Automatic scribing method for silicon rod throwing-cutting thick piece
By acquiring silicon rod image information and using a laser for automatic scribing, the problem of uneven silicon wafer thickness caused by uneven silicon rod end faces was solved, improving silicon rod cutting quality and wafer yield, and achieving efficient silicon rod scribing.
Patent Information
- Application Number
- CN202411047621.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2026-02-10
AI Technical Summary
In existing technologies, uneven silicon rod end faces lead to uneven silicon wafer thickness, affecting cutting quality and efficiency. Furthermore, inaccurate scribing causes diamond wire breakage, severely impacting silicon rod yield.
By acquiring image information of silicon rods, the locations of ends, seams, and defects are identified. A laser is used to automatically scribble lines at designated locations, and a camera is used to verify the accuracy of the scribing, thereby improving scribing efficiency and accuracy.
It enables fast and precise silicon rod scribing, improving silicon rod yield and cutting quality. The scribing time for a single silicon rod has been reduced from 300 seconds to 60 seconds, and the number of wafers produced has increased by 6-8.
Smart Images
Figure CN121491546A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of silicon rod splicing technology, and in particular relates to an automatic scribing method for cutting thick silicon rods. Background Technology
[0002] Silicon wafers are produced by cutting silicon rods using a multi-wire dicing machine. However, unevenness or chipping on the end face of the silicon rod (hereinafter referred to as "silicon rod") leads to uneven thickness of the wafers cut from the end face, resulting in a low yield of end-face silicon wafers. Furthermore, if the wafer thickness near the end face of the silicon rod is too thin, the diamond wires near the end face may cut through the end face or contact chipped areas, causing wire breakage or skipping, affecting the cutting effect of adjacent diamond wires and consequently impacting the quality of other silicon wafers. Therefore, it is necessary to cut silicon wafers of a certain width from the end face of the silicon rod, i.e., cutting thicker wafers at both ends of the silicon rod, to ensure the stability of the diamond wire operation and the cutting quality of the silicon wafers. Thus, the marking of the thicker wafers is crucial for ensuring the diamond wire arrangement and silicon wafer cutting.
[0003] The current method for measuring (marking) the width of thick wafers during slicing is completed inside the cutting chamber of the silicon rod installation line slicing machine. This requires opening both cutting chamber doors, installing the silicon rod, and then using a set square to measure (mark) the slicing width based on the position of the diamond wire. This requires operators to frequently move from the left and right sides to measure the slicing width at the beginning, end, and seam. Furthermore, the unstable reference accuracy of the set square and varying operator skill levels lead to inaccurate marking. The limited operating space further exacerbates the inaccuracy, severely impacting cutting quality and the wafer yield per kilogram of silicon rod. Moreover, the low work efficiency significantly restricts production capacity. Summary of the Invention
[0004] This application provides an automatic scribing method for cutting thick silicon rods, which solves the technical problem that the scribing method in the prior art seriously leads to inaccurate scribing of the thick silicon rods, affecting the cutting quality and silicon rod yield.
[0005] To solve at least one of the above-mentioned technical problems, the technical solution adopted in this application is:
[0006] An automatic scribing method for cutting thick silicon rods, comprising the following steps:
[0007] Acquire and process images of the silicon rod's cutting surface and its two outer walls to obtain the silicon rod's end and / or seam and / or defect locations;
[0008] Based on the scribing standard, scribing is performed at the ends of the silicon rod and / or at the joints and / or defect locations.
[0009] Furthermore, the line marking criteria include the line marking position, specifically:
[0010] At a distance of 0.4-0.6 mm from the end of the silicon rod;
[0011] And / or, at both ends of the seam and 0.4-0.6 mm from the two end faces of the seam;
[0012] And / or, at the location of the defect, at its maximum width along the length of the silicon rod and 0.4-0.6 mm from both sides of the maximum width location;
[0013] The scribed lines are all located at non-beveled points on the sidewall of the silicon rod.
[0014] Furthermore, the line marking standard also includes the line length, specifically:
[0015] On the side wall of the silicon rod, a scribing line is drawn along the height direction of the silicon rod, starting from below the chamfer in the cutting surface and moving towards the side where the adhesive surface of the silicon rod is located, with the scribing line length not exceeding 8cm.
