A method of cutting a silicon wafer, a silicon wafer and a cell

Abstract

A silicon wafer cutting method, a silicon wafer and a battery belong to the technical field of photovoltaics, including transferring old wire to the take-up wheel by the pay-off wheel to form a wire mesh, setting the position of the contact between the crystalline silicon rod and the wire mesh as zero, setting the initial feeding position of the crystalline silicon rod at-0.5mm, using old wire to cut, and cutting the crystalline silicon rod from left to right when cutting, the cutting process includes initial stage, middle stage and end stage in turn, the crystalline silicon rod is cut by old wire in the initial stage and the end stage, and the crystalline silicon rod is cut by new wire and old wire in the middle stage. In the initial stage, the pay-off amount of the pay-off wheel is greater than the take-up amount of the take-up wheel, the average blade height H1 of the old wire satisfies: 2.2um<=H1<=2.8um, and the blade rate C1 of the old wire satisfies: 10 grains / mm<=C1<=60 grains / mm. The old wire is cut forward with moderate blade rate and average blade height, the wire transfer amount is reduced, the time consumption is saved, and the cutting efficiency and the utilization rate of diamond wire are improved.

Description

Technical Field

[0001] This invention relates to the field of silicon wafer cutting technology, and in particular to a silicon wafer cutting method and a silicon wafer. Background Technology

[0002] Currently, silicon wafers are the primary material for manufacturing solar cells. With the continuous development of photovoltaic technology, silicon wafers are being cut using a multi-wire cutting process. Currently, in existing photovoltaic silicon wafer cutting processes, reverse cutting is typically used. Using a new wire for the cutting process requires a long time for wire transfer, reducing production efficiency and resulting in low wire utilization. Summary of the Invention

[0003] This application provides a silicon wafer cutting method, a silicon wafer, and a battery to solve the problems of low production efficiency and low line utilization in the current reverse cutting process.

[0004] The first aspect of this application provides a method for cutting a silicon wafer, comprising:

[0005] The feed reel transfers the old wire to the take-up reel, forming a wire net.

[0006] Set the point where the silicon rod contacts the wire mesh as the zero point;

[0007] The initial feed position of the silicon rod is set to -0.5mm. The old wire is used for cutting. When cutting, the wire mesh cuts the silicon rod from left to right. The cutting process includes an initial stage, a middle stage and a final stage. The old wire is used to cut the silicon rod in the initial stage and the final stage. The new wire and the old wire are used to cut the silicon rod in the middle stage.

[0008] In the initial stage, the amount of wire fed by the feed reel is greater than the amount of wire returned by the take-up reel, and the average blade height H1 of the old wire satisfies: 2.2um≤H1≤2.8um, and the blade rate C1 of the old wire satisfies: 10 pieces / mm≤C1≤60 pieces / mm.

[0009] By using the old wire as the cutting tool, the cutting force of the diamond wire is moderate, the cutting process is stabilized, the risk of chipping or cracking at the front edge of the silicon rod is reduced, and the quality of the first silicon wafer is improved. At the same time, when the silicon rod contacts the wire mesh during cutting, the load on the diamond wire increases sharply. The old wire has better toughness than the new wire, which reduces the risk of diamond wire breakage during cutting and improves the reliability and stability of cutting.

[0010] In summary, this application, by employing existing wire with a moderate cutting rate and average cutting height for forward cutting, improves the stability of cutting silicon rods during the cutting process, reduces wire marks on the silicon wafer surface, and improves silicon wafer quality. At the same time, it reduces the amount of wire transfer, saves time, improves cutting efficiency, increases the utilization rate of diamond wire, reduces new wire loss, and lowers cutting costs.

[0011] In this scheme, the intermediate stage includes a first intermediate stage and a second intermediate stage. In the first intermediate stage, new lines are fed into the network, and the amount of line fed by the feeding reel is controlled to be greater than the amount of line returned by the take-up reel. In the second intermediate stage, the amount of line fed by the feeding reel is controlled to be less than the amount of line returned by the take-up reel.

[0012] In the first intermediate stage, the average blade exit height H2 of the old line satisfies: 2.15um≤H2≤2.7um, and the blade exit rate C2 of the old line satisfies: 8 blades / mm≤C2≤55 blades / mm. The average blade exit height H3 of the new line satisfies: 3.1um≤H3≤4.5um, and the blade exit rate C3 of the new line satisfies: 70 blades / mm≤C3≤190 blades / mm.

[0013] In this scheme, during the second intermediate stage, the average blade exit height H4 of the old line satisfies: 2.1um≤H4≤2.6um, and the blade exit rate C4 of the old line satisfies: 6 pieces / mm≤C4≤40 pieces / mm. The average blade exit height H5 of the secondary new line satisfies: 2.8um≤H5≤3.5um, and the blade exit rate C5 of the secondary new line satisfies: 40 pieces / mm≤C5≤100 pieces / mm.

[0014] In this scheme, during the finishing stage, the amount of wire fed by the feed reel is controlled to be less than the amount of wire returned by the take-up reel, and the average blade height H6 of the old wire satisfies: 2um≤H6≤2.4um, and the blade rate C6 of the old wire satisfies: 5 pieces / mm≤C6≤35 pieces / mm.

[0015] In this scheme, the feed position of the silicon rod is between -0.5mm and 30mm in the initial stage. The feed speed V1 and the linear speed F1 are increased, and the amount of wire return of the take-up reel is reduced. The feed speed V1 satisfies: 1.5mm / min≤V1≤2.9mm / min, and the linear speed F1 satisfies: 13m / s≤F1≤39m / s. The torque on the main roller gradually increases.

[0016] In this scheme, the feed position of the silicon rod is between 30mm and 164mm, which is in the first intermediate stage. The amount of wire return of the take-up roller is reduced, the wire speed F2 is maintained at the peak value during the cutting process, and the feed speed V2 satisfies: 2.7mm / min≤V2≤3.1mm / min. The torque on the main roller first increases, then decreases, and then increases again.

[0017] In this scheme, the feed position of the silicon rod is between 164mm and 212mm, which is the second intermediate stage. The feed speed V3 and the linear speed F3 are reduced, while the amount of wire fed by the feed wheel and the amount of wire returned by the take-up wheel are increased. The feed speed V3 satisfies: 0.9mm / min≤V3<2.7mm / min, and the linear speed F3 satisfies: 33m / s≤F3≤38m / s. The torque on the main roller first increases and then decreases.

[0018] In this scheme, the finishing stage is when the silicon rod feed position is between 212mm and 217.2mm. The amount of wire fed by the feed roller and the amount of wire returned by the take-up roller are controlled to be greater than the amount of wire fed by the feed roller and the amount of wire returned by the take-up roller in the second intermediate stage. The feed speed V4 and the line speed F4 are reduced. The feed speed V4 satisfies: 0.08mm / min≤V4<0.9mm / min, and the line speed F4 satisfies: 24m / s≤F4<33m / s. The torque on the main roller gradually decreases.

[0019] In this scheme, the torque N1 experienced by the main roller in the initial stage satisfies: 35N m≤N1≤120N m, the torque N2 experienced by the main roller in the first intermediate stage satisfies: 120N m<N2≤137.5N m, the torque N3 experienced by the main roller in the second intermediate stage satisfies: 134N m≤N3≤140N m, the torque N4 experienced by the main roller during the finishing stage satisfies: 10N m≤N4≤130N m.

[0020] A second aspect of this application provides a silicon wafer prepared by the silicon wafer dicing method described above.

[0021] A third aspect of this application provides a battery comprising the silicon wafer described above.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the cutting device provided in this application in a specific embodiment;

[0024] Figure 2 This is a flowchart of a specific embodiment of the silicon wafer cutting method provided in this application.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1- Paying reel;

[0027] 2- Take-up reel;

[0028] 3- Main roller;

[0029] 31 - First main roller;

[0030] 32 - Second main roller;

[0031] 33 - Third main roller;

[0032] 4-Crystal silicon rod;

[0033] 5- Diamond wire.

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0035] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0036] In one specific embodiment, the present application will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0037] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0038] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0040] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0041] Currently, silicon wafer cutting processes typically employ a reverse cutting method, using new wire as the cutting tool. This requires first transferring all the old wire from the surface of the feed wheel to the take-up wheel, then controlling the feed wheel to continue feeding new wire to the take-up wheel. The take-up wheel then feeds new wire in the reverse direction to form a new wire mesh, a process that takes approximately 8 minutes. The take-up wheel then feeds new wire in the reverse direction to the feed wheel for reverse cutting. This process of transferring new wire takes too long, resulting in low production efficiency. Furthermore, transferring a large amount of new wire to the take-up wheel carries the risk of diamond wire skewing and edge breakage, reducing the cutting force of the new wire and leading to wasted diamond wire cutting force and low diamond wire utilization.

