Silicon wafer cutting method and silicon wafer

Abstract

The invention discloses a silicon wafer cutting method and a silicon wafer, relates to the technical field of silicon wafer cutting, and is used for reducing the damage of a cutting line to the silicon wafer in a material lifting process. The silicon wafer cutting method comprises the following steps: providing a silicon rod and a carrier plate; the silicon rod is driven to move downwards relative to the cutting line, so that the silicon rod is cut by the cutting line to obtain a plurality of silicon wafers; the silicon wafer is lifted up relative to the cutting line, and the motion mode of the cutting line in the carrier plate is different from the motion mode of the cutting line after the cutting line is separated from the carrier plate.

Description

[0001] This application claims the priority of the Chinese patent filed with the China Patent Office on July 1, 2024, with application number 202410873767.9 and invention name “A method for cutting silicon wafers”, all contents of which are incorporated by reference in this application. Technical Field

[0002] The present invention relates to the technical field of silicon wafer cutting, and in particular to a silicon wafer cutting method and a silicon wafer. Background Art

[0003] In the silicon wafer cutting process, generally speaking, the silicon rod needs to be bonded to the lower surface of the carrier, and the carrier is bonded to the lower surface of the crystal tray. Generally, a driving mechanism is used to drive the crystal tray to drive the silicon rod to move from top to bottom relative to the cutting line, so that the cutting line cuts the silicon rod and forms multiple silicon wafers. After that, the material needs to be lifted. Specifically, the driving mechanism drives the crystal tray to move upward, and synchronously drives the silicon wafer to rise relative to the cutting line. At the same time, the cutting line moves to separate the silicon wafer from the cutting line.

[0004] However, with the existing material feeding method, the wire breakage rate of the cutting line needs to be further reduced, and the defective rate of silicon wafers produced is relatively high. Summary of the invention

[0005] The object of the present invention is to provide a silicon wafer cutting method and a silicon wafer, which are used to reduce the breakage of the cutting line and the damage of the cutting line to the silicon wafer during the material extraction process.

[0006] In order to achieve the above object, in a first aspect, the present invention provides a silicon wafer cutting method, comprising:

[0007] Provide silicon rods and carrier plates;

[0008] Driving the silicon rod to move downward relative to the cutting line so that the cutting line cuts the silicon rod to obtain a plurality of silicon wafers;

[0009] The silicon wafer is lifted upward relative to the cutting line, and the movement mode of the cutting line within the carrier is different from the movement mode of the cutting line after it is separated from the carrier.

[0010] When the above technical solution is adopted, in the process of lifting the silicon wafer upward relative to the cutting line, the movement mode of the cutting line in the carrier is different from the movement mode of the cutting line after it is separated from the carrier. Due to the different materials of the carrier and the silicon wafer, as well as the different requirements for the protection of the carrier and the protection quality of the silicon wafer, a more suitable movement mode of the cutting line is selected according to the actual lifting environment of the cutting line in the carrier and between the silicon wafers, so as to ensure that the damage of the cutting line to the silicon wafer is reduced.

[0011] In a possible implementation, the movement mode of the cutting line in the carrier plate and the movement mode of the cutting line after the cutting line is separated from the carrier plate are different, including: determining that the cutting line is in the carrier plate, the cutting line performs a winding movement or a paying-out movement; determining that the cutting line is separated from the carrier plate, the cutting line alternately performs a winding movement and a paying-out movement.

[0012] When the above technical solution is adopted, when the cutting line is located in the carrier, the cutting line only performs unidirectional movement of winding or unwinding. At this time, the cutting line will not swing back and forth in the horizontal direction perpendicular to the surface of the silicon wafer, so that the cutting line always remains in the position where the carrier is cut during the cutting process, that is, the cutting line will not be biased towards any of the two adjacent silicon wafers. In this way, in the process of lifting the silicon wafer upward relative to the cutting line, the cutting line is not easy to hang on the side of the silicon wafer bonded to the carrier. Furthermore, the cutting line is effectively reduced from being broken or the silicon wafer falling as the silicon wafer is lifted. In addition, since the carrier does not have high requirements for protection, the unidirectional movement method is selected to reduce unnecessary switching of movement directions and improve the lifting efficiency of the cutting line in the carrier. Next, in the process of lifting the cutting line from the carrier to the silicon wafer, the cutting line alternately performs the winding movement and the unwinding movement, and the side of the cutting line entering relative to the silicon wafer changes as the cutting line movement direction changes. In this way, the large bow of the cutting line caused by the cutting line entering only from one side of the silicon wafer can be reduced, the friction force of the cutting line on the silicon wafer is large, and the cutting line is not easy to separate the surfaces of two adjacent silicon wafers away from the side where the cutting line enters, thereby reducing the scratches, bright lines and even silicon wafer falling caused by the friction of the cutting line, which is difficult to be separated by the cutting line due to the large suction force. In addition, when the cutting line is located between two adjacent silicon wafers, the winding and unwinding movements are performed alternately, and the cutting line will swing back and forth in the horizontal direction perpendicular to the surface of the silicon wafer. At this time, the cutting line can be prevented from being in contact with any of the two adjacent silicon wafers. At the same time, during the horizontal swinging of the cutting line, it is out of contact with the silicon wafer, thus shortening the contact time between the cutting line and the silicon wafer, reducing the friction on the silicon wafer, reducing the phenomenon of scratches on the surface of the silicon wafer, and reducing the breakage of the cutting line and the damage of the cutting line to the silicon wafer.

