A process design method for reducing the incidence of wire hanging

Abstract

This invention discloses a process design method to reduce the occurrence of wire breakage. This method is based on tension and stage speed schemes designed for different material layers. During the cutting process, the state of the wire mesh and silicon wafer is dynamically monitored, and each cutting wire in the wire mesh is independently monitored and adjusted. A statistical threshold for cutting wire deviation and a deviation amplitude threshold are designed. When the deviation amplitude of any cutting wire exceeds the threshold, the tension of that group of cutting wires is dynamically adjusted independently. When the actual number of deviated cutting wires exceeds the threshold, the silicon rod stage speed is reduced. This forms a basic dynamic adjustment scheme for the tension of the cutting wire mesh and the silicon rod stage speed, ensuring that the cutting wires can "go straight up and down" when passing through different material layers. Furthermore, pre-adjustment of tension and stage speed is performed when passing through material layers to avoid cutting wire breakage and silicon wafer warping caused by instantaneous tension and stage speed adjustments, and to prevent misalignment.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing, and in particular to a process design method for reducing wire breakage rate. Background Technology

[0002] In silicon wafer production and processing, the mainstream process uses a dicing wire mesh. By tightening the dicing wire and controlling the downward movement of the silicon rod, the silicon rod is cut into wafers by the dicing wire mesh as it passes through the dicing wire. In conventional cutting processes, the dicing wire needs to cut at a specified cutting position to cut through the plastic sheet.

[0003] However, during the silicon wafer cutting process, the cutting wire mesh will have about 3-5 grooves, which keeps the cutting wire mesh in a taut and straight state to reduce quality issues such as thickness due to wire fluctuations. Since the adhesive layer and plastic plate are made of different materials than silicon rods, there are fluctuations when the wire mesh is cut to different materials, which may cause the cut to be skewed. During the material lifting process, the wire mesh may get stuck at a certain position and cannot be withdrawn normally, eventually causing the wire mesh to break, affecting the quality and production capacity of silicon wafers. Summary of the Invention

[0004] The purpose of this invention is to provide a process design method to reduce the occurrence rate of wire breakage, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a process design method for reducing the occurrence rate of wire bridging, comprising the following steps: S1. Based on the material properties of different layers of silicon wafers, establish a material-tension-table speed mapping database; S2. Monitor the position of the wire mesh during silicon wafer cutting. When the wire mesh approaches the alternation position of material layers, adjust the tension and table speed in advance according to the mapping database. S3. Dynamically monitor the status of the wire mesh and silicon wafer, and adjust the tension and table speed accordingly. S4. By building an adjustment model, the mapping database is dynamically updated based on historical data; in; In step S3, each cutting line in the wire mesh is independently monitored and adjusted; and the cutting line deviation statistical threshold Smax and deviation amplitude thresholds Lmax and Lmin are designed. When any cutting line deviates by an amount greater than or equal to Lmax, the tension of that group of cutting lines is dynamically adjusted independently. When the actual number of skewed cutting lines is greater than or equal to Smax, reduce the silicon rod stage speed.

[0006] Preferably, in the material-tension-speed mapping database, the hardness and ductility of the silicon rod and the adhesive layer and plastic plate bonded to the silicon rod are tested. Then, the appropriate tension and speed for cutting the material are determined based on the test data. The data is then summarized and tabulated to form the mapping database.

[0007] 3. A process design method for reducing wire breakage rate according to claim 2, characterized in that step S2 is executed based on a mapping database. When cutting silicon wafers, the cutting depth of the wire mesh in the silicon rod is determined according to the table speed of the silicon rod. Then, the spacing between the alternating positions of the wire mesh and the material layer is determined according to the length of the silicon rod and the positions of the adhesive layer and plastic plate on the silicon rod. By setting a threshold Hmin, when the spacing between the alternating positions of the wire mesh and the material layer = Hmin, an early warning is triggered. At this time, the tension and table speed are pre-adjusted according to the mapping database.