[0042] To address the aforementioned problems, this application provides a silicon wafer cutting method, which uses a cutting device to cut a silicon rod 4 to form a silicon wafer. Wherein, as... Figure 1 As shown, the cutting device includes a feed reel 1, a take-up reel 2, and three parallel main rollers 31, 32, and 33. Each main roller 3 has a groove on its outer periphery to accommodate diamond wire 5. Diamond wire 5 is wound on the feed reel 1. The diamond wire 5 transferred from the feed reel 1 is wound along the grooves onto the three main rollers 3, and finally transferred and taken up onto the take-up reel 2, forming a wire mesh in the area between the first and second main rollers 31 and 32. This wire mesh is used to cut the silicon rod 4. Multiple guide rollers are arranged between the first main roller 31 and the feed reel 1, and between the second main roller 32 and the take-up reel 2, to guide the movement of the diamond wire 5 and to tension it.

[0043] like Figure 1 and Figure 2 As shown, S1: Preparing to cut. At this time, the surface of the pay-off reel 1 is wrapped with some old wire, and the inner layer is wrapped with new wire. The pay-off reel 1 rotates to transfer the old wire to the take-up reel 2. The pay-off reel 1 stops rotating when it is about to turn out the new wire, so that all the wires on the wire net are old wires, thus forming an old wire net, ready for cutting.

[0044] It should be noted that "new wire" refers to diamond wire 5 that has never been cut or used, while "old wire" refers to diamond wire 5 that has already been cut and used.

[0045] Before performing step S1, the diamond wire 5 can complete the first cut. During the first cut, the pay-off wheel 1 is fully wound with new wire, and the take-up wheel 2 is an empty wheel without diamond wire 5. The pay-off wheel 1 releases the new wire, which passes through the guide wheel and is wound onto the main roller 3. Finally, the new wire is wound up and fixed on the take-up wheel 2 to form a new wire net. The first cut is performed using the new wire. After the new wire is cut, it is converted into old wire. As the cutting continues, the old wire moves to the main roller 3, the take-up wheel 2, and the pay-off wheel 1.

[0046] The first cut (i.e. the first cut) refers to the first cut made on the first original silicon rod using a brand new diamond wire mesh 5. In other words, the first cut requires the creation of a brand new cutting wire mesh from the beginning, and the entire first cut consumes brand new, never-before-used diamond wire mesh 5.

[0047] Therefore, after the initial cut, compared to the current reverse cutting method using new thread, step S1 of this application does not require running new thread. That is, it eliminates the need to transfer the new thread from the feed reel 1 to the take-up reel 2 until the entire wire mesh is new thread. This reduces time consumption, improves cutting efficiency, and increases the yield per slice. Simultaneously, using the old thread as the starting point avoids wear on the diamond wire 5 caused by thread running, preventing a decrease in the cutting force of the diamond wire 5, improving the utilization rate of the diamond wire 5, and reducing the amount of new thread used. Furthermore, the initial cut can be a forward cut. Compared to the conventional reverse cutting method, the amount of new thread required for the forward initial cut on the feed reel 1 to the take-up reel 2 is less than that required for the conventional reverse cutting method, saving time spent running the thread and improving cutting efficiency.

[0048] It should be noted that forward cutting (abbreviated as forward slicing) refers to: controlling the wire mesh to move from left to right to cut the silicon rod 4 so that the feed reel 1 feeds the wire to the take-up reel 2; reverse cutting (abbreviated as reverse slicing) refers to: controlling the wire mesh to move from right to left to cut the silicon rod 4 so that the take-up reel 2 feeds the wire to the feed reel 1.

[0049] S2: Set the position where the silicon rod 4 contacts the wire mesh to zero;

[0050] S3: Set the initial feed position of the silicon rod 4 to -0.5mm. This means that at the start of cutting, the distance between the front end of the silicon rod 4 and the cutting wire mesh is -0.5mm in the feed direction, and 0.5mm in the direction away from the feed direction. Setting the initial feed position of the silicon rod 4 to -0.5mm provides a buffer distance between the wire mesh and the silicon rod 4, preventing the wire mesh from being subjected to excessive impact loads during cut and reducing the risk of wire breakage.

[0051] It should be noted that, as Figure 1As shown, the feed direction is the direction in which the silicon rod 4 moves towards the wire mesh. The feed position refers to the real-time distance between the workpiece reference surface (or the front end of the silicon rod 4) and the zero point, using the equipment coordinate system as a reference, in the feed direction. That is, in this application, the feed position can be the real-time distance between the front end of the silicon rod 4 and the cutting wire mesh in the feed direction. The front end of the silicon rod 4 is the end closer to the wire mesh than the other end of the silicon rod 4 along the feed direction.

[0052] S4: Start cutting. Use the old wire to enter the cutter. When entering the cutter, the wire mesh cuts the silicon rod 4 from left to right, which is a forward cut. When entering the cutter, control each main roller 3 to rotate in a preset direction, such as clockwise rotation, so that the main roller 3 drives the wire mesh to move from left to right to perform a forward cut, thereby causing the wire feeding wheel 1 to feed the wire to the take-up wheel 2.

[0053] By using the old wire for cutting, the cutting force of the diamond wire 5 is moderate, the cutting process is stabilized, the risk of chipping or cracking at the front edge of the silicon rod 4 is reduced, and the quality of the first silicon wafer is improved. At the same time, when the silicon rod 4 contacts the wire mesh, the load on the diamond wire 5 increases sharply. The old wire has better toughness than the new wire, which reduces the risk of the diamond wire 5 breaking when cutting and improves the reliability and stability of cutting.

[0054] "In-cut" refers to the entire initial action and process of the diamond wire 5 starting to contact and cut into the silicon rod, that is, the initial cutting process in which the diamond wire 5 can completely cut into the crystalline silicon rod 4.

[0055] The cutting process includes an initial stage, a middle stage, and a final stage. The initial and final stages both use the old wire-cut silicon rod 4, while the middle stage uses both the new wire and the old wire-cut silicon rod 4.

[0056] In the initial stage, the amount of wire fed by the feed reel 1 is greater than the amount of wire returned by the take-up reel 2. That is, in the initial stage, a tangential cutting method is used. The average exit height H1 of the old wire satisfies: 2.2um≤H1≤2.8um. ​​In the initial stage, the cutting force of the diamond wire 5 is moderate. The average exit height of the old wire in this stage is not too large, so that the cutting force of the diamond wire 5 when entering the cutter is not too large. This reduces the impact strength between the diamond wire 5 and the silicon rod 4, and prevents the risk of chipping and notches at the front edge of the silicon rod 4 under the cutting action of the diamond wire 5. That is, it prevents the risk of edge chipping, improves the stability of the subsequent cutting process, and is conducive to improving the quality of the cut silicon wafer. At the same time, the average exit height of the old wire in this stage is not too small, so that the cutting force of the diamond wire 5 when entering the cutter is not too small. This prevents the diamond wire 5 from being unable to cut the silicon rod 4, prevents wire breakage, improves the reliability and stability of the cutting process in the initial stage, and is conducive to improving the wire marks on the surface of the silicon wafer, further improving the quality of the cut silicon wafer.

[0057] Optionally, in the initial stage, the average cutting edge height H1 of the old line satisfies: 2.2um≤H1≤2.8um. ​​H1 can be 2.2um, 2.25um, 2.3um, 2.35um, 2.4um, 2.45um, 2.5um, 2.55um, 2.6um, 2.65um, 2.7um, 2.75um or 2.8um, or other values ​​within the above range. This embodiment does not limit this.

[0058] In one possible implementation, in the initial stage, the cutting efficiency C1 of the old wire satisfies: 10 grains / mm ≤ C1 ≤ 60 grains / mm, where C1 is the number of diamond abrasive grains with a height of ≥ 2µm on each millimeter of diamond wire 5, i.e., diamond abrasive grains with a height of ≥ 2µm are the actual diamond abrasive grains participating in effective cutting. When the cutting efficiency C1 of the old wire satisfies: 10 grains / mm ≤ C1 ≤ 60 grains / mm, in the initial stage, the number of diamond abrasive grains effectively cutting on the old wire is moderate, ensuring that the number of diamond abrasive grains effectively cutting on the old wire is not excessive, so that the cutting force applied to the silicon rod 4 at various points on the old wire is relatively uniform and stable, preventing damage to the cut surface of the silicon rod 4 and improving the wire marks on the silicon wafer surface; at the same time, the number of diamond abrasive grains effectively cutting on the old wire is not too small, ensuring that the cutting force of the diamond wire 5 is not too small when it enters the die, preventing the diamond wire 5 from being unable to cut the silicon rod 4, preventing wire breakage, and also helping to improve the wire marks on the silicon wafer surface, further improving the quality of the cut silicon wafer.

[0059] Optionally, in the initial stage, the cutting rate C1 of the old line satisfies: 10 grains / mm ≤ C1 ≤ 60 grains / mm. C1 can be 10 grains / mm, 15 grains / mm, 20 grains / mm, 25 grains / mm, 30 grains / mm, 35 grains / mm, 40 grains / mm, 45 grains / mm, 50 grains / mm, 55 grains / mm, 56 grains / mm, 57 grains / mm, 58 grains / mm, 59 grains / mm, or 60 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0060] It should be noted that the surface of the diamond wire 5 has multiple protruding diamond abrasive grains. The average tip height refers to the average height of the diamond abrasive grains on the diamond wire 5 protruding from the surface of the steel wire matrix. The tip rate refers to the proportion or distribution density of the number of diamond abrasive grains that actually participate in and effectively cut on a unit length of diamond wire 5 during the cutting process.

