Calibration method

Abstract

[Problem] To provide a calibration method that can still perform calibration efficiently and accurately even when the angle of the orientation plane has deviated significantly. [Solution] A calibration method that aligns a first orientation plane formed on a workpiece in a direction parallel to a desired direction. The aforementioned calibration method includes the following steps: a line detection step, in which the first orientation plane is photographed by an imaging unit, and a line region within the photographed image is detected; a first alignment step, in which the deviation angle between the elongation direction of the line region detected in the line detection step and the desired direction is calculated, and the elongation direction of the line region is positioned parallel to the desired direction based on the deviation angle; and a second alignment step, in which the first orientation plane is photographed at a first position and a second position separated along the desired direction, and the line connecting the first orientation plane at the first position and the first orientation plane at the second position is positioned parallel to the desired direction.

Description

Technical Field

[0001] This invention relates to a calibration method. Prior Technology

[0002] As a method for forming wafers from ingots, the following method has been proposed: forming a release layer by focusing a laser beam inside the ingot, and separating the wafer from the ingot starting from this release layer (see, for example, Patent Document 1).

[0003] In Patent Document 1, the direction of movement of the laser beam's focusing point is set to be orthogonal to the direction in which the beam is angled, that is, parallel to the second orientation plane. This clarifies that because the cracks formed by propagation along the c-plane from both sides of the release layer can extend very long, the indexing movement can be increased, thereby improving productivity. Before the release layer is formed, calibration is performed to align the focusing point's movement direction with the second orientation plane. This calibration is generally performed by pattern matching (see, for example, Patent Document 2). Previous technical documents Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-111143 Patent Document 2: Japanese Patent Application Publication No. 60-244803 Summary of the Invention

[0005] The problem the invention aims to solve In the aforementioned situation, the orientation plane is pre-registered as the primary model (teaching), and the orientation plane is inspected by photographing the front of the wafer using a microscope or similar imaging unit, thereby performing calibration. However, if the ingot rotates during transport due to vibration or other reasons, the orientation plane angle will deviate significantly, making calibration impossible and necessitating a repositioning operation performed by the operator. Furthermore, although the operator has been taught to register the orientation plane as the primary model, there are still concerns that this method is time-consuming and may lead to human error, thus requiring improvement.

[0006] Accordingly, the purpose of this invention is to provide a calibration method that can still perform calibration efficiently and accurately even when the angle of the orientation plane has deviated significantly. The means to solve the problem

[0007] According to the present invention, a calibration method is provided to align an orientation plane formed on a workpiece in a direction parallel to a desired direction. The aforementioned calibration method comprises the following steps: The positioning step involves positioning the imaging unit, which captures images of the workpiece, at a location where it can capture images of the directional plane. The line detection step involves capturing an image of the directional plane using the imaging unit and detecting straight line regions within the captured image. The first alignment step involves calculating the deviation angle between the elongation direction of the straight line region detected in the straight line detection step and the desired direction, and using this deviation angle to position the elongation direction of the straight line region parallel to the desired direction; and The second alignment step involves taking pictures of the orientation plane at a first position and a second position that are separated along the desired direction after the first alignment step is performed, and positioning the line connecting the orientation plane at the first position and the orientation plane at the second position so that it is parallel to the desired direction.

[0008] Preferably, the second alignment step involves detecting, at the first and second positions, an orientation plane image with the same orientation plane ratio as the reference orientation plane image by pattern matching, and calculating the deviation angle between the orientation plane and the desired direction based on the XY coordinate positions of the orientation plane image detected at the first position and the orientation plane image detected at the second position, and positioning the orientation plane so that the orientation plane and the desired direction are parallel.

[0009] Preferably, the image of the orientation plane after alignment in the first alignment step is used as the reference orientation plane image.

