Fire-proof safe and efficient LPCVD furnace

Abstract

The utility model discloses an anti-fire safe and efficient LPCVD (Low Pressure Chemical Vapor Deposition) furnace, and relates to the technical field of photovoltaic cells. The LPCVD furnace comprises a furnace body, a furnace cavity is formed in the furnace body, the furnace body is provided with a furnace opening and a furnace tail which are oppositely arranged, and the furnace opening is provided with an air inlet device for feeding air into the furnace cavity; the air supply assembly is arranged in the furnace chamber, is parallel to the axial direction of the furnace body, extends from the furnace tail to the furnace opening, and comprises a first air inlet pipe and a second air inlet pipe; the first air inlet pipe is longer than the second air inlet pipe. According to the LPCVD furnace provided by the utility model, the airflow difference between the furnace mouth and the furnace tail can be effectively reduced, so that the difference of film thickness is reduced, and the uniformity of the film thickness of an amorphous silicon layer is effectively improved. In addition, the air inlet pipe made of silicon carbide materials is adopted, the risk that metal materials are damaged and deformed at high temperature and cause fire disasters can be effectively avoided, and the intrinsic safety level is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic cell technical field especially relates to a fire disaster safety efficient LPCVD furnace. BACKGROUND

[0002] The TOPCon cell structure needs to prepare a passivation layer formed by a tunneling oxide layer and a doped polysilicon layer. The passivation layer is mainly prepared by depositing an amorphous silicon layer using LPCVD. The uniformity of the thickness of the amorphous silicon layer directly affects the performance of the subsequent cell.

[0003] The gas inlet pipe of the LPCVD furnace is generally located at one end of the furnace mouth. The gas is uniformly injected into the furnace cavity through a quartz nozzle or a distributed small hole. Since the distance between each boat and the furnace mouth is different, as the distance from the furnace mouth to the furnace tail increases, the gas flow in the temperature zone away from the gas inlet is less, resulting in a large difference in film thickness and poor uniformity.

[0004] Therefore, there is an urgent need for a new LPCVD deposition device. SUMMARY

[0005] The utility model discloses a LPCVD furnace. The LPCVD furnace provided by the utility model can effectively improve the uniformity of the film thickness and further improve the efficiency of the TOPCon cell.

[0006] The utility model provides a kind of LPCVD furnace, comprising: furnace body, the furnace body is formed with furnace cavity and has oppositely arranged furnace mouth and furnace tail, the furnace mouth is provided with the air inlet device of the air inlet of the furnace cavity;Gas supplementing assembly, the gas supplementing assembly is arranged in the furnace cavity, with the axial direction parallel of the furnace body, from the furnace tail to the furnace mouth extends and is arranged, the gas supplementing assembly includes first air inlet pipe and second air inlet pipe;The length of the first air inlet pipe is greater than the second air inlet pipe.

[0007] In an alternative way, the furnace body is arranged as a front furnace zone, a middle furnace zone and a rear furnace zone from the furnace mouth to the furnace tail, the first air inlet pipe is arranged to extend from the rear furnace zone into the middle furnace zone, and the second air inlet pipe is arranged in the rear furnace zone.

[0008] In an alternative way, the gas outlet end of the first air inlet pipe is arranged at 1 / 3 to 1 / 2 of the middle furnace zone close to the front furnace zone, and / or the gas outlet end of the second air inlet pipe is arranged at 1 / 4 to 1 / 3 of the rear furnace zone close to the middle furnace zone.

[0009] In an alternative way, the furnace body comprises at least three temperature zones, and the temperature of the at least one temperature zone where the middle furnace zone is located and / or the temperature of the at least one temperature zone where the rear furnace zone is located is greater than the temperature of the temperature zone where the front furnace zone is located.

[0010] In an alternative, the furnace body is composed of 6 temperature zones, the front furnace zone is composed of 2 temperature zones, the middle furnace zone is composed of 2 temperature zones, and the rear furnace zone is composed of 2 temperature zones.

[0011] In an alternative, the temperature of the 2 temperature zones of the front furnace zone is equal, the temperature of the 2 temperature zones of the middle furnace zone gradually decreases, and the temperature of the 2 temperature zones of the rear furnace zone gradually increases; and the temperature of the maximum temperature zone of the middle furnace zone is greater than the temperature of the maximum temperature zone of the front furnace zone, and the temperature of the maximum temperature zone of the rear furnace zone is greater than the temperature of the maximum temperature zone of the front furnace zone and / or the middle furnace zone.

[0012] In an alternative, the temperature of the temperature zones is 590-630℃; and / or, the temperature of the maximum temperature zone of the middle furnace zone is 1-10℃ greater than the temperature of the maximum temperature zone of the front furnace zone; and / or, the temperature of the maximum temperature zone of the rear furnace zone is 1-12℃ greater than the temperature of the maximum temperature zone of the front furnace zone; and / or, the temperature of the maximum temperature zone of the rear furnace zone is 1-5℃ greater than the temperature of the maximum temperature zone of the middle furnace zone.

