Laser processing method

Abstract

The application discloses a laser processing method, and divides a sheet material to be processed into N sub-regions. When laser processing is performed, the center coordinates of the i-th sub-region to be processed after the rotation of a carrier table are obtained based on the obtained rotation center coordinates of the carrier table, so that a galvanometer performs laser processing on the i-th sub-region according to the center coordinates of the i-th sub-region. The technical scheme of the application can perform multiple splicing processes on the 1st sub-region to the Nth sub-region of the same sheet material by the same galvanometer, thereby improving the laser processing efficiency and processing precision.

Description

Technical Field

[0001] This application relates to the field of laser processing technology, and more specifically, to a laser processing method. Background Technology

[0002] In the field of laser processing of solar cells, most processes utilize laser processing modules to perform laser processing on the surface of the cells at the laser processing station. A laser processing module includes a laser that emits the laser beam and a laser processing assembly composed of a galvanometer and a field lens. With the current trend towards larger silicon wafers, conventional single galvanometers and field lenses cannot fully meet the requirements of large-size silicon wafers, high spot quality, and high precision. While these requirements can be met by increasing the processing area of ​​the field lens, this results in a loss of spot quality and precision.

[0003] In the existing technology, although there is a method of using multiple galvanometers to process a section at the same processing station and then splicing them together, which increases the processing speed, using multiple galvanometers is not only costly, but also leads to processing errors due to differences between different galvanometers. Summary of the Invention

[0004] In view of this, this application provides a laser processing method, the scheme of which is as follows:

[0005] A laser processing method for laser processing sheet material placed on a stage, wherein the laser processing equipment includes the stage and a first driving device for rotating the stage around its own rotation center.

[0006] The sheet-like material is divided into N sub-regions, where N is a positive integer greater than 1, and the N sub-regions are numbered sequentially from the 1st sub-region to the Nth sub-region based on the laser processing order.

[0007] The laser processing method includes:

[0008] Obtain the coordinates of the rotation center of the stage;

[0009] Based on the rotation center coordinates of the stage, obtain the center coordinates of the i-th sub-region to be processed after the stage rotates, where i is a positive integer and 2≤i≤N;

[0010] The galvanometer performs laser processing on the i-th sub-region based on the center coordinates of the i-th sub-region.

[0011] Preferably, in the above laser processing method, the method for obtaining the rotation center includes:

[0012] Acquire a first set of first images of a standard film or the stage, the first set of first images including an image of a positioning marker, and obtain the first coordinates of the positioning marker based on the first set of first images;

[0013] After controlling the stage to rotate, a standard film or a second set of first images of the stage is acquired. The second set of first images includes an image of a positioning marker. The second coordinates of the positioning marker are obtained based on the second set of first images.

[0014] The coordinates of the rotation center are calculated based on the first coordinate of the positioning identifier and the second coordinate of the positioning identifier.

[0015] Preferably, in the above laser processing method, the method for acquiring the first image includes:

[0016] Acquire an image of a standard piece placed on the stage to obtain the first image, wherein the standard piece has the positioning mark;

[0017] Alternatively, an image of the stage with the positioning mark on its surface can be obtained to obtain the first image.

[0018] Preferably, in the above laser processing method, if the coordinates of the rotation center deviate, the method further includes:

[0019] Obtain the new coordinates of the rotation center;

[0020] Based on the new rotation center coordinates, determine the center coordinates of the i-th sub-region to be processed.

[0021] The galvanometer performs laser processing on the i-th sub-region based on the center coordinates of the i-th sub-region.

[0022] Preferably, in the above laser processing method, a temperature sensor is used to monitor whether the ambient temperature or the temperature of the laser processing equipment exceeds a preset temperature difference range to determine whether the coordinates of the rotation center have deviated.

[0023] Preferably, in the above laser processing method, when the galvanometer performs laser processing on each sub-region, the sub-region is laser processed based on the deflection angle of the sheet material relative to the galvanometer coordinate system and the center coordinates of the sub-region.

[0024] Preferably, in the above-described laser processing method, the method for laser processing the first sub-region includes:

[0025] Acquire a second image of the sheet material placed on the stage;

[0026] The center coordinates of the sheet material are determined based on the second image;

[0027] The center coordinates of the first sub-region are determined based on the center coordinates of the sheet material and the dimensions of the processed pattern.

[0028] The galvanometer performs laser processing on the first sub-region based on the center coordinates of the first sub-region.

[0029] Preferably, in the above laser processing method, the method for obtaining the center coordinates of the i-th sub-region includes:

[0030] Based on the rotation center coordinates of the stage and the center coordinates of the sheet material placed on the stage before processing, the center coordinates of the sheet material when performing laser processing on the i-th sub-region are determined.

[0031] The center coordinates of the i-th sub-region are determined based on the center coordinates of the sheet material during laser processing of the i-th sub-region and the center coordinates of the first sub-region.

[0032] Preferably, the above laser processing method further includes:

[0033] Based on the target processing pattern and the division method of the sheet material, the target processing pattern is divided into blocks to obtain multiple sub-images that correspond sequentially to the first sub-region to the Nth sub-region.

[0034] The galvanometer performs laser processing on each sub-region based on the corresponding sub-image.

[0035] Preferably, in the above laser processing method, the laser processing equipment includes: a camera imaging position, a laser processing position, at least two of the aforementioned stages, and a second driving device; wherein, the at least two stages are connected to the second driving device, and the second driving device is used to switch the at least two stages between the camera imaging position and the laser processing position;

[0036] The image of the sheet material or the stage is acquired at the camera imaging position to determine the rotation center or the center coordinates of the sheet material placed on the stage and the deflection angle of the sheet material relative to the galvanometer coordinate system. At the laser processing position, the first to Nth sub-regions of the sheet material are sequentially laser-processed by the galvanometer.

