Silicon block wire cutting method

Abstract

The invention belongs to the technical field of silicon wafer production, and discloses a silicon block wire cutting method which comprises the following steps: S10, before cutting, conveying a new wire with a preset length to a take-up wheel through a pay-off wheel; s20, reversely routing from the take-up wheel to the pay-off wheel, starting to cut the silicon block from the initial cutting position by using a new wire on the take-up wheel, and recycling an old wire formed after cutting to the pay-off wheel; s30, the pay-off wheel conducts forward routing towards the take-up wheel, and the silicon block continues to be cut through the old wire recycled on the pay-off wheel; and S40, when the old wire recovered on the pay-off wheel is used up, the new wire on the pay-off wheel is used for continuously cutting the silicon block till the silicon block is cut through. According to the silicon block wire cutting method, new wire feeding and new wire discharging can be achieved, the use amount of diamond wires can be reduced, and the problems of edge breakage, bright edges and the like of silicon wafers can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon wafer production, and in particular to a silicon block wire cutting method. Background Art

[0002] Silicon wafer cutting is a crucial step in the photovoltaic industry chain. Currently, wire cutting is the most common process for wafer cutting. Traditionally, from the start of cutting to the end, new wire is fed to a payout reel and the old wire is recycled using a takeup reel. This approach suffers from the significant use of diamond wire after the silicon wafer is cut, resulting in high processing costs and a lack of market competitiveness.

[0003] Therefore, in order to save the amount of diamond wire used, in the existing technology, the industry mostly adopts the method of feeding in new wire and taking out old wire to cut silicon blocks. That is, at the beginning of cutting, the new wire is fed by the pay-out wheel, and the old wire is recovered by the take-up wheel. After cutting to the set depth, the wire is reversed, that is, the old wire of the take-up wheel is fed to the pay-out wheel, so that the remaining depth is cut with the returned old wire. However, there is a problem: at the end of cutting, the old diamond wire is used for cutting, which causes the blunt diamond wire to damage the silicon wafer exit surface when the knife is pulled out. The exit surface is prone to bright edge problems due to the insufficient cutting ability of the old wire. It is difficult to improve the quality of the silicon wafer, which is in conflict with reducing costs and reducing wire usage. Therefore, it is very difficult to improve quality or reduce costs in production with the existing cutting method.

[0004] Therefore, there is an urgent need to provide a silicon block wire sawing method to solve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide a silicon block wire cutting method that can realize new wire feeding and new wire exiting, which can not only reduce the requirements for diamond wire cutting force, but also reduce problems such as silicon wafer edge collapse and bright edge.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A silicon block wire sawing method comprising the steps of:

[0008] S10: Before cutting, a new wire of a preset length is fed to the take-up wheel through the pay-off wheel;

[0009] S20: routing the wire in the reverse direction from the take-up wheel to the pay-out wheel, using the new wire on the take-up wheel to start cutting the silicon block from the initial cutting position, and recovering the old wire formed after cutting onto the pay-out wheel;

[0010] S30: routing the wire forward from the pay-out wheel to the take-up wheel, and continuing to cut the silicon block using the old wire recovered from the pay-out wheel;

[0011] S40: When the old wire recovered from the pay-off wheel is completely used up, the new wire on the pay-off wheel is used to continue cutting the silicon block until the silicon block is cut through.

[0012] As an optional solution, in S20, the depth of cutting with the new wire accounts for 47% to 52% of the total cutting depth; and / or

[0013] In said S30, the depth of cutting with the old wire accounts for 30% to 37% of the total cutting depth; and / or

[0014] In the above S40, the depth of cutting using the new wire accounts for 15% to 17% of the total cutting depth.

[0015] As an optional solution, the total cutting depth is 192mm to 211mm;

[0016] In the S20, the depth of the new wire cutting is 100 mm to 111 mm;

[0017] In the S30, the depth of the old wire cutting is 60 mm to 78 mm;

[0018] In the above S40, the new wire cutting depth is 32 mm to 42 mm.

