Silicon wafer drying method and silicon wafer drying device

Abstract

The embodiment of the invention provides a silicon wafer drying method and a silicon wafer drying device. The silicon wafer drying method comprises the following steps: placing a silicon wafer in a groove body; a groove cover is connected to the groove body in a sealed mode, and vacuumizing and heating operation is executed in the groove body in a staged mode so that the silicon wafer can be dried; wherein each vacuumizing stage corresponds to one target vacuum degree, and the target vacuum degrees of different stages are sequentially increased according to the execution sequence; in each vacuumizing stage, the corresponding target vacuum degree is maintained for at least preset time. According to the silicon wafer drying method, the boiling explosion phenomenon can be avoided, and the yield of the silicon wafers is greatly improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic processing technology, and specifically relates to a silicon wafer drying method and a silicon wafer drying device. Background Art

[0002] With the development of photovoltaic technology, silicon wafers are increasingly used. During the production process, silicon wafers need to be cleaned to remove impurities on the surface. After cleaning, the wafers need to be dried. Vacuum drying, as a low-energy and high-efficiency silicon wafer drying method, has attracted widespread attention.

[0003] In existing vacuum drying techniques, after placing the silicon wafer in a vacuum tank, the tank is sealed with a tank cover, and then the tank is evacuated and heated. Typically, during the heating process, the vacuum level within the tank is directly controlled to the target vacuum level (approximately -90 kPa). However, the high vacuum level causes a large amount of water on the silicon wafer to quickly reach its boiling point, which can easily cause a boiling explosion and shatter the wafer. Furthermore, thinner silicon wafers have a higher fragmentation rate, significantly reducing the wafer's yield rate. Summary of the Invention

[0004] The present application aims to provide a silicon wafer drying method and a silicon wafer drying device to solve the problem of high fragmentation rate in the existing silicon wafer drying process.

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, the present application discloses a method for drying a silicon wafer, the method comprising:

[0007] Place the silicon wafer in the tank;

[0008] The tank cover is sealed and connected to the tank body, and vacuuming and heating the tank body in stages to dry the silicon wafer;

[0009] Each vacuuming stage corresponds to a target vacuum degree, and the target vacuum degrees of different stages increase in sequence according to the execution order; in each vacuuming stage, the corresponding target vacuum degree is maintained for at least a preset time.

[0010] Optionally, the step of maintaining the corresponding target vacuum degree for at least a preset time in each vacuuming stage includes:

[0011] During the process of maintaining the corresponding target vacuum degree for at least a preset time in each vacuuming stage, if the difference between the real-time vacuum degree in the tank body and the target vacuum degree is greater than or equal to a first preset value, further vacuuming operation is performed on the tank body until the real-time vacuum degree in the tank body reaches the target vacuum degree.

[0012] Optionally, the first preset value is 2%-7% of the target vacuum degree.

[0013] Optionally, in the step of performing the vacuuming and heating operations in stages on the tank body, each vacuuming stage corresponds to a target heating temperature, and the target heating temperatures of different stages decrease in order of execution.

[0014] Optionally, the step of performing vacuuming and heating operations in stages on the tank body includes:

[0015] Performing a first stage of vacuuming and heating the tank body so that the real-time vacuum level in the tank body reaches a first target vacuum level and maintains the first target vacuum level for a first preset time period;

[0016] performing a second stage of vacuuming and heating the tank body so that the real-time vacuum degree in the tank body reaches a second target vacuum degree, and maintaining the second target vacuum degree for a second preset time period;

[0017] performing a third stage of vacuuming and heating the tank body so that the real-time vacuum degree in the tank body reaches a third target vacuum degree, and maintaining the third target vacuum degree for a third preset time period;

[0018] Among them, the first target vacuum degree is less than the second target vacuum degree, the second target vacuum degree is less than the third target vacuum degree, the second preset time length is greater than or equal to the first preset time length, and the first preset time length is greater than or equal to the third preset time length.

[0019] Optionally, the first target vacuum degree is -20 to -40 kPa, the second target vacuum degree is -30 to -70 kPa, and the third target vacuum degree is -40 to -101 kPa;

[0020] The first preset time length is 50 seconds to 100 seconds, the second preset time length is 80 seconds to 150 seconds, and the third preset time length is 50 seconds to 100 seconds.