[0008] Preferably, when changing the material layer, a differentiated adjustment strategy is implemented based on the direction of material property change during the pre-adjustment of tension and table speed, including: When the material at the location of the wire mesh changes from hard to soft, a gradual change strategy is adopted. The tension adopts a linear gradual change mode, gradually decreasing from high tension to the target low tension, with an adjustment rate of 5N / 0.1 seconds to match the rhythm of the material hardness decrease. At the same time, the table speed adopts a stepped speed reduction mode, and a holding time is set for each step, and finally the bow shape is restored. When the material at the location of the wire mesh changes from soft to hard, a rapid change strategy is adopted. The tension and table speed are matched in a segmented increase mode. First, the tension and table speed are quickly increased to the transition tension and table speed values, and then gradually increased to the target high tension and table speed range to ensure cutting efficiency.

[0009] Preferably, in step S3, the dynamic monitoring further includes configuring laser displacement sensors at both ends of the cutting line to monitor the height of the two ends of the cutting line on the silicon rod and calculate the height difference between the two ends of the cutting line. And set the position difference threshold. When the height difference between the two ends is ≥ When the tension at both ends of the cutting line is different, it indicates that the tension at both ends is different. If the skewing amplitude of the cutting line is ≤ Lmin, then reduce the tension of the cutting line at the lower end of the silicon rod. If the skewing amplitude of the cutting line is greater than or equal to Lmax, then increase the tension at the higher end of the cutting line on the silicon rod. If Lmax ≤ cutting line skew amplitude ≤ Lmin, then the tension at both ends is calculated, and then the tension value is adjusted synchronously to center the tension.

[0010] Preferably, in step S3, the dynamic monitoring further includes monitoring the uniformity within the material layer, including: The cutting resistance is monitored by a current sensor to detect the real-time current of the cutting wire, and the change in resistance is reflected by the change in current. The vibration amplitude of the wire mesh is determined based on the trajectory data of the skew amplitude of the cutting line. Then, a real-time dynamic strategy for tension and table speed is executed based on changes in cutting resistance and wire mesh vibration amplitude.

[0011] Preferably, the real-time dynamic strategy includes: The tension is adaptively adjusted by setting a current fluctuation threshold. When the fluctuation threshold is reached, it indicates that the material hardness is uneven. The "flexible tension" mode is then adopted, in which the tension is positively correlated with the direction of current fluctuation. This allows the tension value to be dynamically adjusted to increase or decrease within the target range. At the same time, when the skewness of the wire mesh exceeds the preset warning threshold within a preset time, the tension and table speed are immediately reduced.

[0012] Preferably, in step S3, dynamic monitoring also includes silicon wafer status monitoring. When warping of the silicon wafer is detected, it indicates that the overall tension is too high. At this time, the tension is reduced, and the tension is adjusted in real time according to the subsequent changes in the warping amplitude of the silicon wafer until the silicon wafer is no longer warped.

[0013] Preferably, when the wire is about to leave the current material layer, a small-amplitude tension is applied and rapidly increased to reduce the hysteresis at each point of the cutting wire as it crosses the current material layer, so that each point of the cutting wire can synchronously contact the next material layer. At this time, the instantaneous change amplitude of the cutting wire current is used to determine that the cutting wire has reached the next material layer, and then the applied tension is quickly canceled.

[0014] Preferably, in step S4, the adjustment model is designed based on the tension, table speed and silicon wafer quality rating of each material layer in the previous silicon wafer cutting process. With the silicon wafer quality rating as the target, the optimal tension and table speed of the cutting line in each material layer are comprehensively analyzed, and then the model analysis is imported into the mapping database to realize data update.

[0015] The technical effects and advantages of this invention are as follows: 1. This process design method to reduce the occurrence of wire skipping involves dynamically monitoring the state of the wire mesh and silicon wafer during the cutting process. Each cutting wire in the wire mesh is independently monitored and adjusted. A statistical threshold Smax for the amount of wire skipping and thresholds Lmax and Lmin for the skipping amplitude are designed. When the skipping amplitude of any cutting wire is ≥ Lmax, the tension of that group of cutting wires is dynamically adjusted independently. When the actual number of skipped cutting wires is ≥ Smax, the silicon rod speed is reduced. This forms a basic dynamic adjustment scheme for the wire mesh tension and silicon rod speed, ensuring that the cutting wires can "go straight up and down" when passing through different material layers, avoiding miscutting.

