Single crystal furnace, crystal bar production process and silicon wafer

Abstract

The invention relates to a single crystal furnace, a crystal bar production process and a silicon wafer, and relates to the technical field of single crystal silicon bar production. The single crystal furnace comprises a main furnace chamber, a first auxiliary chamber, a second auxiliary chamber, a seed crystal holder and a cooling module, and the first auxiliary chamber and the second auxiliary chamber are located above the main furnace chamber and are both parallel to the gravity direction; each of the first auxiliary chamber and the second auxiliary chamber comprises a main body, a cover body and a heating assembly; each main body is of a hollow structure, and openings are formed in the upper end and the lower end of each main body; the cover body opens or seals the lower end opening of the main body; the heating assembly is mounted in the main body; the seed crystal holder is arranged above the main furnace chamber; the cooling module is connected with the openings in the upper ends of the first auxiliary chamber and the second auxiliary chamber. Rapid cooling annealing of the crystal bar can be achieved, and the quality of the crystal bar is effectively improved.

Description

Technical Field

[0001] This application relates to the field of monocrystalline silicon production technology, and in particular to a monocrystalline furnace, a crystal rod production process, and a silicon wafer. Background Technology

[0002] In related technologies, single-crystal silicon rods are mostly produced by the Czochralski method. During the single-crystal pulling process, the temperature of the single-crystal rod decreases slowly. The single-crystal rod, which is maintained at 600℃~1000℃ for a long time, contains a high content of oxygen, which will form oxygen donors and cause resistivity distortion. Summary of the Invention

[0003] Therefore, it is necessary to provide a single crystal furnace, crystal rod production process, and silicon wafer to address the problem of resistivity distortion in single crystal silicon rods.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0005] In a first aspect, embodiments of this application provide a single crystal furnace, comprising:

[0006] Main furnace chamber;

[0007] The first and second auxiliary chambers are located above the main furnace chamber and are both arranged parallel to the direction of gravity. Each of the first and second auxiliary chambers includes a main body, a cover, and a heating assembly. The main body has a hollow structure and openings at both the top and bottom. The cover can open or seal the lower opening of the main body. The heating assembly is installed inside the main body.

[0008] A seed crystal holder is positioned above the main furnace chamber;

[0009] The cooling module is connected to the upper openings of the first and second sub-chambers, respectively.

[0010] In one embodiment of the first aspect, the cover is rotatably connected to the body, the cover rotates relative to the body on the horizontal plane where the cover is located, or the cover flips up and down relative to the body.

[0011] In one embodiment of the first aspect, the single crystal furnace further includes a base, on which both the first sub-chamber and the second sub-chamber are rotatably mounted;

[0012] The base includes a column and a drive unit mounted on the column. One end of the drive unit is provided with a rotating shaft. The first sub-chamber and the second sub-chamber are respectively connected to the rotating shaft. The drive unit drives the first sub-chamber and the second sub-chamber to rotate relative to the column along the central axis of the rotating shaft.

[0013] In one embodiment of the first aspect, the heating assembly includes a plurality of laser heaters and a detection element, each of the laser heaters being circumferentially distributed along the central axis of the body, the detection element being electrically connected to the laser heaters and acquiring the temperature within the body.

[0014] In one embodiment of the first aspect, a plurality of heating zones are equidistantly distributed along the central axis of the body, and each heating zone is circumferentially provided with a plurality of laser heaters.

[0015] In one embodiment of the first aspect, the heating power of the laser heater is less than or equal to 100W, and / or the laser spot of the laser heater is less than or equal to 9mm.

[0016] In one embodiment of the first aspect, the first sub-chamber and the second sub-chamber further include a clamping member installed within the body and located at one end of the body away from the cover.

[0017] In one embodiment of the first aspect, the clamping member includes a plurality of clamping blocks, each of which is circumferentially distributed along the central axis of the body and is controllably rotatable relative to the body.

[0018] Secondly, embodiments of this application also provide a crystal rod manufacturing process, including:

[0019] The single-crystal silicon ingot to be annealed is pulled and cut off after the ingot reaches the designated position in the first auxiliary chamber;

[0020] The lower end of the first sub-chamber is sealed and pressed against both ends of the crystal rod, thus confining the crystal rod within the first sub-chamber.