[0021] Optionally, before the step of sealing the tank cover to the tank body and performing vacuuming and heating operations in stages in the tank body to dry the silicon wafer, the method further includes:

[0022] The silicon wafer is preheated.

[0023] Optionally, the step of preheating the silicon wafer includes:

[0024] Placing the tank cover on the tank body so that a gap is formed between the tank cover and the tank body;

[0025] The heating mechanism is started to heat the silicon wafer, and the swing mechanism is started to drive the silicon wafer to swing.

[0026] In a second aspect, the present application further discloses a silicon wafer drying device for performing any of the above-mentioned silicon wafer drying methods, wherein the silicon wafer drying device comprises: a tank body, a tank cover, a vacuuming mechanism, and a heating mechanism;

[0027] The tank cover is detachably connected to the tank body, and the tank body is used to accommodate silicon wafers;

[0028] The heating mechanism and the vacuuming mechanism are connected to the tank body or the tank cover, and the vacuuming mechanism and the heating mechanism are used to perform vacuuming and heating operations in stages in the tank body to dry the silicon wafer;

[0029] Each vacuuming stage corresponds to a target vacuum degree, and the target vacuum degrees of different stages increase in sequence according to the execution order; in each vacuuming stage, the corresponding target vacuum degree is maintained for at least a preset time.

[0030] Optionally, the silicon wafer drying device further includes: a swing mechanism, which is disposed in the tank body and is used to drive the silicon wafer to swing.

[0031] Optionally, the silicon wafer drying device further comprises a basket mounting rack, the basket mounting rack being disposed in the tank body and being used for mounting a basket containing the silicon wafers;

[0032] The swing mechanism includes a driving member and a swing rod, the swing rod is connected to the flower basket mounting frame, the driving member is connected to the swing rod, and the driving member is used to drive the swing rod to swing together with the flower basket mounting frame.

[0033] In an embodiment of the present application, during the vacuum drying process for drying the silicon wafer, vacuuming and heating operations can be performed in stages within the tank. Each vacuuming stage corresponds to a target vacuum level, and the target vacuum levels of different stages increase in the order in which they are performed. During each vacuuming stage, the target vacuum level is maintained for at least a predetermined time, and as much water vapor as possible is removed from the surface of the silicon wafer, thereby stabilizing the water vapor flow within the tank, preventing boiling explosions, and significantly improving the yield rate of the silicon wafer.

[0034] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0036] Figure 1 This is a flow chart of the steps of a silicon wafer drying method described in an embodiment of the present application;

[0037] Figure 2 This is a schematic structural diagram of a silicon wafer drying device according to an embodiment of the present application;

[0038] Figure 3 yes Figure 2 The schematic diagram of the structure of the silicon wafer drying tank at a certain angle is shown;

[0039] Figure 4 yes Figure 3 A top view of the tank body is shown.

[0040] Figure 5 yes Figure 3 The schematic diagram of the structure of the flower basket mounting frame and the swing mechanism in the trough body is shown.

[0041] Figure 6 yes Figure 5 The structural diagram of the swing mechanism is shown.

[0042] Figure 7 This is a flow chart of the steps of a silicon wafer drying method described in an embodiment of the present application;

[0043] Figure 8 yes Figure 7 The process setting principle diagram of the silicon wafer drying method is shown.

[0044] Figure numerals: 10 - trough body, 11 - trough cover, 12 - heating mechanism, 13 - swing mechanism, 131 - driving member, 132 - swing rod, 133 - connecting rod, 134 - connecting pin, 14 - vacuum pumping mechanism, 15 - vacuum breaking mechanism, 16 - flower basket mounting frame, 161 - bracket connecting member, 20 - flower basket. DETAILED DESCRIPTION

[0045] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of this application.

[0046] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly refer to one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. Furthermore, the term "and / or" in the specification and claims refers to at least one of the connected entities, and the character " / " generally indicates an "or" relationship between the connected entities.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0048] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0049] Reference Figure 1 , shows a flow chart of the steps of a silicon wafer drying method according to an embodiment of the present application, such as Figure 1 As shown, the silicon wafer drying method may specifically include:

[0050] Step 101: Place the silicon wafer in the tank.