[0013] In a second aspect, the present invention further provides a silicon wafer, the silicon wafer having a first set of opposite sides and a second set of opposite sides, the first set of opposite sides including a first side and a second side arranged oppositely, the second set of opposite sides including a third side and a fourth side arranged oppositely, wherein the first side and / or the second side intersects with the third side and / or the fourth side;

[0014] The surface of the silicon wafer has two groups of scratches, one group of scratches is inclined toward the third side in a first direction, and the other group of scratches is inclined toward the fourth side in the first direction, and the first direction is the direction from the first side to the second side.

[0015] In the case of adopting the above technical solution, the two groups of scratches on the surface of the silicon wafer are formed by the cutting line scratching the silicon wafer when the silicon wafer is lifted upward relative to the cutting line, wherein one group of scratches is formed by randomly scratching the surface of the silicon wafer when the cutting line runs in one direction, and the other group of scratches is formed by randomly scratching the surface of the silicon wafer when the cutting line runs in another opposite direction. Therefore, one group of scratches is inclined toward the third side of the silicon wafer in the first direction, and the other group of scratches is inclined toward the fourth side of the silicon wafer opposite to the third side in the first direction. Since the cutting and slicing operations of the silicon wafer are performed according to the silicon wafer cutting method in this application, the phenomenon of scratches on the surface of the silicon wafer is weakened, and the damage caused to the silicon wafer by the cutting line is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 A schematic diagram of the steps of a silicon wafer cutting method provided by an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the positional relationship between the silicon rod and the cutting wire during the process of the cutting wire cutting the silicon rod;

[0019] Figure 3 When the silicon wafer obtained by cutting the silicon rod is lifted upward relative to the cutting line, the cutting line is partially located inside the carrier, and the positional relationship between the silicon wafer and the cutting line is shown;

[0020] Figure 4 A schematic diagram of the positional relationship between the silicon wafer and the cutting line when the silicon wafer obtained by cutting the silicon rod is lifted upward relative to the cutting line and the cutting line is separated from the carrier;

[0021] Figure 5 A local structural diagram showing a first group of scratches on a silicon wafer provided by an embodiment of the present invention;

[0022] Figure 6 A partial structural diagram showing a second group of scratches on a silicon wafer provided in an embodiment of the present invention.

[0023] Reference numerals:

[0024] 1-silicon rod, 2-silicon wafer, 21-first group of scratches, 22-second group of scratches, 23-cutting line marks, 201-first edge, 202-second edge, 203-third edge, 204-fourth edge, 3-carrier, 4-cutting line, 5-driving roller, 6-crystal support. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] It should be noted that, in the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] First of all, it should be noted that see Figure 2 and Figure 4 As shown, the winding or unwinding movement of the cutting wire 4 is driven by the driving roller 5. In specific implementation, one end of the cutting wire 4 is wound from the surface of the first driving roller 5 to the surface of the second driving roller 5, then to the surface of the third driving roller 5, and then to the surface of the first driving roller 5, so as to form a cutting wire net in this winding manner.

[0029] See also Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a silicon wafer cutting method, comprising the following steps:

[0030] Step S100, providing a silicon rod 1 and a carrier plate 3;

[0031] The silicon rod 1 is directly connected to the carrier plate 3. First, the carrier plate 3 of the corresponding size is selected according to the size of the silicon rod 1 to be cut. Figure 1 As shown, the silicon rod is bonded to the lower surface of the wafer support 6 through the carrier 3. In specific implementation, the carrier 3 can be a resin plate or a plastic plate, and the thickness of the carrier 3 can be selected according to actual conditions, which is not specifically limited here.

