Wafer correction device and wafer correction method

Abstract

A wafer correction device and a wafer correction method are provided. The wafer correction device comprises a rotating table, a lower chuck, an XY-axis moving platform, a measuring sensor, a Z-axis lifting mechanism, an upper chuck and a PLC system. The lower chuck is used to adsorb the wafer, the rotating table is used to drive the lower chuck to rotate, and the XY-axis moving platform is used to drive the rotating table to translate. The measuring sensor is located on the X-axis and is used to measure the distance of the point of the outer peripheral contour of the wafer when rotating into the sensing area of the measuring sensor. The wafer correction method comprises: rotating a first circle to determine and correct the X-axis direction offset distance ΔX between the first rotation center of the rotating table and the center of the wafer, rotating a second circle to determine and correct the Y-axis direction offset distance ΔY between the second rotation center of the rotating table and the center of the wafer, rotating a third circle to verify whether ΔX and ΔY are within the allowable error range, and determining the orientation of the V-shaped notch or straight edge based on the corrected center of the wafer.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor wafer processing, and more specifically to a wafer calibration apparatus and a wafer calibration method. Background Technology

[0002] In semiconductor wafer manufacturing, wafers involve a series of processes including cutting, grinding, etching, cleaning, edge grinding, and chamfering. During edge grinding and chamfering, it is necessary to determine the wafer's center and crystal orientation, and to correct any misalignments.

[0003] Traditional fixtures or jigs come into contact with the wafer edges, easily causing scratches. Furthermore, wafer centering and orientation are typically determined manually, which is prone to errors and lacks accuracy. Existing calculation methods for determining wafer centering and orientation are complex and not conducive to rapid calculation and correction of large batches of wafers. Additionally, the operation of correcting the wafer center is also complex and inefficient. Therefore, further improvements to wafer correction devices are necessary. Summary of the Invention

[0004] In view of the problems existing in the background art, one object of this disclosure is to provide a wafer correction device that eliminates the risk of wafer edge scratches when determining the wafer center and crystal orientation and correcting the wafer.

[0005] Another object of this disclosure is to provide a wafer calibration apparatus that can improve the accuracy of determining the wafer center and crystal orientation.

[0006] Another object of this disclosure is to provide a wafer calibration apparatus that reduces operational complexity.

[0007] Another object of this disclosure is to provide a wafer calibration method that can reduce the computational load for wafer centering and crystal orientation in large-volume wafer production.

[0008] Thus, a wafer calibration device includes a rotary table, a lower suction cup, an XY axis moving platform, a measuring sensor, a Z-axis lifting mechanism, an upper suction cup, and a PLC system;

[0009] The rotary table has a center, enabling it to rotate around this center in the XY-axis plane. A lower suction cup is fixed to the rotary table and is used to pick up wafers with V-shaped notches or straight edges from below. An XY-axis moving platform is fixedly connected to the rotary table and can move the rotary table along the X-axis or Y-axis. A measurement sensor is located on the X-axis of the XY-axis moving platform in the XY-axis plane. The measurement sensor is used to sense the distance between a point on the outer periphery of the wafer picked up from below and the sensor's sensing area as the rotary table rotates in the XY-axis plane. A Z-axis lifting mechanism is located above the rotary table and can move up and down in the Z-axis direction. An upper suction cup is fixed to the Z-axis lifting mechanism and is used to pick up wafers from above.

[0010] The PLC system is connected to the rotary table, lower suction cup, XY axis moving platform, measuring sensor, Z axis lifting mechanism and upper suction cup. The PLC system is used to control the rotation of the rotary table and record the rotation angle of the rotary table in real time.

[0011] PLC systems are also used for:

[0012] (a) After the wafer is initially placed on the lower chuck, the center of the first rotation of the rotary table is the first rotation center. The rotary table rotates around the first rotation center for the first revolution, and the X-axis offset distance ΔX between the first rotation center and the center of the wafer is determined.

[0013] (b) The first rotation center of the rotary table moves along the X-axis toward the center of the wafer by an offset distance ΔX in the X-axis direction, so that the offset distance between the first rotation center of the rotary table and the center of the wafer in the X-axis direction is zero ΔX, and the center of the rotary table changes from the first rotation center to the second rotation center.

[0014] (c) The rotary table rotates around the second rotation center for the second revolution, and the Y-axis offset distance ΔY between the second rotation center of the rotary table and the center of the wafer is determined;

[0015] (d) The second rotation center of the rotary table moves along the Y-axis toward the center of the wafer by a Y-axis offset distance ΔY, so that the offset distance ΔY between the second rotation center of the rotary table and the center of the wafer in the Y-axis direction is zero, and the center of the rotary table changes from the second rotation center to the third rotation center.

[0016] (e) The rotary table rotates around the third rotation center for the third revolution. The PLC system operates to confirm whether the ΔX and ΔY of the third rotation center and the center of the wafer are within the allowable error range, that is, to verify and determine that the third rotation center of the rotary table is the center of the wafer.

[0017] (f) The rotary table rotates again around the third rotation center to determine the orientation of the V-notch or straight edge of the wafer;

[0018] (g) Rotate the rotary table by a specified angle based on the determined angle of the V-notch or straight edge so that the V-notch or straight edge of the wafer is in the specified crystal orientation position. The wafer in the specified crystal orientation position is used by the transport tool to transport to the next chamfering process for peripheral edge grinding and chamfering.

[0019] A wafer calibration method includes the following steps:

[0020] (a) After the wafer is initially placed on the lower chuck, the center of the first rotation of the rotary table is the first rotation center. The rotary table rotates around the first rotation center for the first revolution, and the X-axis offset distance ΔX between the first rotation center and the center of the wafer is determined.

[0021] (b) The first rotation center of the rotary table moves along the X-axis toward the center of the wafer by an offset distance ΔX in the X-axis direction, so that the offset distance ΔX between the first rotation center of the rotary table and the center of the wafer in the X-axis direction is zero, and the center of the rotary table changes from the first rotation center to the second rotation center.

[0022] (c) The rotary table rotates around the second rotation center for the second revolution, and the Y-axis offset distance ΔY between the second rotation center of the rotary table and the center of the wafer is determined;

[0023] (d) The second rotation center of the rotary table moves along the Y-axis toward the center of the wafer by a Y-axis offset distance ΔY, so that the offset distance ΔY between the second rotation center of the rotary table and the center of the wafer in the Y-axis direction is zero, and the center of the rotary table changes from the second rotation center to the third rotation center.