[0051] In the embodiment of the present application, the silicon wafer drying method can be used in a silicon wafer drying device, and the silicon wafer drying device can be a vacuum drying tank. Figure 2 As shown, the silicon wafer drying device may include a tank body 10 and a tank cover 11. The tank cover 11 is detachably connected to the tank body 10. The tank body 10 has a storage space for accommodating silicon wafers. When the silicon wafers need to be dried, the tank cover 11 can be removed from the tank body 10 and the silicon wafers can be placed in the tank body 10.

[0052] Step 102: Seal the tank cover 11 to the tank body 10, and perform vacuuming and heating operations in the tank body 10 in stages to dry the silicon wafer; wherein each vacuuming stage corresponds to a target vacuum degree, and the target vacuum degrees of different stages increase in sequence according to the execution order; in each vacuuming stage, maintain the corresponding target vacuum degree for at least a preset time.

[0053] Specifically, after the silicon wafer is placed in the trough body 10, the trough cover 11 can be covered on the trough body 10 and sealed to the trough body 10 to form a sealed space in the trough body 10, so as to facilitate the vacuum operation of the sealed space in the trough body 10.

[0054] In the embodiment of the present application, during the process of drying the silicon wafers using a vacuum drying process, vacuuming and heating operations can be performed in stages within the tank body 10. Each vacuuming stage corresponds to a target vacuum level, and the target vacuum levels of different stages increase in sequence according to the execution order. During each vacuuming stage, the corresponding target vacuum level is maintained for at least a preset time, and as much water vapor as possible is discharged from the surface of the silicon wafer, so that the water vapor flow within the tank body 10 is more stable, the occurrence of boiling explosions is avoided, and the yield rate of the silicon wafers is greatly improved.

[0055] For example, during the vacuum drying process, when the final target vacuum degree needs to be controlled at -90kPa, it can be increased to -90kPa in a plurality of stages. For example, the first stage of vacuuming and heating can be performed first, and the vacuum degree in the tank body 10 is controlled to -30kPa, and maintained for a period of time, so as to discharge as much water vapor as possible from the surface of the silicon wafer at this vacuum degree; then, the second stage of vacuuming and heating can be performed, and the vacuum degree in the tank body 10 is controlled to -50kPa, and maintained for a period of time, so as to discharge as much water vapor as possible from the surface of the silicon wafer at this vacuum degree; and then the vacuuming and heating operations can be performed in a plurality of stages until the vacuum degree in the tank body 10 is finally increased to -90kPa. At this time, since more water vapor is discharged from the surface of the silicon wafer in the previous stages, less water vapor needs to be discharged in this final stage, and the airflow of water vapor discharge is more uniform, which can avoid the phenomenon of boiling explosion.

[0056] It should be noted that, in specific applications, the vacuuming and heating operations in the tank body 10 can be divided into 2, 3, 5, 6 or 8 stages. The embodiment of the present application does not specifically limit the number of the above stages.

[0057] Optionally, the step of maintaining the corresponding target vacuum degree for at least a preset time in each vacuum pumping stage may include: in the process of maintaining the corresponding target vacuum degree for at least a preset time in each vacuum pumping stage, when the difference between the real-time vacuum degree in the tank body 10 and the target vacuum degree is greater than or equal to a first preset value, performing further vacuum pumping operation on the tank body 10 until the real-time vacuum degree in the tank body 10 reaches the target vacuum degree, so as to discharge as much water vapor as possible from the surface of the silicon wafer at the target vacuum degree.

[0058] In a specific application, during each vacuuming stage, while maintaining the target vacuum level for that stage to dry the silicon wafer, as the water vapor on the surface of the silicon wafer is further extracted, the real-time vacuum level within the tank body 10 will decrease, resulting in a poorer drying effect on the silicon wafer. In the embodiment of the present application, when the difference between the real-time vacuum level and the target vacuum level within the tank body 10 is greater than or equal to a first preset value, it can be considered that the drying effect of the silicon wafer is poor. In this case, a vacuuming operation can be further performed so that during the vacuuming stage, the target vacuum level corresponding to that stage can be maintained as much as possible to dry the silicon wafer, thereby removing as much water vapor as possible from the surface of the silicon wafer.