[0019] As an optional solution, the total cutting depth is greater than the dimension of the silicon block in the feeding direction.

[0020] As an optional solution, in S10, the length of the new line transported from the pay-out wheel to the take-up wheel is 3 km to 8 km.

[0021] As an optional solution, in S40, the wire consumption of the new wire is 7 km to 10 km.

[0022] As an optional solution, S20 to S40 all adopt a bidirectional pay-off method. In S20, the wire feeding length of the pay-off wheel is shorter than the wire return length; in S30 and S40, the wire feeding length of the pay-off wheel is longer than the wire return length.

[0023] As an optional solution, the length of the feed line is 700m to 1400m, and the length of the return line is 700m to 2000m.

[0024] As an optional solution, the left tension and the right tension of the diamond wire are controlled to be the same and between 3.1N and 3.6N.

[0025] As an optional solution, the feeding speed of the silicon block is 100-2600 μm / min, and the linear speed of the diamond wire movement is 1200-2450 m / min.

[0026] Beneficial effects of the present invention:

[0027] The present invention provides a method for wire sawing a silicon block. Before cutting, a new wire of a preset length is fed to a take-up wheel via a pay-off wheel. After cutting begins, if the wire breaks during cutting, both the feed wheel and the take-up wheel have new wire, allowing continued cutting with the new wire from the feed wheel or the take-up wheel. This prevents excessive changes in the old and new wires caused by lifting the silicon block, laying the wire net, and then pressing the silicon block hard, which could lead to color differences in the silicon wafer. During cutting, the wire is first routed backward from the take-up wheel to the pay-off wheel, and the new wire on the take-up wheel is used to cut the silicon block from the initial cutting position. The old wire formed after cutting is recovered and returned to the pay-off wheel. After cutting to a set depth, the wire is routed forward from the pay-off wheel to the take-up wheel, and the old wire recovered from the pay-off wheel is used to continue cutting the silicon block. When the old wire recovered from the pay-off wheel is used up, the new wire on the pay-off wheel is used to continue cutting the silicon block until the silicon block is completely cut through. That is to say, the present invention adopts new wire for cutting in and new wire for cutting out, and uses old wire for cutting in the middle section, which can not only reduce the requirements for the cutting force of the diamond wire, but also ensure the cutting force of the diamond wire on the exit surface of the silicon wafer, reducing problems such as chipped edges and bright edges of the silicon wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a simplified structural diagram of a silicon wafer wire sawing device provided by an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the structure of a silicon wafer wire sawing device provided by an embodiment of the present invention;

[0030] Figure 3 It is a specific flow chart of the silicon block wire cutting method provided by an embodiment of the present invention.

[0031] In the picture:

[0032] 10. Pay-off wheel; 20. Take-up wheel; 30. Left main roller; 40. Right main roller; 50. Lower main roller; 60. Diamond wire; 70. Silicon block; 80. Carrier. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0034] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0035] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meanings.

[0037] This embodiment provides a silicon block wire cutting method, which is implemented by using a silicon block wire cutting device to cut the silicon block 70 to form silicon wafers of preset specifications. Figure 1 and Figure 2As shown, the silicon wafer wire sawing device includes a pay-off wheel 10 and a take-up wheel 20 arranged on the left and right. The axes of the pay-off wheel 10 and the take-up wheel 20 are parallel to each other and are driven to rotate synchronously by corresponding motors. A plurality of parallel main rollers are provided between the pay-off wheel 10 and the take-up wheel 20. The axes of the main rollers are parallel to the axis of the pay-off wheel 10. Specifically, there are three main rollers arranged in an inverted triangle, namely the left main roller 30, the right main roller 40 and the lower main roller 50. The outer periphery of each main roller is provided with a thread groove for accommodating the diamond wire 60. The diamond wire 60 is wound on the pay-off wheel 10. The diamond wire 60 released by the pay-off wheel 10 is spirally wound on the three main rollers along the thread groove to form a wire web, which is finally wound on the take-up wheel 20. The area between the left main roller 30 and the right main roller 40 is the cutting area, that is, the silicon block 70 is cut by the wire web between the left main roller 30 and the right main roller 40. A liftable carrier 80 is provided above the left main roller 30 and the right main roller 40 , and the silicon block 70 is adhered to the carrier 80 .