[0013] In an alternative, the length of the first air inlet pipe is 1.4-2 times the length of the second air inlet pipe; and / or, the length of the first air inlet pipe is 0.30-0.5 times the length of the furnace body; and / or, the length of the second air inlet pipe is 0.15-0.40 times the length of the furnace body; and / or, the length of the furnace body is 3-6 meters; and / or, the length of the first air inlet pipe is 1.5-2.2 meters; and / or, the length of the second air inlet pipe is 1-1.8 meters; and / or, the material of the first air inlet pipe and / or the second air inlet pipe is silicon carbide; and / or, the first air inlet pipe and / or the second air inlet pipe is a straight pipe; and / or, the air outlet end of the first air inlet pipe and / or the second air inlet pipe is flush; and / or, the first air inlet pipe and / or the second air inlet pipe is arranged at the bottom of the furnace body; and / or, the inner diameter of the first air inlet pipe and / or the second air inlet pipe is 8-16mm; and / or, the outer diameter of the first air inlet pipe and / or the second air inlet pipe is 12-24mm; and / or, the first air inlet pipe and / or the second air inlet pipe is respectively provided with a flow meter.

[0014] In an alternative, the air inlet device comprises a ring-shaped air inlet pipe arranged at the end of the furnace mouth and air outlet holes facing the furnace cavity.

[0015] In an alternative, the ring-shaped air inlet pipe is arranged inside the end of the furnace mouth, and a plurality of air outlet holes are uniformly distributed on the inner side of the ring-shaped air inlet pipe facing the furnace cavity.

[0016] In an alternative mode, the number of the gas outlet holes is 4-20; and / or, the diameter of the gas outlet holes is 1-3mm.

[0017] Compared with the prior art, the LPCVD furnace provided by the utility model, the air inlet structure is composed of a furnace mouth air inlet device and a gas supplement assembly, the furnace mouth air inlet device is arranged at the furnace mouth position, the gas supplement assembly extends from the furnace tail to the furnace mouth, and the consumption of the air flow of the furnace mouth by the boat can be compensated when the boat enters the furnace mouth; further, the furnace tail is provided with two long and short air inlet pipes, and the air flow difference between the furnace mouth and the furnace tail can be effectively reduced; thereby, the film thickness difference can be effectively reduced, and the uniformity of the film thickness of the amorphous silicon layer is effectively improved. In addition, the air inlet pipe made of silicon carbide is adopted, the risk of fire caused by damage and deformation of metal materials under high temperature can be effectively avoided, and the intrinsic safety level is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings described herein are used to provide further understanding of the utility model, and form a part of the utility model, the illustrative embodiments of the utility model and the description thereof are used to explain the utility model, and do not constitute improper limitation on the utility model. In the drawings:

[0019] Figure 1 A front view schematic diagram of one embodiment of the LPCVD furnace of the utility model is shown.

[0020] Figure 2 A side cross-sectional schematic diagram of one embodiment of the LPCVD furnace of the utility model is shown.

[0021] Reference signs:

[0022] 10-furnace body; 101-front furnace zone; 102-middle furnace zone; 103-rear furnace zone; 20-furnace mouth; 201-annular air inlet pipe; 202-gas outlet hole; 30-furnace tail; 40-gas supplement assembly; 401-first air inlet pipe; 402-second air inlet pipe; 50-boat. DETAILED DESCRIPTION

[0023] The embodiments of the utility model are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, and are only used to explain the utility model, and cannot be understood as the limitation on the utility model.

[0024] The disclosure below provides many different embodiments or examples for implementing different structures of the present application. For the sake of simplicity, the description below of a particular embodiment or example does not cite every feature of the application. This omission, however, does not result in a disclaimer of those features of the application. Indeed, all features of the application described below can be combined with the features of the embodiments described or claimed in any combination. Furthermore, specific embodiments described below are provided for the sake of simplicity and clarity. They are not intended to be limiting. Therefore, persons of ordinary skill in the art will recognize that other processes and / or materials can be employed without departing from the principles described herein. Likewise, other functions and / or benefits can be achieved using the described technology without departing from the scope of the present application.

[0025] In the description of the embodiments of the present application, the term "and / or" is merely used to describe an associated relationship between associated objects, that is, there can be three relationships, for example, A and / or B, which can represent three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0026] The present application provides a kind of LPCVD furnace, as shown in Figures 1-2 The LPCVD furnace is a horizontally placed cylindrical quartz tube, and the silicon wafer is vertically placed in the quartz boat boat, which is continuously or batch processed through the furnace tube. The LPCVD furnace includes a furnace body 10, which forms a furnace cavity. The two ends of the furnace body 10 are provided with a furnace mouth 20 and a furnace tail 30. The boat 50 enters from the furnace mouth 20, and the end of the furnace mouth 20 is provided with a gas inlet device for introducing gas into the furnace cavity. The gas flows through the boat 50 from front to back. A gas supplement assembly 40 is installed in the furnace cavity. The gas supplement assembly 40 is parallel to the axial direction of the furnace body 10 and is arranged from the furnace tail 30 to the furnace mouth 20. The gas supplement assembly 40 introduces gas to flow through the boat 50. The gas supplement assembly 40 is arranged from the furnace tail 30 to the furnace mouth 20, so that the gas flows from back to front. Thus, the gas flow shortage of the gas inlet device of the furnace mouth 20 is effectively compensated. The gas supplement assembly 40 includes a first gas inlet pipe 401 and a second gas inlet pipe 402. The length of the first gas inlet pipe 401 is greater than that of the second gas inlet pipe 402, which can further improve the difference in gas flow in the furnace, thereby effectively reducing the difference in film thickness and effectively improving the uniformity of the amorphous silicon layer.