[0032] Step S200, driving the silicon rod 1 to move downward relative to the cutting line 4, so that the cutting line 4 cuts the silicon rod 1 to obtain a plurality of silicon wafers 2;

[0033] In step S300, the silicon wafer 2 is lifted upward relative to the cutting line 4, and the movement mode of the cutting line 4 in the carrier 3 is different from the movement mode of the cutting line 4 after it is separated from the carrier 3. It should be noted that the movement mode of the cutting line 4 actually refers to the routing direction of the cutting line, that is, the cutting line only performs a unidirectional movement of the winding movement or the unwinding movement, or alternately performs a bidirectional movement of the winding movement and the unwinding movement.

[0034] It should be noted that, in the process of driving the silicon rod 1 to move downward relative to the cutting line 4 so that the cutting line 4 cuts the silicon rod 1 to obtain multiple silicon wafers 2, since the cutting line 4 has a line bow in the cutting state, it is necessary to cut the cutting line 4 into the carrier 3 when cutting to the rear end of the silicon rod (the carrier 3 acts as a sacrificial plate at this time) so that the silicon rod 1 is completely cut through and multiple silicon wafers are independent of each other. The cutting through state at this time refers to the state in which the silicon wafers 2 are independent of each other and the cutting line 4 is in the gap between the silicon wafers 2. Based on this, there are two movement modes in the material lifting process, namely, the cutting line 4 is located in the carrier 3 and the cutting line 4 is separated from the carrier 3.

[0035] In this way, in the process of lifting the silicon wafer upward relative to the cutting line, the movement mode of the cutting line in the carrier is different from the movement mode of the cutting line after it is separated from the carrier. Due to the different materials of the carrier and the silicon wafer, and the different requirements for the protection of the carrier and the protection quality of the silicon wafer, a more suitable movement mode of the cutting line is selected according to the actual lifting environment of the cutting line in the carrier and between the silicon wafers. In actual conditions, the movement mode of the cutting line in the carrier and the movement mode of the cutting line after it is separated from the carrier are selected to ensure that the damage to the silicon wafer caused by the cutting line is reduced. In one example, the movement mode of the cutting line 4 in the carrier 3 and the movement mode of the cutting line 4 after it is separated from the carrier 3 in step S300 are different, and specifically include the following steps:

[0036] Step S301, determining that the cutting line 4 is located in the carrier plate 3, and the cutting line 4 performs a winding motion or a paying-out motion;

[0037] Step S302, determining that the cutting line 4 is separated from the carrier plate, and the cutting line 4 performs a winding motion and a releasing motion alternately.

[0038] In this way, when the cutting line 4 is located in the carrier 3, the cutting line 4 only performs a unidirectional movement of winding or unwinding. At this time, the cutting line 4 will not swing back and forth in the horizontal direction perpendicular to the surface of the silicon wafer, so that the cutting line 4 always remains in the position for cutting the carrier 3 during the cutting process, that is, the cutting line 4 will not be biased towards any of the two adjacent silicon wafers 2. In this way, in the process of lifting the silicon wafer 2 upward relative to the cutting line 4, it is not easy for the cutting line 4 to hang on the side of the silicon wafer 2 that is bonded to the carrier 3. Furthermore, the cutting line 4 is effectively reduced. The situation where the cutting line 4 is pulled off or the silicon wafer 2 falls as the silicon wafer 2 is lifted is reduced. In addition, since the carrier does not have high requirements for protection, the unidirectional movement method is selected to reduce unnecessary switching of movement directions and improve the lifting efficiency of the cutting line in the carrier. Next, in the process of lifting from the cutting line 4 being separated from the carrier 3 to the cutting line 4 being separated from the silicon wafer 2, the cutting line 4 alternately performs the winding movement and the unwinding movement, and the side of the cutting line 4 entering relative to the silicon wafer 2 changes as the movement direction of the cutting line 4 changes. In this way, the larger bow of the cutting line 4 caused by the cutting line 4 entering only from one side of the silicon wafer 2 can be reduced, the friction force of the silicon wafer 2 on the cutting line 4 is larger, and the cutting line 4 is not easy to separate the surfaces of two adjacent silicon wafers 2 away from the side where the cutting line 4 enters, thereby reducing the occurrence of scratches, bright lines and even falling of the silicon wafer 2 caused by the friction of the cutting line 4, which is caused by the silicon wafer 2 being difficult to be separated by the cutting line 4 due to the large suction force. In addition, when the cutting line 4 is located between two adjacent silicon wafers 2, the winding movement and the unwinding movement are performed alternately, and the cutting line 4 will swing back and forth in the horizontal direction perpendicular to the surface of the silicon wafer. At this time, the cutting line 4 can be prevented from being in contact with any of the two adjacent silicon wafers 2. At the same time, during the horizontal swinging of the cutting line 4, it is out of contact with the silicon wafer 2, which shortens the contact time between the cutting line 4 and the silicon wafer 2, can reduce the friction on the silicon wafer 2, reduce the phenomenon of scratches on the surface of the silicon wafer 2, and reduce the damage of the cutting line to the silicon wafer.

