Wafer concentric positioning device and positioning method

Abstract

The invention discloses a wafer concentric positioning device and a wafer concentric positioning method. The wafer concentric positioning device comprises a wafer carrying mechanism, a feeding mechanism and a collecting and fitting mechanism. The wafer carrying mechanism comprises a wafer carrying table and a rotating motor, the wafer carrying table is used for placing wafers, and the rotating motor is used for driving the wafer carrying table to rotate; the feeding mechanism is arranged on one side of the slide holder and comprises a mechanical arm, and the mechanical arm is used for carrying the wafers and placing the wafers on the slide holder; the collecting and fitting mechanism is arranged on the other side of the slide holder and comprises an area correlation sensor and a controller, the area correlation sensor is used for collecting the light quantity value when the wafer rotates to pass through the detection area, and the controller is used for fitting the wafer and obtaining the circle center position of the wafer. Concentric positioning is carried out through the area correlation sensor, the mobile mechanical arm and the rotary slide holder, primary concentric positioning can be carried out on a wafer to be tested at the wafer feeding part, the calibration time of the wafer is shortened, and the efficiency of a product to be tested is improved.

Description

Technical Field

[0001] The present invention relates to the field of wafer technology, and in particular to a wafer concentric positioning device and a positioning method. Background Art

[0002] When testing wafer products, in order to help accurately position and align the wafer during the manufacturing process and ensure the accuracy of each manufacturing step, the wafer will be subjected to a "V" groove or "edge trimming" operation in the front process of the test. When the wafer is placed on the probe station equipment for testing, the wafer will first be preliminarily concentrically positioned on the upper part, and then moved to the host probe station equipment by a robotic arm for testing. However, the existing concentric positioning devices and positioning methods are relatively complex, and the calibration time of the wafer is relatively long, which seriously affects the test efficiency of the wafer. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a wafer concentric positioning device, which first performs preliminary concentric positioning on the wafer to be tested on the upper sheet part, thereby reducing the calibration time of the wafer and improving the efficiency of the product to be tested.

[0004] The invention also provides a wafer concentric positioning method.

[0005] In a first aspect of the present invention, a wafer concentric positioning device is provided, comprising: The wafer loading mechanism comprises a wafer loading platform and a rotating motor, wherein the wafer loading platform is used to place the wafer, and the rotating motor is used to drive the wafer loading platform to rotate; A loading mechanism, arranged on one side of the wafer stage, comprises a mechanical arm, and the mechanical arm is used to carry the wafer and place it on the wafer stage; The collecting and fitting mechanism is arranged on the other side of the wafer stage, and the collecting and fitting mechanism includes an area matching sensor and a controller. The area matching sensor is used to collect the light value when the wafer rotates through the detection area, and the controller is used to fit the wafer and obtain the center position of the wafer.

[0006] According to some embodiments of the present invention, the wafer carrier mechanism further includes a lifting component for driving the wafer carrier stage to rise and fall.

[0007] Advantageously, when the robot arm sucks the wafer and reaches above the wafer carrier, the lifting component can drive the wafer carrier to rise and hold the wafer.

[0008] According to some embodiments of the present invention, a vacuum suction hole for adsorbing the wafer is provided on the wafer carrier, and the vacuum suction hole is connected to a vacuum device.

[0009] Advantageously, the wafer stage is provided with vacuum suction holes so that the wafer can be firmly adsorbed on the wafer stage, thereby preventing the position of the wafer from changing when the wafer stage is rotated.

[0010] According to some embodiments of the present invention, the loading mechanism also includes a loading platform and a lifting motor. The loading platform is provided with a material box for placing the wafers. The lifting motor is used to drive the loading platform to rise and fall. The robotic arm can enter the material box and take out the wafers in the material box.

[0011] What is useful is that after the front-end process of engraving circuits and electronic components on the wafers to be tested is completed, the wafers to be tested will be placed on the material boxes loaded with wafers, and then the material boxes containing wafers will be placed on the loading platform of the loading mechanism, and the lifting motor drives the loading platform to rise and fall to the height where the first wafer is placed, and the robotic arm moves to the inside of the material box and absorbs the wafer by vacuum. After sucking the wafer, the robotic arm moves to the top of the carrier.

[0012] According to some embodiments of the present invention, the loading mechanism further includes a synchronous belt for driving the robotic arm to move back and forth between the loading platform and the wafer stage.

[0013] The benefit is that the synchronous belt can stably drive the robot arm to move back and forth between the loading platform and the top of the wafer stage. In addition, compared with a multi-axis robot, it can save costs.

[0014] According to some embodiments of the present invention, a photoelectric sensor is provided at the bottom of the material loading platform, and the photoelectric sensor is used to detect the material box.