[0024] (e) The rotary table rotates around the third rotation center for the third revolution. The PLC system operates to confirm whether the ΔX and ΔY of the third rotation center and the center of the wafer are within the allowable error range, that is, to verify and determine that the third rotation center of the rotary table is the center of the wafer.

[0025] (f) The rotary table rotates again around the third rotation center to determine the orientation of the V-notch or straight edge of the wafer;

[0026] (g) Based on the determined rotation angle of the V-notch or straight edge relative to the third rotation center, the rotary table is rotated by a specified angle so that the V-notch or straight edge of the wafer is in a specified crystal orientation position. The wafer in the specified crystal orientation position is used by the transport tool to transport to the next chamfering process for peripheral edge grinding and chamfering.

[0027] The beneficial effects of this disclosure are as follows: Unlike traditional jigs or fixtures, the wafer calibration device of this disclosure uses upper and lower suction cups to adsorb the wafer, reducing the risk of scratching the wafer edges. A measuring sensor is used to measure all points on the outer periphery of the wafer in a non-contact manner, avoiding the impact of traditional jigs or fixtures on the accuracy of measuring the outer periphery of the wafer. This disclosure uses a method of calibrating the offset distance ΔX in the X-axis direction first, and then calibrating the offset distance ΔY in the Y-axis direction, which helps to avoid the influence of the offset distance ΔX in the X-axis direction on the offset distance ΔY in the Y-axis direction. Specifically, since the measuring sensor is always positioned on the X-axis, the points on the outer periphery used to measure the offset distance ΔY in the Y-axis direction need to be rotated to the X-axis direction for measurement. If the offset distance ΔX in the X-axis direction is not zero, the measured distance of the point to be measured in the Y-axis direction after rotation in the X-axis direction will be greater than or less than the distance measured when the offset distance ΔX in the X-axis direction is zero, increasing the workload of calculating the offset distance ΔY in the Y-axis direction and hindering rapid calibration of the offset distance ΔY in the Y-axis direction. Therefore, one of the advantages of this disclosure is that it calibrates the offset distance ΔY in the Y-axis direction without changing the measurement direction of the measuring sensor, and makes the calculation formulas of the offset distance ΔY in the Y-axis direction and the offset distance ΔX in the X-axis direction similar. It is not necessary to use trigonometric function relationships to calculate the offset distance ΔY in the Y-axis direction based on the angle θ1 corresponding to the longest distance L1 of the full circumference and the offset distance ΔX in the X-axis direction. ΔY can be obtained simply by taking the difference between the values ​​of the sensing distance obtained by rotation, which simplifies the calculation, saves calibration time, and improves work efficiency.

[0028] Compared to existing methods for determining wafer center and crystal orientation, the wafer calibration method described above uses simpler methods for calculating the offset distance ΔX along the X-axis and the offset distance ΔY along the Y-axis, which reduces the computational workload for determining wafer center and crystal orientation in large batches of wafers. Compared to determining the crystal orientation first and then calibrating the wafer center, this method first calibrates the wafer center and then determines the crystal orientation. The wafers are evenly placed at the center of the rotary table, making it easier for handling tools to align them and reducing the risk of the wafer slipping to one side. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a wafer calibration apparatus according to the present disclosure, wherein the rotary table, lower suction cup, wafer and upper suction cup are shown in a half-section view.

[0030] Figure 2 This is a schematic diagram of the wafer calibration apparatus according to the present disclosure, showing the state in which the wafer is initially placed on the upper suction cup above the rotary table, wherein the rotation center of the rotary table is the first rotation center, and wherein points A and C marked in the figure are the two points where the straight line formed by the first rotation center of the rotary table and the center of the wafer intersects the periphery of the wafer.

[0031] Figure 3 It shows the rotary table from Figure 2 The first rotation center is moved along the X-axis to the second rotation center so that the offset distance between the first rotation center of the rotary table and the center of the wafer in the X-axis direction is zero. Points B and D marked in the figure are the two points where the straight line formed by the second rotation center of the rotary table and the center of the wafer intersects the periphery of the wafer.

[0032] Figure 4 It shows the rotary table from Figure 3 The second rotation center is moved along the Y-axis to the third rotation center so that the offset distance between the second rotation center of the rotary table and the center of the wafer in the Y-axis direction is zero.

[0033] The reference numerals in the attached figures are explained as follows:

[0034] 100 wafer calibration device 10 upper vacuum tube

[0035] 1. Valves for suction cups on rotary table 11

[0036] Q1' First Rotation Center 12HMI System

[0037] Q1” Second rotation center θ1 angle

[0038] Q1”'Third rotation center θ3 angle

[0039] 2 lower suction cups, 200 chips

[0040] 3XY axis moving platform Q2 center

[0041] 4. Measurement sensor 200a V-notch

[0042] 5Z axis lifting mechanism F lowest point

[0043] 6. Upper suction cup G1, G2 inflection points

[0044] 7PLC system δ angle

[0045] 8 Lower vacuum tube 200b straight edge

[0046] 9. Lower suction cup valve Detailed Implementation

[0047] The accompanying drawings illustrate embodiments of this disclosure, and it will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0048] [Wafer Correction Device]

[0049] Reference Figure 1 The wafer correction device 100 includes a rotary table 1, a lower suction cup 2, an XY axis moving platform 3, a measuring sensor 4, a Z axis lifting mechanism 5, an upper suction cup 6, and a PLC system 7.

[0050] Rotary stage 1 has a center, and it is capable of rotating about this center in the XY-axis plane. Figures 2 to 4 In the diagram, the centers of the rotary tables in the three figures change, denoted by Q1', Q1”, and Q1”', and named as the first rotation center, second rotation center, and third rotation center, respectively. The rotary table 1 can be driven by a motor. The rotation speed of the rotary table 1 is controlled by the PLC system 7 to meet the requirements of the wafer 200 correction speed, thereby improving the working efficiency of the wafer correction device 100.

[0051] The lower suction cup 2 is fixed on the rotary table 1. The lower suction cup 2 is used to adsorb the wafer 200 with a V-shaped notch 200a or a straight edge 200b from below. The lower suction cup 2 can adsorb the wafer 200 by vacuum adsorption to prevent the center of the wafer 200 from slipping in the X-axis or Y-axis direction or the crystal orientation of the wafer 200 from changing when the rotary table 1 rotates.