[0010] Alternatively, a pre-generated oriented plane image in a simulated manner can be used as the reference oriented plane image. Invention Effects

[0011] According to the present invention, calibration can still be performed efficiently and accurately even when the angle of the orientation plane has deviated significantly. Simple Explanation of the Diagram

[0012] Figure 1 is a perspective view of a laser processing apparatus configuration example showing the calibration method implemented in the embodiment. Figure 2 is a top view showing an example of a calibration object, i.e., a workpiece, in which the calibration method is implemented. Figure 3 is a flowchart showing the processing procedure of the calibration method in the implementation form. Figure 4 is a perspective view illustrating the positioning steps in Figure 3. Figure 5 is a top view illustrating the positioning steps in Figure 3. Figure 6 is an example of an image captured during the line detection step in Figure 3. Figure 7 is an example of an image taken after the first alignment step in Figure 3. Figure 8 is a top view illustrating the second alignment step in Figure 3. Figure 9 is a top view illustrating the second alignment step in Figure 3. Figure 10 is a diagram illustrating the second alignment step in Figure 3. Figure 11 is a diagram showing an example of an orientation plane image of the reference used in the second alignment step of the calibration method in a modified embodiment. Implementation

[0013] Forms used to implement inventions Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the constituent elements described below include constituent elements that can be easily conceived by those skilled in the art, and substantially the same constituent elements. In addition, the configurations described below are adaptable combinations. Furthermore, various omissions, substitutions, or modifications to the configuration can be made without departing from the spirit of the present invention.

[0014] The calibration method of the present invention will be explained with reference to the figures. Figure 1 is a perspective view showing an example of the configuration of the laser processing apparatus 1 according to the calibration method of the embodiment. Figure 2 is a top view showing an example of the calibration object, i.e., the workpiece 100, according to the calibration method of the embodiment. As shown in Figure 1, the laser processing apparatus 1 according to the calibration method of the embodiment includes: a holding worktable 10, a laser beam irradiation unit 20, an imaging unit 30, an X-axis direction movement unit 41, a Y-axis direction movement unit 42, a Z-axis direction movement unit 43, a display unit 50, an input unit 60, and a controller 70.

[0015] In the implementation form, the calibration object of the calibration method in the implementation form, namely the workpiece 100, is composed of, for example, silicon carbide (SiC) or gallium nitride (GaN), and is formed as a whole into a cylindrical single crystal ingot.

[0016] As shown in Figures 1 and 2, the workpiece 100 has a generally circular end face, namely a first face 101, a generally circular second face 102 on the back side of the first face 101, and a peripheral face 104 connected to the outer edge of the first face 101 and the outer edge of the second face 102. Furthermore, the workpiece 100 has a first orientation plane 105 indicating the crystal orientation and a second orientation plane 106 orthogonal to the first orientation plane 105 formed on the peripheral face 104. In this embodiment, the first orientation plane 105 is a straight region that is longer than the second orientation plane 106.

[0017] Furthermore, the workpiece 100 has a c-axis that is inclined at an angle relative to the vertical line of the first surface 101 toward the second orientation plane 106, and a c-plane orthogonal to the c-axis. The c-plane is inclined at the same angle as the first surface 101 of the workpiece 100. The angle is freely set within a range of, for example, 1° to 6°. The direction forming the angle is orthogonal to the extension direction of the second orientation plane 106 and parallel to the first orientation plane 105.

[0018] The workpiece 100 is irradiated with a laser beam that is penetrating the workpiece 100 by setting the direction of the laser beam's focusing point to be orthogonal to the direction forming the deflection angle, i.e., parallel to the second orientation plane 106. A modified portion is formed inside the workpiece 100, and very long cracks are formed extending along the c-plane from both sides of the modified portion. The wafer is then separated from the workpiece using a release layer containing the modified portion and the cracks as the starting point. Furthermore, the modified portion is a region where, for example, its density, refractive index, mechanical strength, or other physical properties have become different from those of its surroundings.

[0019] The holding table 10 includes a disc-shaped frame with recesses and a disc-shaped adsorption part embedded in the recesses. The adsorption part of the holding table 10 is formed of porous ceramic or the like with a plurality of porous pores, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown). As shown in FIG2, the upper surface of the adsorption part of the holding table 10 is a surface on which the workpiece 100 can be placed, and the workpiece 100 is held by a negative pressure introduced from the vacuum suction source. In this embodiment, the holding surface 11 is for placing the workpiece 100 with its first surface 101 facing upwards, and the workpiece 100 is held by suction from the second surface 102 side. The holding surface 11 and the upper surface of the frame of the holding table 10 are arranged on the same plane and are formed in a manner parallel to the horizontal plane, i.e., the XY plane.