[0039] like Figure 4 As shown, in a possible implementation, in step S302, it is determined that the cutting line is detached from the carrier plate, and during the process of the cutting line alternatingly performing the winding movement and the paying-out movement, the winding length of the cutting line 4 during the winding movement is 0.05m-0.2m, and the paying-out length of the cutting line 4 during the paying-out movement is 0.05m-0.2m.

[0040] In this way, the wire bow of the cutting wire 4 caused by the longer wire-reeling length and the longer wire-releasing length of the cutting wire 4 during the wire-reeling movement is avoided, thereby reducing the contact area between the cutting wire 4 and the silicon wafer 2, reducing the friction between the cutting wire 4 and the silicon wafer 2, and further reducing the occurrence of more scratches on the silicon wafer 2 caused by the cutting wire 4, thereby reducing the damage of the cutting wire to the silicon wafer.

[0041] Exemplarily, the winding length of the cutting line 4 can be 0.05m, 0.08m, 0.1m, 0.12m, 0.15m, 0.18m, 0.2m, etc., and the pay-off length of the cutting line 4 can be 0.05m, 0.06m, 0.08m, 0.1m, 0.12m, 0.16m, 0.17m, 0.2m, etc. Of course, this is just an example and not a specific limitation.

[0042] In one example, in step S302, it is determined that the cutting line 4 is separated from the carrier 3. During the process in which the cutting line 4 alternately performs the winding motion and the unwinding motion, the winding length of the cutting line 4 is equal to the unwinding length of the unwinding motion. In this case, two adjacent silicon wafers 2 are separated more evenly to avoid the situation that one side of the silicon wafer 2 parallel to the cutting line is separated slower than the other side, thereby reducing the friction between the silicon wafer and the cutting line 4 and weakening the phenomenon of scratches on the silicon wafer 2.

[0043] In some embodiments, it is determined in step S301 that the cutting line 4 is located in the carrier 3, and during the process of the cutting line 4 performing the winding or unwinding movement, the line speed of the cutting line 4 performing the winding or unwinding movement is S1, and it is determined in step S302 that the cutting line 4 is separated from the carrier 3, and during the process of the cutting line 4 performing the winding or unwinding movement alternately, the maximum line speed of the cutting line 4 performing the winding or unwinding movement is S2, and S1<S2. At this time, it is determined in step S301 that the cutting line 4 is located in the carrier 3, and during the process of the cutting line performing the winding or unwinding movement, the line speed of the cutting line 4 is relatively low, so as to avoid the cutting line 4 from being biased toward any one of the two adjacent silicon wafers 2 due to shaking, and further reduce the occurrence of the situation where the cutting line 4 hangs on the side of the silicon wafer 2 that is bonded to the carrier 3. In the process from the cutting line separating from the carrier to the cutting line separating from the silicon wafer, the line speed of the cutting line is relatively high, which can speed up the separation speed of the two adjacent silicon wafers 2 and improve the efficiency of separating the silicon wafer 2 from the cutting line 4. It should be noted that, due to the existence of a line bow in the cutting line 4, the cutting line 4 defined in the present invention as being located within the carrier 3 means that at least part of the cutting line is located within the carrier 3; and the cutting line 4 being detached from the carrier 3 means that all of the cutting line is detached from the carrier 3.

[0044] As an optional method, in step S301, it is determined that the cutting line 4 is located inside the carrier 3. During the process of the cutting line 4 taking up or releasing the cutting line, S1 gradually increases. When the cutting line 4 is completely inside the carrier 3, the speed is low, so as to avoid the cutting line 4 from being biased toward any of the two adjacent silicon wafers 2 due to shaking, and reduce the probability of the cutting line 4 hanging on the side of the silicon wafer 2 that is bonded to the carrier 3. As the silicon wafer 2 is lifted relative to the cutting line 4, due to the existence of the cutting line 4 bow, when the cutting line 4 is partially located in the silicon wafer 2, see Figure 3As shown, at this time, the top of the wire bow of the cutting line 4 and the part of the cutting line 4 close to the top of the wire bow are located in the carrier 3, and the routing speed of the cutting line 4 gradually increases. The cutting line 4 close to the side where the cutting line 4 walks out of the silicon wafer 2 can drive the part of the cutting line 4 located in the carrier 3, forcing the part of the cutting line 4 located in the carrier 3 to move to the middle of two adjacent silicon wafers 2, avoiding the cutting line 4 hanging on the side of the silicon wafer 2 bonded to the carrier 3.