[0016] 2. The process design method for reducing wire breakage rate determines the cutting depth of the wire mesh in the silicon rod based on the table speed. Then, it determines the spacing between the alternating positions of the wire mesh and the material layer based on the length of the silicon rod and the positions of the adhesive layer and plastic plate on the silicon rod. By setting a threshold Hmin, an early warning is triggered when the spacing between the alternating positions of the wire mesh and the material layer equals Hmin. At this time, the tension and table speed are pre-adjusted according to the mapping database, thereby realizing the transition of tension and table speed changes and avoiding wire breakage and silicon wafer warping caused by instantaneous tension and table speed adjustments. Attached Figure Description

[0017] Figure 1 This is a flowchart of the cutting process of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention provides, for example Figure 1 The process design method shown includes the following steps to reduce the occurrence rate of wire bridging: S1. Based on the material properties of different layers of silicon wafers, establish a material-tension-table speed mapping database; S2. Monitor the position of the wire mesh during silicon wafer cutting. When the wire mesh approaches the alternation position of material layers, adjust the tension and table speed in advance according to the mapping database. S3. Dynamically monitor the status of the wire mesh and silicon wafer, and adjust the tension and table speed accordingly. S4. By building an adjustment model, the mapping database is dynamically updated based on historical data; in; In step S3, each cutting line in the wire mesh is independently monitored and adjusted; the cutting line deviation statistical threshold Smax and deviation amplitude thresholds Lmax and Lmin are designed. When any cutting line deviates by an amount greater than or equal to Lmax, the tension of that group of cutting lines is dynamically adjusted independently. When the actual number of skewed cutting lines is greater than or equal to Smax, reduce the silicon rod stage speed.

[0020] In the material-tension-speed mapping database, the hardness and ductility of the silicon rod and the adhesive layer and plastic plate attached to it are tested. Then, the appropriate tension and speed for cutting the material are determined based on the test data. The data is then summarized and tabulated to form the mapping database.

[0021] 3. A process design method for reducing wire breakage rate according to claim 2, characterized in that step S2 is executed based on a mapping database. When cutting silicon wafers, the cutting depth of the wire mesh in the silicon rod is determined according to the table speed of the silicon rod. Then, the spacing between the alternating positions of the wire mesh and the material layer is determined according to the length of the silicon rod and the positions of the adhesive layer and the plastic plate on the silicon rod. By setting a threshold Hmin, when the spacing between the alternating positions of the wire mesh and the material layer = Hmin, an early warning is triggered. At this time, the tension and table speed are pre-adjusted according to the mapping database.

[0022] When performing material layer changes, a differentiated adjustment strategy is implemented based on the direction of material property changes during the pre-adjustment of tension and table speed, including: When the material at the location of the wire mesh changes from hard to soft, a gradual change strategy is adopted. The tension adopts a linear gradual change mode, gradually decreasing from high tension to the target low tension, with an adjustment rate of 5N / 0.1 seconds to match the rhythm of the material hardness decrease. At the same time, the table speed adopts a stepped speed reduction mode, and a holding time is set for each step, and finally the bow shape is restored. When the material at the location of the wire mesh changes from soft to hard, a rapid change strategy is adopted. The tension and table speed are matched in a segmented increase mode. First, the tension and table speed are quickly increased to the transition tension and table speed values, and then gradually increased to the target high tension and table speed range to ensure cutting efficiency.