[0021] The first auxiliary chamber is moved away from the main furnace chamber, and the second auxiliary chamber is moved to the throat of the main furnace chamber for single-crystal silicon pulling.

[0022] The first auxiliary chamber is evacuated to a set vacuum level, and then heated to a first set temperature.

[0023] A cold source is introduced into the first auxiliary chamber at a first set flow rate until the temperature of the first auxiliary chamber drops to a second set temperature, at which point the vacuum module is turned off.

[0024] A cold source is input into the first auxiliary chamber at a second set flow rate until the first auxiliary chamber is cooled to room temperature, and then the crystal rod is removed.

[0025] In one embodiment of the second aspect, the set vacuum degree is ≤30 mtorr.

[0026] In one embodiment of the second aspect, the first set temperature is 1000°C-1200°C, and / or the second set temperature is 500°C.

[0027] In one embodiment of the second aspect, the first set flow rate is 200 lpm, and / or the second set flow rate is 100 lpm.

[0028] Thirdly, embodiments of this application also provide a silicon wafer manufactured using the ingot manufacturing process described in any of the above embodiments.

[0029] Compared with related technologies, the beneficial effects of this application are: This application provides a single crystal furnace, crystal rod production process and silicon wafer. After the crystal rod is pulled, the crystal rod is directly confined in the auxiliary chamber for vacuum heating treatment, and then a cold source is introduced to achieve rapid cooling and annealing, which effectively improves the quality of the crystal rod. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of a single crystal furnace in some embodiments of this application;

[0032] Figure 2 This is a schematic diagram of the base structure in some embodiments of this application;

[0033] Figure 3 This is a schematic diagram illustrating the connection relationship between the cover and the main body in one embodiment of this application;

[0034] Figure 4 This is a schematic diagram showing the connection relationship between the cover and the main body in another embodiment of this application;

[0035] Figure 5 This is an isometric structural schematic diagram of the first auxiliary chamber in some embodiments of this application;

[0036] Figure 6 This is a cross-sectional structural diagram of the first auxiliary chamber in some embodiments of this application;

[0037] Figure 7 This is a schematic flowchart of the crystal rod manufacturing process in some embodiments of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100. Single crystal furnace; 110. Main furnace chamber; 120. First auxiliary chamber; 121. Main body; 1211. Connecting lug; 1212. Turning pin; 122. Cover; 1221. Through hole; 123. Heating assembly; 1231. Laser heater; 1232. Detection component; 124. Observation window; 125. Clamping component; 130. Second auxiliary chamber; 140. Base; 141. Column; 142. Drive component; 143. Rotating shaft; 150. Connecting bracket; 151. Snap ring. Detailed Implementation

[0040] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0041] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] Furthermore, where the term "and / or" appears, "and / or" merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. Where the terms "first" and "second" appear, these terms are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" can explicitly or implicitly include at least one of those features. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0044] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0046] The monocrystalline silicon rods used in solar cells are currently mainly produced using the Czochralski method. The crucible used in this process is a quartz crucible, and the crucible and the monocrystalline rod rotate in opposite directions during the pulling process. Due to the prolonged pulling process, the molten silicon continuously erodes the crucible wall, causing oxygen from the quartz crucible to continuously precipitate into the molten silicon.

[0047] During the single crystal pulling process, the temperature of the single crystal rod decreases slowly. If the single crystal rod is kept at 600℃-1000℃ for a long time, the high oxygen content will form oxygen donors, causing resistivity distortion. For N-type single crystal rods, low-resistivity silicon rods will be formed.

[0048] See Figure 1 As shown, in order to improve the above problems, the embodiments of this application provide a single crystal furnace 100 to achieve rapid cooling of the single crystal rod and improve the quality of the crystal rod.

[0049] For example, the single crystal furnace 100 includes a main furnace chamber 110, a first auxiliary chamber 120, a second auxiliary chamber 130, a seed crystal holder, and a cooling module. The main furnace chamber 110 is used to place polycrystalline silicon blocks and melt them into a silicon solution by heating. The first auxiliary chamber 120 and the second auxiliary chamber 130 can serve as crystal rod formation carriers and simultaneously as crystal rod cooling carriers. After crystal rod formation, rapid cooling can be performed directly in the first auxiliary chamber 120 or the second auxiliary chamber 130 without the need for additional transfer to a cooling container, thus improving efficiency. The seed crystal holder is positioned above the main furnace chamber 110 and on its central axis. When one of the first auxiliary chamber 120 or the second auxiliary chamber 130 is directly above the main furnace chamber 110, the seed crystal holder holds the seed crystal and stretches it within the auxiliary chamber to form a crystal rod. The cooling module is connected to the first sub-chamber 120 and the second sub-chamber 130 respectively, so as to rapidly cool and anneal the first sub-chamber 120 or the second sub-chamber 130 after the crystal rod is generated, thereby reducing the oxygen content of the crystal rod.