[0016] Furthermore, the acquisition and processing of image information of the silicon rod's cutting surface and its two outer wall surfaces specifically involves:
[0017] Images of the silicon rod's cut surface and its two outer walls were taken with a camera.
[0018] The captured images are then digitally converted to obtain an unfolded two-dimensional image that includes the silicon rod's entry surface and both side walls.
[0019] Based on this two-dimensional image, one or more of the following can be identified: silicon rod end, seam, and defect location. The total length of the silicon rod, seam width, and the maximum width of one or more of the following defects along the length of the silicon rod can also be obtained.
[0020] Furthermore, it also includes judging whether the defects meet the marking criteria, specifically:
[0021] If the maximum width of the defect along the length of the silicon rod is greater than or equal to 1 mm, then the location of the defect needs to be marked.
[0022] If the maximum width of the defect along the length of the silicon rod is less than 1 mm, then there is no need to scribing the defect location.
[0023] Furthermore, the camera that takes pictures of the silicon rod's inlet cut surface is positioned differently from the camera that takes pictures of the silicon rod's sidewall surface; the camera that takes pictures of the silicon rod's inlet cut surface is suspended on top of the frame used to support the silicon rod lying flat, while the camera that takes pictures of the silicon rod's inlet cut surface's sidewall surface is fixed to the sidewall surface of the frame.
[0024] Furthermore, the scribe line marking at the ends of the silicon rod and / or at the seams and / or defects specifically involves:
[0025] A laser is used to scribing lines on a silicon rod;
[0026] First, adjust the position of the laser so that it is located outside the side wall of the silicon rod where the scribed line is located, and align the laser head with the side wall of the silicon rod.
[0027] The laser is controlled and its position is adjusted by a movable component mounted on the side wall of the rack.
[0028] Based on the marking position, markings are made sequentially along the length of the silicon rod at the ends and / or seams and / or defects.
[0029] Furthermore, scribing of the silicon rod includes laser scribing on one or both sides of the silicon rod, specifically:
[0030] First, control the laser to scribing all the positions to be scribed on one side of the silicon rod, and then scribble them sequentially along the length of the silicon rod.
[0031] Based on the scribing sequence on the upper side wall, the laser is controlled to scribing all the positions to be scribed on the other side wall of the silicon rod.
[0032] Furthermore, it also includes a step of determining whether the line drawing result is qualified, specifically:
[0033] Take another photo of the scale lines on the side wall of the silicon rod using the camera;
[0034] After processing, the actual position of the scribing line and its height can be obtained;
[0035] Compare the actual scribing position with the standard scribing position to see if they overlap. If they do, the scribing position is correct; if not, an alarm is triggered and the scribing is repeated.
[0036] Based on the scribing standard, the scribing height is judged to be clear. If the scribing length is not less than 8cm, it is qualified; if the scribing length is less than 8cm, the scribing is redone.
[0037] Furthermore, before acquiring image information of the silicon rod's infeed cut surface and its two outer walls, the process also includes controlling the silicon rod to be transferred to a designated position with its infeed cut surface facing upwards, and the silicon rod being adhered to the material holder. The silicon rod is then moved to the designated position by a roller placed at the bottom of the frame.
[0038] The automatic scribing method for thick silicon ingot cutting designed in this application can quickly identify the location and seam width of the outer end face and splicing surface of the silicon ingot, and can perform precise scribing; it can also quickly verify the scribing position to determine whether the scribing is successful; this method can improve the efficiency of scribing cutting, reducing the scribing time of a single silicon ingot from 300s to 60s; it can improve the accuracy of laser scribing, while also increasing the wafer yield of silicon ingots, and increasing the average number of wafers produced from a single ingot by 6-8. Attached Figure Description
[0039] Figure 1 This is a flowchart of an automatic scribing method for cutting thick silicon rods into wafers according to an embodiment of this application;
[0040] Figure 2 This is a structural diagram of a marking device according to an embodiment of this application;
[0041] Figure 3 This is a schematic diagram of a marking device according to an embodiment of this application from another angle;
[0042] Figure 4 This is a simplified schematic diagram illustrating the position of the scribed line according to an embodiment of this application;
[0043] Figure 5 These are the various scribing positions on the side of the silicon rod according to an embodiment of this application;
[0044] Figure 6 This is a schematic diagram of an unfolded two-dimensional image according to an embodiment of this application.