[0061] In summary, by adopting a pre-cutting method with a moderate cutting edge rate and average cutting edge height, this application improves the stability of cutting the silicon rod 4 during the cutting process, reduces wire marks on the silicon wafer surface, improves silicon wafer quality, reduces the amount of wire transfer, saves time, improves cutting efficiency, increases the utilization rate of diamond wire 5, reduces new wire loss, and lowers cutting costs.

[0062] In addition, in the initial stage, the cutting efficiency C7 of the old wire meets the following condition: 1 grain / mm ≤ C7 ≤ 30 grains / mm. This ensures that the wire mesh has good cutting force in the initial stage, establishes a stable cutting kerf, reduces entry edge chipping, and facilitates appropriate increases in feed rate and wire speed, improving cutting efficiency. This, in turn, reduces the squeezing and tearing of the wire mesh on the silicon wafer surface, improves the wire mark depth, and enhances the uniformity of wire mesh cutting, thereby significantly improving the silicon wafer quality. Simultaneously, it improves the wire mesh bending degree, enhances the stability of wire mesh cutting, and slows down the accumulation of wire mesh fatigue, preventing wire breakage. C7 refers to the number of diamond abrasive grains with a height of ≥ 3µm per millimeter of diamond wire 5.

[0063] Optionally, in the initial stage, the cutting edge rate C7 of the old line satisfies: 1 grain / mm ≤ C7 ≤ 30 grains / mm. C7 can be 1 grain / mm, 2 grains / mm, 3 grains / mm, 4 grains / mm, 5 grains / mm, 6 grains / mm, 7 grains / mm, 8 grains / mm, 9 grains / mm, 10 grains / mm, 11 grains / mm, 12 grains / mm, 13 grains / mm, 14 grains / mm, 15 grains / mm, 16 grains / mm, 17 grains / mm, 18 grains / mm, 19 grains / mm, 20 grains / mm, 21 grains / mm, 22 grains / mm, 23 grains / mm, 25 grains / mm, 26 grains / mm, 27 grains / mm, 28 grains / mm, 29 grains / mm, or 30 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0064] In one possible implementation, such as Figure 2 As shown, the intermediate stage includes a first intermediate stage and a second intermediate stage. In the first intermediate stage, new line enters the wire network, and the amount of line released by the line release reel 1 is controlled to be greater than the amount of line returned by the line take-up reel 2. In the second intermediate stage, the amount of line released by the line release reel 1 is controlled to be less than the amount of line returned by the line take-up reel 2.

[0065] Specifically, as the feed reel 1 continues to feed wire to the take-up reel 2, in step S5, new wire gradually enters the wire mesh, allowing the cutting process to transition from the initial stage to the first intermediate stage. The amount of wire fed from the feed reel 1 continues to be greater than the amount returned from the take-up reel 2 for forward cutting. In this first intermediate stage, the wire mesh contains both new and old wire zones. The addition of new wire to the mesh increases the cutting force, allowing for higher wire speeds and feed rates, thus improving cutting speed and efficiency. Simultaneously, the use of both new and old wire in this first intermediate stage enables the reuse of old wire, increasing wire utilization and reducing production costs.

[0066] As cutting continues, the structural strength of the silicon rod 4 gradually decreases. S6: Control the amount of wire fed from the feed roller 1 to be less than the amount of wire returned from the take-up roller 2, i.e., change the cutting direction and begin cutting the silicon rod 4 in a reverse cutting manner, so that the cutting process transitions from the first intermediate stage to the second intermediate stage. By changing the cutting direction, the secondary new wire (i.e., old wire) used in the first intermediate stage and the old wire used in the initial stage on the feed roller 1 gradually enter the wire mesh, appropriately reducing the cutting capacity of the wire mesh. This helps optimize and compensate for the bending deformation of the wire mesh during cutting, improves the stability of wire mesh cutting, reduces the vibration amplitude of the wire mesh, and helps improve the wire marks on the silicon wafer surface. Simultaneously, it makes the silicon rod 4 more evenly stressed, preventing local stress concentration, reducing the risk of wire breakage, and improving the reliability and stability of the cutting process in the second intermediate stage. Furthermore, the old wire entering the wire mesh for cutting fully utilizes its cutting capacity, increasing the utilization rate of the wire in this stage and reducing cutting costs.

[0067] It should be noted that "secondary new line" refers to the new line used for cutting during the first intermediate stage.

[0068] In some embodiments, the average blade height H2 of the old wire used in the first intermediate stage satisfies: 2.15um ≤ H2 ≤ 2.7um, and the blade exit rate C2 of the old wire satisfies: 8 blades / mm ≤ C2 ≤ 55 blades / mm. This ensures that the cutting force of the old wire used in the first intermediate stage is moderate, preventing the overall cutting force of the wire mesh in the first intermediate stage from being too small, preventing insufficient wire mesh cutting capacity, preventing abnormally large bending deformation of the wire mesh during cutting, preventing wire breakage, and facilitating increased feed rate and cutting speed, thereby improving production efficiency. Furthermore, it improves the reliability and rate at which silicon powder (chips) generated during cutting are carried away by the cutting fluid, enhancing the wire chip removal capacity, preventing the risk of wire jamming due to increased local frictional heat caused by silicon powder accumulation in the wire seam, thus improving the wire marks on the silicon wafer surface and reducing the wire breakage rate.

[0069] Wherein, C2 is the number of diamond abrasive grains with a height of 2um or more on each millimeter of diamond wire 5, that is, diamond abrasive grains with a height of 2um or more are the actual diamond abrasive grains that participate in and effectively cut.

[0070] Optionally, in the first intermediate stage, the average cutting edge height H2 of the old line satisfies: 2.15um ≤ H2 ≤ 2.7um. H2 can be 2.15um, 2.16um, 2.17um, 2.18um, 2.19um, 2.2um, 2.25um, 2.3um, 2.35um, 2.4um, 2.45um, 2.5um, 2.55um, 2.6um, 2.65um, or 2.7um, or other values ​​within the above range. This embodiment does not limit this value.

[0071] Optionally, in the first intermediate stage, the cutting edge rate C2 of the old line satisfies: 8 pieces / mm ≤ C2 ≤ 55 pieces / mm. C2 can be 8 pieces / mm, 9 pieces / mm, 10 pieces / mm, 15 pieces / mm, 20 pieces / mm, 25 pieces / mm, 30 pieces / mm, 35 pieces / mm, 40 pieces / mm, 45 pieces / mm, 50 pieces / mm or 55 pieces / mm, or other values ​​within the above range. This embodiment does not limit this.

[0072] In addition, during the first intermediate stage, the cutting edge rate C8 of the old wire satisfies: 1 grain / mm ≤ C8 ≤ 23 grains / mm. This ensures that the wire mesh in the first intermediate stage has good cutting force, allowing the old wire with a high cutting edge rate to effectively complete cutting even at lower wire speeds or higher feed rates, improving cutting efficiency, increasing process tolerance, improving production stability, and reducing wire mesh compression and tearing on the silicon wafer surface. This helps improve the depth of the wire marks and the uniformity of wire mesh cutting, thus significantly improving the quality of the silicon wafer. Simultaneously, it improves the degree of wire mesh curvature, enhances the stability of wire mesh cutting, and slows down the accumulation of wire mesh fatigue, preventing wire breakage. C8 refers to the number of diamond abrasive grains with a height of ≥ 3µm on each millimeter of diamond wire 5.

[0073] Optionally, in the first intermediate stage, the cutting edge rate C8 of the old line satisfies: 1 grain / mm ≤ C8 ≤ 23 grains / mm. C8 can be 1 grain / mm, 2 grains / mm, 3 grains / mm, 4 grains / mm, 5 grains / mm, 6 grains / mm, 7 grains / mm, 8 grains / mm, 9 grains / mm, 10 grains / mm, 11 grains / mm, 12 grains / mm, 13 grains / mm, 14 grains / mm, 15 grains / mm, 16 grains / mm, 17 grains / mm, 18 grains / mm, 19 grains / mm, 20 grains / mm, 21 grains / mm, 22 grains / mm, or 23 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0074] In some embodiments, during the first intermediate stage, the average tip height H3 of the new wire satisfies: 3.1µm ≤ H3 ≤ 4.5µm, and the tip rate C3 of the new wire satisfies: 70 grains / mm ≤ C3 ≤ 190 grains / mm. This ensures that the cutting force of the new wire is moderate, preventing excessive overall cutting force of the wire mesh during the first intermediate stage. This reduces the risk of deep wire-cutting marks caused by diamond abrasive grains on the silicon wafer, improves the surface texture of the silicon wafer, helps reduce surface damage, and prevents local stress concentration caused by excessive tip height of diamond abrasive grains. This reduces stress concentration points, improves the wire marks on the silicon wafer surface, increases the mechanical strength of the silicon wafer, and improves its quality. Furthermore, it helps reduce the load on each diamond abrasive grain and improves the vibration intensity during the diamond wire 5 cutting process, thereby reducing the probability of wire breakage.

