step 10, there is also step S11: the transport member transports the wafer stage from the unloading table to the loading table.

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