[0038] Before cutting, the silicon block 70 is first bonded to the carrier 80, then the carrier 80 is inverted and fixed on the feed table of the slicer. After the cutting begins, the carrier 80 and the silicon block 70 are driven by the feed table to move continuously downward, from the top of the wire mesh formed by the diamond wire 60 toward the wire mesh, to achieve automated cutting. The direction of the arrow is the feed direction (downward). The wire mesh formed by the diamond wire 60 can cut only one silicon block 70, or it can cut multiple silicon blocks 70 at the same time. The cutting process parameters and the routing method of the diamond wire 60 can be set in advance in the control system, that is, the routing method of the diamond wire 60 during the entire cutting process can be controlled by the program.

[0039] It should be noted that a plurality of guide wheels are provided between the pay-off wheel 10 and the left main roller 30 and between the take-up wheel 20 and the right main roller 40 for guiding and tensioning the diamond wire 60. The above-mentioned silicon wafer wire sawing device belongs to the prior art and will not be described in detail here.

[0040] like Figure 3 As shown, in this embodiment, the silicon block wire sawing method includes the following steps:

[0041] S10: Before cutting, a new wire of a preset length is fed to the take-up wheel 20 via the pay-off wheel 10;

[0042] S20: The wire is routed in the reverse direction from the take-up wheel 20 to the pay-off wheel 10, and the new wire on the take-up wheel 20 is used to cut the silicon block 70 from the initial cutting position. The old wire formed after cutting is recovered to the pay-off wheel 10;

[0043] S30: The wire is moved forward from the pay-off wheel 10 to the take-up wheel 20, and the old wire recovered from the pay-off wheel 10 is used to continue cutting the silicon block 70;

[0044] S40: When the old wire recovered on the pay-off wheel 10 is used up, the new wire on the pay-off wheel 10 is used to continue cutting the silicon block 70 until the silicon block 70 is cut through.

[0045] It should be noted that the new line refers to the cutting line that has never been used, and the old line refers to the cutting line that has been used. Forward pay-off refers to the line running from the pay-off reel 10 to the take-up reel 20, and reverse pay-off refers to the line running from the take-up reel 20 to the pay-off reel 10.

[0046] In the prior art, the cutting method that operators habitually adopt is: 1. From the beginning to the end of cutting, new wire is always fed to the pay-off wheel 10, and the old wire is recovered by the take-up wheel 20; 2. At the beginning of cutting, the pay-off wheel 10 is used to feed the new wire, and the take-up wheel 20 is used to recover the old wire. After cutting to the set depth, the wire is reversed, that is, the old wire of the take-up wheel 20 is fed to the pay-off wheel 10, so that the remaining depth of the silicon block 70 is cut using the returned old wire, and the method of feeding the new wire in and the old wire out is adopted. However, there are problems: the first cutting method is that after the silicon block 70 is cut, the amount of diamond wire 60 used is too large, the processing cost is high, and the company has no market competitiveness; although the second cutting method solves the problem of large amount of diamond wire 60 used, it ignores the problem of insufficient cutting force when the old wire is out of the knife, resulting in the blunt diamond wire 60 damaging the silicon wafer outgoing surface, causing problems such as broken edges and bright edges on the silicon wafer outgoing surface.