[0015] The benefit is that the photoelectric sensor can detect whether the material box loaded with wafers is placed on the loading platform, so that the host computer sends a pulse command to the lifting motor to drive the loading platform and the material box loaded with wafers on it to move from top to bottom.

[0016] According to some embodiments of the present invention, a laser sensor is provided on a side of the loading platform, and the laser sensor is used to detect the stacking height of the wafers.

[0017] What is helpful is that when the loading platform moves up and down, the wafers placed inside the material box will block the straight light path of the laser sensor. The host computer counts the level changes of the laser sensor output within a fixed stroke to determine how many wafers are in the material box. After the loading platform moves up and down to determine the number of wafers, the height of the loading platform will move to the height where the first wafer is placed.

[0018] According to some embodiments of the present invention, the robot arm is provided with a vacuum head for sucking the wafer, and the vacuum head is connected to a vacuum device.

[0019] The benefit is that the robot arm is equipped with a vacuum suction head, which is conducive to the handling of wafers and prevents the wafers from being damaged during handling.

[0020] According to some embodiments of the present invention, the acquisition and fitting mechanism includes a C-shaped bracket, the area matching sensor is relatively arranged at the upper and lower ends of the C-shaped bracket, and the wafer passes between the upper and lower ends of the C-shaped bracket when rotating.

[0021] Advantageously, the C-shaped bracket is provided to facilitate installation of the area-based sensor, and a detection area is formed between the two area-based sensors, so that the wafer passes between the upper and lower ends of the C-shaped bracket when rotating.

[0022] A second aspect of the present invention further proposes a wafer concentric positioning method, which is applied to the above-mentioned wafer concentric positioning device, comprising the following steps: S100, the robotic arm moves the wafer to the wafer stage; S200, the rotating motor drives the wafer stage to rotate, and the area beam sensor collects the light value when the wafer rotates through the detection area; S300, the controller fits the collected light value points into a circle and obtains the position of the center of the circle, and calculates the relative distance between the center of the fitted circle and the center of the slide stage; S400, rotating the wafer stage to cooperate with the moving mechanical arm to compensate for the position deviation between the wafer and the center of the wafer stage; S500, re-fit the center of the circle of the compensated wafer, and recalculate the relative distance between the center of the fitted circle and the center of the wafer stage. When the relative distance is within the allowable error range, the center correction is completed.

[0023] A wafer concentric positioning device and positioning method according to an embodiment of the present invention have at least the following beneficial effects: this solution uses a robotic arm to transport the wafer and place it on a wafer stage, and performs concentric positioning through area matching sensors, a mobile robotic arm, and a rotating wafer stage, so that the wafer to be tested is first preliminarily concentrically positioned on the upper portion, thereby reducing the calibration time of the wafer and improving the efficiency of the product to be tested. Of course, this solution is also suitable for relatively transparent silicon carbide products.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 Schematic diagram of a wafer concentric positioning device according to an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram from another angle; Figure 3 This is a schematic diagram of the feeding mechanism of the present invention without the mechanical arm; Figure 4 3 is a schematic diagram from another angle; Figure 5 Schematic diagram of a wafer concentric positioning method according to an embodiment of the present invention; Figure 6 for Figure 5 Schematic diagram of the S300.

[0027] Figure numerals: wafer stage 100 , rotating motor 110 , wafer 120 , robot arm 130 , area beam sensor 140 , lifting component 150 , material loading platform 160 , lifting motor 170 , material box 180 , synchronous belt 190 , laser sensor 200 , C-shaped bracket 210 . DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it is necessary to understand that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of first and second, this is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation, connection and connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Reference below Figure 1-Figure 6 A wafer 120 concentric positioning device and positioning method is described in detail with a specific embodiment. It is worth noting that the following description is only an exemplary description and is not a specific limitation of the invention.

[0033] like Figure 1-Figure 4 As shown, a wafer concentric positioning device includes a wafer carrier mechanism, a loading mechanism and a collection and fitting mechanism.

[0034] The wafer loading mechanism includes a wafer loading stage 100 and a rotating motor 110. The wafer loading stage 100 is used to place a wafer 120, and the rotating motor 110 is used to drive the wafer loading stage 100 to rotate; the loading mechanism is arranged on one side of the wafer loading stage 100, including a robot arm 130, and the robot arm 130 is used to carry the wafer 120 and place it on the wafer loading stage 100; the collection and fitting mechanism is arranged on the other side of the wafer loading stage 100, and the collection and fitting mechanism includes an area matching sensor 140 and a controller (the controller is not shown in the figure), and the area matching sensor 140 is used to collect the light value when the wafer 120 rotates through the detection area, and the controller fits the wafer 120 and obtains the center position of the wafer 120. The wafer concentric positioning device transports the wafer 120 and places it on the wafer stage 100 through the robot arm 130, and performs concentric positioning through the area matching sensor 140, the mobile robot arm 130 and the rotating wafer stage 100, so that the wafer 120 to be tested is preliminarily concentrically positioned on the upper portion, thereby reducing the calibration time of the wafer 120 and improving the efficiency of the product to be tested.