[0023] In step S3, dynamic monitoring also includes configuring laser displacement sensors at both ends of the cutting line to monitor the height of the two ends of the cutting line on the silicon rod and calculate the height difference between the two ends of the cutting line. And set the position difference threshold. When the height difference between the two ends is ≥ When the tension at both ends of the cutting line is different, it indicates that the tension at both ends is different. If the skewing amplitude of the cutting line is ≤ Lmin, then reduce the tension of the cutting line at the lower end of the silicon rod. If the skewing amplitude of the cutting line is greater than or equal to Lmax, then increase the tension at the higher end of the cutting line on the silicon rod. If Lmax ≤ cutting line skew amplitude ≤ Lmin, then the tension at both ends is calculated, and then the tension value is adjusted synchronously to center the tension.

[0024] In step S3, dynamic monitoring also includes monitoring the uniformity within the material layer, including: Cutting resistance is monitored by a current sensor to detect the real-time current of the cutting wire, and the change in resistance is reflected by the change in current. The vibration amplitude of the wire mesh is determined based on the trajectory data of the skew amplitude of the cutting line. Then, a real-time dynamic strategy for tension and table speed is executed based on changes in cutting resistance and wire mesh vibration amplitude.

[0025] Real-time dynamic strategies include: The tension is adaptively adjusted by setting a current fluctuation threshold. When the fluctuation threshold is reached, it indicates that the material hardness is uneven. The "flexible tension" mode is then adopted, in which the tension is positively correlated with the direction of current fluctuation. This allows the tension value to be dynamically adjusted to increase or decrease within the target range. At the same time, when the skewness of the wire mesh exceeds the preset warning threshold within a preset time, the tension and table speed are immediately reduced.

[0026] In step S3, dynamic monitoring also includes silicon wafer status monitoring. When warping of the silicon wafer is detected, it indicates that the overall tension is too high. At this time, the tension is reduced, and the tension is adjusted in real time according to the subsequent changes in the warping amplitude of the silicon wafer until the silicon wafer is no longer warped.

[0027] When the wire is about to leave the current material layer, a small-amplitude tension is applied and rapidly increased to reduce the hysteresis at each point of the cutting wire as it crosses the current material layer, so that each point of the cutting wire can synchronously contact the next material layer. At this time, the instantaneous change amplitude of the cutting wire current is used to determine that the cutting wire has reached the next material layer, and then the applied tension is quickly canceled.

[0028] In step S4, the adjustment model is designed based on the tension, table speed and silicon wafer quality rating of each material layer in the previous silicon wafer cutting process. With the silicon wafer quality rating as the target, the optimal tension and table speed of the cutting line in each material layer are comprehensively analyzed. Then, the model analysis is imported into the mapping database to realize data update.

[0029] Working principle: In this process design method to reduce the occurrence of wire skipping, the state of the wire mesh and silicon wafer is dynamically monitored during the cutting process. Each cutting wire in the wire mesh is independently monitored and adjusted. The statistical threshold Smax for the amount of cutting wire deviation and the thresholds Lmax and Lmin for the deviation amplitude are designed. When the deviation amplitude of any cutting wire is ≥ Lmax, the tension of that group of cutting wires is dynamically adjusted independently. When the actual number of deviated cutting wires is ≥ Smax, the silicon rod speed is reduced. This forms a basic dynamic adjustment scheme for the tension of the cutting wire mesh and the silicon rod speed, so as to ensure that the cutting wire can go straight up and down when passing through different material layers and avoid miscutting. Furthermore, the current cutting depth of the wire mesh in the silicon rod is determined by the table speed of the silicon rod. Then, the spacing between the alternating positions of the wire mesh and the material layer is determined by the length of the silicon rod and the positions of the adhesive layer and plastic plate on the silicon rod. By setting a threshold Hmin, an early warning is triggered when the spacing between the alternating positions of the wire mesh and the material layer equals Hmin. At this time, the tension and table speed are pre-adjusted according to the mapping database, so as to realize the transition of tension and table speed changes and avoid the occurrence of cutting wire breakage and silicon wafer warping caused by instantaneous tension and table speed adjustments. Meanwhile, when adjusting tension and table speed, a small-amplitude tension increase needs to be applied when the wire is about to leave the current material layer. This reduces the lag at each point of the cutting wire as it passes through the current material layer, allowing each point of the cutting wire to synchronously contact the next material layer. At this time, the instantaneous change amplitude of the cutting wire current is used to determine when the cutting wire reaches the next material layer. Then, the applied tension increase is quickly canceled to avoid "material jamming" caused by cutting lag.