[0047] Compared with the cutting method in the prior art, in this embodiment, before cutting, forward pay-off is first adopted, and a new wire of a preset length is wound onto the take-up wheel 20. This embodiment can divide the total cutting depth into three sections. The first section adopts reverse pay-off, and the new wire wound onto the take-up wheel 20 in advance is used for cutting to ensure the cutting force when the knife is inserted; the second section adopts forward pay-off, and the old wire formed by the first section is used for cutting until the old wire is used up, thereby achieving the purpose of reusing the diamond wire 60, saving the use of the diamond wire 60, and saving costs; the third section continues to pay-off in the forward direction, and uses the new wire on the pay-off wheel 10 to continue cutting until the silicon block 70 is cut through, to ensure that the new wire is cut out, meet the cutting force when the knife is cut out, and reduce problems such as chipped edges and bright edges of silicon wafers. In this embodiment, the new routing sequence is different from the routing sequence of the existing cutting method, which overcomes the inherent habits and technical prejudices of the existing routing method. Only by creatively and cleverly changing the routing sequence, it is ensured that the new wire can be used for cutting in the early and late stages of cutting when the cutting difficulty and cutting requirements are higher, without increasing the use of the new wire, thereby achieving unexpected technical effects.

[0048] Specifically, in the wire sawing method for silicon ingots provided in this embodiment, in S10, before cutting, a new wire of a preset length is first fed from the pay-out reel 10 to the take-up reel 20, so that both the pay-out reel 10 and the take-up reel 20 have new wire. After cutting begins, if the wire breaks during cutting, since both the pay-out reel 10 and the take-up reel 20 have new wire, cutting can continue using the new wire from the pay-out reel 10 or the take-up reel 20. This prevents excessive variation in the new and old wires caused by lifting the silicon ingot 70, then laying the wire net, and then pressing the silicon ingot 70, which could lead to color differences in the silicon wafers.

[0049] In S20, during cutting, the wire is first routed in the opposite direction from the take-up wheel 20 to the pay-off wheel 10, and the new wire on the take-up wheel 20 is used to cut the silicon block 70 starting from the initial cutting position. The old wire formed after cutting is recovered to the pay-off wheel 10. The cutting force required for the initial cutting of the silicon block 70 is relatively large. At this time, if the old wire is used for cutting, the old wire has a relatively weak cutting force, which may easily affect the quality of the silicon wafer. Therefore, in this step, the new wire is used to cut the silicon block 70 starting from the initial cutting position. Since the new wire has a relatively strong cutting force, the wire bow formed by the new wire during cutting is relatively small, so that the force on the silicon wafer is more uniform, which is less likely to cause edge collapse and other problems that affect the quality of the silicon wafer, thereby helping to ensure the yield rate.

[0050] In S30, after cutting to the set depth, the new wire on the take-up wheel 20 is used up, and the wire starts to be routed forward from the pay-off wheel 10 to the take-up wheel 20, and the old wire recovered from the pay-off wheel 10 is used to continue cutting the silicon block 70. The old wire recovered on the pay-off wheel 10 refers to the old diamond wire 60 returned after cutting in S20. Cutting at a specific depth using the old wire achieves the purpose of reusing the diamond wire 60, which can not only save the use of new diamond wire 60, but also optimize the cost of diamond wire 60, providing a sustainable solution for production. Moreover, this step belongs to the middle stage of cutting, and its cutting difficulty and cutting requirements are lower than those in the early and late stages of cutting. Therefore, the old wire can be used for cutting, reducing the cutting force requirements of the diamond wire 60.

[0051] In S40, when the old wire recovered from the pay-off wheel 10 is used up, the new wire on the pay-off wheel 10 is used to continue cutting the silicon block 70 until the silicon block 70 is cut through. In other words, the final cutting stage is cut with the new wire, so the new wire is used to cut the silicon wafer. This ensures the cutting force of the diamond wire 60 on the silicon wafer exit surface, reducing problems such as chipped and bright edges of the silicon wafer.

[0052] Optionally, in S20, the cutting depth using the new wire accounts for 47% to 58% of the total cutting depth; and / or in S30, the cutting depth using the old wire accounts for 28% to 41% of the total cutting depth; and / or in S40, the cutting depth using the new wire accounts for 15% to 22% of the total cutting depth.