[0045] In a specific implementation, 3m / min≤S1≤50m / min, and illustratively, S1 may be 3m / min, 10m / min, 20m / min, 25m / min, 30m / min, 40m / min, 50m / min, etc. S2≤50m / min, and S2 may be 20m / min, 25m / min, 30m / min, 36m / min, 42m / min, 45m / min, 50m / min, etc.

[0046] It can be understood that the direction of the line bow formed by the cutting line 4 is the same as the movement direction of the carrier 3 relative to the cutting line 4. Figure 2 As shown, during the cutting process, the carrier plate 3 drives the silicon rod 1 to move from top to bottom relative to the cutting line 4. At this time, the cutting line 4 bends downward to form a line bow. Therefore, when the cutting line 4 cuts into the carrier plate 3, the line bow of the cutting line 4 is in a downward bending state. Figure 3 and Figure 4 , when the silicon wafer 2 obtained by cutting the silicon rod 1 is lifted upward relative to the cutting line 4, the cutting line 4 bends upward to form a line bow. In this case, in order to separate the cutting line 4 from the carrier 3, in the process of lifting the carrier 3 upward relative to the cutting line 4, the line bow of the cutting line 4 gradually changes from bending downward to bending upward. In order to ensure that the cutting line 4 is completely separated from the carrier 3, the cutting line 4 is switched from a unidirectional motion mode to a bidirectional motion mode. In step S301, it is determined that the cutting line is located in the carrier. During the process of the cutting line taking up or unwinding, the distance that the silicon wafer 2 is lifted upward relative to the cutting line 4 is 15%-25% of the size of the silicon wafer in the vertical direction. In this way, corresponding to silicon wafers of different sizes, a suitable lifting distance is selected to ensure that the lifting distance makes the cutting line 4 completely separated from the carrier 3. In specific implementation, the distance that the silicon wafer 2 is lifted upward relative to the cutting line 4 can be 30mm to 50mm, specifically 30mm, 32mm, 40mm, 46mm, 50mm, etc.

[0047] In an optional manner, the speed of lifting the silicon wafer 2 obtained by cutting the silicon rod 1 relative to the cutting line 4 is 15 mm / min-60 mm / min. On the one hand, it is prevented that the speed of lifting the silicon wafer 2 relative to the cutting line 4 is too high, causing the cutting line 4 to break or the silicon wafer 2 to break. On the other hand, it is prevented that the speed of lifting the silicon wafer 2 relative to the cutting line 4 is too low, which causes the silicon wafer 2 to be separated from the cutting line 4 in a low efficiency.

[0048] In actual situations, in the process of lifting the silicon wafer 2 upward relative to the cutting line 4 in step S300, the silicon wafer cutting method provided by the embodiment of the present invention further includes the step of spraying cutting liquid on the cutting line 4. The cutting liquid is preferably a mixed mortar, which can reduce the adsorption force between two adjacent silicon wafers 2, and at the same time, facilitate the cutting line 4 to separate the two adjacent silicon wafers 2. In specific implementation, the mixed mortar includes cutting liquid and silicon powder, and the presence of silicon powder can reduce the adsorption force between two adjacent silicon wafers 2, and can also achieve the reuse of cutting liquid to avoid waste of resources.

[0049] In a possible implementation, in step S302, it is determined that the cutting line is separated from the carrier, and during the process of the cutting line alternately performing the winding motion and the unwinding motion, the silicon wafer cutting method further includes the step of: spraying clean water between the silicon wafers 2. The setting of clean water, on the one hand, cleans the silicon wafer 2, and on the other hand, the clean water is sprayed between the silicon wafers 2, and the spray force of the clean water facilitates the separation of two adjacent silicon wafers 2. The spray flow rate of the clean water is 50L / min-300L / min to ensure that the spray force of the clean water can separate the two adjacent silicon wafers 2. Exemplarily, the spray flow rate of the clean water can be 50L / min, 60L / min, 80L / min, 100L / min, 160L / min, 200L / min, 245L / min, 280L / min, 300L / min, etc.

[0050] The present application is further described below in conjunction with specific embodiments.

[0051] Example 1

[0052] In this embodiment 1, the cutting wire is wound around the surface of three cutting rollers to form a cutting wire net. The roller grooves of the three cutting rollers are V-shaped grooves. The cutting wire net is used to cut the silicon rods and then cut them into silicon wafers. The size of the cut silicon wafers is 182.2mm*183.75mm*0.13mm. The cutting wire routing speed is 20mm / min, and the silicon wafer lifting speed is 30mm / min.