[0030] Example 2, see attached document Figure 1 In this embodiment, the cutting effect is explained using practical data based on the theoretical method of Embodiment 1. Cutting targets: Silicon rod dimensions 210mm x 830mm, hardness HV1100-1200, ductility 0.15%; Adhesive layer thickness 5mm, hardness HV200-300, ductility 15%; Plastic sheet thickness 5.5mm, hardness HV100-150, ductility 25%; Equipment model: Multi-line slicer, main roller groove distance 0.236mm, shaft spacing 415mm, maximum linear speed 830m / min, maximum table speed 2100mm / min; Core objectives: Incidence rate of wire breakage ≤ 0.1%, wafer skew error ≤ 0.01mm, thickness deviation ± 0.01mm, wafer pass rate > 99.8%. Monitoring configuration: 3 sets of laser displacement sensors, deployed on the left, center and right, with an accuracy of ±0.005mm and a sampling frequency of 50Hz; current sensor sampling frequency of 10Hz; online monitoring of silicon wafer thickness / warp detector, with an accuracy of ±0.005mm;

[0031] Material hardness and ductility tests have been completed, and the above mapping database has been established; the laser displacement sensor has been calibrated, with a three-point height deviation of <0.003mm and a current sensor measurement error of ≤0.1A; the silicon rod loading length is 830mm.

[0032] The specific work process is as follows; I. Silicon rod cutting stage Initial parameters: tension 710N, table speed 2000mm / min, line speed 830m / min, line speed-to-table speed ratio 1.00; current stabilized at 19A, net heights at the left, center, and right points are 210.00mm, 210.00mm, and 210.00mm respectively, number of skewed cutting lines 0, wafer thickness deviation 0.005mm, no warping; maintain target tension and table speed at this point, no adjustments. II. Silicon rod-adhesive layer transition When the cutting depth reaches 192mm, the distance between the wire mesh and the adhesive layer is 8mm = Hmin. The system triggers an alarm. At this point, the tension gradually changes linearly from 710N, with the adjustment rate at 5N / 0.1 seconds. After 1.6 seconds, it drops to the target transition tension of 660N. The table speed decreases in steps: 2000mm / min for 0.5 seconds, 1800mm / min for 0.5 seconds, and then stabilizes at 1600mm / min. After the transition, the tension is 660N, the table speed is 1600mm / min, the current drops to 16A, and the wire mesh vibration amplitude is 0.006mm. III. Adhesive Layer Cutting Stage At this point, the current fluctuation range is 15.5-16.3A, indicating slight material inhomogeneity. The skewness of the 23rd, 47th, and 61st cutting lines is 0.008mm, and the heights of the left, center, and right points are 205.00mm, 205.005mm, and 205.00mm respectively, with a positional difference of 0.005mm (below the threshold). The silicon wafer shows no warping, and the thickness deviation is 0.007mm. Tension adjustment is then performed, activating the "flexible tension" mode. The tension is finely adjusted synchronously with current fluctuations, increasing by +2N when the current rises and decreasing by -2N when it falls, maintaining it within the 640-660N range. Then, the tension at both ends of the three skewed cutting lines is adjusted to center the tension, decreasing the left tension by 3N and increasing the right tension by 3N. After 0.3 seconds, the skewness drops to 0.004mm. Once stable, the tension is 650N, the table speed is 1500mm / min, and the number of skewed cutting lines is 3. <Smax。