[0020] The holding stage 10 is movable freely in the X-axis direction (parallel to the horizontal direction) by means of the X-axis moving unit 41, and in the Y-axis direction (parallel to the horizontal direction and orthogonal to the X-axis direction) by means of the Y-axis moving unit 42. The holding stage 10 moves along the X-axis and Y-axis directions respectively by means of the X-axis moving unit 41 and the Y-axis moving unit 42, thereby allowing the workpiece 100 held on the holding stage 10 to move relative to the focusing point formed by the laser beam irradiation unit 20 and the imaging unit 30 in the X-axis and Y-axis directions respectively. The holding stage 10 is rotatably mounted about the Z-axis (parallel to the vertical direction and orthogonal to the XY plane) by means of a rotary drive source (not shown).

[0021] In this embodiment, the laser beam irradiation unit 20 irradiates the interior of the workpiece 100 held on the holding table 10 with a laser beam of a wavelength that has penetrability to the workpiece 100 from the first surface 101 side, thereby forming a release layer inside the workpiece 100 by means of the laser beam. The laser beam irradiation unit 20 is configured, for example, to include a laser beam oscillator (not shown) that emits a laser beam, and a concentrator that focuses the laser beam emitted from the laser beam oscillator and irradiates the interior of the workpiece 100.

[0022] The condenser included in the laser beam irradiation unit 20 is movably positioned in the Z-axis direction by means of the Z-axis direction moving unit 43. The condenser included in the laser beam irradiation unit 20 moves along the Z-axis direction by means of the Z-axis direction moving unit 43, thereby causing the focusing point of the laser beam to move relative to the workpiece 100 held on the holding table 10 in the Z-axis direction.

[0023] The imaging unit 30 includes an imaging element that captures images of the first surface 101 or outer edge, first orientation plane 105, etc., of the workpiece 100 held on the holding table 10. The imaging element can be, for example, a CCD (Charge-Coupled Device) imaging element or a CMOS (Complementary Metal-Oxide-Semiconductor) imaging element. In this embodiment, the imaging unit 30 is configured adjacent to the condenser included in the laser beam irradiation unit 20, and moves integrally with the condenser included in the laser beam irradiation unit 20. A reference line (center line) 31 extending along the X-axis and bisecting the imaging area in the Y-axis direction is provided within the imaging unit 30 (see Figures 6 and 7).

[0024] The imaging unit 30 captures three points on the outer edge of the first surface 101 of the workpiece 100 before the formation of the peel layer on the holding table 10, excluding the points where the first orientation plane 105 and the second orientation plane 106 are formed. Through geometric processing based on the coordinates of these three points, an image for edge alignment is obtained, and the obtained image is output to the controller 70. The aforementioned edge alignment involves determining the correct center coordinates and diameter of the first surface 101 of the workpiece 100 when it is considered a circle. In this embodiment, the image used for edge alignment is captured with the outer edge as the boundary, with the inner periphery captured at a higher brightness than the outer edge illuminated by the imaging unit 30 reflected from the first surface 101 of the workpiece 100, and the outer periphery captured at a lower brightness than the outer edge illuminated by the non-reflective imaging unit 30.

[0025] After completing edge calibration, the imaging unit 30 is positioned toward the center of the first surface 101 of the workpiece 100 determined by edge calibration, and automatically completes autofocus to align the focus of the image with the center of the first surface 101 of the workpiece 100, and automatically adjusts the amount of light illumination of the imaging unit 30 in an automatic manner, so as to automatically and most clearly capture the center of the first surface 101 of the workpiece 100.

[0026] Furthermore, the imaging unit 30 is positioned on the first orientation plane 105 of the workpiece 100 to capture an image of the first orientation plane 105, thereby obtaining an image for completing the calibration (orientation plane calibration), and the obtained image is output to the controller 70. The aforementioned calibration utilizes the first orientation plane 105 to align the movement direction of the laser beam's focal point with the second orientation plane 106. In the calibration method of this embodiment, the processing of the first alignment step 1003 (see Figure 3) and the processing of the second alignment step 1004 (see Figure 3) are included in the orientation plane calibration process. In this embodiment, the image used to complete the orientation plane calibration is captured with the first orientation plane 105 as the boundary. The inner periphery is captured with a higher brightness than the first orientation plane 105 illuminated by the first surface 101 of the workpiece 100 reflecting the illumination of the imaging unit 30, while the outer periphery is captured with a lower brightness than the first orientation plane 105 that does not reflect the illumination of the imaging unit 30. The images used to complete the orientation plane calibration are, in this embodiment, for example, the captured images 201, 202, and orientation plane image 203 described later (see Figures 6 and 7). Furthermore, in this invention, the capturing unit 30 is not limited to this; it can also be positioned at the second orientation plane 106 of the workpiece 100 and capture images of the second orientation plane 106 to obtain images used to complete the orientation plane calibration using the second orientation plane 106, and output the obtained images to the controller 70.