[0045] In the picture:
[0046] 10. Rack; 20. Camera; 30. Laser
[0047] 40. Controller; 50. Display; 60. Silicon rod
[0048] 61. End; 62. Joint; 63. Defect
[0049] 70. Laser emitter; 80. Industrial control computer Detailed Implementation
[0050] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0051] This embodiment proposes an automatic scribing method for silicon rod slicing into thick wafers, such as... Figure 1 As shown, the steps include:
[0052] S1. Control the silicon rod to be transferred to the specified position and set its infeed cutting surface to face upwards.
[0053] like Figure 2-3As shown, the silicon rod 60 is first bonded to the material holder, and the silicon rod and the material holder are placed together on the bottom roller belt of the frame 10 in the automatic marking equipment. The length of the silicon rod 60 is set along the length direction of the frame 11, so that the infeed surface of the silicon rod 60 is facing upward, and both sides of the infeed surface are vertically set.
[0054] The frame 10 has open ends and closed sides. Two positioning blocks are located in the middle of the roller belt to support the bottom of the material holder and position the silicon rod at a designated location. These positioning blocks are positioned along the width of the silicon rod, and each block is equipped with a motor. The motor drives the positioning block to rise and fall, pressing against the material holder to position the silicon rod at the designated location. After the marking is completed, the positioning blocks are lowered to bring the material holder into contact with the roller belt, which then moves the silicon rod out of the marking equipment.
[0055] Correspondingly, inside the frame 10, there are also a number of cameras 20 for taking pictures of the upper end of the silicon rod's entry surface and its side wall surface. Two of these cameras are suspended at the top of the frame 10 for taking pictures of the entry surface of the silicon rod. Two sets of cameras 20 are provided on each of the two sides of the frame 10 along its length for taking pictures of the two side walls of the silicon rod. Since camera 30, which photographs the sidewall of the silicon rod, primarily monitors the position of the silicon rod's end face, it is positioned close to the outer end face of the silicon rod 60. Camera 20, which photographs the inlet face of the silicon rod, primarily photographs and inspects the upper end face of the silicon rod 60, i.e., the inlet face where the silicon rod 60 contacts the wire mesh during slicing. Its main purpose is to facilitate monitoring the position of the seams on the silicon rod. Therefore, the positions of camera 20 photographing the inlet face and camera 30 photographing the sidewall of the silicon rod are not aligned along the length of the silicon rod, and camera 20 photographing the inlet face is farther from the end face of the silicon rod than camera 30 photographing the sidewall. In this embodiment, the monitor is a commonly used industrial camera.
[0056] A laser 30 for scribing is provided on the long side of the silicon rod. Correspondingly, a moving assembly for driving the laser 30 is provided on one side wall of the frame 10 along its length. This assembly includes a translation group for controlling the laser 30 to move along the length of the silicon rod (i.e., along the length of the frame 10), a transverse group for controlling the laser 30 to move across the width of the silicon rod (i.e., along the width of the frame 10), and a longitudinal group for controlling the laser 30 to move up and down. The translation group, transverse group, and longitudinal group work together to control the laser 30 to perform the scribing task at the corresponding scribing position.
[0057] Correspondingly, at the top of the rack 10, there is also a laser emitter 70 for controlling the laser 30; an industrial computer 80 for controlling the laser generator and displaying the position and working status of the laser 30 on the display 50; and a controller 40 for data acquisition, image processing, and communication transmission, which is housed in a control cabinet. The display 70 is located on one side of the end of the rack 10 for easy operation by the operator.
[0058] In this embodiment, the laser 30 can scribble lines on one side of the silicon rod or sequentially scribble lines on both sides of the silicon rod, and the scribing operation direction is the same. That is, based on the scribing standard and scribing position, laser scribing is performed on one side of the silicon rod in sequence; then the above steps are repeated to scribble lines on the corresponding scribing position on the other side of the silicon rod, and the scribing position and order on both sides are the same.
[0059] S2. Obtain and process image information of the silicon rod cutting surface and its two outer walls to obtain the silicon rod end and / or seam and / or defect location.