[0052] The XY-axis moving platform 3 is fixedly connected to the rotary table 1 and can drive the rotary table 1 to translate along the X-axis or Y-axis. Under the control of the PLC system 7, the XY-axis moving platform 3 drives the rotary table 1 to rotate, correcting or compensating for the offset distance of the rotating center of the rotary table 1 relative to the wafer 200, so that the rotating center of the rotary table 1 is concentric with the center of the wafer 200.

[0053] The measuring sensor 4 is located on the X-axis of the XY-axis moving platform 3 in the XY-axis plane. The measuring sensor 4 is used to sense the distance between points on the outer periphery of the wafer 200, which is adsorbed from below by the lower suction cup 2, and the points entering the sensing area of ​​the measuring sensor 4 as the wafer 200 rotates with the rotary table 1 in the XY-axis plane. Compared to traditional fixtures or jigs that come into contact with the edge of the wafer 200, this non-contact measurement method using the measuring sensor 4 reduces the risk of scratching the edge of the wafer 200 and allows for the acquisition of the aforementioned specific values ​​of points on the outer periphery of the wafer 200 without contact with fixtures or jigs.

[0054] The Z-axis lifting mechanism 5 is located above the rotary table 1 and can move up and down in the Z-axis direction. The Z-axis lifting mechanism 5 can be a Z-axis motor. Under the control of the PLC system 7, the Z-axis lifting mechanism 5 acts as an auxiliary correction mechanism. When the XY-axis moving platform 3 is used to correct or compensate for the displacement of the wafer, the upper suction cup 6 (described later) is used to fix or keep the center of the wafer 200 in the X-axis or Y-axis direction so as not to shift, and also to ensure that the crystal orientation of the wafer 200 does not change.

[0055] The upper suction cup 6 is fixed to the Z-axis lifting mechanism 5. The upper suction cup 6 is used to adsorb the wafer 200 from above. The upper suction cup 6 can adsorb the wafer 200 by vacuum adsorption to prevent the center of the wafer 200 from slipping in the X-axis or Y-axis direction or the crystal orientation of the wafer 200 from changing when the rotary table 1 rotates.

[0056] The PLC system 7 is communicatively connected to the rotary table 1, the lower suction cup 2, the XY axis moving platform 3, the measuring sensor 4, the Z-axis lifting mechanism 5, and the upper suction cup 6. The PLC system 7 controls the rotation of the rotary table 1 and records the rotation angle of the rotary table 1 in real time. The PLC system 7 also controls the rotation of the rotary table 1 and records in real time the distance along the X-axis from the point on the outer periphery of the wafer 200 measured by the measuring sensor 4 into the sensor's sensing area.

[0057] PLC system 7 is also used for:

[0058] (a) Reference Figure 2 After the wafer 200 is initially placed in the lower suction cup 2 (vacuum adsorption can be used instead of traditional jigs or clamps), the center of the first rotation of the rotary table 1 is the first rotation center Q1'. The rotary table 1 rotates around the first rotation center Q1' for the first revolution, and the X-axis offset distance ΔX between the first rotation center Q1' and the center Q2 of the wafer 200 is determined. The relative distance between the position of a point on the outer periphery of the wafer 200 when it rotates into the sensing area of ​​the measuring sensor 4 and the boundary of the sensing area or the preset initial position is measured. By comparing the above distances measured between the points on the outer periphery of the wafer 200, the X-axis offset distance ΔX is calculated.

[0059] (b) Reference Figure 3 The first rotation center Q1' of the rotary stage 1 is moved along the X-axis towards the center Q2 of the wafer 200 by an X-axis offset distance ΔX, so that the offset distance ΔX between the first rotation center Q1' of the rotary stage 1 and the center Q2 of the wafer 200 in the X-axis direction is zero, and the center of the rotary stage 1 changes from the first rotation center Q1' to the second rotation center Q1". It should be noted that when correcting the offset distance ΔX in the X-axis direction, the offset distance ΔY in the Y-axis direction, which will be described later, is kept unchanged.

[0060] (c) Reference Figure 3 The rotary stage 1 rotates a second revolution around the second rotation center Q1” to determine the Y-axis offset distance ΔY between the second rotation center Q1” of the rotary stage 1 and the center Q2 of the wafer 200. The Y-axis offset distance ΔY is also measured by the measuring sensor 4 located in the X-axis direction.

[0061] (d) Reference Figure 4 The second rotation center Q1” of the rotary stage 1 moves along the Y-axis toward the center Q2 of the wafer 200 by a Y-axis offset distance ΔY, so that the offset distance ΔY between the second rotation center Q1” of the rotary stage 1 and the center Q2 of the wafer 200 in the Y-axis direction is zero, and the center of the rotary stage 1 changes from the second rotation center Q1” to the third rotation center Q1”'.

[0062] (e) The rotary table 1 rotates for the third revolution around the third rotation center Q1”'. The PLC system 7 operates to confirm whether the ΔX and ΔY of the third rotation center Q1”' and the center Q2 of the wafer are within the allowable error range, that is, to verify that the third rotation center Q1”' of the rotary table 1 is the center Q2 of the wafer 200. The error range can be selected between 0.1 and 5 mm. If it exceeds the allowable error range, repeat (a)-(d).

[0063] (f) Rotate the rotary table 1 around the third rotation center Q1”' to determine the orientation of the V-shaped notch 200a or the straight edge 200b of the wafer 200.

[0064] (g) Rotate the rotary table 1 by a specified angle based on the determined angle of the V-notch 200a or the straight edge 200b, so that the V-notch 200a or the straight edge 200b of the wafer 200 is in a specified crystal orientation position. The wafer 200 in the specified crystal orientation position is used by the transport tool to transport to the next chamfering process for peripheral edge grinding and chamfering.