[0059] Optionally, the first preset value is 2%-7% of the target vacuum level, and its specific value can be set according to actual conditions. For example, if the first preset value is 5% of the target vacuum level, during each vacuuming stage, if the real-time vacuum level within the tank body 10 decreases by 5% of the corresponding target vacuum level, the vacuuming operation needs to be performed again until the real-time vacuum level within the tank body 10 reaches the target vacuum level, so as to remove as much water vapor as possible from the surface of the silicon wafer at the target vacuum level.

[0060] For example, when the target vacuum degree corresponding to a certain vacuum pumping stage is -50 kPa, while maintaining the target vacuum degree to dry the silicon wafer, if it is detected that the vacuum degree in the tank body 10 drops to -47.5 kPa, the vacuum pumping operation needs to be performed again until the real-time vacuum degree in the tank body 10 reaches -50 kPa.

[0061] It should be noted that, in actual applications, those skilled in the art may further set a specific value of the first preset value according to actual needs. For example, the first preset value may be 2%, 2.5%, 2.8%, 4%, or 6% of the target vacuum degree. This embodiment of the present application does not specifically limit this.

[0062] In the embodiment of the present application, when the temperature in the tank 10 is lower than 70 DEG C, it is difficult to dry the moisture on the surface of the silicon wafer due to the low temperature, and a large number of wet wafers exist, which is poor for the drying effect of the silicon wafer. When the temperature in the tank 10 is higher than 90 DEG C, the vacuum drying process will not have the advantage of low energy consumption due to the high temperature. Therefore, in the embodiment of the present application, the temperature in the tank 10 can be controlled between 70 DEG C and 90 DEG C during the whole process of vacuumizing and heating, so as to balance the drying effect and the drying energy consumption.

[0063] Optionally, in the step of performing the vacuumizing and heating operations in the tank in stages, each vacuumizing stage corresponds to a target heating temperature, and the target heating temperatures of different stages decrease in turn according to the execution order.

[0064] In actual application, the higher the vacuum degree in the tank 10 is, the lower the boiling point of the moisture in the tank 10 is. Since the target vacuum degrees of different stages increase in turn according to the execution order, in order to avoid the boiling explosion of the silicon wafer due to the boiling point reached in a short time, the target heating temperatures of different stages should decrease in turn according to the execution order. In this way, on the one hand, the boiling explosion of the silicon wafer can be avoided, and on the other hand, the energy consumption of the silicon wafer drying can be reduced, so as to reduce the drying cost of the silicon wafer.

[0065] For example, the target heating temperatures of different stages can be 80 DEG C, 78 DEG C, 76 DEG C, 75 DEG C and 70 DEG C in turn, which is not limited in the embodiment of the present application.

[0066] In summary, the silicon wafer drying method in the embodiment of the present application can at least have the following advantages:

[0067] In the embodiment of the present application, during the process of drying the silicon wafer by the vacuum drying process, the vacuumizing and heating operations in the tank can be performed in stages. Each vacuumizing stage corresponds to a target vacuum degree, and the target vacuum degrees of different stages increase in turn according to the execution order. In each vacuumizing stage, the corresponding target vacuum degree is maintained for at least a preset time, so as to discharge as much moisture vapor on the surface of the silicon wafer as possible, so that the moisture vapor flow in the tank is more stable, and the boiling explosion phenomenon is avoided, which greatly improves the yield of the silicon wafer.

[0068] Referring to Figure 7 , a step flow chart of another silicon wafer drying method in the embodiment of the present application is shown, as Figure 7 shown, the silicon wafer drying method can specifically include:

[0069] Step 701: placing a silicon wafer in a tank.

[0070] In the embodiments of the present application, the specific operation of step 701 can refer to step 101 in the foregoing embodiments, and will not be repeated here.

[0071] Step 702: Preheat the silicon wafer.

[0072] In the embodiments of the present application, before the operation of vacuumizing the tank body 10, the silicon wafer can be preheated to reduce the moisture in the tank body 10, so as to reduce the moisture to be removed in the vacuumizing stage, and further avoid the phenomenon of boiling explosion.

[0073] In some optional embodiments of the present application, the step of preheating the silicon wafer can include the following sub-steps:

[0074] Sub-step S11: Place the tank cover above the tank body, and form a gap between the tank cover and the tank body.