[0027] In an alternative way, as shown in Figure 1As shown, the furnace body 10 is provided with a front furnace area 101, a middle furnace area 102 and a rear furnace area 103 from the furnace mouth 20 to the furnace tail 30, the first air inlet pipe 401 is arranged to extend from the rear furnace area 103 to the middle furnace area 102; the first air inlet pipe 401 extends from the furnace tail 30 of the rear furnace area 103 to the middle furnace area 102, and the outlet end of the first air inlet pipe 401 can be arranged at the start position of the middle furnace area 102, or at the middle of the middle furnace area 102, or at the last position of the middle furnace area 102; the second air inlet pipe 402 is arranged in the rear furnace area 103 and extends from the furnace tail 30 of the rear furnace area 103 to a position close to the middle furnace area 102 in the rear furnace area 103, and the outlet end of the second air inlet pipe 402 can be arranged at the start position of the rear furnace area 103, or at the middle of the rear furnace area 103, or at the rear position of the middle furnace area 102.

[0028] In a preferred mode, as shown, Figure 1 the outlet end of the first air inlet pipe 401 is arranged at 1 / 3-1 / 2 of the middle furnace area 102 close to the front furnace area 101. The outlet end of the first air inlet pipe 401 extends from the furnace tail 30 of the rear furnace area 103 to the front furnace area 101 in the middle furnace area 102, and the outlet end is arranged at 1 / 3-1 / 2 of the middle furnace area 102 close to the front furnace area 101; for example, it can be 1 / 3, 1 / 2 or any range between 1 / 3 and 1 / 2.

[0029] In a preferred mode, as shown, Figure 1 the outlet end of the second air inlet pipe 402 is arranged at 1 / 4-1 / 3 of the rear furnace area 103 close to the middle furnace area 102. The second air inlet pipe 402 is arranged in the rear furnace area 103 and extends from the furnace tail 30 of the rear furnace area 103 to a position close to the middle furnace area 102 in the rear furnace area 103, and the outlet end of the second air inlet pipe 402 can be arranged at 1 / 4-1 / 3 of the rear furnace area 103 close to the middle furnace area 102 in the rear furnace area 103, for example, it can be 1 / 4, 1 / 3 or any range between 1 / 4 and 1 / 3.

[0030] In an alternative mode, as shown, Figure 1As shown, the furnace body 10 is provided with a front furnace zone 101, a middle furnace zone 102 and a rear furnace zone 103 from the furnace mouth 20 to the furnace tail 30; the furnace body 10 contains six temperature zones, the temperature zones of the LPCVD furnace are mainly realized by six independent temperature control heaters, the resistance wire heaters can be evenly distributed around the outer wall of the quartz tube and set to independent temperatures, and the temperature can be fed back in real time by the internal metal tubular thermocouple and the power can be adjusted to ensure the axial temperature uniformity. The front furnace zone 101, the middle furnace zone 102 and the rear furnace zone 103 each contain at least one temperature zone, since the exhaust structure of the furnace mouth 20 is arranged at the furnace mouth 20, the temperature zone of the front furnace zone 101 is mainly affected by the airflow of the exhaust structure of the furnace mouth 20; the first gas inlet pipe 401 is arranged in the middle furnace zone 102 extending from the rear furnace zone 103, so the temperature zone of the middle furnace zone 102 is mainly affected by the airflow of the first gas inlet pipe 401; the second gas inlet pipe 402 is arranged in the rear furnace zone 103; so the temperature zone of the rear furnace zone 103 is mainly affected by the airflow of the second gas inlet pipe 402; thus the three furnace zones are adjusted and controlled by the three gas inlet structures, which can further reduce the difference in film thickness and improve the uniformity of the film thickness of the amorphous silicon layer.

[0031] In some specific embodiments, the furnace body 10 is composed of six temperature zones, the front furnace zone 101 is composed of two temperature zones, the middle furnace zone 102 is composed of two temperature zones, and the rear furnace zone 103 is composed of two temperature zones; in some specific embodiments, the temperatures of the two temperature zones of the front furnace zone 101 are equal, the temperature of the middle furnace zone 102 is greater than that of the front furnace zone 101, and the temperatures of the three temperature zones of the rear furnace zone 103 gradually increase. Thus, by controlling the temperature zones in the furnace zone, the difference in film thickness is further reduced, and the uniformity of the film thickness of the amorphous silicon layer is improved.