[0065] Unlike traditional jigs or fixtures, the wafer alignment device 100 of this disclosure uses an upper suction cup 6 and a lower suction cup 2 to hold the wafer 200, reducing the risk of scratching the wafer 200. A measuring sensor 4 is used to measure all points on the outer periphery of the wafer 200 in a non-contact manner, avoiding the impact of traditional jigs or fixtures on the accuracy of measuring the outer periphery of the wafer 200. This disclosure uses a method of first calibrating the offset distance ΔX in the X-axis direction and then calibrating the offset distance ΔY in the Y-axis direction, which helps to avoid the influence of the offset distance ΔX in the X-axis direction on the offset distance ΔY in the Y-axis direction. Specifically, since the measuring sensor 4 is always positioned along the X-axis, the points on the outer periphery used to measure the offset distance ΔY in the Y-axis direction need to be rotated to the X-axis direction for measurement. If the offset distance ΔX in the X-axis direction is not zero, the measured distance of the point to be measured in the Y-axis direction after rotation will be greater than or less than the distance measured when the offset distance ΔX in the X-axis direction is zero. This increases the workload of calculating the offset distance ΔY in the Y-axis direction and is not conducive to the rapid calibration of the offset distance ΔY in the Y-axis direction. Therefore, an advantage of this disclosure is that it calibrates the offset distance ΔY in the Y-axis direction without changing the measurement direction of the measuring sensor 4, and makes the calculation formulas of the offset distance ΔY in the Y-axis direction and the offset distance ΔX in the X-axis direction similar. It is not necessary to calculate the offset distance ΔY in the Y-axis direction based on the angle θ1 corresponding to the longest distance L1 of the full circumference and the offset distance ΔX in the X-axis direction using trigonometric functions. ΔY can be obtained simply by subtracting the value of the sensing distance obtained by rotation, which simplifies the calculation, saves calibration time, and improves work efficiency.

[0066] The operation process of step (a) in PLC system 7 is as follows:

[0067] (a1) The PLC system 7 receives the distance of the point on the outer periphery of the wafer 200 measured by the measuring sensor 4 as it rotates one revolution into the sensing area of ​​the measuring sensor 4.

[0068] (a2) Determine the longest distance L1 and the corresponding angle θ1 of the full circumference of the point outside the angle range of the V-shaped notch 200a and the straight edge 200b of the wafer 200 and the 180-degree symmetrical range of the angle range from the distance sensed into the sensing area of ​​the measuring sensor 4.

[0069] (a3) Based on the angle θ1 corresponding to the longest distance L1 in the entire circumference, determine the distance of the point that is 180 degrees symmetrical to the point that is symmetrical to the longest distance L1 in the entire circumference as the shortest distance L2 in the entire circumference. Here, the point that is 180 degrees symmetrical to the point that is ...

[0070] (a4) Based on the longest distance L1 and the shortest distance L2 around the entire circumference, determine the X-axis offset distance ΔX between the first rotation center Q1' of the rotary table 1 and the center Q2 of the wafer 200.

[0071] ΔX = (L1 - L2) / 2.

[0072] The operation process for step (b) of PLC system 7 is as follows:

[0073] (b1) The PLC system 7 controls the lower suction cup 2 to release the vacuum adsorption operation, the PLC system 7 controls the Z-axis lifting mechanism 5 to descend and the PLC system 7 controls the upper suction cup 6 to perform vacuum adsorption operation to adsorb the wafer 200. Then the PLC system 7 controls the Z-axis lifting mechanism 5 to rise along the Z-axis to make the wafer 200 detach from the lower suction cup 2.

[0074] (b2) The PLC system 7 controls the XY axis moving platform 3 to drive the rotary table 1 to translate ΔX along the X axis so that the X-axis offset distance ΔX between the first rotation center Q1' of the rotary table 1 and the center Q2 of the wafer 200 is 0;

[0075] (b3) The PLC system 7 controls the Z-axis lifting mechanism 5 to drive the lower suction cup 2 to descend along the Z-axis so that the wafer 200 is positioned on the rotary table 1 after being translated ΔX along the X-axis. The PLC system 7 controls the upper suction cup 6 to release the vacuum adsorption operation so that the positioned wafer 200 falls onto the rotary table 1. The PLC system 7 controls the lower suction cup 2 to start the vacuum adsorption operation so that the wafer 200 falling onto the rotary table 1 is adsorbed onto the rotary table 1.

[0076] The operation process of step (c) of PLC system 7 is as follows:

[0077] (c1) The PLC system 7 receives the distance of the point on the outer periphery of the wafer 200 measured by the measuring sensor 4 as it rotates for the second time and enters the sensing area of ​​the measuring sensor 4.

[0078] (c2) Determine the longest distance L3 and the corresponding angle θ3 of the full circumference of the point outside the angle range of the V-shaped notch 200a and the straight edge 200b of the wafer 200 and the 180-degree symmetrical range of the angle range from the distance sensed into the sensing area of ​​the measuring sensor 4.

[0079] (c3) Based on the angle θ3 corresponding to the longest distance L3 of the whole circumference, determine the distance of the point that is 180 degrees symmetrical to the point of the longest distance L3 of the whole circumference as the shortest distance L4 of the whole circumference;

[0080] (c4) Based on the longest distance L3 and the shortest distance L4 around the entire circumference, determine the Y-axis offset distance ΔY between the second rotation center Q1” of the rotary table 1 and the center Q2 of the wafer 200.

[0081] ΔY = (L3 - L4) / 2.

[0082] The operation process of step (d) in PLC system 7 is as follows:

[0083] (d1) PLC system 7 controls the lower suction cup 2 to release the vacuum adsorption operation, PLC system 7 controls the Z-axis lifting mechanism 5 to descend and PLC system 7 controls the upper suction cup 6 to perform vacuum adsorption operation to adsorb the wafer 200. After that, PLC system 7 controls the Z-axis lifting mechanism 5 to rise along the Z-axis to make the wafer 200 detach from the lower suction cup 2.

[0084] (d2) The PLC system 7 controls the XY axis moving platform 3 to drive the rotary table 1 to translate ΔY along the Y axis so that the Y-axis offset distance ΔY between the second rotation center Q1” of the rotary table 1 and the center Q2 of the wafer 200 is 0;

[0085] (d3) PLC system 7 controls Z-axis lifting mechanism 5 to drive lower suction cup 2 to descend along Z-axis so that wafer 200 is positioned on rotary table 1 after translation ΔY along Y-axis. PLC system 7 controls upper suction cup 6 to release vacuum adsorption operation so that wafer 200 after positioning falls on rotary table 1. PLC system 7 controls lower suction cup 2 to start vacuum adsorption operation so that wafer 200 falling on rotary table 1 is adsorbed on rotary table 1.

[0086] The operation process of step (e) of PLC system 7 is as follows:

[0087] (e1) The PLC system 7 receives the distance of the point on the outer periphery of the wafer 200 measured by the measuring sensor 4 as it rotates one revolution into the sensing area of ​​the measuring sensor 4.