[0050] Continue reading Figure 2 As shown, exemplarily, both the first auxiliary chamber 120 and the second auxiliary chamber 130 are located above the main furnace chamber 110 and are vertically arranged parallel to the direction of gravity. During operation, the first auxiliary chamber 120 can be moved directly above the main furnace chamber 110 for ingot pulling, while the second auxiliary chamber 130 is moved away from the main furnace chamber 110 for ingot annealing. It is understood that the first auxiliary chamber 120 and the second auxiliary chamber 130 operate alternately, without a specific order of operation; the above process is merely illustrative. That is, while one of the first auxiliary chamber 120 and the second auxiliary chamber 130 is performing ingot pulling, the other is performing annealing.

[0051] Continue reading Figure 3 and Figure 4 As shown, exemplarily, both the first auxiliary chamber 120 and the second auxiliary chamber 130 include a main body 121, a cover 122, and a heating assembly 123. The generation and cooling of the crystal rod both occur within the main body 121. The main body 121 has a hollow structure with openings at both its upper and lower ends to allow a seed crystal holder to grip the seed crystal and pull it upwards within the main body 121 to form the crystal rod. The cover 122 is rotatably disposed at the lower end of a corresponding main body 121. During crystal rod pulling, the cover 122 rotates relative to the main body 121, opening the lower opening of the main body 121 to allow the seed crystal holder to grip the seed crystal from the lower end of the main body 121 and pull it upwards. After the crystal rod is pulled to a predetermined length, it is cut off, and the lower end of the main body 121 is sealed by the cover 122 to confine the crystal rod within the main body 121. The heating component 123 is installed inside the main body 121. After the crystal rod is confined inside the main body 121, the heating operation is performed to bring the crystal rod to the set annealing temperature.

[0052] In some embodiments, the cover 122 is rotatably connected to one side of the body 121 via a pin, so as to open or seal the lower opening of the body 121 by rotating itself, thereby realizing the process conversion between crystal pulling and annealing.

[0053] For example, the cover 122 can be rotated by a motor, thereby opening or sealing the lower opening of the body 121 by rotating the cover 122.

[0054] Continue reading Figure 3 As shown, in one embodiment, a connecting ear 1211 is provided on one side of the main body 121, and a pivot pin 1212 is fixedly mounted on the connecting ear 1211. A through hole 1221 is provided on one side of the cover 122, and the pivot pin 1212 passes through the through hole 1221 of the cover 122 to rotatably connect the main body 121 and the cover 122. The cover 122 is arranged parallel to the horizontal plane, so that the cover 122 can rotate horizontally relative to the main body 121 along the central axis of the pivot pin 1212. The radius of the cover 122 is larger than the radius of the lower opening of the main body 121, so that when the cover 122 is closed on the main body, the cover 122 can completely block the lower opening of the main body 121. When opening the lower opening of the main body 121, it is only necessary to rotate the cover 122 180° relative to the main body 121 along the central axis of the pivot pin 1212, and the lower opening of the main body 121 will be fully opened. Similarly, the cover 122 rotates 180° again, and the lower opening of the main body 121 is blocked by the cover 122 again.

[0055] Continue reading Figure 4 As shown, in another embodiment, a pivot pin 1212 is fixed horizontally to one side of the main body 121, and a through hole 1221 is formed horizontally on one side of the cover 122. The pivot pin 1212 passes through the through hole 1221 of the cover 122 to rotatably connect the main body 121 and the cover 122, thereby allowing the cover 122 to flip up and down relative to the main body 121 along the central axis of the pivot pin 1212. After the cover 122 is closed with the main body 121, the lower opening of the main body 121 can be fully opened by simply rotating the cover 122 relative to the main body 121 by 90°.