[0027] The X-axis moving unit 41 and the Y-axis moving unit 42 respectively move the holding stage 10 relative to the condenser included in the laser beam irradiation unit 20 along the X-axis and Y-axis directions. The Z-axis moving unit 43 moves the condenser included in the laser beam irradiation unit 20 relative to the holding stage 10 along the Z-axis direction. The X-axis moving unit 41, the Y-axis moving unit 42, and the Z-axis moving unit 43 are respectively equipped with, for example, a conventional ball screw, a conventional pulse motor, and a conventional guide rail. The ball screw is rotatably arranged about the axes of the X-axis, Y-axis, and Z-axis. The pulse motor rotates the ball screw about the axis. The guide rail supports the holding stage 10 or the condenser included in the laser beam irradiation unit 20 so that it can move freely in the X-axis, Y-axis, or Z-axis direction.

[0028] The X-axis movement unit 41, Y-axis movement unit 42, and Z-axis movement unit 43 include encoders for reading the rotational position of the pulse motor. Based on the rotational position of the pulse motor read by the encoder, they detect and maintain the relative positions of the stage 10 and the condenser included in the laser beam irradiation unit 20 in the X-axis, Y-axis, and Z-axis directions, and output the detected relative positions to the controller 70. Furthermore, the X-axis movement unit 41, Y-axis movement unit 42, and Z-axis movement unit 43 are not limited to the configuration of detecting the relative positions of the stage 10 and the condenser included in the laser beam irradiation unit 20 by an encoder. They can also be configured by using linear scales parallel to the X-axis, Y-axis, and Z-axis directions, respectively, and reading heads that are freely movable in the X-axis, Y-axis, and Z-axis directions by the X-axis movement unit 41, Y-axis movement unit 42, and Z-axis movement unit 43, respectively, and reading the scale of the linear scales.

[0029] The display unit 50 is an unshown cover disposed on the laser processing apparatus 1 with the display side facing outwards. It displays images such as settings for the laser beam irradiation conditions of the laser processing apparatus 1, or images showing the results of edge calibration, autofocus, automatic light intensity adjustment, orientation plane calibration, and the formation of a release layer, in a visually identifiable manner to the operator. The display unit 50 is constructed using a liquid crystal display device or the like. The display unit 50 is provided with an input unit 60, which is used when the operator inputs command information related to various actions of the laser processing apparatus 1, laser beam irradiation conditions, image display, etc. The input unit 60 disposed on the display unit 50 is constructed using at least one of a touch panel or a keyboard disposed on the display unit 50.

[0030] The controller 70 controls the operation of each component of the laser processing apparatus 1, enabling the laser processing apparatus 1 to perform the following actions: edge calibration or autofocus, automatic light intensity adjustment, orientation plane calibration, and processing to form a peel layer by irradiation with a laser beam. The controller 70 performs image processing on images used for edge calibration or orientation plane calibration. In this image processing, the controller 70 uses an orthogonal coordinate system (XY coordinate system) with the center of the worktable 10 as the origin, and an orthogonal coordinate system (XY coordinate system) with the center of each image as the origin, to perform various XY coordinate calculations. As shown in FIG1, the controller 70 includes a memory unit 71. The memory unit 71 stores information such as the diameter or thickness of the workpiece 100, the position or length of the straight area where the first orientation plane 105 and the second orientation plane 106 are formed, and the images used for edge calibration or orientation plane calibration.