[0075] Wherein, C3 is the number of diamond abrasive grains with a height of 2um or more on each millimeter of diamond wire 5, that is, diamond abrasive grains with a height of 2um or more are the actual diamond abrasive grains that participate in and effectively cut.

[0076] Optionally, in the first intermediate stage, the average cutting edge height H3 of the new line satisfies: 3.1um ≤ H3 ≤ 4.5um. H3 can be 3.1um, 3.2um, 3.3um, 3.4um, 3.5um, 3.6um, 3.7um, 3.8um, 3.9um, 4um, 4.1um, 4.2um, 4.3um, 4.4um or 4.5um, or other values ​​within the above range. This embodiment does not limit this value.

[0077] Optionally, in the first intermediate stage, the cutting edge rate C3 of the new line satisfies: 70 particles / mm ≤ C3 ≤ 190 particles / mm. C3 can be 70 particles / mm, 75 particles / mm, 80 particles / mm, 85 particles / mm, 90 particles / mm, 95 particles / mm, 100 particles / mm, 105 particles / mm, 110 particles / mm, 115 particles / mm, 120 particles / mm, 125 particles / mm, 130 particles / mm, 135 particles / mm, 140 particles / mm, 145 particles / mm, 150 particles / mm, 155 particles / mm, 160 particles / mm, 165 particles / mm, 170 particles / mm, 175 particles / mm, 180 particles / mm, 185 particles / mm, or 190 particles / mm, or other values ​​within the above range. This embodiment does not limit this.

[0078] In summary, through the first intermediate stage, the average blade exit height H2 of the old wire satisfies: 2.15um ≤ H2 ≤ 2.7um, and the blade exit rate C2 of the old wire satisfies: 8 blades / mm ≤ C2 ≤ 55 blades / mm. The average blade exit height H3 of the new wire satisfies: 3.1um ≤ H3 ≤ 4.5um, and the blade exit rate C3 of the new wire satisfies: 70 blades / mm ≤ C3 ≤ 190 blades / mm. This ensures that the overall average blade exit height and blade exit rate of the wire mesh in the first intermediate stage are moderate, preventing excessive bending deformation of the wire mesh and improving the cutting performance of the wire mesh in this stage. This is beneficial for improving the wire marks on the silicon wafers. In addition to improving the quality of the silicon wafers, this first intermediate stage is conducive to appropriately increasing the feed rate, cutting speed, cutting efficiency, cutting reliability, and stability in the first intermediate stage.

[0079] In addition, during the first intermediate stage, the new wire's cutting edge rate C9 satisfies: 30 grains / mm ≤ C9 ≤ 110 grains / mm. This ensures the new wire has good cutting force, which is beneficial for appropriately increasing the feed rate and wire speed, improving cutting efficiency, and thus reducing the squeezing and tearing of the silicon wafer surface by the wire mesh. This also helps improve the wire mark depth and the uniformity of wire mesh cutting, significantly improving the uniformity of wire marks on the silicon wafer surface, thereby greatly improving silicon wafer quality. Simultaneously, it improves the degree of wire mesh curvature, enhances the stability of wire mesh cutting, and slows down the accumulation of wire mesh fatigue, preventing wire breakage. C9 refers to the number of diamond abrasive grains with a height of 3µm or higher on each millimeter of diamond wire 5.

[0080] Optionally, in the first intermediate stage, the cutting edge rate C9 of the new line satisfies: 30 blades / mm ≤ C9 ≤ 110 blades / mm. C9 can be 30 blades / mm, 40 blades / mm, 50 blades / mm, 60 blades / mm, 70 blades / mm, 80 blades / mm, 90 blades / mm, 100 blades / mm, or 110 blades / mm, or other values ​​within the above range. This embodiment does not limit this. In one possible implementation, such as... Figure 2 As shown, in the second intermediate stage, the average cutting height H4 of the old wire satisfies: 2.1um ≤ H4 ≤ 2.6um, and the cutting rate C4 of the old wire satisfies: 6 grains / mm ≤ C4 ≤ 40 grains / mm. This ensures that the cutting force of the wire mesh in the second intermediate stage is not too small, preventing insufficient cutting force, preventing the diamond wire 5 from being squeezed when cutting into the silicon rod 4, avoiding chipping at the cutting entrance edge of the silicon rod 4, preventing inconsistent silicon wafer kerf lines, and improving the surface kerf lines of the silicon wafer. Here, C4 represents the number of diamond abrasive grains with a height of ≥ 2um per millimeter of diamond wire 5, meaning that diamond abrasive grains with a height of ≥ 2um are the actual diamond abrasive grains participating in and effectively cutting.

[0081] Optionally, in the second intermediate stage, the average cutting edge height H4 of the old line satisfies: 2.1um ≤ H4 ≤ 2.6um. H4 can be 2.1um, 2.15um, 2.2um, 2.25um, 2.3um, 2.35um, 2.4um, 2.45um, 2.5um, 2.55um, or 2.6um, or other values ​​within the above range. This embodiment does not limit this value.

[0082] Optionally, in the second intermediate stage, the cutting edge rate C4 of the old line satisfies: 6 pieces / mm ≤ C4 ≤ 40 pieces / mm. C4 can be 6 pieces / mm, 7 pieces / mm, 8 pieces / mm, 9 pieces / mm, 10 pieces / mm, 12 pieces / mm, 14 pieces / mm, 15 pieces / mm, 16 pieces / mm, 18 pieces / mm, 20 pieces / mm, 22 pieces / mm, 24 pieces / mm, 25 pieces / mm, 26 pieces / mm, 28 pieces / mm, 30 pieces / mm, 32 pieces / mm, 34 pieces / mm, 35 pieces / mm, 36 pieces / mm, 38 pieces / mm, or 40 pieces / mm, or other values ​​within the above range. This embodiment does not limit this.

[0083] Furthermore, in the second intermediate stage, the cutting efficiency C10 of the old wire meets the following condition: 1 grain / mm ≤ C10 ≤ 17 grains / mm. This ensures that the wire mesh has good cutting force in the second intermediate stage, improves edge chipping at the exit, ensures normal and stable execution in the final stage, and improves cutting efficiency. This, in turn, reduces the squeezing and tearing of the wire mesh on the silicon wafer surface, which is beneficial for improving the wire mark depth and the uniformity of wire mesh cutting, thus significantly improving the silicon wafer quality. Simultaneously, it improves the degree of wire mesh bending, enhances the stability of wire mesh cutting, and slows down the accumulation of wire mesh fatigue, preventing wire breakage. Here, C10 refers to the number of diamond abrasive grains with a height of ≥ 3µm on each millimeter of diamond wire.

[0084] Optionally, in the second intermediate stage, the cutting edge rate C10 of the old line satisfies: 1 grain / mm ≤ C10 ≤ 17 grains / mm. C10 can be 1 grain / mm, 2 grains / mm, 3 grains / mm, 4 grains / mm, 5 grains / mm, 6 grains / mm, 7 grains / mm, 8 grains / mm, 9 grains / mm, 10 grains / mm, 11 grains / mm, 12 grains / mm, 13 grains / mm, 14 grains / mm, 15 grains / mm, 16 grains / mm, or 17 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0085] In one possible implementation, such as Figure 2 As shown, the average exit height H5 of the secondary new wire satisfies: 2.8um ≤ H5 ≤ 3.5um, and the exit rate C5 of the secondary new wire satisfies: 40 grains / mm ≤ C5 ≤ 100 grains / mm. This ensures that the cutting force of the secondary new wire is moderate. Since the wire mesh in this stage consists of both secondary new and old wires, it prevents excessive local exit rates, thus ensuring a more uniform cutting force on the wire mesh and improving the degree of wire mesh vibration. Simultaneously, it helps reduce the depth of wire marks on the silicon wafer surface, improving silicon wafer quality. C5 represents the number of diamond abrasive grains with a height of ≥ 2um per millimeter of diamond wire 5; that is, diamond abrasive grains with a height of ≥ 2um are the actual diamond abrasive grains participating in and effectively cutting.

[0086] Optionally, in the second intermediate stage, the average cutting edge height H5 of the secondary new line satisfies: 2.8um≤H5≤3.5um. H5 can be 2.8um, 2.9um, 3um, 3.1um, 3.2um, 3.3um, 3.4um or 3.5um, or other values ​​within the above range. This embodiment does not limit this.