[0060] After the silicon rod is driven by the roller belt to move to the designated position, the positioning block is driven by the motor to automatically rise and lift the material seat, so that the infeed surface and the two side walls of the silicon rod are exposed to the range that the camera 20 can capture.
[0061] The top camera 20 and the side cameras 20 capture images of the cut surface at the top of the silicon ingot and the outer walls on both sides, respectively. The cameras 20 then transmit the captured images to the controller 40, which digitally converts the images into a two-dimensional image that includes the cut surface and the two side walls of the silicon ingot. Figure 6 As shown, the two-dimensional image is displayed directly on the display 50.
[0062] like Figure 6 As shown, the shaded area in the middle of the image represents the top of the silicon rod 60, i.e., the entry surface. When unfolded, the entry surface is in the middle, and the surfaces of the two side walls are on the sides. On this two-dimensional image, the position of the end 61 can be directly identified at least. If the silicon rod is a spliced rod, the position of its seam 62 can also be identified. Simultaneously, based on these three surface images obtained through monitoring, a comparison with a standard surface image can be made. Whether it is a whole silicon rod or a spliced silicon rod, the presence of defects on these three surfaces can be determined. That is, the position of the defect 63 can be monitored and identified on both sides or the top of the silicon rod. Accordingly, the condition of defect 63 at any location can be displayed on this two-dimensional image. In other words, based on this two-dimensional image, one or at least two of the silicon rod end, seam, or defect positions can be identified, and the total length of the silicon rod, the seam width, or the maximum width of one or at least two defects along the length of the silicon rod can be obtained.
[0063] Based on the location of defect 63, controller 40 can also monitor the maximum width w of the area occupied by defect 63 along the length of silicon rod; and at the same time, determine whether defect 63 meets the scribing standard.
[0064] If the maximum width w of defect 63 along the length of the silicon rod is greater than or equal to 1 mm, then the position of defect 63 must be removed during cutting, that is, the position must be avoided during cutting; furthermore, laser scribing is required on both sides of defect 63.
[0065] If the maximum width of defect 63 along the length of the silicon rod is less than 1 mm, then there is no need to consider the impact of this position on subsequent slicing. That is, there is no need to scribing at this defect position, and the operation can be carried out according to normal surface quality.
[0066] Based on the monitor's recognition data, the controller can quickly and accurately locate the end face 61, the seam 62, and the defect 63 on the silicon rod 60. It will also calculate the total length of the silicon rod, the seam width, and the maximum width w of the defect along the length of the silicon rod.
[0067] The controller 40 then transmits the processed information to the display 50 for display. At the same time, it performs calculations based on the preset line drawing standard and inputs the calculated results into the system. Simultaneously, it notifies the industrial control computer 80 to control the laser 30 to prepare for the line drawing task.
[0068] S3. Based on the scribing standard, scribing is performed at the ends of the silicon rod and / or at the seams and / or defect locations.
[0069] The marking criteria include the marking position and the marking length.
[0070] The scribing locations include: 0.4-0.6 mm from the end of the silicon rod; and / or at both ends of the joint and 0.4-0.6 mm from the joint end face; and / or at the location of the defect at its maximum width w along the length of the silicon rod and 0.4-0.6 mm from both sides of the maximum width w. All scribing locations are within the non-chamfered area of the silicon rod's sidewall, that is, within the sidewall closest to the entry face, and scribing cannot be performed at chamfered areas.
[0071] like Figure 6 As shown, the scribing positions include points a and b, located inside the two ends 61 of the silicon rod and 0.4-0.6 mm away from the two ends, along the length direction of the silicon rod 60; and / or points c and d, located on both sides of the seam 62 and 0.4-0.6 mm away from the seam; and / or points e and f, located on both sides of the maximum width W of the defect 63 and 0.4-0.6 mm away from the defect.
[0072] Furthermore, the scribing length is defined as the length of the scribing on both side walls of the silicon rod 60. During scribing, the laser 30 moves continuously along the height direction of the silicon rod 60, starting from below the chamfer in the cutting surface and moving towards the side where the adhesive surface where the silicon rod is bonded to the material seat is located. The scribing length is no more than 8cm.