[0056] For example, the cooling module includes a delivery pump and a delivery pipeline. One end of the delivery pipeline is connected to the output end of the delivery pump, and the other end is connected to the upper openings of the first sub-chamber 120 and the second sub-chamber 130, respectively. The input end of the delivery pump is connected to a cold source storage device. After the crystal rod is heated to the set annealing temperature, the delivery pump draws cold source from the input and delivers the cold source to the corresponding sub-chamber through the output end and the delivery pipeline for rapid cooling, thereby completing the annealing of the crystal rod and improving the problem of excessive oxygen content caused by the crystal rod being at high temperature for a long time.

[0057] In this embodiment, by setting up two sub-chambers, and by allowing the first sub-chamber 120 and the second sub-chamber 130 to be moved, while one of the first sub-chamber 120 and the second sub-chamber 130 is undergoing annealing and cooling, the other can be used for crystal pulling again. This enables an integrated process of continuous crystal pulling and annealing, effectively improving the quality of single crystals and increasing labor productivity.

[0058] Of course, in other embodiments, the single crystal furnace 100 may have three, four, five, or other auxiliary chambers, which can be reasonably selected according to actual needs, and no specific limitation is made here. For ease of understanding, this embodiment uses the production needs of two auxiliary chambers as an example.

[0059] In some embodiments, the single crystal furnace 100 further includes a base 140, on which the first sub-chamber 120 and the second sub-chamber 130 are rotatably mounted.

[0060] Optionally, the first auxiliary chamber 120 and the second auxiliary chamber 130 can be staggered vertically along the direction of gravity to avoid interference between them during assembly while ensuring that their structures and dimensions are exactly the same.

[0061] For example, the base 140 is vertically fixed to the ground, the main furnace chamber 110 can be placed on the ground or a work platform, and the first auxiliary chamber 120 and the second auxiliary chamber 130 are rotatably mounted on the base 140 and suspended above the main furnace chamber 110.

[0062] See again Figure 2 As shown, the base 140 includes a column 141 and a drive member 142 mounted on the column 141. One end of the drive member 142 is provided with a rotating shaft 143. Both the first auxiliary chamber 120 and the second auxiliary chamber 130 are provided with connecting brackets 150 on the side near the base 140. Each connecting bracket 150 has multiple retaining rings 151. The retaining rings 151 of the two connecting brackets 150 alternate along the direction of gravity. The rotating shaft 143 passes through all the retaining rings 151 of the two connecting brackets 150 in sequence to fix the first auxiliary chamber 120 and the second auxiliary chamber 130 to the rotating shaft 143, thereby driving the rotating shaft 143 to rotate via the drive member 142. Thus, the first auxiliary chamber 120 and the second auxiliary chamber 130 rotate along the central axis of the rotating shaft 143 under the drive of the rotating shaft 143, and perform corresponding work processes alternately, so that one of the first auxiliary chamber 120 and the second auxiliary chamber 130 moves to the top of the main furnace chamber 110 to perform crystal rod pulling operation, while the other is moved away from the main furnace chamber 110 to perform crystal rod annealing operation.

[0063] Optionally, the drive element 142 may be a motor capable of driving the shaft 143 to rotate.

[0064] In some embodiments, the single crystal furnace 100 further includes a vacuum module, which is connected to the sub-chamber via a pipeline.

[0065] For example, the vacuum module includes a vacuum pump and a vacuum extraction line, one end of which is connected to the vacuum pump and the other end of which is connected to the upper opening of the sub-chamber. Thus, during the annealing and cooling of the sub-chamber, the bottom of the sub-chamber is sealed by the cover 122, and the top is evacuated by the vacuum module to ensure that the vacuum level of the sub-chamber meets the annealing requirements.

[0066] See again Figure 5 and Figure 6 As shown, in some embodiments, an observation window 124 is provided on one side of the lower end of the main body 121.

[0067] For example, the observation window 124 can monitor the crystal growth status in real time, such as diameter, liquid level, and crystal interface morphology, while also meeting the stability and sealing requirements under high temperature, vacuum, or inert gas environments. Through the observation window 124, the pulling status of the crystal rod in the sub-chamber can be continuously observed. If abnormalities are detected, such as silicon melt splashing or crucible breakage, timely intervention can be provided to ensure the pulling quality.