[0087] Optionally, in the second intermediate stage, the cutting edge rate C5 of the secondary new line satisfies: 40 grains / mm ≤ C5 ≤ 100 grains / mm. C5 can be 40 grains / mm, 45 grains / mm, 50 grains / mm, 55 grains / mm, 60 grains / mm, 65 grains / mm, 70 grains / mm, 75 grains / mm, 80 grains / mm, 85 grains / mm, 90 grains / mm, 95 grains / mm or 100 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0088] In summary, through the second intermediate stage, the average blade exit height H4 of the old wire satisfies: 2.1um≤H4≤2.6um, and the blade exit rate C4 of the old wire satisfies: 6 blades / mm≤C4≤40 blades / mm. The average blade exit height H5 of the new secondary wire satisfies: 2.8um≤H5≤3.5um, and the blade exit rate C5 of the new secondary wire satisfies: 40 blades / mm≤C5≤100 blades / mm. This ensures that the overall average blade exit height and blade exit rate of the wire mesh are moderate in the second intermediate stage, improving the depth of wire marks on the silicon wafer surface and enhancing the quality of the silicon wafer.

[0089] Furthermore, in the second intermediate stage, the cutting efficiency C11 of the secondary new wire meets the following requirement: 10 grains / mm ≤ C11 ≤ 50 grains / mm. This ensures that the secondary new wire has good cutting force, allowing it to be fully utilized in the second intermediate stage, improving cutting efficiency, and reducing the squeezing and tearing of the wire mesh on the silicon wafer surface. This helps improve the wire mark depth and the uniformity of wire mesh cutting, thereby significantly improving the silicon wafer quality. It also improves the degree of wire mesh bending, enhances the stability of wire mesh cutting, slows down the accumulation of wire mesh fatigue, prevents wire breakage, and ensures normal and stable execution in the final stage. Here, C11 refers to the number of diamond abrasive grains with a height of ≥ 3µm on each millimeter of diamond wire.

[0090] Optionally, in the second intermediate stage, the cutting rate C11 of the secondary new line satisfies: 10 grains / mm ≤ C11 ≤ 50 grains / mm. C11 can be 10 grains / mm, 15 grains / mm, 20 grains / mm, 25 grains / mm, 30 grains / mm, 35 grains / mm, 40 grains / mm, 45 grains / mm, or 50 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0091] In one possible implementation, such as Figure 1 and Figure 2As shown, S7: Reduce the feed speed and line speed to allow the cutting process to gradually transition from the second intermediate stage to the finishing stage. In the finishing stage, control the amount of wire fed by the feed roller 1 to be less than the amount of wire returned by the take-up roller 2. The average exit height H6 of the old wire satisfies: 2um ≤ H6 ≤ 2.4um, and the exit rate C6 of the old wire satisfies: 5 pieces / mm ≤ C6 ≤ 35 pieces / mm. This ensures that the cutting force of the wire mesh is moderate in the finishing stage, preventing the average exit height and exit rate from being too small, thus preventing abnormally large bending deformation of the wire mesh that leads to excessive compression and bending of the wire, improving the accuracy of the cutting path, increasing the uniformity of the cut silicon wafer thickness, and reducing the risk of wire breakage. Simultaneously, ensuring that the average exit height and exit rate of the wire mesh are not too large, since the other end of the silicon rod 4 opposite the front end is sequentially equipped with a plastic plate and an adhesive surface, prevents the risk of wire breakage when cutting to the plastic plate, and also prevents edge chipping of the adhesive surface, improving the yield of the last few silicon wafers. C6 represents the number of diamond abrasive grains with a height of 2µm or higher on each millimeter of diamond wire 5, meaning that diamond abrasive grains with a height of 2µm or higher are the actual diamond abrasive grains that participate in and effectively cut.

[0092] It should be noted that after the silicon rod is cut through, the plastic plate is used for cushioning and support, and the adhesive side adheres to all the silicon wafers to prevent them from scattering.

[0093] Optionally, in the final stage, the average blade exit height H6 of the old line satisfies: 2um≤H6≤2.4um. H6 can be 2um, 2.1um, 2.15um, 2.2um, 2.25um, 2.3um, 2.35um or 2.4um, or other values ​​within the above range. This embodiment does not limit this value.

[0094] Optionally, in the finishing stage, the cutting rate C6 of the old wire satisfies: 5 pieces / mm ≤ C6 ≤ 35 pieces / mm. C6 can be 5 pieces / mm, 6 pieces / mm, 7 pieces / mm, 8 pieces / mm, 9 pieces / mm, 10 pieces / mm, 15 pieces / mm, 20 pieces / mm, 25 pieces / mm, 30 pieces / mm or 35 pieces / mm, or other values ​​within the above range. This embodiment does not limit this.

[0095] Furthermore, during the finishing stage, the cutting efficiency C12 of the old wire satisfies: 1 grain / mm ≤ C12 ≤ 10 grains / mm. This ensures good cutting force during the finishing stage, reduces edge chipping at the exit, improves the uniformity of the silicon wafer wire marks, increases silicon wafer strength, prevents fragmentation, and improves the quality of the silicon wafers cut during the finishing stage, while also preventing wire breakage. C12 refers to the number of diamond abrasive grains with a height of 3µm or higher on each millimeter of diamond wire.

[0096] Optionally, in the finishing stage, the cutting rate C12 of the old line satisfies: 1 grain / mm ≤ C12 ≤ 10 grains / mm. C12 can be 1 grain / mm, 2 grains / mm, 3 grains / mm, 4 grains / mm, 5 grains / mm, 6 grains / mm, 7 grains / mm, 8 grains / mm, 9 grains / mm or 10 grains / mm, or other values ​​within the above range. This embodiment does not limit this.

[0097] It should be noted that the feed rate refers to the speed at which the silicon rod 4 moves relative to the wire mesh along the feed direction. The linear speed refers to the linear speed at which the diamond wire 5 circulates on the wire mesh.

[0098] In one possible implementation, such as Figure 2 As shown in Table 1, the feed position of the silicon rod 4 is in the initial stage between -0.5mm and 30mm. The feed speed V1 and the linear speed F1 are increased. The feed speed V1 satisfies: 1.5mm / min≤V1≤2.9mm / min, and the linear speed F1 satisfies: 13m / s≤F1≤39m / s. The torque on the main roller 3 gradually increases.

[0099] As shown in Table 1 below, Table 1 shows the cutting parameter settings for a silicon wafer cutting method provided in this application.

[0100] Table 1

[0101]

[0102] Specifically, in the initial stage, both the linear speed and the feed rate gradually increase, causing the old wire on the main roller 3 to cut back and forth at a higher linear speed and with a greater amount of wire movement. This fully utilizes the worn diamond abrasive grains on the old wire, which helps to release the cutting force of the old wire, improves silicon wafer quality, and increases cutting efficiency. In addition, in the initial stage, as the silicon rod 4 gradually presses down and contacts the wire mesh, the torque of the main roller 3 gradually increases.

[0103] In one possible implementation, in the initial stage, the feed rate V1 satisfies: 1.5mm / min≤V1≤2.9mm / min, so that the feed rate V1 is moderate and not too high, preventing the diamond abrasive grains on the old wire from breaking and falling off. This ensures that the blade exit rate and average blade exit height of the old wire meet the preset range in the initial stage, improving the cutting quality. At the same time, the feed rate is not too low, which improves the reliability and stability of cutting the silicon rod 4 into silicon wafers and prevents wire breakage.

[0104] Optionally, in the initial stage, the feed rate V1 satisfies: 1.5mm / min≤V1≤2.9mm / min. V1 can be 1.5mm / min, 1.6mm / min, 1.7mm / min, 1.8mm / min, 1.9mm / min, 2mm / min, 2.1mm / min, 2.2mm / min, 2.3mm / min, 2.4mm / min, 2.5mm / min, 2.6mm / min, 2.7mm / min, 2.8mm / min, or 2.9mm / min, or other values ​​within the above range. This embodiment does not limit this.

[0105] In one possible implementation, in the initial stage, the linear speed F1 satisfies: 13m / s≤F1≤39m / s, so that the linear speed F1 is moderate and not too fast, so that the wear of the diamond abrasive grains on the old wire is not excessive, thus extending the service life of the old wire. This ensures that the wire mesh still has good cutting force in the subsequent cutting stage, so that the linear speed is not too slow, preventing the diamond abrasive grains from breaking and detaching, and preventing wire breakage.

[0106] Optionally, in the initial stage, the linear velocity F1 satisfies: 13m / s≤F1≤39m / s. F1 can be 13m / s, 14m / s, 15m / s, 16m / s, 17m / s, 18m / s, 19m / s, 20m / s, 21m / s, 25m / s, 30m / s, 35m / s, 38m / s, or 39m / s, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0107] It should be noted that the amount of wire released refers to the length of diamond wire 5 released from the wire release wheel 1 to the wire take-up wheel 2, and the amount of wire returned refers to the length of diamond wire 5 released from the wire take-up wheel 2 to the wire release wheel 1.

[0108] In the initial stage, the wire laying amount L1 satisfies: 850m≤L1<900m, to prevent the same section of wire from being cut back and forth on the wire mesh and to improve the utilization rate of diamond wire 5. The wire return amount D1 satisfies: 700m<D1≤800m, to improve the stability of wire mesh cutting.