[0032] In some more specific embodiments, the temperatures of the two temperature zones of the front furnace zone 101 are equal, the temperatures of the two temperature zones of the middle furnace zone 102 gradually decrease, and the temperatures of the two temperature zones of the rear furnace zone 103 gradually increase; and the temperature of the largest temperature zone of the middle furnace zone 102 is greater than that of the largest temperature zone of the front furnace zone 101, and the temperature of the largest temperature zone of the rear furnace zone 103 is greater than that of the largest temperature zone of the middle furnace zone 102. Thus, by controlling the temperature zones in the furnace zone, the difference in film thickness is further reduced, and the uniformity of the film thickness of the amorphous silicon layer is improved.

[0033] In some more specific embodiments, the temperature of the temperature zone is 590-630℃; for example, it can be 590℃, 600℃, 610℃, 620℃ or 630℃.

[0034] In some more specific embodiments, the temperature of the largest temperature zone of the middle furnace zone 102 is 1-10℃ greater than that of the largest temperature zone of the front furnace zone 101; for example, it can be 1℃, 2℃, 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, 9℃ or 10℃.

[0035] The temperature of the maximum temperature zone in the rear furnace zone 103 is 1 to 12 degrees Celsius higher than the temperature of the maximum temperature zone in the front furnace zone 101; for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 degrees Celsius.

[0036] The temperature of the maximum temperature zone in the rear furnace zone 103 is 1 to 5°C higher than the temperature of the maximum temperature zone in the middle furnace zone 102; for example, it can be 1°C, 2°C, 3°C, 4°C or 5°C.

[0037] In one alternative approach, such as Figure 1 As shown, the length of the first air inlet pipe 401 is 1.4 to 2 times the length of the second air inlet pipe 402; for example, it can be 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times or 2 times. Within this range, the first air inlet pipe 401 and the second air inlet pipe 402 cooperate with each other to compensate for the airflow in the furnace body 10, thereby reducing the airflow difference from the furnace opening 20 to the furnace tail 30, effectively reducing the difference in film thickness, and effectively improving the uniformity of the film thickness of the amorphous silicon layer.

[0038] In one alternative approach, the length of the first air inlet pipe is 0.30 to 0.5 times the length of the furnace body; for example, it can be 0.3, 0.35, 0.4, 0.45, or 0.5 times.

[0039] In one alternative approach, the length of the second air inlet pipe is 0.15 to 0.40 times the length of the furnace body; for example, it can be 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4 times.

[0040] In some specific embodiments, the length of the furnace body is 3-6 meters; for example, it can be 3 meters, 3.1 meters, 3.2 meters, 3.3 meters, 3.4 meters, 3.5 meters, 3.6 meters, 3.7 meters, 3.8 meters, 3.9 meters, 4 meters, 4.1 meters, 4.2 meters, 4.3 meters, 4.4 meters, 4.5 meters, 4.6 meters, 4.7 meters, 4.8 meters, 4.9 meters, 5 meters, 5.1 meters, 5.2 meters, 5.3 meters, 5.4 meters, 5.5 meters, 5.6 meters, 5.7 meters, 5.8 meters, 5.9 meters, or 6 meters.

[0041] In some specific embodiments, the length of the first air intake pipe 401 is 1.5 to 2.2 meters; for example, it can be 1.5 meters, 1.6 meters, 1.7 meters, 1.8 meters, 1.9 meters, 2 meters, 2.1 meters, or 2.2 meters. Within this range, the first air intake pipe 401...

[0042] In some specific embodiments, the length of the second air intake pipe 402 is 1 to 1.8 meters; for example, it can be 1 meter, 1.1 meters, 1.2 meters, 1.3 meters, 1.4 meters, 1.5 meters, 1.6 meters, 1.7 meters, 1.8 meters, 1.9 meters or 2 meters.

[0043] In one alternative embodiment, the first air inlet pipe 401 and / or the second air inlet pipe 402 are made of silicon carbide. Since the air inlet pipe of the gas supply assembly carries silane gas, leakage of silane gas can lead to spontaneous combustion upon contact with air, posing a fire risk. Metal air inlet pipes are prone to deformation and damage at high temperatures. If the damage occurs at the connection point, there is a risk of gas leakage. The air inlet pipe of this invention is made of silicon carbide, which is less prone to deformation and damage, avoiding contamination of the furnace tube and blockage of the air inlet pipe. Furthermore, it effectively prevents the risk of fire caused by metal material deformation and damage at high temperatures, thus improving the intrinsic safety level.

[0044] In one alternative configuration, the first intake pipe 401 and / or the second intake pipe 402 are straight-through pipes; a straight-through pipe means that there are no holes on the side of the pipe, and the gas flows from the tail of the intake pipe to the inlet of the intake pipe without any other outlet holes in between. This avoids the problems of easy clogging, easy deformation, and short service life associated with multi-hole outlet pipes.