[0033] IV. Adhesive Layer - Plastic Sheet Transition When the cutting depth reaches 197mm and the distance between the wire mesh and the plastic plate is 3mm (Hmin), an alarm is triggered. At this time, the tension gradually changes linearly from 650N to 640N after 1.2 seconds. The table speed is maintained at 1600mm / min for 0.5 seconds, then decreases to 1500mm / min and is maintained for 0.5 seconds, and finally decreases to 1300mm / min and stabilizes. After the transition, the current drops to 11A, the wire mesh vibration amplitude is 0.005mm, and there is no cutting line skew. V. Plastic Sheet Cutting Stage At this time, among the 13 cutting lines from the 156th to the 168th of the wire mesh, the skew amplitude is 0.021 mm (≥Lmax), and the number of skewed lines is 13 < Smax; the material layer leaves the warning: the cutting depth reaches 208.5 mm and is about to leave the plastic board. At this time, the tension of a single line is adjusted: the tension at the higher end of the position of the 13 skewed cutting lines is increased by 5 N. After 0.2 seconds, the skew amplitude drops to 0.007 mm; the tension increase value before leaving; apply a tension increase value of 10 N, and the tension is increased from 640 N to 650 N. After 0.5 seconds, the current instantaneously rises to 12 A, and it is determined that the cutting end is contacted, and the increase value is immediately cancelled, and 640 N is restored; at this time, the tension is 640 N, the table speed is 1200 mm / min, and the number of skewed cutting lines is 0.

[0034] The operation results after final processing are as follows;

[0035] The size specification of the silicon wafer after cutting is 210 mm x 210 mm x 0.236 mm, meeting the design requirements; there are no chipping and scratches on the surface of the silicon wafer, and the surface roughness Ra ≤ 0.3 um; the warpage amplitude of the silicon wafer ≤ 0.01 mm, and the fracture strength ≥ 250 MPa; among 3517 silicon wafers of the same batch, the proportion of those with a thickness deviation < 0.008 mm is 99.7%, and the proportion of those with a cutting skew error < 0.006 mm is 99.8%.

[0036] This cutting operation is strictly carried out according to the process logic of "material - tension - table speed mapping database - pre - judgment adjustment - dynamic feedback - database update". Through means such as differential transition strategy, independent control of single cutting lines, and flexible tension adjustment within the material layer, the risk of wire hanging is completely avoided, and at the same time, the quality and production efficiency of the silicon wafers are guaranteed. During the operation process, various parameters respond in a timely manner (adjustment delay ≤ 0.3 seconds), and abnormal scenarios are effectively handled, verifying the practicability and stability of this process design method, which can be directly and scaled - up applied to the cutting production of similar silicon wafers.

[0037] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A process design method for reducing the incidence of wire-hanging, characterized by, Includes the following steps: S1. Based on the material properties of different layers of silicon wafers, establish a material-tension-table speed mapping database; S2. Monitor the position of the wire mesh during silicon wafer cutting. When the wire mesh approaches the alternation position of material layers, adjust the tension and table speed in advance according to the mapping database. S3. Dynamically monitor the status of the wire mesh and silicon wafer, and adjust the tension and table speed accordingly. S4. By building an adjustment model, the mapping database is dynamically updated based on historical data; in; In step S3, each cutting line in the wire mesh is independently monitored and adjusted; and the cutting line deviation statistical threshold Smax and deviation amplitude thresholds Lmax and Lmin are designed. When any cutting line deviates by an amount greater than or equal to Lmax, the tension of that group of cutting lines is dynamically adjusted independently. When the actual number of skewed cutting lines is greater than or equal to Smax, reduce the silicon rod stage speed.

2. The process design method of claim 1, wherein, In the material-tension-speed mapping database, the hardness and ductility of the silicon rod and the adhesive layer and plastic plate attached to it are tested. Then, the appropriate tension and speed for cutting the material are determined based on the test data. The data is then summarized and tabulated to form the mapping database.

3. The process design method of claim 2, wherein, Step S2 is executed based on the mapping database. When cutting silicon wafers, the cutting depth of the current wire mesh in the silicon rod is determined according to the table speed of the silicon rod. Then, the spacing between the alternating positions of the wire mesh and the material layer is determined according to the length of the silicon rod and the positions of the adhesive layer and plastic plate on the silicon rod. By setting a threshold Hmin, when the spacing between the alternating positions of the wire mesh and the material layer is equal to Hmin, an early warning is triggered. At this time, the tension and table speed are pre-adjusted according to the mapping database.