[0075] In specific applications, after the silicon wafer is placed in the tank body 10, the tank cover 11 can be placed above the tank body 10, and a gap can be formed between the tank cover 11 and the tank body 10, so that the water vapor can flow out of the gap during the subsequent preheating process, avoiding the risk of silicon wafer boiling explosion caused by the water vapor remaining in the tank body 10 during the preheating process.

[0076] Specifically, in the case where the width of the gap is less than 20 mm, it is not conducive to the discharge of water vapor. In the case where the width of the gap is greater than 30 mm, the connection between the tank cover 11 and the tank body 10 is not very stable, and the risk of the tank cover 11 falling off is easy to occur. Therefore, the width of the gap can be 20-30 mm, so that the water vapor can flow out of the gap, and at the same time, the tank cover 11 can be reliably connected to the tank body 10.

[0077] Sub-step S12: Start the heating mechanism to heat the silicon wafer, and start the swing mechanism to drive the silicon wafer to swing.

[0078] In specific applications, after the tank cover 11 covers the tank body 10, the heating mechanism 12 located in the tank body 10 can be started to heat the silicon wafer. The water vapor generated during the heating process will flow out of the gap between the tank body 10 and the tank cover 11, reducing the water molecules in the tank body 10. At the same time, the swing mechanism 13 connected to the tank body 10 can be started, and the swing mechanism 13 drives the silicon wafer to swing, so that the silicon wafer is uniformly and quickly heated, thereby accelerating the movement of water molecules and quickly discharging the water vapor formed on the surface of the silicon wafer.

[0079] Step 703: Seal and connect the tank cover to the tank body, and perform the first stage of vacuumizing and heating operation on the tank body, so that the real-time vacuum degree in the tank body reaches the first target vacuum degree, and maintains the first target vacuum degree for a first preset time length.

[0080] In the embodiment of the present application, the vacuuming and heating stages can be divided into three stages. Specifically, after preheating the silicon wafer, the silicon wafer can be rotated to a horizontal state by the swing mechanism 13, and the swing mechanism 13 is closed. Then, the tank cover 11 is closed, the gap between the tank cover 11 and the tank body 10 is eliminated, the tank cover 11 is sealed and connected to the tank body 10, and preparations for the vacuuming operation are made. Finally, the vacuuming mechanism 14 is started to perform the first stage of the vacuuming operation in the tank body 10. Specifically, the vacuuming mechanism 14 may include a vacuum pump, a pipe connecting the vacuum pump, and a corresponding vacuum detection instrument, etc. The embodiment of the present application does not limit the specific content of the vacuuming mechanism 14.

[0081] Specifically, during the first stage of vacuuming and heating the tank body 10, the heating temperature can be lower than the boiling point of water at normal atmospheric pressure, and the real-time vacuum level within the tank body 10 can reach a first target vacuum level and maintain the first target vacuum level for a first preset time period. If the real-time vacuum level within the tank body 10 drops by 5% of the first target vacuum level, the vacuuming operation needs to be performed again to gradually discharge as much water vapor as possible from the tank body 10.

[0082] For example, the first preset vacuum degree may be -20 to -40 kPa, and the first preset duration may be 50 seconds to 100 seconds. Preferably, the first preset vacuum degree may be -20 kPa, -30 kPa, -32 kPa, or -40 kPa, and the first preset duration may be 50 seconds, 60 seconds, 80 seconds, or 100 seconds, etc.

[0083] Step 704: performing a second stage of vacuuming and heating operations on the tank body, so that the real-time vacuum degree in the tank body reaches a second target vacuum degree, and the second target vacuum degree is maintained for a second preset time period.

[0084] In a specific application, after completing the first stage of vacuuming and heating, the tank body 10 can be subjected to a second stage of vacuuming and heating. During the second stage of vacuuming and heating, the heating temperature can be lower than the boiling point of water at normal atmospheric pressure. The real-time vacuum level within the tank body 10 can reach a second target vacuum level and be maintained at the second target vacuum level for a second preset duration. If the real-time vacuum level within the tank body 10 drops below 5% of the second target vacuum level, the vacuuming operation needs to be performed again to gradually expel as much water vapor as possible from the tank body 10.