[0109] In summary, in the initial stage, the feed speed V1 and the linear speed F1 meet the above ranges, ensuring that the feed speed V1 and the linear speed F1 are precisely matched with the cutting capability of the old wire. This allows the wire mesh to apply a stable cutting force to the silicon rod 4 in the initial stage, which helps to reduce the degree of wire mesh vibration, improve wire marks, and enhance the quality of the cut silicon wafers. At the same time, the feed speed V1 and the linear speed F1, as well as the wire feed amount L1 and the wire return amount D1, meet the above ranges, which helps to control the average blade height H1 of the old wire in this stage to meet the following requirements: 2.2um≤H1≤2.8um, the blade yield C1 of the old wire to meet the following requirements: 10 pieces / mm≤C1≤60 pieces / mm, and the blade yield C7 of the old wire to meet the following requirements: 1 piece / mm≤C7≤30 pieces / mm.

[0110] In one possible implementation, such as Figure 2 As shown in Table 1, the feed position of the silicon rod 4 is in the first intermediate stage when it is between 30mm and 164mm. The amount of wire return of the take-up roller 2 is reduced, the wire speed F2 is maintained at the peak value during the cutting process, and the feed speed V2 satisfies: 2.7mm / min≤V2≤3.1mm / min. The torque on the main roller 3 first increases, then decreases, and then increases again.

[0111] Specifically, in the first stage, the linear speed is at its peak during the entire cutting process, and the feed rate also reaches its peak during the entire cutting process. The silicon rod 4 presses down on the wire mesh, causing the wire mesh to bend and deform to form a wire bow structure. In the first stage, the number of times the new wire cuts back and forth increases, which is conducive to fully releasing the cutting capacity of the new wire and reducing the amount of new wire used.

[0112] As the feed rate gradually increases to its peak, the arc length increases rapidly, causing the torque on the main roller 3 to increase initially. As cutting continues, the overall mechanical stiffness of the silicon rod 4 decreases significantly because the middle part of the silicon rod 4 has been cut off. Consequently, the actual pressure exerted on the silicon rod 4 by the wire mesh decreases, which in turn reduces the torque on the main roller 3. In the later part of the first intermediate stage, the cutting kerf is deeper, making it difficult for the coolant to effectively enter the deepest part of the cutting area. The silicon powder (chips) generated during cutting is also difficult to remove, leading to local friction and increased temperature, which increases the cutting resistance and causes the torque on the main roller 3 to increase again.

[0113] In one embodiment, the feed rate V2 satisfies: 2.7mm / min≤V2≤3.1mm / min. In the first intermediate stage, this ensures that the feed rate V2 is not too high, preventing the old wires in the wire mesh from being overloaded and breaking, thereby improving the depth of the cut marks on the silicon wafer surface. At the same time, this ensures that the feed rate V2 is not too low, which is conducive to making full use of the cutting capacity of the new wires in the wire mesh and improving the cutting efficiency.

[0114] Optionally, in the first intermediate stage, the feed rate V2 satisfies: 2.7mm / min≤V2≤3.1mm / min. V2 can be 2.7mm / min, 2.8mm / min, 2.9mm / min, 3mm / min or 3.1mm / min, or other values ​​within the above range. This embodiment does not limit this.

[0115] In the first intermediate stage, the wire laying amount L2 satisfies: 810m < L2 < 890m, to prevent the same section of wire from being cut back and forth on the wire mesh and to improve the utilization rate of diamond wire 5. The wire return amount D2 satisfies: 670m < D2 ≤ 720m, to improve the stability of wire mesh cutting.

[0116] In summary, during the first intermediate stage, the linear velocity F2 is maintained at its peak value during the cutting process, and the feed rate V2 meets the aforementioned range. This ensures that the feed rate V2 and linear velocity F2 are precisely matched with the cutting capability of the wire mesh, allowing the wire mesh to apply a stable cutting force to the silicon rod 4 during the first intermediate stage. This helps to reduce wire mesh vibration, improve wire marks, and enhance the quality of the cut silicon wafers. Simultaneously, the feed rate V2, wire release amount L2, and wire return amount D2 all meet the aforementioned ranges, which is beneficial for controlling the first intermediate stage. The average blade exit height H2 of the new wire satisfies: 2.15um≤H2≤2.7um; the blade exit rate C2 of the old wire satisfies: 8 blades / mm≤C2≤55 blades / mm; the blade exit rate C8 of the old wire satisfies: 1 blade / mm≤C8≤23 blades / mm; the average blade exit height H3 of the new wire satisfies: 3.1um≤H3≤4.5um; the blade exit rate C3 of the new wire satisfies: 70 blades / mm≤C3≤190 blades / mm; and the blade exit rate C9 of the new wire satisfies: 30 blades / mm≤C9≤110 blades / mm.

[0117] In one possible implementation, such as Figure 2 As shown in Table 1, the feed position of the silicon rod 4 is between 164mm and 212mm, which is in the second intermediate stage. The feed speed V3 and the linear speed F3 are reduced, while the amount of wire fed by the feed roller 1 and the amount of wire returned by the take-up roller 2 are increased. The feed speed V3 satisfies: 0.9mm / min≤V3<2.7mm / min, and the linear speed F3 satisfies: 33m / s≤F3≤38m / s. The torque on the main roller 3 first increases and then decreases.

[0118] Specifically, in the second intermediate stage, reverse cutting is adopted. The new thread is cut in the first intermediate stage to form a secondary new thread. The cutting force of the secondary new thread is gradually reduced, and the amount of thread released is controlled to be less than the amount of thread returned, so that the secondary new thread can cut back and forth with a larger thread speed and a larger amount of thread movement, making full use of the cutting force of the secondary new thread.

[0119] As the second intermediate stage progresses, the linear speed gradually decreases, the load per unit length of diamond wire 5 gradually increases, and the cutting resistance per unit length of diamond wire 5 gradually increases. The torque on the main roller 3 further increases. As cutting continues, the table speed decreases, the amount of wire fed and returned increases, the amount of wire used per unit feed depth of silicon rod 4 increases, the resistance per unit length of diamond wire 5 decreases, and the torque on the main roller 3 gradually decreases.

[0120] In one possible implementation, the feed rate V3 satisfies: 0.9 mm / min ≤ V3 < 2.7 mm / min. This ensures that the feed rate V3 in the second intermediate stage is moderate, preventing it from being too high and thus reducing the wire mesh load and preventing old wire breakage. At the same time, it ensures that the feed rate V3 is not too low, which is conducive to continuing to cut the wire mesh smoothly into the depth of the silicon rod 4 and improving the quality of the silicon wafer formed by cutting the middle and rear parts of the silicon rod 4.

[0121] Optionally, in the second intermediate stage, the feed rate V3 satisfies: 0.9 mm / min ≤ V3 < 2.7 mm / min. V3 can be 0.9 mm / min, 1 mm / min, 1.1 mm / min, 1.2 mm / min, 1.3 mm / min, 1.4 mm / min, 1.5 mm / min, 1.6 mm / min, 1.7 mm / min, 1.8 mm / min, 1.9 mm / min, 2 mm / min, 2.1 mm / min, 2.2 mm / min, 2.3 mm / min, 2.4 mm / min, 2.5 mm / min, 2.6 mm / min, or 2.65 mm / min, or other values ​​within the above range. This embodiment does not limit this.

[0122] In one possible implementation, during the second intermediate stage, the linear velocity F3 satisfies: 33m / s≤F3≤38m / s. This ensures that the linear velocity F3 is moderate, preventing it from being too high and improving the stability of the diamond abrasive grains adhering to the diamond wire 5, preventing the diamond abrasive grains from falling off, and improving the reliability and stability of wire mesh cutting. Conversely, if the linear velocity is not too low, it facilitates the smooth discharge of silicon powder formed during cutting, reduces the cutting temperature, and prevents wire breakage.

[0123] Optionally, in the second intermediate stage, the linear velocity F3 satisfies: 33m / s≤F3≤38m / s. F3 can be 33m / s, 34m / s, 35m / s, 36m / s, 37m / s, or 38m / s, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0124] In the second intermediate stage, the incoming wire quantity L3 satisfies: 700m < L3 < 820m, to prevent the same section of wire from being cut back and forth on the wire mesh and to improve the utilization rate of diamond wire 5. The take-up wire quantity D3 satisfies: 1000m < D3 < 1800m, to improve the stability of wire mesh cutting.

[0125] In summary, during the second intermediate stage, the feed rate V3 and the linear speed F3 meet the aforementioned ranges. These rates precisely match the cutting capabilities of the old wire and the secondary new wire, enabling the wire mesh to apply a stable cutting force to the silicon rod 4 during this stage. This helps mitigate wire mesh vibration, improves wire marks, and enhances the quality of the cut silicon wafers. Furthermore, the feed rate V3 and linear speed F3, along with the wire feed amount L3 and return amount D3, meet these ranges, which helps control the average output of the old wire during the second intermediate stage. The blade height H4 satisfies: 2.1um≤H4≤2.6um; the blade exit rate C4 of the old line satisfies: 6 blades / mm≤C4≤40 blades / mm; the blade exit rate C10 of the old line satisfies: 1 blade / mm≤C10≤17 blades / mm; the average blade exit height H5 of the new secondary line satisfies: 2.8um≤H5≤3.5um; the blade exit rate C5 of the new secondary line satisfies: 40 blades / mm≤C5≤100 blades / mm; and the blade exit rate C11 of the new secondary line satisfies: 10 blades / mm≤C11≤50 blades / mm.