[0073] Because stress is concentrated at the chamfer on the silicon rod's entry surface, to avoid damage to this area during laser scribing, the starting point A of the scribing must be below the chamfer. The chamfer dimensions vary for different silicon rods; the maximum chamfer height is 5-8mm. Therefore, the height of the starting point A from the entry surface includes the chamfer height, and the height h of the starting point A from the entry surface is 6-10mm, with the starting point A located below the chamfer.
[0074] like Figure 4 As shown, the scribing positions are located on the side wall of the silicon rod. For each scribing, its length along the height direction of the silicon rod is the same, that is, its starting position is point A and its ending position is point B, and the scribing length is H. To ensure the clarity of the scribing, the depth and width of the scribing are not specifically limited and can be determined based on actual needs.
[0075] The scribing of a silicon rod involves laser scribing on both sides of the rod. Specifically, the laser is first controlled to scribing all the positions to be scribed on one side of the rod, and then scribing is performed sequentially along the length of the rod. Then, based on the scribing sequence on one side of the rod, the laser is controlled to scribing all the positions to be scribed on the other side of the rod.
[0076] Simultaneously, when scribing at each location, the position of the laser 30 is first adjusted so that it is located outside the side wall of the silicon rod where the scribing position is located, and the laser head is aligned with the side wall of the silicon rod. Then, the laser 30 is controlled by the moving component to adjust its position so that it is aligned with the calculated scribing position. Based on the scribing position, scribing is then performed sequentially along the length of the silicon rod at the end of the silicon rod and / or the seam.
[0077] That is, first control the laser 30 to move to one end of the silicon rod, and first scribing the end face of that end, that is, scribing the inside of that end and 0.4-0.6cm from that end of the silicon rod; and when scribing, control the laser 30 to scribing from top to bottom along the height direction of the silicon rod, and the length H of the scribing is not greater than 8cm.
[0078] like Figure 5As shown, based on the length of the silicon rod, the positions of the various scribing lines on it can be measured, namely points a and b at the ends; and / or points c and d at the joints. The horizontal distance W from points a and b to their respective side surfaces is 0.4-0.6 mm; and / or the horizontal distance W from points c and d to the side end face of their respective joints is 0.4-0.6 mm. During scribing, based on the position of the silicon rod length, points a and / or c and / or d and b on the same side surface are scribed first; then, based on the same scribing sequence, points a and / or c and / or d and b on the other side surface are scribed.
[0079] S4. Then, based on the line drawing results, determine whether they are qualified.
[0080] The actual marking position and height of the markings can be obtained by taking another picture of the scale lines on the side wall of the silicon rod 60 with the camera and processing the image with the controller 40.
[0081] The controller 40 then compares the actual marking position with the standard marking position to see if they overlap. If they do, the marking position is correct; otherwise, an alarm is triggered and the marking is repeated.
[0082] At the same time, the controller 40 will judge whether the height of the scribing line is clear based on the scribing standard. If the scribing line length H is not less than 8cm, it is qualified; if the scribing line length H is less than 8cm, the scribing line will be re-scribing.
[0083] The automatic scribing method for thick silicon ingot cutting designed in this application can quickly identify the location and seam width of the outer end face and splicing surface of the silicon ingot, and can perform precise scribing; it can also quickly verify the scribing position to determine whether the scribing is successful; this method can improve the efficiency of scribing cutting, reducing the scribing time of a single silicon ingot from 300s to 60s; it can improve the accuracy of laser scribing, while also increasing the wafer yield of silicon ingots, and increasing the average number of wafers produced from a single ingot by 6-8.
[0084] The embodiments of this application have been described in detail above. These descriptions are merely preferred embodiments and should not be construed as limiting the scope of this application. All equivalent variations and modifications made within the scope of this application should still fall within the patent coverage of this application.
Claims
1. An automatic scribing method for cutting thick silicon rods, characterized in that the steps include: include: Acquire and process images of the silicon rod's cutting surface and its two outer walls to obtain the silicon rod's end and / or seam and / or defect locations; Based on the scribing standard, scribing is performed at the ends of the silicon rod and / or at the joints and / or defect locations.