[0085] For example, the second preset vacuum degree may be -30 to -70 kPa, and the first preset time length may be 80 seconds to 150 seconds. Preferably, the second preset vacuum degree may be -30 kPa, -40 kPa, -60 kPa, and -70 kPa, etc., and the second preset time length may be 80 seconds, 100 seconds, 120 seconds, or 150 seconds, etc.

[0086] Step 705: performing a third stage of vacuuming and heating operations on the tank body, so that the real-time vacuum degree in the tank body reaches a third target vacuum degree, and the third target vacuum degree is maintained for a third preset time period.

[0087] In a specific application, after completing the second stage of vacuuming and heating operations, the tank body 10 can be subjected to the third stage of vacuuming and heating operations. During the third stage of vacuuming and heating operations on the tank body 10, the heating temperature can exceed the boiling point of water at the vacuum level to evaporate the remaining small amount or residual water. The real-time vacuum level in the tank body 10 can reach a third target vacuum level and maintain the third target vacuum level for a third preset time. In the case where the real-time vacuum level in the tank body 10 is reduced by 5% of the third target vacuum level, it is necessary to perform the vacuuming operation again so that the water vapor in the tank body 10 can be gradually discharged as much as possible.

[0088] Optionally, during the third stage of vacuuming and heating, the swing mechanism 13 can be activated to separate the contact area between the silicon wafer and the flower basket 20, remove residual moisture there, and achieve uniform heating of the silicon wafer to improve the overall drying effect.

[0089] For example, the third preset vacuum degree may be -40 to -101 kPa, and the first preset time length may be 50 seconds to 100 seconds.

[0090] Preferably, the third preset vacuum degree may be -40 kPa, -60 kPa, -70 kPa, -101 kPa, etc., and the third preset time length may be 50 seconds, 55 seconds, 70 seconds, or 100 seconds, etc.

[0091] Optionally, the first preset time and the second preset time can be greater than or equal to the third preset time, so that the moisture on the silicon wafer can be discharged as much as possible in the first two vacuuming and heating stages. Since the vacuum degree of the first two vacuuming stages is lower than the vacuum degree of the third vacuuming stage, allowing the moisture on the silicon wafer to be discharged as much as possible in the first two vacuuming stages can effectively avoid the risk of boiling and exploding of the silicon wafer. Moreover, since the vacuum degree of the second stage is higher, the efficiency of moisture discharge is higher, and the second preset time can be greater than or equal to the first preset time to improve the drying efficiency. That is, the second preset time is greater than or equal to the first preset time, and the first preset time is greater than or equal to the third preset time.

[0092] Step 706: performing a vacuum breaking operation on the tank body.

[0093] In a specific application, after the silicon wafer is dried, the vacuum breaking mechanism 15 connected to the tank body 10 can be opened to ventilate the tank body 10 to break the vacuum. After the vacuum is broken, the tank cover 11 can be opened to take out the silicon wafer, completing the entire silicon wafer drying process.

[0094] During the implementation of the silicon wafer drying method described in the examples of this application, the inventors set up three process schemes as shown in Table 1 and applied them to silicon wafers of different specifications. The fragmentation rates are shown in Table 2. Vacuum 1 represents the first stage of vacuuming and heating operations, Vacuum 2 represents the second stage of vacuuming and heating operations, and Vacuum 3 represents the third stage of vacuuming and heating operations. The vacuum level in the table represents the target vacuum level for each stage, and the temperature represents the target heating temperature.

[0095] Table 1 Process scheme and its corresponding process parameters

[0096]

[0097] Table 2. Fragmentation rates of silicon wafers of different sizes obtained by different processes

[0098]

[0099] As can be seen from Tables 1 and 2, the application of Scheme 1, Process 2, and Process 3 of this case to silicon wafers of different specifications can significantly reduce the fragmentation rate of silicon wafers. Moreover, compared with Scheme 1 and Scheme 3 of this case, Scheme 2 of this case has a greater reduction in the fragmentation rate. That is, when the first target vacuum degree is -30 to -40 kPa, the second target vacuum degree is -60 to -70 kPa, and the third target vacuum degree is -70 to -90 kPa, and the vacuuming and heating operations are performed in stages in the tank body, and the target heating temperatures of different stages decrease in the order of execution, the fragmentation rate of the silicon wafer is reduced the most and the drying effect is the best.