[0053] The silicon wafer cutting method involved in this embodiment 1 includes the following steps: first, provide a silicon rod 1 and a carrier 3; second, drive the silicon rod 1 to move downward relative to the cutting line 4, so that the cutting line 4 cuts the silicon rod 1 to obtain multiple silicon wafers 2. At this time, the cutting line 4 needs to cut into the carrier to ensure that the silicon rod 1 is completely cut through; finally, lift the silicon wafer 2 upward relative to the cutting line 4. When the cutting line 4 is located on the carrier 3, the movement mode of the cutting line is unidirectional routing and material lifting; when the cutting line completely enters the silicon rod and it is determined that the cutting line 4 is separated from the carrier, the cutting line performs bidirectional routing and material lifting, that is, alternately performs winding movement and unwinding movement. Specifically, the routing length of the unidirectional routing and material lifting is 4.2m, and the routing length of the bidirectional routing and material lifting is 0.6m.

[0054] Comparative Example 1

[0055] The difference from Example 1 is that during the whole material lifting process, the cutting line performs the one-way material lifting in Example 1, and when all the one-way material lifting is performed, the length of the line is 17m. The other parts are the same as Example 1.

[0056] Comparative Example 2

[0057] The difference from the first embodiment is that during the whole material lifting process, the cutting line performs the bidirectional material lifting in the first embodiment, and the length of all bidirectional material lifting is within 0.6 m. The other parts are the same as the first embodiment.

[0058] The following is a 2000-knife cutting experiment conducted on 70 slicers of the same specifications, recording the wire breakage ratio and silicon wafer abnormality rate of Example 1 and Comparative Examples 1-2 respectively. It should be noted that the silicon wafer abnormality rate is the total amount of silicon wafer abnormalities produced by 2000 cuts divided by the total amount of silicon wafers produced. The silicon wafer abnormality rate mainly refers to abnormalities such as material lifting scratches and chamfering fragments. The specific comparison results are shown in Table 1.

[0059] Disconnection ratio Wafer abnormality rate This application 2.5％ 0.3％ Comparative Example 1 8％ 1％ Comparative Example 2 10％ 0.7％

[0060] As can be seen from Table 1, the silicon wafer cutting method provided by the present application can reduce the proportion of broken cutting lines and reduce the abnormality rate of silicon wafers. Of course, the impact of different types of silicon wafers is different. Generally, as the cutting line becomes thinner and the size of the silicon wafer becomes larger, the silicon wafer cutting method provided by the embodiment of the present invention will show greater advantages.

[0061] like Figure 3 , Figure 5 and Figure 6 As shown, an embodiment of the present invention further provides a silicon wafer, wherein the silicon wafer 2 has a first set of opposite sides and a second set of opposite sides, wherein the first set of opposite sides includes a first side 201 and a second side 202 that are oppositely arranged. Figure 3The left and right sides of the silicon wafer 2 are shown as a first side 201 and a second side 202, respectively, and the second set of opposite sides includes a third side 203 and a fourth side 204 that are arranged opposite to each other. Figure 3 The upper and lower sides of the silicon wafer 2 are shown as the third side 203 and the fourth side 204, respectively, wherein the first side 201 and / or the second side 202 intersect with the third side 203 and / or the fourth side 204; the surface of the silicon wafer 2 has a plurality of cutting line marks 23 and two groups of scratches, such as Figure 5 The first set of scratches 21 shown in the rectangular frame and the Figure 6 The second group of scratches 22 shown in the rectangular frame, wherein the cutting line marks 23 extend along the first group of opposite sides of the silicon wafer 2, that is, extend from the first side 201 to the second side 202 of the first group of opposite sides. The figure shows that the cutting line marks 23 extend in the horizontal direction; among the two groups of scratches, one group of scratches is inclined toward the third side 203 of the silicon wafer 2 in the first direction, and the first direction is the direction from the first side 201 to the second side 202, as shown in FIG. Figure 5 As shown, the first side 201 is located at Figure 5 and Figure 6 The second side 202 is located on the left side of Figure 5 and Figure 6 The third side 203 is located on the right side of Figure 5 and Figure 6 another set of scratches in the first direction toward the fourth side 204 of the silicon wafer 2 is inclined, such as Figure 6 As shown, the fourth side 204 is located at Figure 5 and Figure 6 The lower part of the.