[0068] In some embodiments, the heating assembly 123 includes a plurality of laser heaters 1231 and a detection element 1232. Each laser heater 1231 is circumferentially distributed along the central axis of the body 121. The detection element 1232 is electrically connected to the laser heaters 1231 and is capable of acquiring the temperature inside the body 121.

[0069] For example, multiple heating zones are equidistantly distributed along the central axis within the main body 121, and each heating zone is circumferentially equipped with multiple laser heaters 1231. Thus, during crystal ingot annealing, each laser heater 1231 operates synchronously, enabling simultaneous heating of both ends and the middle of the crystal ingot. Furthermore, the circumferentially arranged laser heaters 1231 can simultaneously heat different directions of the crystal ingot, ensuring that all parts of the crystal ingot are in the same high-temperature environment and guaranteeing the effective heating and annealing of the crystal ingot.

[0070] The detection element 1232 can be a temperature sensor to detect the temperature inside the main body 121 in real time. After the control system obtains the temperature information of the detection element 1232, it controls the operation status of the laser heater 1231 accordingly.

[0071] In one embodiment, the heating power of the laser heater 1231 is less than or equal to 100W.

[0072] For example, monocrystalline silicon at 10 6 -10 7 W / cm² (continuous laser) or 10 8At power densities of W / cm² (pulsed laser), silicon readily melts or vaporizes. A 100W laser can control the power density within a safe range, reducing amorphization or microcracks. This allows for adaptation to the absorption characteristics of single-crystal silicon rods, reducing the risk of thermal damage, maintaining crystal integrity, preventing excessive melting and ablation, and suppressing thermal stress cracks.

[0073] In yet another embodiment, the laser spot of the laser heater 1231 is less than or equal to 9 mm.

[0074] For example, taking a 100W laser as an example, the power density of a 9mm spot is only 16W / cm², compared to 1300W / cm² for a 1mm spot. This avoids microcracks or lattice distortion caused by local overheating, reduces power density, achieves uniform heating, reduces local thermal stress, and ensures rapid local heating.

[0075] In some embodiments, the sub-chamber further includes a clamping member 125, which is installed within the body 121 and located at one end of the body 121 away from the cover 122.

[0076] For example, the clamping member 125 is located at the upper end of the body 121 so that after the crystal rod is formed, the clamping member 125 abuts against the upper end of the crystal rod. At this time, the lower end of the crystal rod is supported by the cover 122, so that the crystal rod is confined within the body 121, thereby facilitating subsequent heating annealing and rapid cooling.

[0077] In some embodiments, the clamping member 125 includes a plurality of clamping blocks distributed circumferentially along the central axis of the body 121 and capable of being rotated in a controlled manner relative to the body 121.

[0078] For example, each clamp can be flipped up and down under the drive of a motor, so that after the crystal rod is generated, the clamp is driven by the motor to move closer to the central axis of the main body 121, thereby abutting against the peripheral surface of the crystal rod and restricting the upper displacement of the crystal rod.

[0079] Furthermore, the side of each clamp that contacts the crystal rod is provided with a wavy, textured surface to increase contact friction with the crystal rod and improve clamping stability.

[0080] Continue reading Figure 7 As shown, the embodiments of this application also provide a crystal rod production process, which can use the single crystal furnace 100 provided in the above embodiments to achieve continuous crystal pulling and annealing heat treatment at the same time, effectively improving the quality of single crystals and increasing labor productivity.

[0081] Specifically, the crystal rod manufacturing process includes:

[0082] S10, pull the single-crystal silicon ingot to be annealed, and cut it off after the ingot reaches the designated position in the first auxiliary chamber.

[0083] For example, the base 140 moves the first auxiliary chamber above the main furnace chamber, at which point the lower end cover 122 of the main body 121 opens. A seed crystal holder holds the seed crystal, passes it through the top of the auxiliary chamber, and brings it into contact with the solution surface inside the main furnace chamber. Crystallization occurs at the silicon solution interface under temperature control. Through the pulling action of the seed crystal holder, a crystal rod is slowly formed within the main body 121 of the first auxiliary chamber. During the pulling process, the pulling status of the crystal rod can be observed in real time through the observation window 114. If any abnormalities are detected, timely intervention is provided to ensure the quality of the crystal rod pulling. Once the crystal rod reaches the set pulling length, it is cut off, completing the pulling of a single crystal rod.