[0037] As described above, the laser processing method provided in this application divides the sheet material to be processed into N sub-regions. During laser processing, based on the obtained rotation center coordinates of the stage, the center coordinates of the i-th sub-region to be processed after the stage rotation are obtained. This allows the galvanometer to perform laser processing on the i-th sub-region according to its center coordinates. This application's technical solution can sequentially process the first to Nth sub-regions of the same sheet material multiple times using the same galvanometer at the same laser processing position, improving both the efficiency and accuracy of laser processing. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0040] Figure 1 A schematic flowchart of a laser processing method provided in an embodiment of this application;

[0041] Figure 2 A flowchart illustrating a method for obtaining the rotation center of a stage, provided in an embodiment of this application;

[0042] Figure 3 A flowchart illustrating another method for obtaining the rotation center of a stage provided in an embodiment of this application;

[0043] Figure 4 and Figure 5 A schematic diagram illustrating the principle of obtaining the coordinates of the rotation center of a stage, provided in an embodiment of this application;

[0044] Figure 6 A schematic flowchart of another laser processing method provided in an embodiment of this application;

[0045] Figure 7 A schematic flowchart illustrating a method for laser processing of a first sub-region provided in an embodiment of this application;

[0046] Figure 8 A flowchart illustrating a method for obtaining the center coordinates of the i-th sub-region provided in an embodiment of this application;

[0047] Figure 9 A top view of a laser processing device;

[0048] Figure 10 A side view of a laser device;

[0049] Figure 11 This is a schematic diagram of another type of laser processing equipment;

[0050] Figure 12 A schematic diagram of a target processing pattern on the surface of a sheet material designed for an embodiment of this application;

[0051] Figure 13 For based on Figure 12 The diagram shows the target processing pattern after laser processing of the first sub-region S1.

[0052] Figure 14 For based on Figure 12 The diagram shows the target processing pattern after laser processing of the second sub-region S2.

[0053] Figure 15 For based on Figure 12 The diagram shows the target processing pattern after laser processing of the third sub-region S3.

[0054] Figure 16 For based on Figure 12 The diagram shows the target processing pattern after laser processing of the fourth sub-region S4.

[0055] Figure 17 A schematic diagram illustrating the block-based principle of dividing and arranging sub-regions in sheet-like materials to create a target pattern;

[0056] Figures 18-23 This is a schematic diagram illustrating the principle of laser processing of sheet materials based on the laser processing method described in the embodiments of this application. Detailed Implementation

[0057] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0058] It should be noted that the sheet material in the embodiments of this application includes, but is not limited to, silicon wafers, and can be any sheet material suitable for laser processing.

[0059] To address the aforementioned issues, this application provides a laser processing method that can sequentially process the first to Nth sub-regions using the same galvanometer, thereby reducing the cost of laser processing. Furthermore, the galvanometer can process the i-th sub-region using the center coordinates of the i-th sub-region, enabling multiple splicing processes of the same sheet material, thus improving the efficiency and accuracy of laser processing.

[0060] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0061] This application provides a laser processing method for processing sheet material placed on a stage. The laser processing equipment includes a stage and a first driving device that causes the stage to rotate around its own rotation center. The sheet material is divided into N sub-regions, where N is a positive integer greater than 1, and the N sub-regions are numbered from the first sub-region to the Nth sub-region based on the laser processing sequence.

[0062] The laser processing equipment has a fixed camera position and a laser processing position. The camera position is used to acquire images for visual positioning and position correction, and the laser processing position is used for laser processing.

[0063] like Figure 1 As shown, Figure 1 This is a schematic flowchart of a laser processing method provided in an embodiment of this application. The laser processing method includes:

[0064] Step S11: Obtain the coordinates of the rotation center of the stage.

[0065] Step S12: Based on the rotation center coordinates of the stage, obtain the center coordinates of the i-th sub-region to be processed after the stage rotates. i is a positive integer and 2≤i≤N.

[0066] Step S13: The galvanometer performs laser processing on the i-th sub-region based on the center coordinates of the i-th sub-region.

[0067] The laser processing method, before starting laser processing on the first sub-region, involves... Figure 2 The method shown obtains the rotation center coordinates of the stage, which is then used to obtain the center coordinates of the second to Nth sub-regions, enabling the splicing and processing of sheet materials.

[0068] Furthermore, the technical solution of this application can sequentially splice and process the first to Nth sub-regions of the same sheet material using the same galvanometer, thereby improving the efficiency and accuracy of laser processing. This method of dividing the material into N regions and then rotating and splicing them together solves the problem that the processing area of ​​a single galvanometer cannot completely cover the sheet material to be processed.

[0069] In the laser processing method of this application embodiment, the method for obtaining the rotation center is as follows: Figure 2 As shown, Figure 2 A flowchart illustrating a method for obtaining the rotation center of a stage, provided in an embodiment of this application, includes:

[0070] Step S21: Obtain multiple first images of the stage, including an image of a positioning marker, which is used to obtain the coordinates of the positioning marker.

[0071] Step S22: Obtain the coordinates of the rotation center based on the coordinates of the positioning marker.

[0072] exist Figure 2 In the method shown, the rotation center coordinates of the stage can be determined based on the first image with positioning marks. The rotation center coordinates of the stage can be determined through image acquisition and image recognition technology, which is a simple method.