[0053] Illustratively, the total cutting depth is 192 mm to 211 mm; in S20 , the cutting depth using the new wire is 100 mm to 111 mm; in S30 , the cutting depth using the old wire is 60 mm to 78 mm; and in S40 , the cutting depth using the new wire is 32 mm to 42 mm.

[0054] The cutting depth of the silicon block 70 by the diamond wire 60 in each step is determined by a combination of factors such as the size of the silicon block to be cut, the cutting process parameters, and the acceptable consumption of new wire. For example, in an optional embodiment, the total cutting depth of the silicon block 70 is 192 mm. In S20, the cutting depth using the new wire is 100 mm, i.e., the cutting depth using the new wire accounts for 52% of the total cutting depth; in S30, the cutting depth using the old wire is 60 mm, i.e., the cutting depth using the old wire accounts for 31% of the total cutting depth; and in S40, the cutting depth using the new wire is 32 mm, i.e., the cutting depth using the new wire accounts for 16.6% of the total cutting depth. In other words, the cutting range 0 mm to 100 mm is cut using the new wire, the cutting range 100 mm to 160 mm is cut using the old wire, and the remaining cutting range 160 mm to 192 mm is cut using the new wire, ensuring that the new wire is cut.

[0055] Optionally, in S10, the length of the new wire transported from the pay-off reel 10 to the take-up reel 20 is 3 km to 8 km, and in S40, the wire consumption of the new wire is 7 km to 10 km.

[0056] For example, in an optional embodiment, in S10, the length of the new line transported from the pay-off wheel 10 to the take-up wheel 20 is 8 km; in S20, when cutting starts, the new line is transported from the take-up wheel 20 to the pay-off wheel 10, and the above-mentioned 8 km of new line is used to cut the 0 mm to 100 mm interval; in S30, since all the new line on the take-up wheel 20 has been used up, the line is started to be routed forward from the pay-off wheel 10 to the take-up wheel 20, and the 8 km of old line recovered in S20 is used to cut the 100 mm to 160 mm interval; in S40, since all the old line on the pay-off wheel 10 has been used up, the new line on the pay-off wheel 10 is started to cut the 160 mm to 192 mm interval, and the amount of new line used in this interval is 9.4 km. Therefore, the length of new wire consumed in the entire process is 17.4 km, while the traditional process of using new wire in the forward direction throughout the process requires at least 25.4 km of new wire. Therefore, the process provided in this embodiment can save the use of diamond wire 60 while ensuring that the new wire is cut out.

[0057] It should be noted that the total cutting depth is greater than the dimension of the silicon block 70 in the feeding direction, which fully ensures that the silicon block 70 can be cut through.

[0058] For example, in an optional embodiment, when cutting a 182.2*182.2 silicon wafer, the size of the silicon block 70 in the feed direction is 182.2 mm, and the total cutting depth from the initial cutting position to the cutting end point is 192 mm. In other words, after the silicon block 70 is cut to the required height, it is necessary to continue to move the wire in the original direction and move the silicon block 70 downward by 9.8 mm. Because the diamond wire 60 is inside the silicon block 70 when the silicon block 70 is just cut through, it is difficult to observe and confirm whether the silicon block 70 has been cut through. Therefore, after the silicon block 70 is cut to the required height, it is necessary to continue to move the silicon block 70 downward by a few millimeters to ensure that the silicon block 70 is completely cut through.

[0059] Optionally, the entire process uses a bidirectional pay-off method, that is, the diamond wire 60 reciprocates between the pay-off wheel 10 and the take-up wheel 20 to cut the silicon block 70. In S20, the wire delivery length of the pay-off wheel 10 is less than the wire return length; in S30 and S40, the wire delivery length of the pay-off wheel 10 is greater than the wire return length. The wire delivery length is the length of the diamond wire 60 paid out by the pay-off wheel 10 per unit time, and the wire return length is the length of the diamond wire 60 taken back by the pay-off wheel 10 per unit time. The entire process uses a bidirectional wire running method to cut the silicon block 70, which is beneficial to saving the amount of diamond wire 60 used.