[0084] S20, seal the lower end of the first auxiliary chamber and abut against both ends of the crystal rod, confining the crystal rod within the first auxiliary chamber.

[0085] For example, after the crystal rod is cut off, the cover 122 of the first auxiliary chamber is controlled to rotate towards the lower opening of the main body 121, thereby sealing the lower end of the main body 121. At the same time, each clamping block is controlled to rotate and move towards the central axis of the main body 121 to clamp and fix the upper end of the crystal rod, fixing the crystal rod inside the main body 121 to facilitate subsequent annealing operations.

[0086] S30 controls the first auxiliary chamber to move away from the main furnace chamber, and the second auxiliary chamber to move to the throat of the main furnace chamber for another single-crystal silicon pulling process.

[0087] For example, under the control of the base 140, the two auxiliary chambers rotate synchronously, so that the first auxiliary chamber, after being drawn, moves away from the main furnace chamber and reaches the annealing station, while the second auxiliary chamber is placed above the main furnace chamber again to perform the crystal rod drawing operation again.

[0088] As is understood, in this embodiment, the first and second auxiliary chambers operate alternately. When the first auxiliary chamber is performing ingot pulling, the second auxiliary chamber is performing annealing; and when the second auxiliary chamber is performing ingot pulling, the first auxiliary chamber is performing annealing. Therefore, the above steps are merely illustrative and do not limit the operating sequence of the first and second auxiliary chambers.

[0089] S40, evacuate the first auxiliary chamber to achieve the set vacuum level, and then heat it to the first set temperature.

[0090] For example, after the bottom of the sub-chamber is sealed, the vacuum module is activated to perform vacuum extraction from above the sub-chamber until the sub-chamber vacuum level is ≤30 mtorr. Then, the heating module is activated, and the heating power is adjusted according to the temperature parameters obtained from the detection device to rapidly raise the temperature to the target temperature of 1000℃-1200℃, after which the laser heater is turned off.

[0091] In some embodiments, during the heating process to the first set temperature, the heating rate is 300℃ / s-500℃ / s to achieve rapid heating of the crystal rod, and heating is stopped after the temperature reaches the target temperature of 1000℃-1200℃.

[0092] S50: Input cold source into the first auxiliary chamber at the first set flow rate until the temperature of the first auxiliary chamber drops to the second set temperature, then shut down the vacuum module.

[0093] For example, the cold source is liquid argon. After the secondary chamber reaches the first set temperature, the cold source is delivered to the upper opening of the main body 121 via the delivery pump and delivery pipeline of the cooling module, and a continuous flow rate of 200 lpm is maintained to rapidly cool it down. During the delivery of the cold source, the liquid argon absorbs heat and turns into argon gas. The vacuum module continues to operate to extract the argon gas that is continuously delivering heat, allowing the crystal rod to quickly skip the oxygen donor formation stage. The delivery flow rate of the cold source is adjusted after the detection device in the secondary chamber detects that the temperature in the secondary chamber has rapidly dropped to 500°C.

[0094] In some embodiments, during the process of cooling the first sub-chamber to the second set temperature, the cooling rate is 500℃ / s-1000℃ / s, thereby achieving rapid cooling of the crystal rod and skipping the oxygen precipitation stage.

[0095] S60, input the cold source into the first sub-chamber at the second set flow rate until the first sub-chamber cools down to room temperature, then remove the crystal rod.

[0096] For example, after the sub-chamber temperature reaches 500°C, the liquid argon delivery flow rate is reduced to 100 lpm, and the vacuum module is turned off, allowing the sub-chamber to recover to atmospheric pressure of 540 torr with the replenishment of argon gas, and finally cooled to room temperature.

[0097] In some embodiments, during the cooling process of the first auxiliary chamber to room temperature, the cooling rate is 50°C / s-100°C / s, and it is eventually cooled to room temperature.

[0098] Finally, each clamp is reset in a controlled manner to release the upper end of the crystal rod, and the cover 122 at the bottom of the main body 121 is rotated open to complete the annealing operation of the crystal rod, and the annealed crystal rod is taken out from the lower opening of the main body 121.

[0099] Embodiments of this application also provide a silicon wafer manufactured using the ingot manufacturing process described in any of the above embodiments.