[0073] In the laser processing method of this application embodiment, the method for obtaining the coordinates of the rotation center is further shown in Figure 3. Figure 3 This is a flowchart illustrating another method for obtaining the rotation center of a stage provided in an embodiment of this application. The method includes:

[0074] Step S31: Obtain a first set of first images of the standard film or the stage, wherein the first set of first images includes an image of a positioning marker, and obtain the first coordinates of the positioning marker based on the first set of first images;

[0075] Step S32: After controlling the stage to rotate, acquire the standard film or the second set of first images of the stage. The second set of first images includes the image of the positioning mark. Acquire the second coordinates of the positioning mark based on the second set of first images.

[0076] Step S33: Calculate the coordinates of the rotation center based on the first coordinate of the positioning marker and the second coordinate of the positioning marker.

[0077] exist Figure 3 In the method shown, since the two sets of first images include the coordinates of the positioning marker before and after the rotation center of the stage, the coordinates of the rotation center of the stage can be determined based on the geometric relationship before and after the rotation. The operation is simple and the calculation method is simple.

[0078] In one embodiment of the laser processing method of this application, the method of obtaining a first image includes: obtaining multiple first images of a standard sheet placed on a stage, wherein the standard sheet has positioning marks, and in this embodiment, the standard sheet may have one or more positioning marks; in another embodiment, the method of obtaining a first image includes: obtaining an image of a stage with positioning marks on its surface to obtain a first image, and in this embodiment, the stage may have one or more positioning marks.

[0079] Taking the acquisition of the rotation center coordinates of the stage using a standard film with positioning marks as an example, there are four fixed cameras at the camera shooting position, which correspond to the positions near the four apex corners of the standard film on the stage. These four cameras are the first camera CCD1 to the fourth camera CCD4.

[0080] like Figure 4 and Figure 5 As shown, Figure 4 and Figure 5 This is a schematic diagram of the principle of obtaining the rotation center coordinates of the stage provided in the embodiment of this application. Taking a standard piece with two positioning marks as an example, the two positioning marks are located in a top corner area of ​​the standard piece, and the two positioning marks can be set as the first positioning mark mark1 and the second positioning mark mark2.

[0081] First, such as Figure 4 As shown, when the stage holding the standard film is positioned at the camera's imaging location, the first positioning marker 'mark1' and the second positioning marker 'mark2' are respectively within the field of view of the first camera CCD1 and the second camera CCD2. By acquiring images through the first camera CCD1 and the second camera CCD2, a first set of first images can be obtained. Thus, the first positioning marker 'mark1' is located by photographing it with the first camera CCD1, obtaining its first coordinates (Xa, Ya). The second positioning marker 'mark2' is located by photographing it with the second camera CCD2, obtaining its first coordinates (Xb, Yb).

[0082] Then, as Figure 5 As shown, the stage is in Figure 4The camera image position is rotated by a set angle, such as 180° (other rotation angles are also possible, but the calculation formula will change accordingly, which will not be elaborated here). At this time, the first positioning marker mark1 and the second positioning marker mark2 are located within the field of view of the third camera CCD3 and the fourth camera CCD4, respectively. The second set of first images is obtained through the third camera CCD3 and the fourth camera CCD4. Similarly, the third camera is used to image and position the first positioning marker mark1, obtaining its second coordinates (Xc, Yc). The fourth camera CCD4 is used to image and position the second positioning marker mark2, obtaining its second coordinates (Xd, Yd).

[0083] The coordinates of the rotation center can be calculated based on the coordinates of the first positioning marker (mark1) and the second positioning marker (mark2) before and after rotation. Let the coordinates of the rotation center be (X0, Y, 0). Based on geometric relationships, we know that:

[0084] X0=1 / 2*[(Xa+Xb) / 2+(Xc+Xd) / 2] (1)

[0085] Y0=1 / 2*[(Ya+Yb) / 2+(Yc+Yd) / 2] (2)

[0086] In other methods, a positioning marker can be used. At the camera's position, first obtain the first coordinates (Xm, Ym) of the positioning marker before the stage rotates. Then, at the camera's position, rotate the stage by a set angle, such as 180°, and obtain the second coordinates (Xn, Yn) of the positioning marker. Based on the coordinates of the positioning marker before and after rotation, the coordinates of the rotation center can be calculated. Based on geometric relationships, we know that:

[0087] X0=1 / 2*[(Xm+Xm) / 2] (3)

[0088] Y0=1 / 2*[(Ym+Ym) / 2] (4)

[0089] During laser processing, the coordinates of the stage's rotation center may change due to the heat generated by the laser processing equipment's motor during prolonged operation or the influence of ambient temperature, causing a shift in the rotation center. This shift results in inconsistencies between the rotation center coordinates and the previously calibrated coordinate values, necessitating further correction during rotation. In the laser processing method described in this application embodiment, the graphic coordinates of the laser processing of the second to Nth sub-regions of the same sheet material are calculated based on the rotation center coordinates. A shift in the rotation center directly leads to increased splicing accuracy errors. Therefore, in the laser processing method described in this application embodiment, as... Figure 6 As shown, Figure 6This is a schematic flowchart of another laser processing method provided in an embodiment of this application. If a deviation in the coordinates of the rotation center is detected, the method further includes:

[0090] Step S41: Obtain the new rotation center coordinates.

[0091] Step S42: Based on the new rotation center coordinates, determine the center coordinates of the i-th sub-region to be processed.

[0092] Step S43: The galvanometer performs laser processing on the i-th sub-region based on the center coordinates of the i-th sub-region.