[0045] In one alternative configuration, the outlet ends of the first air inlet pipe 401 and / or the second air inlet pipe 402 are flush; the pipe openings are not slotted, thus preventing dust inside the furnace tube from falling back and accumulating at the slotted position.

[0046] In one alternative configuration, the first air inlet pipe 401 and / or the second air inlet pipe 402 are disposed at the bottom of the furnace body 10, so that the gas flows upward toward the corresponding boat 50, further reducing the thickness difference of the amorphous silicon film.

[0047] In one alternative approach, such as Figure 2 As shown, the air intake device at the furnace opening comprises an annular air intake pipe 201 and air outlets 202 facing the furnace cavity; this allows the air intake at the furnace opening to flow into the furnace cavity through the air outlets. Specifically, the annular air intake pipe 201 is located inside the end of the furnace opening, and the inner diameter of the annular air intake pipe 201 is 3-6 mm; for example, it can be 3 mm, 4 mm, 5 mm, or 6 mm. Multiple air outlets 202 are evenly distributed on the inner surface of the annular air intake pipe 201 facing the furnace cavity; in a specific embodiment, the number of air outlets is 4-20, for example, 4, 6, 8, 12, 16, or 20. In a more specific embodiment, the diameter of the air outlets is 1-3 mm; for example, it can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0048] In one alternative configuration, the inner diameter of the furnace body is 300mm to 600mm; for example, it can be 300mm, 350mm, 400mm, 450mm, 500mm, 550mm or 600mm.

[0049] In an alternative way, the gas inlet device of the furnace mouth comprises an annular gas inlet pipe 201 with an inner diameter of 10-20 mm; for example, it can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm or 20 mm.

[0050] In an alternative way, the first gas inlet pipe 401 and / or the second gas inlet pipe 402 has an inner diameter of 8-16 mm; for example, it can be 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or 16 mm.

[0051] In an alternative way, the first gas inlet pipe 401 and / or the second gas inlet pipe 402 has an outer diameter of 12-24 mm; for example, it can be 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm or 24 mm.

[0052] In an alternative way, the first gas inlet pipe 401 and / or the second gas inlet pipe 402 is respectively provided with a flow meter. In this way, the flow of the first gas inlet pipe 401 and the second gas inlet pipe 402 can be controlled separately.

[0053] The preparation method of the LPCVD furnace for preparing photovoltaic cells and the final effect thereof will be described below in combination with several specific embodiments of the utility model, and the LPCVD furnace of the utility model will be further explained and described. It should be understood that the following description is only exemplary and is not a specific limitation of the utility model.

[0054] In the utility model, LPCVD (Low Pressure Chemical Vapor Deposition) is a conventional method for amorphous silicon deposition in TOPCon cell pieces. It mainly passes oxygen gas at high temperature under low pressure conditions, and the oxygen gas reacts with silicon to produce silicon oxide and form an oxide layer. It passes silane at high temperature, and the silane is thermally decomposed into silicon and hydrogen gas to form an amorphous silicon layer on the surface of the silicon wafer.

[0055] Specifically, as shown in Figure 1 The working process of the LPCVD furnace is to push a plurality of boats 50 loaded with silicon wafers from the furnace mouth 20 into the furnace cavity and distribute them at intervals in the furnace. After vacuumizing, heating, leak detection, and subsequent gas introduction and deposition, the furnace mouth 20 is provided with a gas inlet device, and the gas flow is uniformly introduced into the furnace cavity through the gas inlet device. The gas inlet device introduces oxygen and silane gas into the furnace cavity.

[0056] The air supplement assembly 40 is arranged from the furnace tail 30 to the furnace mouth 20, and the air supplement assembly 40 comprises a first air inlet pipe 401 and a second air inlet pipe 402. The length of the first air inlet pipe 401 is greater than that of the second air inlet pipe 402. The first air inlet pipe 401 and the second air inlet pipe 402 respectively introduce the gas, and the gas flows from back to front. The air supplement assembly introduces the silane gas into the furnace cavity. Thus, the difference of the gas flow in the furnace can be further improved, the difference of the film thickness can be effectively reduced, and the uniformity of the film thickness of the amorphous silicon layer can be effectively improved.

[0057] In an alternative way, the flow rate of the first air inlet pipe 401 is greater than that of the second air inlet pipe 402. Thus, the difference of the gas flow in the furnace can be further improved, and the uniformity of the film thickness of the amorphous silicon layer can be improved.

[0058] In an alternative way, in the air inlet device, the flow rate of the oxygen is 30000-50000 SCCM, for example, 30000 SCCM, 35000 SCCM, 40000 SCCM, 45000 SCCM or 50000 SCCM. The flow rate of the silane is 100-1000 SCCM, for example, 100 SCCM, 200 SCCM, 300 SCCM, 400 SCCM, 500 SCCM, 600 SCCM, 700 SCCM, 800 SCCM, 900 SCCM or 1000 SCCM.