[0062] It should be noted that the cutting line marks 23 are formed when the cutting line 4 cuts the silicon rod 1. Specifically, the cutting line marks 23 are grinding textures formed on the surface of the silicon wafer due to the grinding between the cutting line 4 and the surface of the silicon wafer during the cutting process. Figure 2 As shown, since the silicon rod 1 is fed downward relative to the cutting line 4, the cutting line 4 is subjected to pressure from the silicon rod 1. The cutting line 4 forms a certain degree of bending in the feeding direction while reciprocating. Each corresponding cutting line mark 23 appears as an arc visible to the naked eye on the surface of the silicon wafer. Figure 5 and Figure 6 The figure shows the state of the cutting line marks 23 on the silicon wafer. It can be seen in the figure that multiple cutting line marks 23 are densely arranged along the cutting direction. The silicon wafer cutting method also includes lifting the silicon wafer 2 upward relative to the cutting line 4 after the silicon wafer is cut. During the lifting process of the silicon wafer 2, due to the different degrees of contact between the cutting line 4 and the silicon wafer 2, scratches will be formed on the surface of the silicon wafer 2, that is, the scratches are traces formed by the contact between the cut silicon wafer 2 and the cutting line 4 when it is lifted upward relative to the cutting line 4. Each group of scratches has one, two or other fewer scratches, and each scratch in the same group of scratches has the same inclination direction relative to the cutting line marks 23, that is, Figure 5 and Figure 6 As shown, along the direction from left to right, the relative cutting line marks 23 are inclined upward or downward.

[0063] It can be understood that the intersection of the first edge 201 and / or the second edge 202 with the third edge 203 and / or the fourth edge 204 in the present application can be achieved by connecting them with each other through chamfers, or by intersecting with each edge or its extension line, for example, for silicon wafers of polygonal or other shapes, which is not limited to the embodiments of the present application.

[0064] In the case of adopting the above technical solution, the two groups of scratches on the surface of the silicon wafer are formed by the rubbing of the cutting line when the silicon wafer is lifted upward relative to the cutting line, wherein one group of scratches is formed by randomly rubbing the surface of the silicon wafer when the cutting line is routed in one direction, for example, the first group of scratches 21 is formed by rubbing the surface of the silicon wafer when the cutting line is reeling in between the silicon wafers; the other group of scratches is formed by randomly rubbing the surface of the silicon wafer when the cutting line is routed in another opposite direction, for example, the second group of scratches 22 is formed by rubbing the surface of the silicon wafer when the cutting line is unwinding between the silicon wafers. Since the silicon wafer is lifted upward relative to the cutting line while the cutting line is routed, the two groups of scratches are formed by rubbing corresponding to the two opposite directions of the cutting line movement, wherein one group of scratches is inclined in the first direction relative to the cutting line marks 23 toward the third side 203 of the silicon wafer, and the other group of scratches is inclined in the first direction relative to the cutting line marks 23 toward the fourth side 204 on the silicon wafer opposite to the third side 203. Since the silicon wafer cutting and slicing operations are performed according to the silicon wafer cutting method of the present application, the phenomenon of scratches on the silicon wafer surface is reduced, and the damage to the silicon wafer caused by the cutting line is reduced. For details, please refer to the beneficial effects of the method, which will not be repeated here.

[0065] In some embodiments, the angle between the scratch and the cutting line mark 23 is less than 20°, for example, the angle can be 1°, 5°, 10°, 15°, 19°, etc. The angles between each scratch in the same group of scratches and the cutting line mark 23 can be the same or different. The angle refers to the angle between the scratch and the tangent on the cutting line mark 23, wherein the tangent is a tangent passing through the intersection of the scratch and the cutting line mark 23. Since the cutting line mark 23 is slightly arc-shaped as a whole, from a local view with the scratch, the cutting line mark 23 in the local view can be considered to be basically a straight line, and the scratch can also be considered to be basically a straight line.

[0066] The size of the angle is related to the speed at which the silicon wafer is lifted up relative to the cutting line and the routing speed of the cutting line. The greater the speed, the greater the angle between the scratch and the cutting line mark, the higher the slicing efficiency, and the more scratches and damage to the silicon wafer. Therefore, in order to ensure the slicing efficiency of the silicon wafer and reduce scratches and damage on the silicon wafer, a suitable speed is selected. The specific speed can be found in the relevant description of the method. At this speed, the angle between the scratch formed on the silicon wafer and the cutting line mark 23 is less than 20°.

[0067] In some embodiments, the depth of the scratches is 2μm to 17μm, specifically 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, etc. The silicon wafer obtained by the above method has a smaller depth of scratches on its surface, which is beneficial to improve the surface passivation effect of the subsequently prepared battery cell and improve the photoelectric conversion efficiency.