[0093] pass Figure 6 The method shown can correct the coordinates of the rotation center after the rotation center of the stage shifts, so as to ensure the accuracy of the laser-processed pattern after long-term processing and reduce the pattern splicing error.

[0094] The method for obtaining new rotation center coordinates is the same as that described above. A standard piece with positioning marks can be used, whose position matches the initial rotation center coordinate calibration. A robotic arm can then pick up the standard piece and place it on a stage located at the camera's imaging position. Specifically, when splicing accuracy becomes abnormal or temperature fluctuates, the robotic arm picks up the standard piece and places it on the stage at the camera's imaging position. New rotation center coordinates are obtained using the method described above. After the rotation center coordinates are corrected, the robotic arm returns the standard piece to its original position. Alternatively, positioning marks can be engraved on the stage surface. These marks can be recognized by the camera and maintain the same position as the rotation center calibration. When splicing accuracy becomes abnormal or temperature fluctuates, the camera captures an image of the stage at the camera's imaging position to obtain the coordinates of the positioning marks and recalibrate the rotation center coordinates. After the rotation center coordinates are corrected, laser processing can be performed on each subsequent sub-region in the same manner, allowing for the laser processing of the subsequent sub-regions of the sheet material using a rotation splicing method.

[0095] In this embodiment, a temperature sensor can be used to monitor whether the ambient temperature or the temperature of the laser processing equipment exceeds a preset temperature difference range to determine whether the rotation center coordinates have deviated. Specifically, when the temperature sensor detects that the ambient temperature fluctuation exceeds the preset temperature difference range, the rotation center coordinates of the stage are redefined before laser processing the next piece of material. Alternatively, when the temperature of the laser processing equipment (generally the temperature of the motor in the drive device that drives the stage and the temperature of the fixture supporting the stage) exceeds the preset temperature difference range, the rotation center coordinates of the stage are redefined before laser processing the next piece of material. The preset temperature difference range can be set according to specific process accuracy requirements.

[0096] In other methods, after the processing time meets the set cycle, a new rotation center coordinate can be obtained. By periodically obtaining a new rotation center coordinate, the problem of reduced splicing accuracy caused by a cheap rotation center can be avoided. Alternatively, when the accuracy of the splicing image formed by laser processing on the surface of sheet material does not meet the quality standard, a new rotation center coordinate can be obtained. Based on the real-time quality inspection results of the splicing image, it can be determined whether to obtain a new rotation center coordinate to avoid the problem of reduced splicing accuracy caused by a cheap rotation center.

[0097] In the laser processing method described in this application embodiment, the galvanometer uses a scanning motor to drive the optical lens to perform a deflection motion, positioning and marking the laser according to the specified position given by the control software (that is, the target processing pattern set by the marking software). Generally, when processing sheet materials with a galvanometer, the silicon wafer has a deflection angle relative to the galvanometer coordinate system. Therefore, when the galvanometer performs laser processing on each sub-region, it performs laser processing on the sub-region based on the deflection angle of the sheet material relative to the galvanometer coordinate system and the center coordinates of the sub-region. After sequentially performing laser processing on each sub-region, the accuracy of the spliced ​​pattern is ensured.

[0098] In the embodiments of this application, such as Figure 7 As shown, Figure 7 A flowchart illustrating a method for laser processing of a first sub-region provided in this application embodiment, the method comprising:

[0099] Step S51: Obtain a second image of the sheet material placed on the stage.

[0100] Step S52: Determine the center coordinates of the sheet material based on the second image.

[0101] Step S53: Determine the center coordinates of the first sub-region based on the center coordinates of the sheet material and the dimensions of the processing pattern.

[0102] Step S54: The galvanometer performs laser processing on the first sub-region based on the center coordinates of the first sub-region.

[0103] At the camera's imaging position, a second image of the sheet-like material on the stage is acquired. Based on this second image, not only can the center coordinates of the sheet-like material be determined, but also the deflection angle of the sheet-like material relative to the galvanometer coordinate system can be confirmed. Then, based on the center coordinates of the sheet-like material and the size of the processing pattern, the center coordinates of the first sub-region are determined, so that the first sub-region can be laser-processed using the center coordinates of the galvanometer.

[0104] In the laser processing method described in this application embodiment, the method for obtaining the center coordinates of the i-th sub-region is as follows: Figure 8 As shown, Figure 8A flowchart illustrating a method for obtaining the center coordinates of the i-th sub-region provided in this application embodiment, the method comprising:

[0105] Step S61: Based on the rotation center coordinates of the stage and the center coordinates of the sheet material placed on the stage obtained before processing, determine the center coordinates of the sheet material when performing laser processing on the i-th sub-region.

[0106] Step S62: Determine the center coordinates of the i-th sub-region based on the center coordinates of the sheet material during laser processing of the i-th sub-region and the center coordinates of the first sub-region.

[0107] The geometric shape of the sheet material to be processed is determined. During rotation, revolution, and laser processing, its position relative to the stage is fixed. Therefore, the center coordinates of the sheet material during the processing of the i-th sub-region can be determined based on the rotation center coordinates of the stage and the center coordinates of the sheet material determined during the processing of the first sub-region. Furthermore, the center coordinates of the i-th sub-region can be determined based on the center coordinates of the sheet material during laser processing of the i-th sub-region and the center coordinates of the first sub-region, so as to facilitate laser processing of the i-th sub-region.

[0108] The laser processing method described in this application further includes: dividing the target processing pattern into blocks based on the target processing pattern and the division method of the sheet material to obtain multiple sub-images corresponding sequentially to the first to Nth sub-regions; wherein, the galvanometer performs laser processing on each sub-region based on the corresponding sub-image. This allows for the sequential splicing and processing of each sub-region of the sheet material.