[0060] Specifically, in S20, when cutting starts, the wire feeding length of the pay-off wheel 10 is less than the wire return length, that is, the diamond wire 60 first moves a certain length toward the take-up wheel 20, and then moves a certain distance toward the pay-off wheel 10. The distance moved toward the take-up wheel 20 is less than the distance moved toward the pay-off wheel 10, so the diamond wire 60 moves toward the pay-off wheel 10 as a whole. In this way, the new wire moves toward the pay-off wheel 10, which is essentially the new wire on the take-up wheel 20 is used for cutting when the knife is inserted. In S30 and S40, the wire feeding length of the pay-off wheel 10 is greater than the wire return length, that is, the distance moved toward the take-up wheel 20 by the diamond wire 60 is greater than the distance moved toward the pay-off wheel 10, so the diamond wire 60 moves toward the take-up wheel 20 as a whole. In this way, the old wire and the new wire move toward the take-up wheel 20 in turn, so that the old wire is used for cutting in the middle of the cutting, saving the amount of diamond wire 60, and the new wire is used for cutting when the knife is removed, so as to reduce problems such as chipped edges and bright edges of silicon wafers.

[0061] Based on the above embodiment, the wire feed length can be controlled between 700m and 1400m, and the return wire length can be controlled between 700m and 2000m. The feed speed of the silicon block 70 is controlled between 100 and 2600μm / min, and the linear speed of the diamond wire 60 is controlled between 1200 and 2450m / min. Furthermore, the left and right tensions of the diamond wire 60 can be controlled to be the same, between 3.1N and 3.6N, to avoid insufficient cutting force or wire breakage.

[0062] By adjusting and controlling parameters such as the wire feed length, loop length, feed speed, linear speed and tension of the diamond wire 60, the feed speed of the silicon block 70 is controlled within a reasonable range. This is coordinated with the cutting linear speed to minimize the probability of scratches and breakage on the silicon wafer surface, ensuring the flatness and uniformity of the silicon wafer surface, thereby reducing the occurrence of color difference problems.

[0063] For example, in an optional embodiment, when cutting a silicon wafer with a specification of 182.2*182.2, the cutting process parameters are set as shown in Table 1.

[0064] Table 1

[0065]

[0066] In Table 1, the total cutting depth is set to 192 mm, and the total cutting depth is evenly divided into several cutting positions. Table 1 shows the cutting parameters of each cutting position. The overall wire cutting process of the above cutting scheme is completed through the cutting parameters of each cutting position.

[0067] In Table 1, the initial cutting position of the silicon block 70 is set at -0.1 mm. This means that the initial cutting position is 0.1 mm away from the silicon block 70. This spacing allows for a predictive estimate of the position where the diamond wire 60 will cut the silicon block 70 before cutting begins. If the cutting position is not ideal, adjustments can be made immediately to ensure optimal cutting results.

[0068] Specifically, in S10 , before cutting, 8 km of new wire is first delivered to the take-up reel 20 via the pay-out reel 10 , so that both the pay-out reel and the take-up reel 20 have new wire.

[0069] In S20, that is, during the cutting process from -1mm to 100mm depth, the wire feeding length of the pay-off wheel 10 is less than the wire return length. For example, when the cutting position in Table 1 is 10mm, the wire feeding length is 900m and the wire return length is 1100m, that is, the diamond wire 60 moves 1100m toward the pay-off wheel 10 and then moves 900m toward the take-up wheel 20. In other words, the diamond wire 60 as a whole moves 210m toward the pay-off wheel 10. In this way, the new wire moves toward the pay-off wheel 10, so that the new wire on the take-up wheel 20 is used for cutting when the knife is inserted, increasing the cutting force, making the silicon wafer more evenly stressed, and not easily causing edge collapse and other conditions that affect the quality of the silicon wafer, thereby helping to ensure the yield rate. Among them, at the cutting position of 100mm, the cumulative wire consumption is -8000m, which means that the take-up wheel 20 has fed 8km of diamond wire 60 to the pay-off wheel 10, indicating that at this cutting position, all 8km of new wire on the take-up wheel 20 has been used up.