4. The process design method of claim 3, wherein, When performing material layer changes, a differentiated adjustment strategy is implemented based on the direction of material property changes during the pre-adjustment of tension and table speed, including: When the material at the location of the wire mesh changes from hard to soft, a gradual change strategy is adopted. The tension adopts a linear gradual change mode, gradually decreasing from high tension to the target low tension, with an adjustment rate of 5N / 0.1 seconds to match the rhythm of the material hardness decrease. At the same time, the table speed adopts a stepped speed reduction mode, and a holding time is set for each step, and finally the bow shape is restored. When the material at the location of the wire mesh changes from soft to hard, a rapid change strategy is adopted. The tension and table speed are matched in a segmented increase mode. First, the tension and table speed are quickly increased to the transition tension and table speed values, and then gradually increased to the target high tension and table speed range to ensure cutting efficiency.

5. The process design method for reducing the occurrence rate of wire snagging according to claim 1, characterized in that, The step S3 further comprises configuring laser displacement sensors at both ends of the cutting line, monitoring the height of both ends of the cutting line on the silicon rod, and calculating the height difference between both ends of the cutting line , and setting a position difference threshold When the height difference between both ends is greater than or equal to , it indicates that the tension at both ends of the cutting line is different, and at this time If the skewing amplitude of the cutting line is ≤ Lmin, then reduce the tension of the cutting line at the lower end of the silicon rod. If the skewing amplitude of the cutting line is greater than or equal to Lmax, then increase the tension at the higher end of the cutting line on the silicon rod. If Lmax ≤ cutting line skew amplitude ≤ Lmin, then the tension at both ends is calculated, and then the tension value is adjusted synchronously to center the tension.

6. The process design method of claim 5, wherein, In step S3, dynamic monitoring also includes monitoring the uniformity within the material layer, including: The cutting resistance is monitored by a current sensor to detect the real-time current of the cutting wire, and the change in resistance is reflected by the change in current. The vibration amplitude of the wire mesh is determined based on the trajectory data of the skew amplitude of the cutting line. Then, a real-time dynamic strategy for tension and table speed is executed based on changes in cutting resistance and wire mesh vibration amplitude.

7. The process design method of claim 6, wherein, The real-time dynamic strategy includes: The tension is adaptively adjusted by setting a current fluctuation threshold. When the fluctuation threshold is reached, it indicates that the material hardness is uneven. The "flexible tension" mode is then adopted, in which the tension is positively correlated with the direction of current fluctuation. This allows the tension value to be dynamically adjusted to increase or decrease within the target range. At the same time, when the skewness of the wire mesh exceeds the preset warning threshold within a preset time, the tension and table speed are immediately reduced.

8. The process design method for reducing the occurrence rate of wire snagging according to claim 1, characterized in that, In step S3, dynamic monitoring also includes silicon wafer status monitoring. When warping of the silicon wafer is detected, it indicates that the overall tension is too high. At this time, the tension is reduced, and the tension is adjusted in real time according to the subsequent changes in the warping amplitude of the silicon wafer until the silicon wafer is no longer warped.

9. The process design method for reducing the occurrence rate of wire snagging according to claim 4, characterized in that, When the wire is about to leave the current material layer, a small-amplitude tension is applied and rapidly increased to reduce the hysteresis at each point of the cutting wire as it crosses the current material layer, so that each point of the cutting wire can synchronously contact the next material layer. At this time, the instantaneous change amplitude of the cutting wire current is used to determine that the cutting wire has reached the next material layer, and then the applied tension is quickly canceled.

10. The process design method for reducing the occurrence rate of wire snagging according to claim 1, characterized in that, In step S4, the adjustment model is designed based on the tension, table speed and silicon wafer quality rating of each material layer in the previous silicon wafer cutting process. With the silicon wafer quality rating as the target, the optimal tension and table speed of the cutting line in each material layer are comprehensively analyzed. Then, the model analysis is imported into the mapping database to realize data update.

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