[0109] The laser equipment applicable to the laser processing method described in this application includes: a camera imaging position, a laser processing position, at least two of the aforementioned stages, and a second driving device; wherein, the at least two stages are connected to the second driving device, and the second driving device is used to switch the at least two stages between the camera imaging position and the laser processing position; at the camera imaging position, an image of the sheet material or the stage is acquired to determine the rotation center or the center coordinates of the sheet material placed on the stage and the deflection angle of the sheet material relative to the galvanometer coordinate system; at the laser processing position, laser processing is performed sequentially on the first to Nth sub-regions of the sheet material through the galvanometer.

[0110] In one embodiment, the structure of the laser processing equipment can be as follows: Figure 9 and Figure 10 As shown, Figure 9 This is a top view of a laser processing device. Figure 10This is a side view of a laser processing device, which includes: a stage 1 for placing sheet material and a first driving device 2 for rotating the stage 1 around its own rotation center, i.e., the stage 1 is capable of rotating based on the center of the first driving device 2.

[0111] exist Figure 9 and Figure 10 In the illustrated configuration, an example is a laser processing device with one camera position W1, one laser processing position W2, and two stages 1. Each stage 1 corresponds to a first driving device 2. The first driving device 2 is mounted on the same second driving device 4 via a support frame 3. The second driving device 4 can control the rotation of each stage 1 around the center of the second driving device 4 by rotating the support frame 3, i.e., each stage 1 can revolve around the center of the second driving device 4. The positions of the camera position W1 and the laser processing position W2 are fixed. The camera position W1 is equipped with a camera, and the laser processing position W2 is equipped with a laser processing assembly with a galvanometer. One stage 1 is located at the camera position W1, and the other is located at the laser processing position W2. The stage 1 can switch between the camera position W1 and the laser processing position W2 based on the second driving device 4.

[0112] In another embodiment, the structure of the laser processing equipment can be as follows: Figure 11 As shown, Figure 11 This is a schematic diagram of another type of laser processing equipment. In this configuration, there are two camera positions W1, two laser processing positions W2, and four stages 1. Each of the four stages 1 corresponds to a first driving device 2 mounted on a support frame 3, and the support frame 3 is mounted on a first driving device 4. Similarly, in this configuration, each stage 1 can rotate around its own center based on the first driving device 2, and can also revolve around the center of the second driving device 4.

[0113] In this embodiment, the camera imaging position W1 and the laser processing position W2 are correspondingly set. Based on the second driving device 4, the platform 1 located at the camera imaging position W1 can switch to the corresponding laser processing position W2 through revolution, and the platform 1 located at the laser processing position W2 can switch to the corresponding camera imaging position W1 through revolution. The camera imaging position W1 and the corresponding laser processing position W2 can be set on both sides of the revolution axis and symmetrically arranged. By setting two sets of camera imaging positions and laser processing positions, two lines can operate simultaneously, improving production capacity. In addition, the camera imaging position can also be both the loading position and the unloading position. That is, after the sheet material is transferred to the camera imaging position, it is photographed and positioned. Then, the platform is moved from the camera imaging position to the laser processing position by the rotation of the second driving device 4. At the laser processing position, the platform is spliced ​​and processed by the rotation of the first driving device 2. After processing, the platform of the laser processing position is moved back to the camera imaging position by the second driving device 4 for unloading. Simultaneously, the next sheet material that has been loaded and photographed at the camera imaging position moves to the laser processing position.

[0114] The number of camera positions, laser processing positions, and stage can be set according to requirements. The structure of the laser processing equipment includes, but is not limited to, those specified above. Figures 9-11 As shown in the diagram. Alternatively, a linear drive module can be used to switch at least two stages between the camera's imaging position and the laser processing position.

[0115] As described above, the embodiments of this application provide a laser processing method that improves laser processing accuracy and has visual positioning and correction functions. The laser processing method is applicable to laser processing equipment that can perform splicing processing on sheet materials, and improves the visual positioning accuracy and correction accuracy of the laser processing equipment in performing regional splicing laser processing on sheet materials.

[0116] The laser processing method of this application will be described in detail below using a rectangular sheet material as an example.

[0117] Divide the rectangle into four identical rectangular sub-regions, i.e., N=4, with the geometric center of the rectangle as the common vertex. These four rectangular sub-regions are successively divided into sub-region 1 S1 to sub-region 4 S4.

[0118] Before performing laser processing on each sub-region sequentially according to the laser processing method described in this application embodiment, the camera coordinate system needs to be calibrated to ensure that the galvanometer coordinate system and the camera coordinate system coincide. This calibration method is the same as conventional calibration methods in the industry and will not be described again in this application embodiment. Here, the galvanometer coordinate system refers to a coordinate system established with the galvanometer origin as its origin.

[0119] After calibrating the camera coordinate system, the rotation center of the stage needs to be calibrated to obtain its coordinates. Generally, when sheet-like materials are placed on the stage, it's difficult to ensure that the center of the sheet-like material coincides with the rotation center of the stage. For small materials, due to their small size, the processing area of ​​a conventional galvanometer is sufficient to cover the small material while maintaining processing accuracy. The material's position doesn't change during processing, so it's sufficient to take a picture before processing to obtain its relative position. Therefore, even if small materials are placed slightly off-center on the stage, it won't affect processing accuracy. Furthermore, for patterns that don't require splicing, there's no need to consider whether the material's center coincides with the stage's rotation center. For schemes requiring splicing processing in sections, since it's impossible to guarantee that the center of the sheet-like material coincides with the rotation center, the relative position of the sub-region and the galvanometer will differ when processing the next sub-region after rotation. Therefore, it's necessary to calibrate the rotation center coordinates of the stage.