[0031] In this embodiment, the controller 70 includes a computer system. The computer system included in the controller 70 has an arithmetic processing unit, a memory unit, and an input / output interface device. The arithmetic processing unit has a microprocessor such as a CPU (Central Processing Unit), and the memory unit has memory such as ROM (Read Only Memory) or RAM (Random Access Memory). The arithmetic processing unit of the controller 70 performs arithmetic processing according to a computer program stored in the memory unit of the controller 70, and outputs control signals for controlling the laser processing apparatus 1 to the various components of the laser processing apparatus 1 through the input / output interface device of the controller 70. In this embodiment, the function of the memory unit 71 is realized through the memory unit of the controller 70.

[0032] Secondly, this specification describes the calibration method of the embodiment based on the drawings. Figure 3 is a flowchart showing the processing procedure of the calibration method of the embodiment. The calibration method of the embodiment is an example of the operation processing of the laser processing apparatus 1, and it is a method of aligning the first orientation plane 105 or the second orientation plane 106 formed on the workpiece 100 with a direction parallel to the desired direction. As shown in Figure 3, the calibration method of the embodiment includes a positioning step 1001, a straight line detection step 1002, a first alignment step 1003, and a second alignment step 1004.

[0033] In this embodiment, although the alignment object is set as a first orientation plane 105 formed parallel to the direction of the forming angle, and the alignment target, i.e., the desired direction, is set as a direction parallel to the X-axis direction orthogonal to the Y-axis direction of the movement direction of the laser beam's focusing point, this invention is not limited to this. The alignment object can also be set as a second orientation plane 106, and the alignment target, i.e., the desired direction, can be set as the Y-axis direction. The alignment target, i.e., the desired direction, can also be appropriately changed according to the setting of the laser beam's focusing point's movement direction or the alignment object. The calibration method of this embodiment, since it uses a first orientation plane 105 formed with a straight-line region that is longer than the second orientation plane 106, can further improve the accuracy of orientation plane calibration based on the first alignment step 1003 and the second alignment step 1004, and is therefore superior.

[0034] In the calibration method of the implementation form, before the positioning step 1001, the controller 70 first transports the workpiece 100 to the holding table 10 using a transfer unit (not shown), and the holding table 10 holds the workpiece 100. Next, the controller 70 uses the imaging unit 30 to capture images of three separate points on the outer edge of the first surface 101 of the workpiece 100 held on the holding table, excluding the points where the first orientation plane 105 and the second orientation plane 106 are formed, and performs edge calibration based on these images. After the edge calibration is performed, the controller 70 causes the imaging unit 30 to perform automatic focusing and automatic light adjustment.

[0035] In edge calibration, the controller 70 detects the XY coordinates of a point at the boundary between higher and lower brightness in each image based on a total of three points on the outer edge of the first surface 101 of the workpiece 100 used for edge calibration. Then, the controller 70 performs geometric calculations based on the coordinates of these three points to determine the correct center coordinates (XY coordinates) and diameter when the first surface 101 of the workpiece 100 is considered to be circular.

[0036] Figures 4 and 5 are a perspective view and a top view, respectively, illustrating the positioning step 1001 in Figure 3. As shown in Figures 4 and 5, positioning step 1001 is the step of positioning the imaging unit 30 at a position on the first directional plane 105 where it can be photographed.

[0037] In positioning step 1001, the controller 70 first estimates the coordinates of the center of the first orientation plane 105 based on the center coordinates and diameter of the first surface 101 of the workpiece 100 obtained from the previously performed edge calibration, and the information of the position and length of the straight area where the first orientation plane 105 is formed, which is stored in the memory unit 71 beforehand. In positioning step 1001, the controller 70 then moves the holding table 10 along the X-axis and Y-axis directions using the X-axis moving unit 41 and the Y-axis moving unit 42, based on the estimated coordinates of the center of the first orientation plane 105, thereby moving the imaging unit 30 to the vicinity of the center of the first orientation plane 105.

[0038] Figure 6 is an example of an image 201 captured in the line detection step 1002 of Figure 3. The line detection step 1002 involves capturing an image of the first orientation plane 105 using the imaging unit 30, which has been positioned in the positioning step 1001, to obtain the image 201 shown in Figure 6, and detecting straight line regions within the image 201. In the line detection step 1002, the controller 70 detects the XY coordinates of a plurality of points in the image 201 that represent the boundary between higher and lower brightness of the first orientation plane 105, and performs Hough transformation and other computational processing on the XY coordinates of these points to detect straight lines within the image 201 corresponding to the first orientation plane 105.