[0059] In some specific embodiments, the first air inlet pipe 401 and the second air inlet pipe 402 introduce the silane gas, and the flow rate of the first air inlet pipe 401 is greater than that of the second air inlet pipe 402 by 0-50 SCCM, for example, greater than 0.1 SCCM, 1 SCCM, 5 SCCM, 10 SCCM, 15 SCCM, 20 SCCM, 25 SCCM, 30 SCCM, 35 SCCM, 40 SCCM, 45 SCCM or 50 SCCM.

[0060] In some more specific embodiments, the flow rate of the first air inlet pipe 401 is 350-500 SCCM, for example, 350 SCCM, 360 SCCM, 370 SCCM, 380 SCCM, 390 SCCM, 400 SCCM, 410 SCCM, 420 SCCM, 430 SCCM, 440 SCCM, 450 SCCM, 460 SCCM, 470 SCCM, 480 SCCM, 490 SCCM or 500 SCCM.

[0061] In some more specific embodiments, the flow rate of the second gas inlet pipe 401 is 300-450 SCCM, for example, it can be 300 SCCM, 310 SCCM, 320 SCCM, 330 SCCM, 340 SCCM, 350 SCCM, 360 SCCM, 370 SCCM, 380 SCCM, 390 SCCM, 400 SCCM, 410 SCCM, 420 SCCM, 430 SCCM, 440 SCCM or 450 SCCM.

[0062] In an alternative way, in an alternative way, the deposition pressure in the LPCVD furnace is 20-30 Pa; for example, it can be 20 Pa, 21 Pa, 22 Pa, 23 Pa, 24 Pa, 25 Pa, 25 Pa, 26 Pa, 27 Pa, 28 Pa, 29 Pa or 30 Pa. The deposition time in the LPCVD furnace is 110-200 minutes.

[0063] Embodiment 1

[0064] In Embodiment 1, N-type monocrystalline silicon wafers are selected for the preparation of TOPCon cells. The silicon wafers are prepared by texturing, boron diffusion, alkali etching, LPCVD tunneling and amorphous silicon layer deposition, phosphorus doping, RCA cleaning, front surface aluminum oxide, front and back film silicon nitride passivation and metallization, and finally form a TOPCon cell. The TOPCon cell uses an N-type monocrystalline silicon wafer as a substrate, and the front surface of the substrate is provided with an aluminum oxide passivation layer, an anti-reflective film and a front electrode; the back surface of the substrate is provided with a tunneling oxide layer, a phosphorus-doped polysilicon layer, a silicon nitride passivation film and a back electrode.

[0065] In the process of depositing the amorphous silicon layer by LPCVD, the LPCVD furnace is a horizontally placed cylindrical quartz tube, and the silicon wafers are vertically placed in the quartz boat; 12 boat trays are arranged in the furnace; the first 4 boat trays constitute the front furnace zone 101, the middle 4 boat trays constitute the middle furnace zone 102, and the last 4 boat trays constitute the rear furnace zone 103; 2 temperature zones are arranged on each furnace zone, and there are 6 temperature zones in total. The temperatures of the 6 temperature zones are 601℃, 601℃, 609℃, 601℃, 603℃ and 612℃ respectively. The deposition pressure of the LPCVD furnace is 25 Pa.

[0066] The furnace mouth end face is provided with an annular gas inlet pipe, and the annular gas inlet pipe is provided with 16 uniformly distributed gas outlet holes, and the gas outlet holes face the cavity and introduce gas; the inner diameter of the furnace body is 480 mm, the inner diameter of the annular gas inlet pipe is 12 mm, and the diameter of the gas outlet hole is 1 mm;

[0067] The furnace tail is provided with a gas supplement assembly from the furnace mouth, the gas supplement assembly is composed of a first gas inlet pipe and a second gas inlet pipe, the material of the first gas inlet pipe and the second gas inlet pipe is silicon carbide, the diameter of the first gas inlet pipe is 12 mm, the diameter of the second gas inlet pipe is 12 mm, the length of the first gas inlet pipe is 2.1 m, and the length of the second gas inlet pipe is 1.3 m, so that the first gas inlet pipe is located at 1 / 2 of the middle furnace area 102 close to the front furnace area 101; the second gas inlet pipe is located at 1 / 2 of the rear furnace area 103 close to the middle furnace area 102.

[0068] The furnace mouth gas inlet device is connected with oxygen gas flow of 35000 SCCM and silane gas flow of 300 SCCM; the first gas inlet pipe is connected with silane gas flow of 400 SCCM; and the second gas inlet pipe is connected with silane gas flow of 420 SCCM.

[0069] Example 2

[0070] Different from example 1, the first gas inlet pipe is connected with silane gas flow of 410 SCCM; and the second gas inlet pipe is connected with silane gas flow of 410 SCCM.

[0071] Example 3

[0072] Different from example 1, the first gas inlet pipe is connected with silane gas flow of 420 SCCM; and the second gas inlet pipe is connected with silane gas flow of 400 SCCM.