[0088] (e2) Based on step (a), determine the two points corresponding to the offset distance ΔX in the X-axis direction, and determine the ΔX corresponding to these two points in step (e);

[0089] (e3) Based on step (c), determine the two points corresponding to the offset distance ΔY in the Y-axis direction, and determine the ΔY corresponding to the two points in step (e);

[0090] (e4) Determine whether it is within the allowable error range based on the corresponding ΔX and ΔY described in step (e).

[0091] The three points of the V-shaped notch 200a form an isosceles triangle. The line connecting the lowest point F of the V-shaped notch 200a and the center Q2 of the wafer 200 is collinear with the axis of symmetry of the isosceles triangle. The rotation of the rotary table 1 of PLC system 7 (f) is used to determine the orientation of the V-shaped notch 200a or the straight edge 200b of the wafer 200. The process of determining the orientation of the V-shaped notch 200a of the wafer 200 is as follows:

[0092] (f1) The rotary table 1 rotates at least 270 degrees from the first quadrant, and the PLC system 7 receives the distance of the point of the outer periphery of the wafer 200 measured by the measuring sensor 4, which rotates at least 270 degrees into the sensing area of ​​the measuring sensor 4.

[0093] (f2) Determine the shortest distance from the sensed distances within the sensing area of ​​the measuring sensor 4. The point corresponding to the shortest distance is the lowest point F of the V-shaped notch 200a of the chip 200.

[0094] (f3) Based on the determined lowest point F of the V-shaped notch 200a of the wafer 200, two step points G1 and G2 are found along the same direction as the rotation of the rotary table 1 to measure the distance between the point on the outer periphery of the wafer 200 and the sensing area of ​​the measuring sensor 4. The two step points G1 and G2 are the two inflection points G1 and G2 of the outer periphery of the wafer 200 at the V-shaped notch 200a. The position of the V-shaped notch 200a on the wafer 200 is determined by the determined positions of the two inflection points G1 and G2 and the lowest point F of the V-shaped notch 200a, and the rotation angle relative to the third rotation center Q1”'. It should be noted that the two step points G1 and G2 are different from the lowest point F of the V-shaped notch 200a.

[0095] Step (f) of PLC system 7 also includes:

[0096] (f4) Verify the two inflection points G1 and G2 of the V-shaped notch 200a.

[0097] During the rotation around the third rotation center Q1”', the first step point and the lowest point of the distance between points on the outer periphery of the wafer 200 and the sensing area of ​​the measuring sensor 4 are measured sequentially. The rotation continues until the second step point of the distance between points on the outer periphery of the wafer 200 and the sensing area of ​​the measuring sensor 4 appears, at which point the rotation stops. The two step points are the two inflection points G1 and G2 of the outer periphery of the wafer 200 at the V-shaped notch 200a.

[0098] Determine the angle δ between the second step point and the lowest point F and the third rotation center Q1”'. Then rotate the third rotation center Q1”' in the opposite direction by twice the angle δ. Determine the distance of the second step point after rotating the angle δ in the opposite direction into the sensing area of ​​the measuring sensor 4. Compare this distance with the distance of the first inflection point in the sensing area of ​​the measuring sensor 4 determined in step f3 on the outer periphery contour of the wafer 200. If the comparison result is within the error range, the determined V-shaped notch 200a is verified to be correct.

[0099] In step (f) of PLC system 7, the rotary table 1 rotates again to determine the orientation of the V-shaped notch 200a or the straight edge 200b of the wafer 200. The process of determining the orientation of the straight edge 200b of the wafer 200 is as follows:

[0100] (I) The rotary table 1 rotates at least 270 degrees from the first quadrant, and the PLC system 7 receives the distance of the point of the outer periphery of the wafer 200 measured by the measuring sensor 4, which rotates at least 270 degrees into the sensing area of ​​the measuring sensor 4.

[0101] (II) Determine two step points from the distance into the sensing area of ​​the measuring sensor 4 to find the point on the outer periphery of the wafer 200 along the rotation direction to enter the sensing area of ​​the measuring sensor 4. The two step points are the two inflection points of the outer periphery of the wafer 200 at the straight edge 200b. Determine the position of the straight edge 200b on the wafer 200 by determining the two inflection points.

[0102] Rotary table 1 is a motor.

[0103] Z-axis lifting mechanism 5 is a Z-axis motor.

[0104] Measurement sensor 4 is an optical measurement sensor.

[0105] The wafer correction device 100 also includes a lower vacuum tube 8 and a lower suction cup valve 9.

[0106] The lower vacuum tube 8 is installed on the rotary table 1. The upper end of the lower vacuum tube 8 is connected to the lower suction cup 2, and the lower end of the lower vacuum tube 8 is used to connect to an external vacuum pumping device. The external vacuum pumping device is connected to the PLC system 7 for communication.

[0107] The lower suction cup valve 9 is located on the lower vacuum tube 8 and is connected to the PLC system 7. The lower suction cup valve 9 is used to control the suction force of the lower suction cup 2.

[0108] The wafer calibration device 100 also includes an upper vacuum tube 10 and an upper suction cup valve 11.

[0109] One end of the upper vacuum tube 10 passes through the Z-axis lifting mechanism 5 and is connected to the upper suction cup 6 at the end facing the wafer 200. The other end of the upper vacuum tube 10 passes through the Z-axis lifting mechanism 5 and is connected to the vacuum pumping device at the end away from the wafer 200. The upper vacuum tube 10 is equipped with an upper suction cup valve 11, which is communicatively connected to the PLC system 7 to control the suction force of the upper suction cup 6.

[0110] The wafer calibration device 100 also includes an HMI system 12, which is communicatively connected to the PLC system 7.

[0111] The initial orientation of the wafer 200 placed on the upper suction cup 6 is such that the notch or straight edge 200b of the wafer 200 is in the second quadrant of the wafer 200, and the first rotation center Q1' of the rotary table 1 is located in the first or third quadrant of the wafer 200. Figure 2 In the process, the first rotation center Q1' of the rotary stage 1 is located in the first quadrant of the wafer 200.

[0112] The PLC system 7 is also used to control the XY axis moving platform 3 to drive the rotary table 1 to connect the suction cup 2 of the wafer 200 to translate along the X axis and / or along the Y axis so that the wafer 200 reaches the specified position of the sensing area of ​​the measuring sensor 4. At this position, when the rotary table 1 rotates a full circle around the center Q1 of the rotary table 1, all points on the outer periphery of the wafer 200 can enter the sensing area of ​​the measuring sensor 4 and be sensed.