[0120] The coordinates of the rotation center of the stage can be determined by the positioning marks on the standard film or the positioning marks on the stage. Two positioning marks can be set, and when the rotation angle is 180°, the rotation center coordinates can be determined as (X0, Y0) based on the above formulas (1) and (2), or one positioning mark can be set, and the rotation center coordinates can be determined as (X0, Y0) based on the above formulas (3) and (4). The specific principles can be found in the preceding description and will not be repeated here.

[0121] After the camera coordinate system and rotation center are calibrated, the laser processing equipment with visual positioning function completes the visual positioning work before splicing each sub-region. Then, the sheet material to be processed is placed on the stage, and after the camera captures the image and positions it, the stage is rotated to the laser processing position, and each sub-region is processed by laser in sequence.

[0122] It should be noted that when laser processing is performed on each sub-region, the laser processing is based on the target processing pattern set by the marking software. Therefore, before laser processing on a sub-region, the target processing pattern needs to be preset in advance. The laser processing method of this application is a rotation splicing scheme. The preset target processing pattern is not the final processing pattern of each sub-region. It is necessary to divide the target processing pattern into blocks based on the target processing pattern and the division method of the sheet material, that is, according to the distribution of each sub-region of the sheet material and the required rotation angle of two adjacent sub-regions, and then perform laser processing on each sub-region separately.

[0123] like Figures 12-17 As shown, Figure 12 This is a schematic diagram of a target processing pattern on the surface of a sheet material designed for an embodiment of this application. Figure 13 For based on Figure 12The diagram shows the result of laser processing the first sub-region S1 using the target processing pattern shown. Figure 14 For based on Figure 12 The diagram shows the result of laser processing the second sub-region S2 using the target processing pattern shown. Figure 15 For based on Figure 12 The diagram shows the result of laser processing the third sub-region S3 using the target processing pattern shown. Figure 16 For based on Figure 12 The diagram shows the result of laser processing the fourth sub-region S4 using the target processing pattern shown. Figure 17 A schematic diagram illustrating the block-based principle of dividing and arranging sub-regions in sheet-like materials to create a target pattern.

[0124] The target processing pattern consists of multiple spaced and parallel dashed lines. The sheet material includes sub-regions S1 to S4. Laser processing is performed sequentially on sub-regions S1 to S4, processing 1 / 4 of the sheet material each time, rotating 90° each time, to form a pattern on the sheet material as shown in the image. Figure 12 The pattern shown. Based on Figure 12 The geometric symmetry of the pattern shown is important for fabricating on sheet materials. Figure 12 The pattern shown, the sub-regions correspond to the actual processing patterns as follows: Figure 17 As shown, laser processing is performed on the first sub-region S1 and the third sub-region S3. Figure 17 Pattern A is used for laser processing of sub-regions S2 and S3. Figure 17 Pattern B. Both Pattern A and Pattern B are block patterns corresponding to 1 / 4 area of ​​the sheet material. They are the same size, with a length of LM and a width of LN.

[0125] like Figures 18-23 As shown, Figures 18-23 This is a schematic diagram illustrating the principle of laser processing of sheet materials using the laser processing method described in this application. After the camera coordinate system and rotation center are calibrated, the sheet material to be processed is placed on a stage located at the camera's imaging position. A second image is captured to determine the center coordinates (X11, Y11) of the sheet material. Simultaneously, based on the second image, the deflection angle θ of the silicon wafer relative to the galvanometer coordinate system and the center coordinates (X1, Y1) of the first sub-region can also be determined. For solutions that do not require splicing, only the center coordinates and deflection angle θ of the sheet material need to be acquired at the camera's imaging position. Based on the captured data, the camera sends the center coordinates (X1, Y1) and deflection angle θ of the first sub-region to the marking software.

[0126] The center coordinates (X1, Y1) of the first sub-region S1 can be calculated based on the center coordinates (X11, Y11) of the sheet material and the size of the block pattern corresponding to the first sub-region S1. For example, using... Figure 17 Given the block pattern shown, the center coordinates (X1, Y1) of the first sub-region are:

[0127] X1=X11-1 / 2*LM (5)

[0128] Y1=Y11+1 / 2*LN (6)

[0129] After the sheet material to be processed is photographed at the camera's imaging position, the stage is controlled to rotate, moving from the camera's imaging position to the laser processing position. Based on the data sent by the camera, the marking software controls the galvanometer to perform laser processing on the first sub-region S1 according to the center coordinates (X1, Y1) and deflection angle θ. The first sub-region S1 is the first sub-region processed after the stage rotates to the laser processing area; the center coordinates (X1, Y1) of the first sub-region S1 do not need to be calculated based on the calibrated rotation center coordinates (X0, Y0). Figure 12 The pattern shown is the target processing pattern. After laser processing is completed in the first sub-region S1, the surface pattern of the sheet material is as follows: Figure 13 As shown, the graphic processing of 1 / 4 of the sheet material area has been completed at this point. Among them, the center coordinates (X1, Y1) of the first sub-region S1 are the coordinates of the laser processing pattern block required by the galvanometer when performing laser processing on the first sub-region S1.