[0073] Example 4

[0074] Different from example 1, the first gas inlet pipe is connected with silane gas flow of 430 SCCM; and the second gas inlet pipe is connected with silane gas flow of 390 SCCM.

[0075] Example 5

[0076] Different from example 1, the first gas inlet pipe is connected with silane gas flow of 440 SCCM; and the second gas inlet pipe is connected with silane gas flow of 380 SCCM.

[0077] Example 6

[0078] Different from example 3,

[0079] The furnace mouth is provided with a quartz nozzle for connecting gas into the furnace cavity, and the furnace tail is provided with a gas supplement assembly from the furnace mouth, the gas supplement assembly is composed of a first gas inlet pipe and a second gas inlet pipe, the material of the first gas inlet pipe and the second gas inlet pipe is silicon carbide, the length of the first gas inlet pipe is 1.9 m, and the length of the second gas inlet pipe is 1.0 m, so that the first gas inlet pipe is located at 1 / 4 of the middle furnace area 102 close to the front furnace area 101; and the second gas inlet pipe is located at 1 / 4 of the rear furnace area 103 close to the middle furnace area 102.

[0080] Comparative Example 1

[0081] Different from Example 3, the gas supplement assembly only has the first inlet tube, the first inlet tube is made of silicon carbide, and the length of the first inlet tube is 2.1 m, so that the first inlet tube is located at 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101.

[0082] Comparative Example 2

[0083] Different from Example 3, the gas supplement assembly only has the first inlet tube, the first inlet tube is made of silicon carbide, and the length of the first inlet tube is 2.1 m, so that the first inlet tube is located at 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101.

[0084] The gas flow rate of the furnace mouth is 300 SCCM, and the gas flow rate of the first inlet tube is 430 SCCM.

[0085] Comparative Example 3

[0086] Different from Example 3, the gas supplement assembly only has the second inlet tube, the first inlet tube is made of silicon carbide, and the length of the second inlet tube is 1.0 m, so that the second inlet tube is located at 1 / 4 of the middle furnace zone 102 close to the rear furnace zone 103.

[0087] The gas flow rate of the furnace mouth is 300 SCCM, and the gas flow rate of the first inlet tube is 430 SCCM.

[0088] Comparative Example 4

[0089] Different from Example 3, the gas supplement assembly includes two first inlet tubes with the same length, the first inlet tube is made of silicon carbide, and the length of the first inlet tube is 2.1 m, so that the first inlet tube is located at 1 / 2 of the middle furnace zone 102 close to the front furnace zone 101.

[0090] The gas flow rate of the furnace mouth is 300 SCCM, and the gas flow rate of the two first inlet tubes is 430 SCCM.

[0091] Comparative Example 5

[0092] Different from Example 3, the gas supplement assembly includes two second inlet tubes with the same length, the first inlet tube is made of silicon carbide, and the length of the second inlet tube is 1.0 m, so that the second inlet tube is located at 1 / 4 of the middle furnace zone 102 close to the rear furnace zone 103. The gas flow rate of the furnace mouth is 300 SCCM, and the gas flow rate of the two first inlet tubes is 390 SCCM.

[0093] Table 1 below is the film thickness and film thickness uniformity of different boats of Examples 1-6 and Comparative Examples 1-5, the film thickness uniformity is the range uniformity; Range uniformity = (maximum film thickness value - minimum film thickness value) x 100% / (maximum film thickness value + minimum film thickness value).

[0094] From the table, (1) compared with Comparative Examples 1-5, the film thickness uniformity of Examples 1-6 is obviously higher after the gas inlet result of the utility model is adopted.(2) Compared with Examples 1-2, the flow rate of the first gas inlet pipe of Examples 3-5 is greater than that of the second gas inlet pipe, so that the film thickness uniformity is higher.(3) Compared with Example 3, when the flow rate difference between the first gas inlet pipe and the second gas inlet pipe is greater than 50 SCCM in Example 5, the film thickness uniformity effect becomes poor.(4) Compared with Example 3, the first gas inlet pipe and the second gas inlet pipe in Example 6 are too close to the furnace mouth, and the film thickness uniformity effect is slightly poor.

[0095] Table 1 Film thickness and film thickness uniformity of different boats of Examples 1-6 and Comparative Examples 1-5

[0096]

[0097]

[0098]

[0099] In addition, the battery efficiency tester is used to test the electrical performance data of the battery pieces of Example 3 and Comparative Example 1, and Table 2 is the electrical performance data of the battery pieces prepared by Example 3 and Comparative Example 1. From the table, with the film thickness uniformity becoming better, the battery efficiency of Example 3 increases, and the proportion of low-efficiency batteries obviously decreases.

[0100] Table 2 Electrical performance data of battery pieces prepared by Example 3 and Comparative Example 1

[0101]

[0102] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the utility model does not further describe various possible combination manners. In addition, various different embodiments of the utility model can also be combined arbitrarily, as long as it does not deviate from the idea of the utility model, and it should also be regarded as the disclosed content of the utility model.