[0035] like Figure 1 and Figure 2As shown, the wafer carrier mechanism also includes a lifting component 150 for driving the wafer carrier 100 to rise and fall. In this way, when the robot arm 130 sucks the wafer 120 and reaches the top of the wafer carrier 100, the lifting component 150 can drive the wafer carrier 100 to rise and hold the wafer 120. It should be noted that the lifting component 150 is a lifting cylinder. The wafer carrier 100 is provided with a vacuum suction hole for adsorbing the wafer 120, and the vacuum suction hole is connected to the vacuum equipment. The wafer carrier 100 is provided with a vacuum suction hole (the vacuum suction hole is not shown in the figure) so that the wafer 120 can be firmly adsorbed on the wafer carrier 100, preventing the position of the wafer 120 from changing when the rotating wafer carrier 100 rotates.

[0036] like Figure 3 and Figure 4 As shown, the loading mechanism also includes a loading platform 160 and a lifting motor 170. The loading platform 160 is provided with a material box 180 for placing the wafer 120. The lifting motor 170 is used to drive the loading platform 160 to rise and fall. The robot 130 can enter the material box 180 and take away the wafer 120 in the material box 180. After the process of front-end engraving circuits and electronic components of the wafers 120 to be tested is completed, the wafers 120 to be tested will be placed on the material box 180 loaded with the wafers 120, and then the material boxes 180 containing the wafers 120 will be placed on the loading platform 160 of the loading mechanism. The lifting motor 170 drives the loading platform 160 to rise and fall to the height where the first wafer 120 is placed. The robot 130 moves to the inside of the material box 180 to suck the wafer 120 by vacuum. After sucking the wafer 120, the robot 130 moves to the top of the wafer stage 100.

[0037] Specifically, the loading mechanism also includes a synchronous belt 190 for driving the mechanical arm 130 to and from the loading platform 160 and the wafer stage 100. The synchronous belt is driven by the servo motor to move, and the mechanical arm 130 is fixed on the synchronous belt 190 and moves with the synchronous belt 190. The synchronous belt 190 can stably drive the mechanical arm 130 to and from the loading platform 160 and the top of the wafer stage 100. In addition, compared with the multi-axis manipulator, it can save costs. It should be noted that the mechanical arm 130 is provided with a vacuum suction head (the vacuum suction head is not shown in the figure) to suck the wafer 120, and the vacuum suction head is connected to the vacuum equipment. The vacuum suction head of the mechanical arm 130 is conducive to the transportation of the wafer 120, and prevents the wafer 120 from being damaged during transportation. Of course, the mechanical arm 130 can also be driven by other methods such as motor screws, cylinders, etc., and the gripping method of the mechanical arm 130 can also be other than the vacuum suction head.

[0038] In addition, a photoelectric sensor (not shown in the figure) is provided at the bottom of the loading platform 160, and the photoelectric sensor is used to detect the material box 180. The photoelectric sensor can detect whether the material box 180 loaded with wafers 120 is placed on the loading platform 160, so that the upper computer sends a pulse command to the lifting motor 170 to drive the loading platform 160 and the material box 180 loaded with wafers 120 thereon to move from top to bottom. Figure 4 As shown, a pair of laser sensors 200 are provided on the side of the loading platform 160, and the laser sensors 200 are used to detect the stacking height of the wafers. When the loading platform 160 moves up and down, because the wafers 120 are placed inside the material box 180, the wafers 120 will block the straight light path of the laser sensor 200, and the upper computer counts the level changes output by the laser sensor 200 within a fixed stroke to determine how many wafers 120 are in the material box 180. After the number of wafers 120 is determined by the up and down movement of the loading platform 160, the height of the loading platform 160 will move to the height where the first wafer 120 is placed.

[0039] like Figure 2 As shown, the acquisition and fitting mechanism includes a C-shaped bracket 210, and the regional matching sensors 140 are relatively arranged at the upper and lower ends of the C-shaped bracket 210, and the wafer 120 passes between the upper and lower ends of the C-shaped bracket 210 when rotating. The C-shaped bracket 210 is arranged to facilitate the installation of the regional matching sensors 140, and a detection area is formed between the two regional matching sensors 140, so that the wafer 120 passes between the upper and lower ends of the C-shaped bracket 210 when rotating.