[0070] In S30, that is, during the cutting process at a depth of 100mm to 160mm, the wire feeding length of the pay-off wheel 10 is greater than the wire return length. At this time, the wire starts to be routed forward from the pay-off wheel 10 to the take-up wheel 20, and the 8km old wire recovered in S20 is used. As shown in Table 1, at the cutting position of 160mm, the cumulative wire consumption is 300m, which means that the pay-off wheel 10 has already delivered 300m of new wire to the take-up wheel 20. In other words, at a certain position before the cutting position of 160mm, the old wire on the pay-off wheel 10 has been used up, but this position is very close to the cutting position of 160mm, so the cutting position of 160mm can be defaulted to the node where the old wire is used up. In this process, the 8km old wire returned after cutting in S20 is used for cutting, which achieves the purpose of reusing the diamond wire 60, which can not only save the use of new diamond wire 60, but also optimize the cost of diamond wire 60, and provide a sustainable solution for production.

[0071] In S40, i.e., during the cutting process from a depth of 160 mm to 192 mm, the wire feed length of the pay-off reel 10 is still greater than the wire return length, and the pay-off reel 10 continues to feed the wire forward toward the take-up reel 20. Since the cumulative wire consumption in Table 1 is all positive, this step indicates that the new wire on the pay-off reel 10 continues to cut the silicon block 70 until the silicon block 70 is completely cut through. In this step, 9.4 km of new wire was used. In other words, the final stage of the cutting is performed using new wire, so the new wire is used for the blade exit, ensuring the cutting force of the diamond wire 60 on the silicon wafer blade exit surface, reducing problems such as chipped and bright edges on the silicon wafer.

[0072] It can be seen that in this embodiment, under the cutting process parameters of Table 1 above, the length of the new wire consumed in the entire process is 17.4 km. Under the same process parameters, the traditional process of using the new wire in the forward direction throughout the process requires at least 25.4 km of new wire. Therefore, the process provided in this embodiment is based on improving the product yield. Under the premise of ensuring the new wire entering and exiting the knife, it can save the use of the diamond wire 60, optimize the cost of the diamond wire 60, and provide a sustainable solution for production.

[0073] In this embodiment, the linear speed, feed speed, and left and right tensions of the diamond wire 60 at each cutting position are precisely controlled, minimizing the probability of scratches and breakage on the silicon wafer surface, thereby significantly improving the yield rate.

[0074] For example, as shown in Table 1, during the cutting process between -1mm and 60mm, after the start of cutting, the feed speed of the silicon block 70 rapidly increases from 1500μm / min to 2100μm / min and remains constant, while the linear speed of the diamond wire 60 gradually increases from 720m / min to 2300m / min. In this process, the increased feed speed of the silicon block 70, combined with the high-speed cutting of the diamond wire 60, accelerates the contact and cutting between the silicon block 70 and the diamond wire 60. This significantly improves production efficiency while ensuring cutting quality, reducing the processing time of a single silicon wafer.

[0075] During the cutting process at the position of 60mm to 100mm, the feed speed of the silicon block 70 remains unchanged at 2100μm / min. Since the new wire on the take-up wheel 20 is about to be used up, the feeding direction of the diamond wire 60 needs to be changed. Therefore, the linear speed of the diamond wire 60 drops to 1320m / min.

[0076] During the process of cutting at the position of 100 mm to 170 mm, the high feed speed of the silicon block 70 is still maintained and combined with the high-speed cutting of the diamond wire 60 to ensure high production efficiency.