[0130] After laser processing is completed in the first sub-region S1, the stage rotates 90° from the laser processing position to the position shown. Figure 20 The position shown makes the second sub-region S2 fall within the galvanometer processing range. Since the rotation center of the stage does not coincide with the center of the sheet material, the position of the second sub-region S2 is... Figure 19 The positions of the first sub-region S1 shown do not coincide, and need to be based on Figure 23 Based on the geometric correspondence shown, the coordinates and angles of the galvanometer pattern processing are readjusted. According to the previously determined stage rotation center coordinates (X0, Y0) and the center coordinates of the sheet material determined by the second image captured by the camera at the camera's position (X11, Y11), the center coordinates of the sheet material (X22, Y22) during laser processing of the second sub-region S2 are calculated using the following formula:

[0131] X22=X0-(Y0-Y11) (7)

[0132] Y22=Y0+(X0-X11) (8)

[0133] The center coordinates (X2, Y2) of the second sub-region S2 are the coordinates of the laser-processed pattern block required by the galvanometer when laser processing the second sub-region S2. The offset of the center coordinates (X2, Y2) of the second sub-region S2 relative to the center coordinates (X1, Y1) of the first sub-region S1 is the same as the offset of the center coordinates (X22, Y22) of the sheet material relative to the center coordinates (X11, Y11) of the sheet material, that is:

[0134] X2 = X1 + (X2² - X1¹) (9)

[0135] Y2=Y1+(Y22-Y11) (10)

[0136] After the galvanometer performs laser processing on the second sub-region S2 based on the center coordinates (X2, Y2) and the deflection angle θ, the surface pattern of the sheet-like material is as follows: Figure 14 As shown, the graphic processing of 2 / 4 of the sheet material area has been completed at this point.

[0137] After laser processing is completed in the second sub-region S2, the stage rotates 90° from the laser processing position to the position shown. Figure 21 The position shown makes the third sub-region S3 fall within the galvanometer processing range. Since the rotation center of the stage does not coincide with the center of the sheet material, the position of the third sub-region S3 is... Figure 19 The positions of the first sub-region S1 shown do not coincide, and need to be based on Figure 23 Based on the geometric correspondence shown, the coordinates and angles of the galvanometer pattern processing are readjusted. According to the previously determined stage rotation center coordinates (X0, Y0) and the center coordinates of the sheet material determined by the second image captured by the camera at the camera's position (X11, Y11), the center coordinates of the sheet material (X33, Y33) during laser processing of the third sub-region S3 are calculated using the following formula:

[0138] X33=X0+(X0-X11) (11)

[0139] Y33=Y0+(Y0-Y11) (12)

[0140] The center coordinates (X3, Y3) of the third sub-region S3 are the coordinates of the laser-processed pattern block required by the galvanometer when laser processing the third sub-region S3. The offset of the center coordinates (X3, Y3) of the third sub-region S3 relative to the center coordinates (X1, Y1) of the first sub-region S1 is the same as the offset of the center coordinates (X33, Y33) of the sheet material relative to the center coordinates (X11, Y11) of the sheet material, that is:

[0141] X3 = X1 + (X33 - X11) (13)

[0142] Y3=Y1+(Y33-Y11) (14)

[0143] After the galvanometer performs laser processing on the third sub-region S3 based on the center coordinates (X3, Y3) and the deflection angle θ, the surface pattern of the sheet-like material is as follows: Figure 15 As shown, the graphic processing of 3 / 4 of the sheet material area has been completed at this point.

[0144] After laser processing is completed in sub-region S3, the stage rotates 90° from the laser processing position to the position shown. Figure 22 The position shown makes the fourth sub-region S4 fall within the galvanometer processing range. Since the rotation center of the stage does not coincide with the center of the sheet material, the position of the fourth sub-region S4 is... Figure 19 The positions of the first sub-region S1 shown do not coincide, and need to be based on Figure 23 Based on the geometric correspondence shown, the coordinates and angles for galvanometer pattern processing are readjusted. According to the previously determined stage rotation center coordinates (X0, Y0) and the center coordinates of the sheet material determined by the second image captured by the camera at the camera's position (X11, Y11), the center coordinates of the sheet material (X44, Y44) during laser processing of the fourth sub-region S4 are calculated using the following formula:

[0145] X44=X0+(Y0-Y11) (15)

[0146] Y44=Y0-(X0-X11) (16)

[0147] The center coordinates (X4, Y4) of the fourth sub-region S4 are the coordinates of the laser-processed pattern block required by the galvanometer when laser processing the fourth sub-region S4. The offset of the center coordinates (X4, Y4) of the fourth sub-region S4 relative to the center coordinates (X1, Y1) of the first sub-region S1 is the same as the offset of the center coordinates (X44, Y44) of the sheet material relative to the center coordinates (X11, Y11) of the sheet material, that is:

[0148] X4 = X1 + (X44 - X11) (17)

[0149] Y4=Y1+(Y44-Y11) (18)

[0150] After the galvanometer performs laser processing on the third sub-region S4 based on the center coordinates (X4, Y4) and deflection angle θ of the fourth sub-region S4, the surface pattern of the sheet-like material is as follows: Figure 16 As shown, the graphic processing of 4 / 4 area of ​​the sheet material has been completed at this point. All sub-areas from S1 to S4 have been spliced ​​and processed, and the graphic processing on the entire sheet material is now complete.

[0151] As described above, in the laser processing method of this application embodiment, the sheet material is first photographed and positioned at the camera's imaging position. After positioning, the second driving device rotates 180° to transfer the sheet material to the laser processing position for laser processing. The galvanometer is located directly above the first sub-region S1 of the laser processing position. First, the laser performs the first laser processing on the first sub-region S1. After processing, the first driving device controls the sheet material to rotate 90° clockwise. At this time, the second sub-region S2 is transferred below the galvanometer, and the laser processes the second sub-region S2. After processing, the first driving device controls the sheet material to rotate 90° clockwise. At this time, the third sub-region S3 is transferred below the galvanometer, and the laser processes the third sub-region S3. After processing, the first driving device controls the sheet material to rotate 90° clockwise. At this time, the fourth sub-region S4 is transferred below the galvanometer, and the laser processes the fourth sub-region S4. After four laser processing operations, the entire pattern of this sheet material is processed and spliced.