[0113] [Wafer Calibration Method]

[0114] The wafer calibration method uses the aforementioned wafer calibration apparatus 100, and the wafer calibration method includes the following steps:

[0115] (a) After the wafer 200 is initially placed in the lower suction cup 2, the center of the first rotation of the rotary table 1 is the first rotation center Q1'. The rotary table 1 rotates around the first rotation center Q1' for the first revolution, and the X-axis offset distance ΔX between the first rotation center Q1' and the center Q2 of the wafer 200 is determined.

[0116] (b) The first rotation center Q1' of the rotary stage 1 moves along the X-axis toward the center Q2 of the wafer 200 by an offset distance ΔX in the X-axis direction, so that the offset distance ΔX between the first rotation center Q1' of the rotary stage 1 and the center Q2 of the wafer 200 in the X-axis direction is zero, and the center of the rotary stage 1 changes from the first rotation center Q1' to the second rotation center Q1".

[0117] (c) Rotate the rotary table 1 around the second rotation center Q1” for the second revolution, and determine the Y-axis offset distance ΔY between the second rotation center Q1” of the rotary table 1 and the center Q2 of the wafer 200;

[0118] (d) The second rotation center Q1” of the rotary stage 1 moves along the Y-axis toward the center Q2 of the wafer 200 by a Y-axis offset distance ΔY, so that the offset distance ΔY between the second rotation center Q1” of the rotary stage 1 and the center Q2 of the wafer 200 in the Y-axis direction is zero, and the center of the rotary stage 1 changes from the second rotation center Q1” to the third rotation center Q1”'.

[0119] (e) The rotary table 1 rotates around the third rotation center Q1”' for the third revolution. The PLC system 7 operates to confirm whether the ΔX and ΔY of the third rotation center Q1”' and the center Q2 of the wafer 200 are within the allowable error range. That is, it verifies and confirms that the third rotation center Q1”' of the rotary table 1 is the center Q2 of the wafer 200. If it exceeds the allowable error range, repeat (a)-(d).

[0120] (f) The rotary table 1 rotates around the third rotation center Q1”' to determine the orientation of the V-shaped notch 200a or the straight edge 200b of the wafer 200;

[0121] (g) Based on the determined rotation angle of the V-notch 200a or straight edge 200b relative to the third rotation center (Q1”'), the rotary table 1 is rotated by a specified angle so that the V-notch 200a or straight edge 200b of the wafer 200 is in a specified crystal orientation position. The wafer 200 in the specified crystal orientation position is used for transport by the transport tool to the next chamfering process for peripheral edge grinding and chamfering.

[0122] The details of steps (a)-(g) above have been described in the aforementioned wafer calibration apparatus 100 and will not be repeated here.

[0123] Compared to existing methods for determining wafer center and crystal orientation, the wafer calibration method described above uses simpler methods for calculating the offset distance ΔX along the X-axis and the offset distance ΔY along the Y-axis, which reduces the computational workload for determining wafer center and crystal orientation in large batches of wafers. Compared to determining the crystal orientation first and then calibrating the wafer center, this disclosure calibrates the wafer center first and then determines the crystal orientation. The wafers are evenly placed at the rotation center of the rotary table, making it easier for handling tools to align them and reducing the risk of the wafer slipping to one side.

[0124] The above detailed description describes several exemplary embodiments, but this document is not intended to limit it to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. A wafer calibration device (100), characterized in that, It includes a rotary table (1), a lower suction cup (2), an XY axis moving platform (3), a measuring sensor (4), a Z-axis lifting mechanism (5), an upper suction cup (6), and a PLC system (7). The rotary table (1) has a rotary table center, and the rotary table (1) can realize rotation around the rotary table center in the XY axis plane; The lower suction cup (2) is fixed on the rotary table (1). The lower suction cup (2) is used to pick up the wafer (200) with a V-shaped notch (200a) or a straight edge (200b) from below. The XY axis moving platform (3) is fixedly connected to the rotary table (1) and can drive the rotary table (1) to translate along the X-axis or Y-axis. The measuring sensor (4) is located on the X-axis of the XY-axis moving platform (3) in the XY-axis plane. The measuring sensor (4) is used to sense the distance of the point of the outer periphery of the wafer (200) adsorbed from below by the lower suction cup (2) as it rotates with the rotary table (1) in the XY-axis plane into the sensing area of ​​the measuring sensor (4). The Z-axis lifting mechanism (5) is located above the rotary table (1), and the Z-axis lifting mechanism (5) can move up and down in the Z-axis direction; The upper suction cup (6) is fixed to the Z-axis lifting mechanism (5). The upper suction cup (6) is used to pick up the chip (200) from above. The PLC system (7) is connected to the rotary table (1), the lower suction cup (2), the XY axis moving platform (3), the measuring sensor (4), the Z axis lifting mechanism (5), and the upper suction cup (6). The PLC system (7) is used to control the rotation of the rotary table (1) and record the rotation angle of the rotary table (1) in real time. The PLC system (7) is also used for: (a) After the wafer (200) is initially placed on the lower suction cup (2), the center of the first rotation of the rotary table (1) is the first rotation center (Q1'). The rotary table (1) rotates around the first rotation center (Q1') for the first revolution, and the X-axis offset distance ΔX between the first rotation center (Q1') and the center (Q2) of the wafer (200) is determined. (b) The first rotation center (Q1') of the rotary stage (1) moves along the X-axis toward the center (Q2) of the wafer (200) by an offset distance ΔX in the X-axis direction, so that the offset distance ΔX between the first rotation center (Q1') of the rotary stage (1) and the center (Q2) of the wafer (200) in the X-axis direction is zero, and the center of the rotary stage (1) changes from the first rotation center (Q1') to the second rotation center (Q1''). (c) The rotary table (1) rotates for the second revolution around the second rotation center (Q1'') to determine the Y-axis offset distance ΔY between the second rotation center (Q1'') of the rotary table (1) and the center (Q2) of the wafer (200); (d) The second rotation center (Q1'') of the rotary stage (1) moves along the Y-axis toward the center (Q2) of the wafer (200) by a Y-axis offset distance ΔY, so that the offset distance ΔY between the second rotation center (Q1'') of the rotary stage (1) and the center (Q2) of the wafer (200) in the Y-axis direction is zero, and the center of the rotary stage (1) changes from the second rotation center (Q1'') to the third rotation center (Q1'''). (e) The rotary table (1) rotates for the third revolution around the third rotation center (Q1'''). The PLC system (7) operates to confirm whether the ΔX and ΔY of the third rotation center (Q1''') and the center (Q2) of the wafer (200) are within the allowable error range, that is, to verify and determine that the third rotation center (Q1''') of the rotary table (1) is the center (Q2) of the wafer (200). If it exceeds the allowable error range, repeat (a)-(d). (f) The rotary table (1) rotates again around the third rotation center (Q1''') to determine the V-notch (200a) or straight edge (200b) of the wafer (200); (g) Rotate the rotary table (1) by a specified angle based on the determined angle of the V-notch (200a) or straight edge (200b) so that the V-notch (200a) or straight edge (200b) of the wafer (200) is in a specified crystal orientation position. The wafer (200) in the specified crystal orientation position is used for transport by a transport tool to the next chamfering process for peripheral edge grinding and chamfering.