[0100] For example, the crystal rods produced by the crystal rod manufacturing process provided in the above embodiments are sliced ​​to obtain silicon wafers. The silicon wafers have low oxygen content, high single crystal quality, and the thickness of the silicon wafers can be significantly reduced without increasing the breakage rate. After being made into cells, this can effectively reduce light-induced degradation of the cells and improve conversion efficiency.

[0101] Embodiments of this application also provide a solar cell, which can be made from the silicon wafer provided in the above embodiments as a substrate.

[0102] The embodiments of this application also provide a stacked battery, including the solar cell and perovskite battery provided in the above embodiments, wherein the solar cell and perovskite battery are stacked.

[0103] The solar cells and tandem cells provided in this application have the silicon wafers of any of the above embodiments, and therefore have all the beneficial effects of the silicon wafers of any of the above embodiments, which will not be described in detail here.

[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A single crystal furnace, characterized in that, include: Main furnace chamber; The first and second auxiliary chambers are located above the main furnace chamber and are both arranged parallel to the direction of gravity. Each of the first and second auxiliary chambers includes a main body, a cover, and a heating assembly. The main body has a hollow structure and openings at both the top and bottom. The cover can open or seal the lower opening of the main body. The heating assembly is installed inside the main body. A seed crystal holder is positioned above the main furnace chamber; The cooling module is connected to the upper openings of the first and second sub-chambers, respectively.

2. The single crystal furnace according to claim 1, characterized in that, The cover is rotatably connected to the main body, and the cover rotates relative to the main body on the horizontal plane where the cover is located, or the cover flips up and down relative to the main body.

3. The single crystal furnace according to claim 1, characterized in that, The single crystal furnace also includes a base, and the first sub-chamber and the second sub-chamber are both rotatably mounted on the base; The base includes a column and a drive unit mounted on the column. One end of the drive unit is provided with a rotating shaft. The first sub-chamber and the second sub-chamber are respectively connected to the rotating shaft. The drive unit drives the first sub-chamber and the second sub-chamber to rotate relative to the column along the central axis of the rotating shaft.

4. The single crystal furnace according to claim 1, characterized in that, The heating assembly includes multiple laser heaters and a detection element. Each laser heater is circumferentially distributed along the central axis of the main body. The detection element is electrically connected to the laser heater and acquires the temperature inside the main body.

5. The single crystal furnace according to claim 4, characterized in that, The main body has multiple heating zones equidistantly distributed along its central axis, and each heating zone is provided with multiple laser heaters circumferentially.

6. The single crystal furnace according to claim 4, characterized in that, The heating power of the laser heater is less than or equal to 100W, and / or the laser spot of the laser heater is less than or equal to 9mm.

7. The single crystal furnace according to claim 1, characterized in that, The first and second sub-chambers further include a clamping member installed inside the main body and located at the end of the main body away from the cover.

8. The single crystal furnace according to claim 7, characterized in that, The clamping member includes multiple clamping blocks, each of which is circumferentially distributed along the central axis of the main body and rotates up and down relative to the main body.

9. A crystal rod manufacturing process, characterized in that, include: The single-crystal silicon ingot to be annealed is pulled and cut off after the ingot reaches the designated position in the first auxiliary chamber; The lower end of the first sub-chamber is sealed and pressed against both ends of the crystal rod, thus confining the crystal rod within the first sub-chamber. The first auxiliary chamber is moved away from the main furnace chamber, and the second auxiliary chamber is moved to the throat of the main furnace chamber for single-crystal silicon pulling. The first auxiliary chamber is evacuated to a set vacuum level, and then heated to a first set temperature. A cold source is introduced into the first auxiliary chamber at a first set flow rate until the temperature of the first auxiliary chamber drops to a second set temperature, at which point the vacuum module is turned off. A cold source is input into the first auxiliary chamber at a second set flow rate until the first auxiliary chamber is cooled to room temperature, and then the crystal rod is removed.

10. The crystal rod manufacturing process according to claim 9, characterized in that, The set vacuum level is ≤30 mtorr.

11. The crystal rod manufacturing process according to claim 9, characterized in that, The first set temperature is 1000℃-1200℃, and / or the second set temperature is 500℃.

12. The crystal rod manufacturing process according to claim 9, characterized in that, The first set flow rate is 200 lpm, and / or the second set flow rate is 100 lpm.

13. A silicon wafer, characterized in that, Made by the crystal rod manufacturing process according to any one of claims 9 to 12.

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