[0077] During the process of cutting at the position of 170mm to 192mm, which is the knife closing stage of cutting the silicon block 70, the feed speed and line speed are gradually reduced in this stage to avoid the silicon block 70 moving too fast, causing the diamond wire 60 to form a large arc downward, thereby reducing the occurrence rate of the closing line mark.

[0078] During the entire process, the left tension and the right tension of the diamond wire 60 can be controlled to be the same and kept constant at 3.4N to avoid insufficient cutting force or wire breakage.

[0079] In this embodiment, the silicon ingot wire sawing method further includes supplying liquid to the diamond wire 60 through the liquid supply pipeline in S20, S30, and S40. The cutting fluid cools, lubricates, and cleans the diamond wire 60 during the cutting process, preventing particles from scratching the silicon wafer and reducing the temperature of the diamond wire 60.

[0080] The impact of cutting fluid flow on silicon wafer surface color variation is also significant. Excessively high or low cutting fluid flow can cause silicon dust to adhere to the surface of diamond wire 60, reducing its cutting performance and resulting in color variation. Therefore, in this embodiment, a cutting fluid flow of 230 L / min and a cutting fluid temperature of 20°C were maintained throughout the entire process.

[0081] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A silicon block wire sawing method, characterized in that: Including steps: S10: Before cutting, a new wire of a preset length is fed to the take-up wheel (20) via the pay-off wheel (10); S20: The wire is routed in the reverse direction from the take-up wheel (20) to the pay-off wheel (10), and the new wire on the take-up wheel (20) is used to cut the silicon block (70) from the initial cutting position, and the old wire formed after cutting is recovered to the pay-off wheel (10); S30: moving the wire from the pay-off wheel (10) to the take-up wheel (20) in a forward direction, and continuing to cut the silicon block (70) using the old wire recovered from the pay-off wheel (10); S40: When the old wire recovered from the pay-off wheel (10) is completely used, the new wire on the pay-off wheel (10) is used to continue cutting the silicon block (70) until the silicon block (70) is cut through.

2. The silicon block wire sawing method according to claim 1, wherein: In said S20, the depth of cutting with the new wire accounts for 47% to 58% of the total cutting depth; and / or In said S30, the depth of cutting using the old wire accounts for 28% to 41% of the total cutting depth; and / or In the above S40, the depth of cutting using the new wire accounts for 15% to 22% of the total cutting depth.

3. The silicon block wire sawing method according to claim 1, wherein: Total cutting depth is 192mm to 211mm; In the S20, the depth of the new wire cutting is 100 mm to 111 mm; In the S30, the depth of the old wire cutting is 60 mm to 78 mm; In the above-mentioned S40, the depth of the new wire cutting is 32 mm to 42 mm.

4. The silicon block wire sawing method according to claim 3, wherein: The total cutting depth is greater than the dimension of the silicon block (70) in the feed direction.

5. The silicon block wire sawing method according to any one of claims 1 to 4, characterized in that: In the S10, the length of the new line transported from the pay-off wheel (10) to the take-up wheel (20) is 3 km to 8 km.

6. The silicon block wire sawing method according to any one of claims 1 to 4, characterized in that: In the S40, the wire consumption of the new wire is 7 km to 10 km.

7. The silicon block wire sawing method according to any one of claims 1 to 4, characterized in that: S20 to S40 all adopt a bidirectional pay-off method. In S20, the wire feeding length of the pay-off wheel (10) is less than the wire return length; in S30 and S40, the wire feeding length of the pay-off wheel (10) is greater than the wire return length.

8. The silicon block wire sawing method according to claim 7, characterized in that: The length of the feed line is 700m to 1400m, and the length of the return line is 700m to 2000m.

9. The silicon block wire sawing method according to any one of claims 1 to 4, characterized in that: The left tension and the right tension of the diamond wire (60) are controlled to be the same and between 3.1N and 3.6N.

10. The silicon block wire sawing method according to any one of claims 1 to 4, characterized in that: The feeding speed of the silicon block (70) is 100-2600 μm / min, and the linear speed of the diamond wire movement is 1200-2450 m / min.

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