2. The automatic scribing method for cutting thick silicon rods into wafers according to claim 1, characterized in that, The criteria for marking lines include the position of the lines, specifically: At a distance of 0.4-0.6 mm from the end of the silicon rod; And / or, at both ends of the seam and 0.4-0.6 mm from the two end faces of the seam; And / or, at the location of the defect, at its maximum width along the length of the silicon rod and 0.4-0.6 mm from both sides of the maximum width location; The scribed lines are all located at non-beveled points on the sidewall of the silicon rod.
3. The automatic scribing method for cutting thick silicon rods into wafers according to claim 2, characterized in that, The line marking standard also includes the line length, specifically: On the side wall of the silicon rod, a scribing line is drawn along the height direction of the silicon rod, starting from below the chamfer in the cutting surface and moving towards the side where the adhesive surface of the silicon rod is located, with the scribing line length not exceeding 8cm.
4. The automatic scribing method for cutting thick silicon rods into wafers according to any one of claims 1-3, characterized in that, The process of acquiring and processing image information of the silicon rod's cutting surface and its two outer side walls specifically involves: Images of the silicon rod's cut surface and its two outer walls were taken with a camera. The captured images are then digitally converted to obtain an unfolded two-dimensional image that includes the silicon rod's entry surface and both side walls. Based on this two-dimensional image, one or more of the following can be identified: silicon rod end, seam, or defect location. The total length of the silicon rod, seam width, or the maximum width of one or more of the following defects along the length of the silicon rod can be obtained.
5. The automatic scribing method for cutting thick silicon rods into wafers according to claim 4, characterized in that, This also includes judging whether the defects meet the marking criteria, specifically: If the maximum width of the defect along the length of the silicon rod is greater than or equal to 1 mm, then the location of the defect needs to be marked. If the maximum width of the defect along the length of the silicon rod is less than 1 mm, then there is no need to scribing the defect location.
6. The automatic scribing method for cutting thick silicon rods into wafers according to claim 5, characterized in that, The camera that takes pictures of the silicon rod's inlet cut surface is positioned differently from the camera that takes pictures of the silicon rod's sidewall surface; the camera that takes pictures of the silicon rod's inlet cut surface is suspended on top of the frame used to support the silicon rod lying flat, while the camera that takes pictures of the silicon rod's sidewall surface is fixed to the sidewall surface of the frame.
7. The automatic scribing method for cutting thick silicon rods into wafers according to any one of claims 1-3 and 5-6, characterized in that, Specifically, the marking at the ends of the silicon rod and / or at the seams and / or defects involves: A laser is used to scribing lines on a silicon rod; First, adjust the position of the laser so that it is located outside the side wall of the silicon rod where the scribed line is located, and align the laser head with the side wall of the silicon rod. The laser is controlled by a movable component set on the side wall of the rack, and the position of the laser is adjusted; based on the scribing position, scribing is performed sequentially along the length of the silicon rod at the end of the silicon rod and / or at the seam and / or at the defect.
8. The automatic scribing method for cutting thick silicon rods into wafers according to claim 7, characterized in that, Scribing of silicon rods, including laser scribing on one or both sides of the silicon rod, specifically: First, control the laser to scribing all the positions to be scribed on one side of the silicon rod, and then scribble them sequentially along the length of the silicon rod. Based on the scribing sequence on the upper side wall, the laser is controlled to scribing all the positions to be scribed on the other side wall of the silicon rod.
9. The automatic scribing method for cutting thick silicon rods into wafers according to any one of claims 1-3, 5-6, and 8, characterized in that, It also includes a step of judging whether the scribing results are qualified, specifically: taking pictures of the scale lines on the side wall of the silicon rod again using a camera; After processing, the actual position of the scribing line and its height can be obtained; Compare the actual scribing position with the standard scribing position to see if they overlap. If they do, the scribing position is correct; if not, an alarm is triggered and the scribing is repeated. Based on the scribing standard, judge whether the scribing height is clear. If the scribing length is not less than 8cm, it is qualified. If the scribing length is less than 8cm, the scribing should be redone.
10. The automatic scribing method for cutting thick silicon rods into wafers according to claim 1, characterized in that, Before acquiring image information of the silicon rod's infeed cut surface and its two outer walls, the process also includes controlling the silicon rod to be transferred to a designated position with its infeed cut surface facing upwards, and the silicon rod being adhered to the material holder. The silicon rod is then moved to the designated position by a roller placed at the bottom of the frame.