[0039] The first alignment step 1003 is as follows: calculate the deviation angle θ1 between the elongation direction of the straight line region detected in the straight line detection step 1002 and the desired direction (refer to Figure 6), and based on the deviation angle θ1, position the elongation direction of the straight line region to be parallel to the desired direction.

[0040] In the first alignment step 1003, as shown in FIG6, the elongation direction of the straight line region detected in the straight line detection step 1002 corresponds to the elongation direction of the first orientation plane 105 in the captured image 201, and the desired direction is set in the X-axis direction as described above, and is the elongation direction of the reference line 31 in the captured image 201. Therefore, in the first alignment step 1003, the controller 70 calculates the angle between the straight line corresponding to the first orientation plane 105 and the reference line 31 based on the formula of the straight line corresponding to the first orientation plane 105 detected in the straight line detection step 1002 and the formula of the straight line corresponding to the reference line 31, and uses it as the deviation angle θ1.

[0041] In the first alignment step 1003, the controller 70 uses a rotary drive source to rotate the holding table 10 in the direction that cancels out the calculated deviation angle θ1 by the same amount as the deviation angle θ1, thereby rotating the workpiece 100 by an angle -θ1, and rotating the elongation direction of the first orientation plane 105 by an angle -θ1, thereby positioning the elongation direction of the first orientation plane 105 parallel to the elongation direction of the reference line 31.

[0042] Therefore, in the first alignment step 1003, alignment can be performed within the detection limit of the deviation angle θ1 when the deviation angle θ1 is calculated using the straight line detected in the range of one captured image 201, by setting the extension direction of the first orientation plane 105 parallel to the desired direction. The first alignment step 1003 is a coarser alignment step than the second alignment step 1004 described later.

[0043] In the first alignment step 1003, the controller 70 sometimes fails to locate the first orientation plane 105 within the shooting area of ​​the shooting unit 30 by aligning the extension direction of the first orientation plane 105 parallel to the extension direction of the reference line 31. In such cases, the controller 70 adjusts the first orientation plane 105 into the shooting area of ​​the shooting unit 30 by moving the holding stage 10 further along the Y-axis direction using the Y-axis direction moving unit 42, thereby causing the shooting unit 30 to move relatively along the Y-axis direction.

[0044] Figure 7 is an example of an image 202 captured after the first alignment step 1003 of Figure 3. After alignment is performed in the first alignment step 1003, the controller 70 captures the first orientation plane 105 by the imaging unit 30. As shown in Figure 7, an image 202 can be obtained in which the extension direction of the first orientation plane 105 is parallel to the extension direction of the reference line 31.

[0045] Figures 8 and 9 are both top views illustrating the second alignment step 1004 of Figure 3. The second alignment step 1004 comprises the following steps: After performing the first alignment step 1003, as shown in Figures 8 and 9, a first orientation plane 105 is photographed at a first position 105-1 and a second position 105-2 separated along the desired direction (X-axis direction). The straight line 105-3 connecting the first orientation plane 105 at the first position 105-1 and the first orientation plane 105 at the second position 105-2 is positioned parallel to the desired direction. Furthermore, in this embodiment, the desired direction is set in the X-axis direction.

[0046] In the second alignment step 1004, as shown in FIG8, the controller 70 first moves the imaging unit 30 relative to the first position 105-1 by means of the X-axis direction movement unit 41 and the Y-axis direction movement unit 42. At the first position 105-1, while the imaging unit 30 is offset relative to the first orientation plane 105 by means of the Y-axis direction movement unit 42 by a small distance each time, the controller 70 captures images of the first orientation plane 105, thereby obtaining a plurality of first orientation plane images. Next, the controller 70 performs pattern matching between the reference orientation plane image 203 (see FIG7) and the plurality of first orientation plane images to detect the first orientation plane image that has the same orientation plane ratio as the reference orientation plane image 203. Here, in this embodiment, the controller 70 uses the captured image 202 after the implementation of the first alignment step 1003 as the reference orientation plane image 203. Furthermore, the orientation plane ratio refers to the ratio of the area of ​​the region further inner than the first orientation plane 105 to the area of ​​the region further outer than the first orientation plane 105 in the orientation plane image. In the orientation plane image, it is the ratio of the area representing the region with higher brightness than the region further inner than the first orientation plane 105 to the area representing the region with lower brightness than the region further outer than the first orientation plane 105. As shown in FIG9, the controller 70 performs the same operation in the second position 105-2 as in the first position 105-1, and obtains a plurality of second orientation plane images. The controller detects, by means of pattern matching, the second orientation plane image with the same orientation plane ratio as the reference orientation plane image 203.