[0100] Figure 8 The schematic diagram of the process setting of the existing silicon wafer drying method and the embodiment of the present application is shown. Figure 8 As shown, during the vacuum drying process of the prior art (current design point), the pressure in the tank body decreases in a straight line (i.e., the vacuum degree increases in a straight line). In the subsequent stage of vacuum drying, it enters the gas phase region and the temperature is increasingly distant from the gas-liquid equilibrium line, making it easy for boiling explosions to occur. In Experiments 1 and 2 in the embodiments of the present application, the preheating stage and the first vacuum stage contain more water, and the temperature is set slightly higher, close to the gas-liquid equilibrium line, and lower than the boiling point temperature (i.e., the preheating stage and the first vacuum stage are located in the liquid phase region). In this way, it is possible to prevent the boiling point of water from being reached in a short time during the vacuuming process, causing boiling explosions and resulting in fragments. The second vacuum stage is close to the boiling point (located on the gas-liquid equilibrium line), which accelerates drying. The third vacuum stage exceeds the boiling point and enters the gas phase region, evaporating the remaining small amount or residual water to thoroughly dry the silicon wafer.

[0101] The present application also provides a Figures 2 to 6 The silicon wafer drying device shown can be used to perform the silicon wafer drying method described in any of the above embodiments. The silicon wafer drying device specifically includes: a trough body 10, a trough cover 11, a vacuuming mechanism 14, and a heating mechanism 12. The trough cover 11 is detachably connected to the trough body 10, and the trough body 10 can be used to accommodate silicon wafers. The heating mechanism 12 and the swing mechanism 13 are at least partially disposed within the trough body 10, and the heating mechanism 12 can be used to heat the silicon wafers. The vacuuming mechanism 14 is connected to the trough body 10 or the trough cover 11, and can be used to perform a vacuum operation within the trough body 10. During the drying process of the silicon wafers, the vacuuming mechanism 14 and the heating mechanism 12 can be used to perform vacuuming and heating operations within the trough body in stages to dry the silicon wafers. Each vacuuming stage corresponds to a target vacuum level, and the target vacuum levels of different stages increase in order of execution. In each vacuuming stage, the corresponding target vacuum level is maintained for at least a preset time.

[0102] In the embodiment of the present application, during the vacuum drying process for drying the silicon wafers, the vacuuming mechanism 14 and the heating mechanism 12 can perform vacuuming and heating operations in the tank body 10 in stages. Each vacuuming stage corresponds to a target vacuum level, and the target vacuum levels of different stages increase in sequence according to the execution order. In each vacuuming stage, the corresponding target vacuum level is maintained for at least a preset time, and as much water vapor as possible is discharged from the surface of the silicon wafer, so that the water vapor flow in the tank body is more stable, the occurrence of boiling explosion is avoided, and the yield rate of the silicon wafer is greatly improved.

[0103] Optionally, the silicon wafer drying device may further include a swing mechanism 13 , which is disposed in the tank body 10 , and may be used to drive the silicon wafer to swing.

[0104] In specific applications, during the preheating or vacuuming process, the swing mechanism 13 can be used to drive the silicon wafer to swing, so as to achieve uniform heating of the silicon wafer, accelerate the movement of water molecules, quickly discharge the water vapor formed on the surface of the silicon wafer, and improve the overall drying effect.

[0105] Optionally, the silicon wafer drying device may further include a basket mounting frame 16, which is disposed in the tank body 10 and may be used to mount a basket 20 containing the silicon wafers. Figure 5 and Figure 6 As shown, the swing mechanism 13 may include a driving member 131 and a swing rod 132. The swing rod 132 is connected to the flower basket mounting frame 16. The driving member 131 is connected to the swing rod 132. The driving member 131 can be used to drive the swing rod 132 to swing together with the flower basket mounting frame 16, so as to drive the flower basket 20 and the silicon wafers in the flower basket 20 to swing together.

[0106] Optionally, the flower basket mounting frame 16 may be provided with a bracket connector 161. The swing mechanism 13 may further include a connecting rod 133 and a connecting pin 134, with the connecting pin 134 connected to the bracket connector 161. One end of the connecting rod 133 is connected to the driving member 131, and the other end of the connecting rod 133 is rotatably connected to the connecting pin 134. The driving member 131 can be used to drive the connecting rod 133 to rotate, thereby driving the flower basket mounting frame 16 to rotate.