2. The wafer calibration apparatus (100) according to claim 1, characterized in that, The operation process of step (a) of PLC system (7) is as follows: (a1) The PLC system (7) receives the distance of the point of the outer periphery of the wafer (200) measured by the measuring sensor (4) as it rotates one revolution into the sensing area of ​​the measuring sensor (4); (a2) Determine the longest distance L1 and the corresponding angle θ1 of the full circumference of the point outside the angle range of the V-shaped notch (200a) and straight edge (200b) of the wafer (200) and the 180-degree symmetrical range of the angle range from the distance sensed into the sensing area of ​​the measuring sensor (4); (a3) Based on the angle θ1 corresponding to the longest distance L1 in the entire circumference, determine the distance of the point that is 180 degrees symmetrical to the point that is the longest distance L1 in the entire circumference as the shortest distance L2 in the entire circumference. (a4) Based on the longest distance L1 and the shortest distance L2 around the entire circumference, determine the X-axis offset distance ΔX between the first rotation center (Q1') of the rotary table (1) and the center (Q2) of the wafer (200). ΔX = (L1-L2) / 2.

3. The wafer calibration apparatus (100) according to claim 1, characterized in that, The operation process of step (b) of PLC system (7) is as follows: (b1) The PLC system (7) controls the lower suction cup (2) to release the vacuum adsorption operation, the PLC system (7) controls the Z-axis lifting mechanism (5) to descend and the PLC system (7) controls the upper suction cup (6) to perform vacuum adsorption operation to adsorb the wafer (200), and then the PLC system (7) controls the Z-axis lifting mechanism (5) to rise along the Z-axis to make the wafer (200) detach from the lower suction cup (2). (b2) The PLC system (7) controls the XY axis moving platform (3) to drive the rotary table (1) to translate ΔX along the X axis so that the X-axis offset distance ΔX between the first rotation center (Q1') of the rotary table 1 and the center (Q2) of the wafer (200) is 0; (b3) The PLC system (7) controls the Z-axis lifting mechanism (5) to drive the lower suction cup (2) to descend along the Z-axis so that the wafer (200) is positioned on the rotary table (1) after being translated ΔX along the X-axis. The PLC system (7) controls the upper suction cup (6) to release the vacuum adsorption operation so that the positioned wafer (200) falls on the rotary table (1). The PLC system (7) controls the lower suction cup (2) to start the vacuum adsorption operation so that the wafer (200) falling on the rotary table (1) is adsorbed on the rotary table (1).

4. The wafer calibration apparatus (100) according to claim 1, characterized in that, The operation process of step (c) of PLC system (7) is as follows: (c1) The PLC system (7) receives the distance of the point of the outer periphery of the wafer (200) measured by the measuring sensor (4) during the second rotation into the sensing area of ​​the measuring sensor (4); (c2) Determine the longest distance L3 and the corresponding angle θ3 of the full circumference of the point outside the angle range of the V-shaped notch (200a) and straight edge (200b) of the wafer (200) and the 180-degree symmetrical range of the angle range from the distance sensed into the sensing area of ​​the measuring sensor (4). (c3) Based on the angle θ3 corresponding to the longest distance L3 in the entire circumference, determine the distance of the point that is 180 degrees symmetrical to the point of the longest distance L3 in the entire circumference as the shortest distance L4 in the entire circumference. (c4) Based on the longest distance L3 and the shortest distance L4 around the entire circumference, determine the Y-axis offset distance ΔY between the second rotation center (Q1'') of the rotary table (1) and the center (Q2) of the wafer (200). ΔY=(L3-L4) / 2.

5. The wafer calibration apparatus (100) according to claim 1, characterized in that, The operation process of step (d) of PLC system (7) is as follows: (d1) The PLC system (7) controls the lower suction cup (2) to release the vacuum adsorption operation, the PLC system (7) controls the Z-axis lifting mechanism (5) to descend and the PLC system (7) controls the upper suction cup (6) to perform vacuum adsorption operation to adsorb the wafer (200), and then the PLC system (7) controls the Z-axis lifting mechanism (5) to rise along the Z-axis to make the wafer (200) detach from the lower suction cup (2). (d2) The PLC system (7) controls the XY axis moving platform (3) to drive the rotary table (1) to translate ΔY along the Y axis so that the Y-axis offset distance ΔY between the second rotation center (Q1'') of the rotary table (1) and the center (Q2) of the wafer (200) is 0; (d3) The PLC system (7) controls the Z-axis lifting mechanism (5) to drive the lower suction cup (2) to descend along the Z-axis so that the wafer (200) is positioned on the rotary table (1) after being translated ΔY along the Y-axis. The PLC system (7) controls the upper suction cup (6) to release the vacuum adsorption operation so that the positioned wafer (200) falls on the rotary table (1). The PLC system (7) controls the lower suction cup (2) to start the vacuum adsorption operation so that the wafer (200) falling on the rotary table (1) is adsorbed on the rotary table (1).

6. The wafer calibration apparatus (100) according to claim 1, characterized in that, The operation process of step (e) of PLC system (7) is as follows: (e1) The PLC system (7) receives the distance of the point of the outer periphery of the wafer (200) measured by the measuring sensor (4) as it rotates one revolution into the sensing area of ​​the measuring sensor (4); (e2) Based on step (a), determine the two points corresponding to the offset distance ΔX in the X-axis direction, and determine the ΔX corresponding to these two points in step (e); (e3) Based on step (c), determine the two points corresponding to the offset distance ΔY in the Y-axis direction, and determine the ΔY corresponding to the two points in step (e); (e4) Determine whether it is within the allowable error range based on the corresponding ΔX and ΔY described in step (e).