[0047] Figure 10 illustrates the second alignment step 1004 of Figure 3. In the second alignment step 1004, the controller 70, as shown in Figure 10, calculates the XY coordinate positions of the first directional plane image detected at the first position 105-1 (X1, Y1 in Figure 10) and the XY coordinate positions of the second directional plane image detected at the second position 105-2 (X2, Y2 in Figure 10). The controller 70 calculates the XY coordinate positions of each directional plane image based on the XY coordinates of the position of the imaging unit 30 when the directional plane image is captured. Then, the controller 70 calculates a formula for the straight line 105-3 connecting the first orientation plane 105 at the first position 105-1 and the first orientation plane 105 at the second position 105-2, based on the XY coordinate position of the first orientation plane 105 detected at the first position 105-1 and the XY coordinate position of the second orientation plane 105 detected at the second position 105-2. The controller 70 calculates the angle between the straight line 105-3 of the first orientation plane 105 and the reference line 31 based on the formula for the straight line 105-3 and the formula for the straight line of the reference line 31, and uses this angle as the deviation angle θ2.

[0048] Furthermore, in the second alignment step 1004, the controller 70 uses a rotation drive source to rotate the holding table 10 in the direction that cancels out the calculated deviation angle θ2 by the same amount as the deviation angle θ2, thereby rotating the workpiece 100 by an angle -θ2, and rotating the elongation direction of the first orientation plane 105 by an angle -θ2, thereby positioning the elongation direction of the first orientation plane 105 parallel to the elongation direction of the reference line 31.

[0049] Therefore, in the second alignment step 1004, alignment can be performed by setting the extension direction of the first orientation plane 105 parallel to the desired direction within the detection limit of the deviation angle θ2 calculated using the straight line 105-3 connecting the first orientation plane 105 at the first position 105-1 and the first orientation plane 105 at the second position 105-2, which are separated along the desired direction (X-axis direction). Because the detection limit of the deviation angle θ2 is smaller than the detection limit of the deviation angle θ1 in the first alignment step 1003, the second alignment step 1004 becomes a more detailed alignment than the first alignment step 1003, and thus a detailed alignment step.

[0050] In the calibration method for implementing the morphology, the first orientation plane 105 is aligned in a direction parallel to the X-axis by going through two stages, and the movement direction of the focal point of the laser beam used to form the release layer is accurately aligned in a direction parallel to the Y-axis. Then, by rotating the holding stage 10 by 90 degrees, the workpiece 100 is rotated by 90 degrees, and the movement direction of the focal point of the laser beam used to form the release layer is aligned in a direction parallel to the X-axis. Then, the laser beam irradiation unit 20 irradiates the interior of the workpiece 100 with a laser beam, thereby ideally forming the release layer.

[0051] The calibration method of the embodiment described above involves a first alignment step 1003 where a rough alignment is performed using straight-line detection without using pattern matching, followed by a second alignment step 1004 where a detailed alignment is performed using pattern matching at two separate positions. Therefore, even if the workpiece 100 rotates during transport due to vibration or other reasons, causing a significant deviation of the angle (elongation direction) of the first orientation plane 105 relative to the X-axis, the concern that pattern matching might be impossible due to the large deviation of the first orientation plane 105, thus preventing calibration from being performed, eliminates the need for the repositioning of the workpiece 100 performed by the operator as in the past. Accordingly, the calibration method of this embodiment achieves the following effect: even when the angle (elongation direction) of the first orientation plane 105 has significantly deviated, calibration can still be performed efficiently and with good accuracy. Thus, the calibration method of this embodiment contributes to reducing the number of calibration steps and preventing human error caused by the operator.