[0126] In one possible implementation, such as Figure 2 As shown in Table 1, during the final stage, the feed position of the silicon rod 4 is between 212mm and 217.2mm. The amount of wire fed by the wire feeding wheel 1 and the amount of wire returned by the wire taking wheel 2 are controlled to be greater than the amount of wire fed by the wire feeding wheel 1 and the amount of wire returned by the wire taking wheel 2 in the second intermediate stage. The feed speed V4 and the line speed F4 are reduced. The feed speed V4 satisfies: 0.08mm / min≤V4<0.9mm / min, and the line speed F4 satisfies: 24m / s≤F4<33m / s. The torque on the main roller 3 gradually decreases.

[0127] Specifically, the feed rate and linear speed are further reduced, while the amount of wire fed out and returned is increased, so that the torque on the main roller 3 is gradually reduced.

[0128] In addition, from the second stage to the final stage, the amount of wire returned is greater than the amount of wire released, so that the old wire can be wound onto the wire release wheel 1. After the cutting is completed, the next silicon rod 4 can be cut directly by executing step S1, which facilitates subsequent operations and further improves the cutting efficiency.

[0129] In one possible implementation, the feed rate V4 satisfies: 0.08mm / min ≤ V4 < 0.9mm / min. The feed rate V4 is moderate in the final stage, so that the feed rate V4 is not too large, preventing chipping or micro-cracks from appearing at the exit edge of the silicon wafer and improving the quality of the silicon wafer cut in the final stage. At the same time, the feed rate V4 is not too small, preventing wire jamming and deviation from the cutting path, and improving the uniformity of the thickness of the silicon wafer cut in the final stage.

[0130] Optionally, during the final stage, the feed rate V4 satisfies: 0.08 mm / min ≤ V4 < 0.9. V4 can be 0.08 mm / min, 0.09 mm / min, 0.1 mm / min, 0.15 mm / min, 0.2 mm / min, 0.25 mm / min, 0.3 mm / min, 0.35 mm / min, 0.4 mm / min, 0.45 mm / min, 0.5 mm / min, 0.6 mm / min, 0.7 mm / min, or 0.8 mm / min, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0131] In one possible implementation, during the finishing stage, the wire speed F4 satisfies: 24m / s≤F4<33m / s, making the wire speed F4 moderate to prevent wire breakage and improve the reliability and stability of cutting during the finishing stage.

[0132] Optionally, during the final stage, the linear velocity F4 satisfies: 24m / s ≤ F4 < 33m / s. F4 can be 24m / s, 25m / s, 26m / s, 27m / s, 28m / s, 29m / s, 30m / s, 31m / s, or 32m / s, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0133] In the final stage, the incoming wire quantity L4 meets the following requirements: 790m < L3 < 1500m, to prevent the same section of wire from being cut back and forth on the wire mesh and to improve the utilization rate of the diamond wire 5. The take-up wire quantity D4 meets the following requirements: 1600m < D3 < 3000m, to improve the stability of wire mesh cutting.

[0134] In summary, during the final stage, the feed speed V4 and the linear speed F4 meet the above-mentioned ranges. The feed speed V4 and the linear speed F4 are precisely matched with the cutting capability of the old wire, enabling the wire mesh to apply a stable cutting force to the silicon rod 4 during this stage. This helps to reduce the degree of wire mesh vibration, improve wire marks, and improve the quality of the cut silicon wafers. At the same time, the feed speed V4 and the linear speed F4, as well as the wire feed amount L4 and the wire return amount D4, meet the above-mentioned ranges. This helps to control the average blade height H6 of the old wire in the final stage to meet the following requirements: 2um≤H6≤2.4um, the blade yield C6 of the old wire to meet the following requirements: 5 pieces / mm≤C6≤35 pieces / mm, and the blade yield C12 of the old wire to meet the following requirements: 1 piece / mm≤C12≤10 pieces / mm.

[0135] In one possible implementation, such as Figure 2 As shown in Table 2, the torque N1 experienced by the main roller 3 in the initial stage satisfies: 35N m≤N1≤120N m, the torque N2 experienced by the main roller 3 in the first intermediate stage satisfies: 120N m<N2≤137.5N m, the torque N3 experienced by the main roller 3 in the second intermediate stage satisfies: 134N m≤N3≤140N m, the torque N4 on the main roller 3 during the finishing stage satisfies: 10N m≤N4≤130N m.

[0136] As shown in Table 2 below, Table 2 contains parameters of the sum of torques experienced by the three main rollers 3 during the cutting process using the silicon wafer cutting method provided in this application.

[0137] Table 2

[0138]

[0139]

[0140] In one possible implementation, as shown in Table 2, the torque N1 experienced by the main roller 3 in the initial stage satisfies: 35N m≤N1≤120N The torque N1 is matched with the wire speed F1 and the feed speed V1. By pre-setting the safety range of torque in the initial stage, it is beneficial to accurately control the average exit height H1, exit rate C1, and exit rate C7 within the aforementioned preset ranges. This prevents N1 from being too large, as the tensile strength of the wire mesh is relatively weak when using old wire cutting in the initial stage. This prevents the diamond wire 5 from breaking due to overload, improving the reliability and stability of cutting with old wire in the initial stage, while also reducing the depth of the wire marks on the silicon wafer surface in the initial stage, thus improving the quality of the silicon wafer. Conversely, N1 is also prevented from being too small, preventing the diamond wire 5 from slipping in the wire groove and preventing the wire speed from being too low. This helps to control the wire speed F1 to meet the following condition: 13m / s≤F1≤39m / s, thereby ensuring moderate wire mesh tension and continuous and stable cutting force. This helps to reduce the total thickness variation (TTV) of the cut silicon wafer in the initial stage, improving the uniformity of the silicon wafer thickness.

[0141] It should be noted that Total Thickness Deviation (TTV) refers to the thickness difference between the thickest and thinnest points on the same silicon wafer.

[0142] Optionally, the torque N1 experienced by the main roller 3 in the initial stage satisfies: 35N m≤N1≤120N m, N1 can be 35N m, 40N m, 45N m, 48.2N m, 50N m, 60N m, 70N 80N m、90N m, 100N m, 108.6N m, 110N m, 115.2N m, 118.2N m, or 120N m can also be other values ​​within the above range, and this embodiment does not limit this.

[0143] In one possible implementation, as shown in Table 2, the torque N2 experienced by the main roller 3 in the first intermediate stage satisfies: 120N m<N2≤137.5N The torque N2 is matched with the wire speed F2 and the feed speed V2. By pre-setting the torque safety range for the first intermediate stage, it is beneficial to accurately control the average exit height H2, exit rate C2, exit rate C8, average exit height H3, exit rate C3, and exit rate C9 within the aforementioned preset ranges. This prevents N2 from being too large, which helps to reduce the wear of the diamond abrasive grains on the diamond wire 5, reduce impact damage to the diamond wire 5, and extend the service life of both new and old wires. This ensures that the wire mesh still has good cutting force in the subsequent second intermediate stage and final stage, which helps to reduce diamond wire 5 wear, improve wire utilization, and reduce production costs. At the same time, preventing N2 from being too small helps to increase the cutting speed, fully utilize the cutting ability of the diamond wire 5 on the wire mesh in the first intermediate stage, reduce the wire consumption cost per cut, and improve cutting efficiency.

[0144] Optionally, the torque N2 experienced by the main roller 3 in the first intermediate stage satisfies: 120N m<N2≤137.5N m, N2 can be 121.1N m, 124.6N m, 127N m, 128.7N m, 129.9N m, 131.3N m, 132.3N m, 133.4N m, 134.1N m, 134.5N m, 134.7N m, 134.8N m, 135.0N m, 135.4N m, 135.8N m, 136.5N m, 137.0N m or 137.5N m can also be other values ​​within the above range, and this embodiment does not limit this.

[0145] In one possible implementation, as shown in Table 2, the torque N3 experienced by the main roller 3 in the second intermediate stage satisfies: 134N m≤N3≤140N The torque N3 is matched with the wire speed F3 and the feed speed V3. By pre-setting the torque safety range for the second intermediate stage, it is beneficial to accurately control the average exit height H4, exit rate C4, exit rate C10, average exit height H5, exit rate C5, and exit rate C11 within the aforementioned preset ranges. This prevents N3 from being too large, which helps to reduce the wear of diamond abrasive grains on the diamond wire 5, reduces impact damage to the diamond wire 5, and prevents breakage of new and old wires, thus improving the stability of cutting in the second intermediate stage. At the same time, preventing N3 from being too small helps to increase the cutting speed, fully utilize the cutting ability of the diamond wire 5 on the wire mesh in the second intermediate stage, reduce the wire consumption cost per cut, and improve cutting efficiency.