[0068] In some possible implementations, the two groups of scratches are located on the same surface of the silicon wafer, and / or the two groups of scratches are located on two opposite surfaces of the silicon wafer. Since the scratches formed by the cutting line on the silicon wafer are random, scratches may be formed only on one surface of the silicon wafer, or on both sides of the silicon wafer. When scratches are formed on only one surface of the silicon wafer, there are two groups of scratches on the one surface, including a first group of scratches 21 and a second group of scratches 22. When scratches are formed on both sides of the silicon wafer, one surface may have only one group of scratches (such as the first group of scratches 21), and the other surface may have only the other group of scratches (such as the second group of scratches), or one surface may have only one group of scratches, such as the first group of scratches 21 or the second group of scratches 22, and the other surface may have both groups of scratches, or both surfaces may have both groups of scratches.

[0069] It should be noted that the scratches in different groups mentioned above have different inclination directions, that is, the scratches in the first group 21 and the scratches in the second group 22 have different inclination directions, and the scratches in the same group have the same inclination direction.

[0070] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0071] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A silicon wafer cutting method, characterized in that: include: Provide silicon rods and carrier plates; Driving the silicon rod to move downward relative to the cutting line so that the cutting line cuts the silicon rod to obtain a plurality of silicon wafers; The silicon wafer is lifted upward relative to the cutting line, and the movement mode of the cutting line within the carrier is different from the movement mode of the cutting line after it is separated from the carrier.

2. The silicon wafer cutting method according to claim 1, characterized in that: The difference between the motion mode of the cutting line within the carrier and the motion mode of the cutting line after leaving the carrier includes: When the cutting line is located in the carrier plate, the cutting line performs a winding motion or a releasing motion; when the cutting line is separated from the carrier plate, the cutting line performs a winding motion and a releasing motion alternately.

3. The silicon wafer cutting method according to claim 2, characterized in that: In the process of the cutting line alternately performing the winding motion and the paying-out motion, the winding length of the cutting line in the winding motion is 0.05m-0.2m, and the paying-out length of the cutting line in the paying-out motion is 0.05m-0.2m.

4. The silicon wafer cutting method according to claim 2, characterized in that: In the process that the cutting line alternately performs the winding motion and the unwinding motion, the winding length of the cutting line in the winding motion is equal to the unwinding length in the unwinding motion.

5. The silicon wafer cutting method according to claim 2, characterized in that: When the cutting line is located in the carrier plate and the cutting line is performing a winding movement or a releasing movement, the average wire speed of the cutting line during the winding movement or the releasing movement is S1; When the cutting line is separated from the carrier plate, the cutting line performs a winding motion and a paying-out motion alternately, and the maximum running speed of the cutting line in the winding motion or the paying-out motion is S2, and S1<S2.

6. The silicon wafer cutting method according to claim 5, characterized in that: When it is determined that the cutting line is located in the carrier plate and the cutting line is performing a wire-reeling movement or a wire-releasing movement, the wire-traveling speed gradually increases.

7. The silicon wafer cutting method according to claim 5, characterized in that: 3m / min≤S1≤50m / min and / or S2≤50m / min.

8. The silicon wafer cutting method according to claim 1, characterized in that: The speed of lifting the silicon wafer upward relative to the cutting line is 15 mm / min-60 mm / min.

9. The silicon wafer cutting method according to claim 1, characterized in that: In the process of lifting the silicon wafer upward relative to the cutting line, the silicon wafer cutting method further includes spraying cutting liquid on the cutting line.

10. The silicon wafer cutting method according to claim 2, characterized in that: When the cutting line is separated from the carrier plate and the cutting line performs a winding motion and a paying-out motion alternately, the silicon wafer cutting method further includes spraying clean water between the silicon wafers.

11. A silicon wafer, characterized in that: The silicon wafer has a first set of opposite sides and a second set of opposite sides, the first set of opposite sides includes a first side and a second side that are oppositely disposed, and the second set of opposite sides includes a third side and a fourth side that are oppositely disposed, wherein the first side and / or the second side intersects with the third side and / or the fourth side; The surface of the silicon wafer has two groups of scratches, one group of scratches is inclined toward the third edge in a first direction, and the other group of scratches is inclined toward the fourth edge in the first direction, and the first direction is the direction from the first edge to the second edge.

12. The silicon wafer according to claim 11, characterized in that: The surface of the silicon wafer has a plurality of cutting line marks, and the cutting line marks extend along a set of opposite edges of the silicon wafer; and the angle between the scratches and the cutting line marks is less than 20°.

13. The silicon wafer according to claim 11, characterized in that: The depth of the scratch is 2 μm to 17 μm.

14. The silicon wafer according to any one of claims 11 to 13, characterized in that: The two groups of scratches are located on the same surface of the silicon wafer, and / or the two groups of scratches are located on two opposite surfaces of the silicon wafer.

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