[0103] In the description of the utility model, it needs to understand that, the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model. In addition, the features limited by "first", "second" can be explicitly or implicitly include one or more of the features. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0104] In the description of the utility model, it needs to be explained that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected, can be mechanical connection, can also be electrical connection, can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0105] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0106] Although the embodiments of the utility model have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the utility model, and the scope of the utility model is defined by the claims and their equivalents.

Claims

1. A fire-safe and efficient LPCVD furnace, characterized in that, The application relates to an LPCVD furnace. The furnace body is provided with a furnace cavity, and has oppositely arranged furnace mouths and furnace tails; the furnace mouths are provided with air inlet devices for air inlet into the furnace cavity. The air supplement assembly is arranged in the furnace cavity and parallel to the axial direction of the furnace body, and extends from the furnace tail to the furnace mouth; the air supplement assembly comprises a first air inlet pipe and a second air inlet pipe; the length of the first air inlet pipe is greater than that of the second air inlet pipe.

2. The LPCVD furnace of claim 1, wherein, The furnace body is provided with a front furnace zone, a middle furnace zone and a rear furnace zone from the furnace mouth to the furnace tail; the first air inlet pipe extends from the rear furnace zone to the middle furnace zone; and the second air inlet pipe is arranged in the rear furnace zone.

3. The LPCVD furnace of claim 2, wherein, The air outlet end of the first air inlet pipe is arranged at 1 / 3-1 / 2 of the middle furnace zone close to the front furnace zone; and / or the air outlet end of the second air inlet pipe is arranged at 1 / 4-1 / 3 of the rear furnace zone close to the middle furnace zone.

4. The LPCVD furnace of claim 2, wherein, The furnace body comprises at least three temperature zones; the temperature of at least one temperature zone where the middle furnace zone is located and / or the temperature of at least one temperature zone where the rear furnace zone is located is greater than the temperature of the temperature zone where the front furnace zone is located.

5. The LPCVD furnace of claim 4, wherein, The furnace body is composed of six temperature zones; the front furnace zone is composed of two temperature zones; the middle furnace zone is composed of two temperature zones; and the rear furnace zone is composed of two temperature zones.

6. The LPCVD furnace of claim 5, wherein, The temperatures of the two temperature zones of the front furnace zone are equal; the temperatures of the two temperature zones of the middle furnace zone gradually decrease; the temperatures of the two temperature zones of the rear furnace zone gradually increase; the temperature of the maximum temperature zone of the middle furnace zone is greater than that of the maximum temperature zone of the front furnace zone; and the temperature of the maximum temperature zone of the rear furnace zone is greater than that of the maximum temperature zone of the front furnace zone and / or the maximum temperature zone of the middle furnace zone.

7. The LPCVD furnace of claim 6, wherein, The temperature of the temperature zone is 590-630 DEG C; the temperature of the maximum temperature zone of the middle furnace zone is 1-10 DEG C greater than that of the maximum temperature zone of the front furnace zone; the temperature of the maximum temperature zone of the rear furnace zone is 1-12 DEG C greater than that of the maximum temperature zone of the front furnace zone; and the temperature of the maximum temperature zone of the rear furnace zone is 1-5 DEG C greater than that of the maximum temperature zone of the middle furnace zone.

8. The LPCVD furnace according to claim 1, wherein The length of the first air inlet pipe is 1.4-2 times the length of the second air inlet pipe; and / or The length of the first air inlet pipe is 0.30-0.5 times the length of the furnace body; and / or the length of the second air inlet pipe is 0.15-0.40 times the length of the furnace body; and / or The length of the furnace body is 3-6 meters; and / or The length of the first air inlet pipe is 1.5-2.2 meters; and / or The length of the second air inlet pipe is 1-1.8 meters; and / or The material of the first air inlet pipe and / or the second air inlet pipe is silicon carbide; and / or The first air inlet pipe and / or the second air inlet pipe is a straight-through pipe; and / or The air outlet end of the first air inlet pipe and / or the second air inlet pipe is flush; and / or The first air inlet pipe and / or the second air inlet pipe is arranged at the bottom of the furnace body; and / or The inner diameter of the first air inlet pipe and / or the second air inlet pipe is 8-16 mm; and / or The outer diameter of the first air inlet pipe and / or the second air inlet pipe is 12-24 mm; and / or, The first air inlet pipe and / or the second air inlet pipe is respectively provided with a flow meter.

9. The LPCVD furnace of claim 1, wherein, The air inlet device comprises an annular air inlet pipe arranged at the end of the furnace mouth and air outlet holes facing the furnace cavity.

10. The LPCVD furnace of claim 9, wherein, The annular air inlet pipe is arranged in the end of the furnace mouth, and a plurality of air outlet holes are uniformly distributed on the inner side of the annular air inlet pipe facing the furnace cavity.

11. The LPCVD furnace of claim 10, wherein, The number of air outlet holes is 4-20; and / or, the diameter of the air outlet hole is 1-3 mm.

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