7. The wafer calibration apparatus (100) according to claim 1, characterized in that, The three points of the V-shaped notch (200a) form an isosceles triangle. The line connecting the lowest point (F) of the V-shaped notch (200a) and the center (Q2) of the wafer (200) is collinear with the axis of symmetry of the isosceles triangle. The rotary table (1) of the PLC system (7) rotates again to determine the orientation of the V-shaped notch (200a) or the straight edge (200b) of the wafer (200). The process of determining the orientation of the V-shaped notch (200a) of the wafer (200) is as follows: (f1) The rotary table (1) rotates at least 270 degrees from the first quadrant, and the PLC system (7) receives the distance of the point of the outer periphery of the wafer (200) measured by the measuring sensor (4) at least 270 degrees into the sensing area of ​​the measuring sensor (4). (f2) Determine the shortest distance from the sensed distances within the sensing area of ​​the measurement sensor (4), and the point corresponding to the shortest distance is the lowest point (F) of the V-shaped notch (200a) of the wafer (200). (f3) Based on the lowest point (F) of the V-shaped notch (200a) of the determined wafer (200), the two step points of the distance between the point on the outer periphery of the wafer (200) and the point in the sensing area of ​​the measuring sensor (4) are found along the same direction as the rotation of the rotary table (1). The two step points are the two inflection points (G1, G2) of the outer periphery of the wafer (200) at the V-shaped notch (200a). The position of the V-shaped notch (200a) on the wafer (200) is determined by the position of the two inflection points (G1, G2) and the lowest point (F) of the V-shaped notch (200a) and the rotation angle relative to the third rotation center (Q1''').

8. The wafer calibration apparatus (100) according to claim 7, characterized in that, Step (f) of the PLC system (7) also includes: (f4) Verify the two inflection points (G1, G2) of the V-shaped notch (200a). During the rotation around the third rotation center (Q1'''), the first step point and the lowest point of the distance between the point on the outer periphery of the wafer (200) and the point in the sensing area of ​​the measuring sensor (4) are measured in sequence. The rotation continues, and the rotation stops when the distance between the point on the outer periphery of the wafer (200) and the point in the sensing area of ​​the measuring sensor (4) reaches the second step point. The two step points are the two inflection points (G1, G2) of the outer periphery of the wafer (200) at the V-shaped notch (200a). Determine the angle (δ) between the second step point and the lowest point (F) and the third rotation center (Q1'''). Then rotate the third rotation center (Q1''') twice in the opposite direction. Determine the distance of the second step point after rotating twice in the opposite direction into the sensing area of ​​the measuring sensor (4). Compare this distance with the distance of the first inflection point in the sensing area of ​​the measuring sensor (4) from the point on the outer periphery contour of the wafer (200) determined in step (f3). If the comparison result is within the error range, the determined V-shaped notch (200a) is verified to be correct.

9. The wafer calibration apparatus (100) according to claim 1, characterized in that, In step (f) of the PLC system (7), the rotary table (1) rotates again to determine the orientation of the V-shaped notch (200a) or straight edge (200b) of the wafer (200). The process of determining the orientation of the straight edge (200b) of the wafer (200) is as follows: (I) The rotary table (1) rotates at least 270 degrees from the first quadrant, and the PLC system (7) receives the distance of the point of the outer periphery of the wafer (200) measured by the measuring sensor (4) at least 270 degrees into the sensing area of ​​the measuring sensor (4). (II) Determine two step points from the distance of the point on the outer periphery of the wafer (200) along the rotation direction to enter the sensing area of ​​the measuring sensor (4). The two step points are the two inflection points of the outer periphery of the wafer (200) at the straight edge (200b). Determine the position of the straight edge (200b) on the wafer (200) by determining the two inflection points.

10. The wafer calibration apparatus (100) according to claim 1, characterized in that, The initial orientation of the wafer (200) placed on the upper suction cup (6) is as follows: the notch or straight edge (200b) of the wafer (200) is in the second quadrant of the wafer (200), and the first rotation center (Q1') of the rotary table (1) is located in the first or third quadrant of the wafer (200).

11. A wafer calibration method, characterized in that, Using the wafer calibration apparatus (100) according to any one of claims 1-10, the wafer calibration method includes the steps of: (a) After the wafer (200) is initially placed on the lower suction cup (2), the center of the first rotation of the rotary table (1) is the first rotation center (Q1'). The rotary table (1) rotates around the first rotation center (Q1') for the first revolution, and the X-axis offset distance ΔX between the first rotation center (Q1') and the center (Q2) of the wafer (200) is determined. (b) The first rotation center (Q1') of the rotary stage (1) moves along the X-axis toward the center (Q2) of the wafer (200) by an offset distance ΔX in the X-axis direction, so that the offset distance ΔX between the first rotation center (Q1') of the rotary stage (1) and the center (Q2) of the wafer (200) in the X-axis direction is zero, and the center of the rotary stage (1) changes from the first rotation center (Q1') to the second rotation center (Q1''). (c) The rotary table (1) rotates for the second revolution around the second rotation center (Q1'') to determine the Y-axis offset distance ΔY between the second rotation center (Q1'') of the rotary table (1) and the center (Q2) of the wafer (200); (d) The second rotation center (Q1'') of the rotary stage (1) moves along the Y-axis toward the center (Q2) of the wafer (200) by a Y-axis offset distance ΔY, so that the offset distance ΔY between the second rotation center (Q1'') of the rotary stage (1) and the center (Q2) of the wafer (200) in the Y-axis direction is zero, and the center of the rotary stage (1) changes from the second rotation center (Q1'') to the third rotation center (Q1'''). (e) The rotary table (1) rotates for the third revolution around the third rotation center (Q1'''). The PLC system (7) operates to confirm whether the ΔX and ΔY of the third rotation center (Q1''') and the center (Q2) of the wafer (200) are within the allowable error range, that is, to verify and determine that the third rotation center (Q1''') of the rotary table (1) is the center (Q2) of the wafer (200). If it exceeds the allowable error range, repeat (a)-(d). (f) The rotary table (1) rotates again around the third rotation center (Q1''') to determine the orientation of the V-notch (200a) or straight edge (200b) of the wafer (200); (g) The rotary table (1) is rotated by a specified angle based on the rotation angle of the V-notch (200a) or straight edge (200b) relative to the third rotation center (Q1''') so that the V-notch (200a) or straight edge (200b) of the wafer (200) is in a specified crystal orientation position. The wafer (200) in the specified crystal orientation position is used for transport by a transport tool to the next chamfering process for peripheral edge grinding and chamfering.

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