[0146] Optionally, the torque N3 experienced by the main roller 3 in the second intermediate stage satisfies: 134N m≤N3≤140N m, N3 can be 134.5N m, 135N m, 136N m, 137N m, 137.7N m, 138N m, 138.8N m, 138.9N m, 139N m or 140N m can also be other values ​​within the above range, and this embodiment does not limit this.

[0147] In one possible implementation, as shown in Table 2, the torque N4 experienced by the main roller 3 during the finishing stage satisfies: 10N m≤N4≤130N m, torque N4 matches line speed F4 and feed speed V4. By pre-setting the torque safety range in the finishing stage, it is beneficial to accurately control the average blade exit height H6, blade exit rate C6 and blade exit rate C12 within the above preset ranges. This ensures that the torque N4 on the main roller 3 in the finishing stage is not too large, which helps to alleviate wire vibration, prevent wire breakage, and improve the uniformity of the thickness of the silicon wafer cut in this stage.

[0148] Optionally, the torque N4 experienced by the main roller 3 during the finishing stage satisfies: 10N m≤N4≤130N m, N4 can be 10N m, 20N m, 30N m, 40N m, 50N m, 60N m, 70N m, 80N m、90N m, 100N m, 110N m, 114.5N m, 120N m or 130N m can also be other values ​​within the above range, and this embodiment does not limit this.

[0149] Therefore, the torque N1 experienced by the main roller 3 in the initial stage satisfies: 35N m≤N1≤120N m, the torque N2 experienced by the main roller 3 in the first intermediate stage satisfies: 120N m<N2≤137.5N m, the torque N3 experienced by the main roller 3 in the second intermediate stage satisfies: 134N m≤N3≤140N m, and the torque N4 on the main roller 3 during the finishing stage satisfies: 10N m≤N4≤130N m is beneficial for precisely controlling the actual torque on the main roller 3 at each stage of the cutting process to be within a safe and stable range, preventing wire mesh overload, improving the continuity and stability of cutting at each stage, and at the same time, it is beneficial for improving TTV, reducing the depth of wire marks on the silicon wafer surface, improving wire marks, so as to obtain silicon wafers of better quality.

[0150] This application also provides a silicon wafer, which is prepared by the silicon wafer cutting method in any of the above embodiments, which is beneficial to prepare silicon wafers with shallower line marks and relatively smooth surfaces, thereby improving the quality of silicon wafers.

[0151] This application also provides a battery, which includes the silicon wafer in any of the above embodiments. When the silicon wafer is used in the battery, the silicon wafer serves as the substrate of the battery. Since the surface lines of the silicon wafer are shallow and relatively uniform, it is beneficial to provide a good substrate for the battery, which is beneficial to improving the structural strength and photoelectric conversion efficiency of the battery.

[0152] Among them, the types of batteries in this application include, but are not limited to, back contact batteries (BC), tunnel oxide passivated contact batteries (TOPCon), heterojunction with intrinsic thin-layer (HIT), passivated emitter and rear cell (PERC), or perovskite batteries.

[0153] The above are merely specific embodiments of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the scope of the claims.

Claims

1. A method of cutting a silicon wafer, characterized by, The application relates to a method for cutting a crystal silicon rod (4) by using a wire net, and belongs to the technical field of crystal silicon rod cutting. The application comprises the following steps: A wire displacement wheel (1) is used to displace old wire to a wire collecting wheel (2) to form a wire net; A position, where the crystal silicon rod (4) is contacted with the wire net, is set as a zero point; An initial feeding position of the crystal silicon rod (4) is set at -0.5 mm, old wire is used for cutting, and the wire net cuts the crystal silicon rod (4) from left to right during cutting; the cutting process comprises an initial stage, a middle stage and a finishing stage in sequence; the initial stage and the finishing stage use old wire to cut the crystal silicon rod (4); and the middle stage uses new wire and old wire to cut the crystal silicon rod (4); In the initial stage, the wire displacement amount of the wire displacement wheel (1) is greater than the wire collecting amount of the wire collecting wheel (2), the average wire cutting height H1 of the old wire satisfies 2.2 um<=H1<=2.8 um, and the wire cutting rate C1 of the old wire satisfies 10 particles / mm<=C1<=60 particles / mm; 2. The method of dicing a silicon wafer of claim 1 wherein, The middle stage comprises a first middle stage and a second middle stage; in the first middle stage, new wire is used to form the wire net, the wire displacement amount of the wire displacement wheel (1) is greater than the wire collecting amount of the wire collecting wheel (2), and in the second middle stage, the wire displacement amount of the wire displacement wheel (1) is less than the wire collecting amount of the wire collecting wheel (2).

3. The method of dicing a silicon wafer of claim 2 wherein, In the first middle stage, the average wire cutting height H2 of the old wire satisfies 2.15 um<=H2<=2.7 um, the wire cutting rate C2 of the old wire satisfies 8 particles / mm<=C2<=55 particles / mm, the average wire cutting height H3 of the new wire satisfies 3.1 um<=H3<=4.5 um, and the wire cutting rate C3 of the new wire satisfies 70 particles / mm<=C3<=190 particles / mm.

4. The method of dicing a silicon wafer of claim 3 wherein, In the second middle stage, the average wire cutting height H4 of the old wire satisfies 2.1 um<=H4<=2.6 um, the wire cutting rate C4 of the old wire satisfies 6 particles / mm<=C4<=40 particles / mm, the average wire cutting height H5 of the secondary new wire satisfies 2.8 um<=H5<=3.5 um, and the wire cutting rate C5 of the secondary new wire satisfies 40 particles / mm<=C5<=100 particles / mm.

5. The method of dicing a silicon slice according to any one of claims 1-4, wherein, In the finishing stage, the wire displacement amount of the wire displacement wheel (1) is less than the wire collecting amount of the wire collecting wheel (2), the average wire cutting height H6 of the old wire satisfies 2 um<=H6<=2.4 um, and the wire cutting rate C6 of the old wire satisfies 5 particles / mm<=C6<=35 particles / mm.

6. The method of dicing a silicon slice as set forth in any one of claims 2 to 4, wherein When the feeding position of the crystal silicon rod (4) is between -0.5 mm and 30 mm, the initial stage is entered, the cutting speed V1 is increased, the wire speed F1 is increased, and the wire collecting amount of the wire collecting wheel (2) is reduced; the cutting speed V1 satisfies 1.5 mm / min<=V1<=2.9 mm / min, the wire speed F1 satisfies 13 m / s<=F1<=39 m / s, and the torque of the main roller (3) is gradually increased. When the feeding position of the crystal silicon rod (4) is between 30 mm and 164 mm, the first middle stage is entered, the wire collecting amount of the wire collecting wheel (2) is reduced, the wire speed F2 is maintained at the peak value in the cutting process, the cutting speed V2 satisfies 2.7 mm / min<=V2<=3.1 mm / min, and the torque of the main roller (3) is first increased, then decreased and finally increased again.

7. The method of dicing a silicon slice as set forth in any one of claims 2 to 4, wherein The feeding position of the crystal silicon rod (4) is in the second intermediate stage between 164mm and 212mm, the feeding speed V3 and the linear speed F3 are reduced, the amount of wire unwinding of the wire unwinding wheel (1) and the amount of wire winding of the wire winding wheel (2) are increased, the feeding speed V3 satisfies: 0.9mm / min≤V3<2.7mm / min, the linear speed F3 satisfies: 33m / s≤F3≤38m / s, and the torque received by the main roller (3) first increases and then decreases.

8. The method of dicing a silicon slice as set forth in any one of claims 2 to 4, wherein, The end stage is that the feeding position of the crystal silicon rod (4) is between 212mm and 217.2mm, the amount of wire unwinding of the wire unwinding wheel (1) and the amount of wire winding of the wire winding wheel (2) are controlled to be greater than those in the second intermediate stage, the feeding speed V4 and the linear speed F4 are reduced, the feeding speed V4 satisfies: 0.08mm / min≤V4<0.9mm / min, the linear speed F4 satisfies: 24m / s≤F4<33m / s, and the torque received by the main roller (3) gradually decreases.

9. The method of dicing a silicon slice as set forth in any one of claims 2 to 4, wherein, The torque N1 to which the main roller (3) is subjected in the initial phase satisfies: 35 N m ≤ N1 ≤ 120 N m, the torque N2 to which the main roller (3) is subjected in the first intermediate phase satisfies: 120 N m < N2 ≤ 137.5 N m, the torque N3 to which the main roller (3) is subjected in the second intermediate phase satisfies: 134 N m ≤ N3 ≤ 140 N m, the torque N4 to which the main roller (3) is subjected in the final phase satisfies: 10 N m ≤ N4 ≤ 130 N m.

10. A silicon wafer, characterized by, The silicon wafer is prepared by the silicon wafer cutting method in any one of claims 1-9.

11. A battery, characterized by The battery comprises the silicon wafer in claim 10.

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