[0152] It should be noted that the region division of sheet materials is not limited to the above-described implementation method. For example, a rectangular sheet material can also be divided into two equal rectangular sub-regions. The sheet material can be divided into regions based on requirements, and the target processing pattern can be adapted to the segmentation process. This application does not specifically limit this. The sheet material is not limited to silicon wafers; it can also be other sheet objects requiring laser processing. When performing visual positioning, it is not limited to positioning via a CCD camera; other visual recognition positioning schemes can also be used.

[0153] The laser processing method described in this application completes the surface pattern processing of large-sized sheet materials by rotating the sheet material and performing multiple splicing processes. Multiple splicing processes can be achieved through a single visual positioning. When the rotation center coordinates shift, the new rotation center coordinates can be obtained to eliminate accuracy errors caused by temperature effects on the processing equipment and to eliminate accuracy errors caused by rotation center shift, thereby improving processing accuracy. The laser processing method is simple to operate and easy to implement. While improving processing accuracy, it minimizes the impact on production capacity and has good production efficiency.

[0154] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0155] It should be noted that, in the description of this application, the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0156] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0157] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A laser processing method, characterized in that, Laser processing equipment is used to process sheet materials placed on a stage. The laser processing equipment includes the stage and a first driving device that causes the stage to rotate around its own rotation center. The first driving device rotates to perform splicing processing. The sheet-like material is divided into N sub-regions, where N is a positive integer greater than 1, and the N sub-regions are numbered sequentially from the 1st sub-region to the Nth sub-region based on the laser processing order. The laser processing method includes: Obtain the coordinates of the rotation center of the stage; Based on the rotation center coordinates of the stage, the center coordinates of the i-th sub-region to be processed after the stage rotates are obtained, where i is a positive integer and 2≤i≤N; the galvanometer performs laser processing on the i-th sub-region based on the center coordinates of the i-th sub-region. The method for laser processing the first sub-region includes: acquiring a second image of the sheet material placed on a stage; determining the center coordinates of the sheet material based on the second image; determining the center coordinates of the first sub-region based on the center coordinates of the sheet material and the size of the processing pattern; and the galvanometer performing laser processing on the first sub-region based on the center coordinates of the first sub-region. The method for obtaining the center coordinates of the i-th sub-region includes: determining the center coordinates of the sheet material when performing laser processing on the i-th sub-region based on the rotation center coordinates of the stage and the center coordinates of the sheet material placed on the stage before processing; and determining the center coordinates of the i-th sub-region based on the center coordinates of the sheet material when performing laser processing on the i-th sub-region and the center coordinates of the first sub-region.

2. The laser processing method according to claim 1, characterized in that, The method for obtaining the coordinates of the rotation center includes: Acquire a first set of first images of a standard film or the stage, the first set of first images including an image of a positioning marker, and obtain the first coordinates of the positioning marker based on the first set of first images; After controlling the stage to rotate, a standard film or a second set of first images of the stage is acquired. The second set of first images includes an image of a positioning marker. The second coordinates of the positioning marker are obtained based on the second set of first images. The coordinates of the rotation center are calculated based on the first coordinate of the positioning identifier and the second coordinate of the positioning identifier.

3. The laser processing method according to claim 2, characterized in that, The method for obtaining the first image includes: Acquire an image of a standard piece placed on the stage to obtain the first image, wherein the standard piece has the positioning mark; Alternatively, an image of the stage with the positioning mark on its surface can be obtained to obtain the first image.

4. The laser processing method according to claim 1, characterized in that, If the coordinates of the rotation center deviate, the following also applies: Obtain the new coordinates of the rotation center; Based on the new rotation center coordinates, determine the center coordinates of the i-th sub-region to be processed. The galvanometer performs laser processing on the i-th sub-region based on the center coordinates of the i-th sub-region.

5. The laser processing method according to claim 4, characterized in that, The temperature sensor monitors whether the ambient temperature or the temperature of the laser processing equipment exceeds a preset temperature difference range to determine whether the coordinates of the rotation center have deviated.

6. The laser processing method according to claim 1, characterized in that, When the galvanometer performs laser processing on each sub-region, it performs laser processing on the sub-region based on the deflection angle of the sheet material relative to the galvanometer coordinate system and the center coordinates of the sub-region.

7. The laser processing method according to claim 1, characterized in that, Also includes: Based on the target processing pattern and the division method of the sheet material, the target processing pattern is divided into blocks to obtain multiple sub-images that correspond sequentially to the first sub-region to the Nth sub-region. The galvanometer performs laser processing on each sub-region based on the corresponding sub-image.

8. The laser processing method according to claim 6, characterized in that, The laser processing equipment includes: a camera imaging position, a laser processing position, at least two of the aforementioned stages, and a second driving device; wherein, the at least two stages are connected to the second driving device, and the second driving device is used to switch the at least two stages between the camera imaging position and the laser processing position; The image of the sheet material or the stage is acquired at the camera imaging position to determine the rotation center or the center coordinates of the sheet material placed on the stage and the deflection angle of the sheet material relative to the galvanometer coordinate system. At the laser processing position, the first to Nth sub-regions of the sheet material are sequentially laser-processed by the galvanometer.

Images