[0052] Furthermore, in the second alignment step 1004, the morphological calibration method detects, at the first position 105-1 and the second position 105-2, oriented plane images with the same oriented plane ratio as the reference oriented plane image 203 by pattern matching. Based on the XY coordinate positions of the first oriented plane image detected at the first position 105-1 and the second oriented plane image detected at the second position 105-2, the angle (elongation direction) of the first oriented plane 105 is calculated. Therefore, the morphological calibration method, by utilizing pattern matching of oriented plane ratios, can accurately determine the position of each oriented plane image in the Y-axis direction, and thus can accurately calculate the angle (elongation direction) of the first oriented plane 105, thereby enabling more accurate calibration.

[0053] Furthermore, the calibration method for implementing the form uses the image 202 of the first orientation plane 105 obtained during the line detection for rough alignment as the reference orientation plane image 203 for detailed alignment to perform pattern matching, thus eliminating the need to pre-register (teach) the pattern of the orientation plane as in the past.

[0054] [Variation Example] The calibration method of a modified embodiment will be explained based on the diagram. Figure 11 is a diagram showing an example of the orientation plane image 204 of the reference used in the second alignment step 1004 of the calibration method of the modified embodiment. The same symbols are added to the parts of Figure 11 that are the same as those in the embodiment, and the explanation is omitted.

[0055] The calibration method of the modified example is as follows: the reference orientation plane image 203 used in the second alignment step 1004 of the embodiment is changed to the reference orientation plane image 204 shown in FIG11. As shown in FIG11, the reference orientation plane image 204 is a pattern image generated in advance in a simulated manner and stored in the memory unit 71. With the simulated first orientation plane 115 that overlaps with the reference line 31 as the boundary, the simulated first surface 111 of the simulated workpiece 110 in the area more inner than the simulated first orientation plane 115 has a higher brightness, and the area more outer than the simulated first orientation plane 115 has a lower brightness.

[0056] The calibration method of the modified example is that, even if a reference orientation plane image 204 is used, pattern matching can still be performed between the orientation plane image 204 and a plurality of first orientation plane images and second orientation plane images, just like in the embodiment. It does not require prior registration (teaching) of the orientation plane pattern as in the past, so it can achieve the same effect as the embodiment.

[0057] Furthermore, this invention is not limited to the embodiments described above. That is, various modifications can be made without departing from the essential points of this invention.

[0058] 1: Laser processing equipment 10: Keep the workbench 11: Keep the surface 20: Laser beam illumination unit 30: Filming Unit 31: Baseline 41: X-axis direction moving unit 42: Y-axis moving unit 43: Z-axis moving unit 50: Display Unit 60: Input Unit 70: Controller 71: Memory Department 100: Workpiece 101,111: First page 102: Second page 104: Circumference 105, 115: First orientation plane 105-1: First position 105-2: Second position 105-3: Straight Line 106: Second Orientation Plane 110: Simulated workpiece 201, 202: Images taken 203, 204: Oriented Plane Images 1001: Positioning Steps 1002: Line Detection Steps 1003: First alignment step 1004: Second alignment step θ1, θ2: Deviation angles X, Y, Z: Direction X1, X2, Y1, Y2: Coordinate positions

Claims

1. A calibration method for aligning an orientation plane formed on a workpiece in a direction parallel to a desired direction, the calibration method comprising the following steps: a positioning step, positioning an imaging unit for imaging the workpiece at a position where the orientation plane can be imaged; a line detection step, imaging the orientation plane using the imaging unit and detecting a line region within the image; a first alignment step, calculating the deviation angle between the elongation direction of the line region detected in the line detection step and the desired direction, and positioning the elongation direction of the line region parallel to the desired direction based on the deviation angle; and a second alignment step, after performing the first alignment step, imaging the orientation plane at a first position and a second position separated along the desired direction, and positioning the line connecting the orientation plane at the first position and the orientation plane at the second position parallel to the desired direction.

2. The calibration method of claim 1, wherein the second alignment step involves detecting, at the first position and the second position, an orientation plane image with the same orientation plane ratio as the reference orientation plane image by means of pattern matching, and calculating the deviation angle between the orientation plane and the desired direction based on the XY coordinate positions of the orientation plane image detected at the first position and the XY coordinate positions of the orientation plane image detected at the second position, and positioning the orientation plane and the desired direction to be parallel.

3. The calibration method as described in claim 2, wherein an image of the orientation plane after alignment has been performed in the first alignment step is used as the reference orientation plane image.

4. The calibration method as described in claim 2, wherein a pre-generated orientation plane image in a simulated manner is used as the reference orientation plane image.

Images