[0107] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0108] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A silicon wafer drying method, characterized in that: The silicon wafer drying method comprises: Place the silicon wafer in the tank; The tank cover is sealed and connected to the tank body, and vacuuming and heating the tank body in stages to dry the silicon wafer; Each vacuuming stage corresponds to a target vacuum degree, and the target vacuum degrees of different stages increase in sequence according to the execution order; in each vacuuming stage, the corresponding target vacuum degree is maintained for at least a preset time.

2. The silicon wafer drying method according to claim 1, wherein: The step of maintaining the corresponding target vacuum degree for at least a preset time in each vacuuming stage includes: During the process of maintaining the corresponding target vacuum degree for at least a preset time in each vacuuming stage, if the difference between the real-time vacuum degree in the tank body and the target vacuum degree is greater than or equal to a first preset value, further vacuuming operation is performed on the tank body until the real-time vacuum degree in the tank body reaches the target vacuum degree.

3. The silicon wafer drying method according to claim 2, wherein: The first preset value is 5% of the target vacuum degree.

4. The silicon wafer drying method according to claim 1, wherein: In the step of performing the vacuuming and heating operations in stages on the tank body, each vacuuming stage corresponds to a target heating temperature, and the target heating temperatures of different stages decrease in order of execution.

5. The silicon wafer drying method according to claim 1, wherein: The step of performing vacuuming and heating operations in stages within the tank body comprises: Performing a first stage of vacuuming and heating the tank body so that the real-time vacuum degree in the tank body reaches a first target vacuum degree, and maintaining the first target vacuum degree for a first preset time period; performing a second stage of vacuuming and heating the tank body so that the real-time vacuum degree in the tank body reaches a second target vacuum degree, and maintaining the second target vacuum degree for a second preset time period; performing a third stage of vacuuming and heating the tank body so that the real-time vacuum degree in the tank body reaches a third target vacuum degree, and maintaining the third target vacuum degree for a third preset time period; Among them, the first target vacuum degree is less than the second target vacuum degree, the second target vacuum degree is less than the third target vacuum degree, the second preset time length is greater than or equal to the first preset time length, and the first preset time length is greater than or equal to the third preset time length.

6. The silicon wafer drying method according to claim 1, characterized in that: Before the step of sealing the tank cover to the tank body and performing vacuuming and heating operations in stages on the tank body to dry the silicon wafer, the method further includes: The silicon wafer is preheated.

7. The silicon wafer drying method according to claim 6, characterized in that: The step of preheating the silicon wafer comprises: Placing the tank cover on the tank body so that a gap is formed between the tank cover and the tank body; The heating mechanism is started to heat the silicon wafer, and the swing mechanism is started to drive the silicon wafer to swing.

8. A silicon wafer drying device, used to perform the silicon wafer drying method according to any one of claims 1 to 7, characterized in that: The silicon wafer drying device comprises: a tank body, a tank cover, a vacuuming mechanism and a heating mechanism; The tank cover is detachably connected to the tank body, and the tank body is used to accommodate silicon wafers; The heating mechanism and the vacuuming mechanism are connected to the tank body or the tank cover, and the vacuuming mechanism and the heating mechanism are used to perform vacuuming and heating operations in stages in the tank body to dry the silicon wafer; Each vacuuming stage corresponds to a target vacuum degree, and the target vacuum degrees of different stages increase in sequence according to the execution order; in each vacuuming stage, the corresponding target vacuum degree is maintained for at least a preset time.

9. The silicon wafer drying device according to claim 8, characterized in that: The silicon wafer drying device further includes a swing mechanism, which is disposed in the tank body and is used to drive the silicon wafer to swing.

10. The silicon wafer drying device according to claim 9, characterized in that: The silicon wafer drying device further comprises a basket mounting frame, which is disposed in the tank body and is used to mount a basket containing the silicon wafers. The swing mechanism includes a driving member and a swing rod, the swing rod is connected to the flower basket mounting frame, the driving member is connected to the swing rod, and the driving member is used to drive the swing rod to swing together with the flower basket mounting frame.

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