[0040] In a second aspect of the present invention, a wafer concentric positioning method is also proposed, which is applied to the above-mentioned wafer concentric positioning device, such as Figure 5 and Figure 6 As shown, the following steps are included: S100, the robot arm 130 moves the wafer 120 to the wafer stage 100; (1) After the wafers 120 to be tested have been processed by the front-end engraving process of circuits and electronic components, the wafers 120 to be tested will be placed on the material box 180 loaded with the wafers 120. Then, the material box 180 loaded with the wafers 120 will be placed on the loading platform 160 of the loading structure, and the loading platform 160 can move up and down in the Z direction by relying on the lifting motor 170 at the bottom. (2) When the material box 180 loaded with the wafers 120 is placed on the loading platform 160, the photoelectric sensor at the bottom of the platform will generate a signal that changes from a high level to a low level and send it to the host computer. The host computer will determine that there is a material box 180 placed on the loading platform 160. At this time, the host computer will send a pulse command to the lifting motor 170 of the loading platform 160 that moves in the Z direction, and the lifting motor 170 in the Z direction will drag the loading platform 160 and the material box 180 loaded with the wafers 120 on it from top to bottom. (3) A pair of laser sensors 200 for opposing purposes are installed in front and behind the loading platform 160. When there is no obstruction by default, the level signal of the laser sensor 200 is stable and will not jump. When the loading platform 160 moves up and down, because there are wafers 120 placed inside the material box 180, the wafers 120 will block the straight light path of the laser sensor 200. The laser sensor 200 will generate a rising edge signal to the host computer, and the host computer will determine that there are wafers 120 placed on this layer of the material box 180. The host computer will count the level changes output by the laser sensor 200 within a fixed stroke to determine how many wafers 120 are in the material box 180. (4) After the number of wafers 120 is determined by the up and down movement of the loading platform 160, the height of the loading platform 160 will move to the height where the first wafer 120 is placed. At this time, the robot arm 130 will move a certain distance according to the number of command pulses sent by the host computer, and go deep into the material box 180 to absorb the wafer 120 by vacuum. After sucking the wafer 120, the robot arm 130 will move to the top of the carrier 100 according to the pulse command sent by the host computer. (5) The bottom of the carrier 100 is equipped with a rotating motor 110 to drive the carrier 100 to rotate 360 ​​degrees. At the same time, a lifting component 150 is also provided to drive the carrier 100 and the rotating motor 110 to rise and fall. When the robot arm 130 moves the wafer 120 to the top of the carrier 100. The lifting component 150 drives the carrier 100 to rise, and the robot arm 130 releases the vacuum to place the wafer 120 on the carrier 100, and then the wafer 120 is adsorbed on the carrier 100 through the vacuum suction hole on the carrier 100.

[0041] S200, the rotating motor 110 drives the wafer stage 100 to rotate, and the regional beam sensor 140 collects the light value when the wafer 120 rotates through the detection area. The regional beam sensors 140 are set at the upper and lower ends of the C-shaped bracket 210 of the collection fitting mechanism. Since the wafer 120 is placed on the wafer stage 100, it will block the light of the regional optical fiber. The beam sensor has a fixed light value when there is no obstruction. When there is a wafer 120 on the wafer stage 100, the wafer 120 will block the beam sensor, causing its light value to change. First, the host computer sends 3413 pulses to rotate the wafer stage 100 and the wafer 120 adsorbed thereon for one circle. During the rotation process, the ADC analog-to-digital conversion module will collect the output voltage value of the beam sensor amplifier every 2 pulses, that is, 1707 voltage points will be collected when the motor rotates one circle. The light value range of the area detection sensor is 0-4095, and the corresponding output analog voltage range is 1-5V. When there is no obstruction, the light value of the sensor is 4095, and the output analog voltage is 5V. When the area optical fiber is completely blocked and the light transmittance is 0, the analog output voltage is 1V, that is, the light value represented by each volt of voltage is 4095-0 / 5-1=1024. At this time, the 1707 points collected have corresponding light values.

[0042] S300, such as Figure 6 As shown, the controller can fit the collected 1707 data points into a circle, and the center of the fitted circle is determined. At this time, the stage 100 can be regarded as an XY coordinate system, with the center of the stage 100 set as the (0, 0) coordinate system point. There is a coordinate difference between the fitted circle obtained by rotating one circle and the 0-point coordinate system, and the relative distance between the two center points can be calculated.

[0043] S400, after calculating the distance, the host computer sends a pulse command to rotate the wafer stage 100 and cooperate with the mechanical arm 130 to suck the wafer 120 and move it, so as to correct the center of the wafer 120 and the wafer stage 100. Because the mechanical arm 130 can only move in one direction under the drive of the synchronous belt 190, the wafer stage 100 needs to rotate to change the direction of the wafer 120, and then the mechanical arm 130 sucks the wafer 120 and moves it, so as to complete the position deviation compensation between the wafer 120 and the center of the wafer stage 100.

[0044] S500, re-fit the center of the compensated wafer 120, and recalculate the relative distance between the center of the fitted circle and the center of the wafer stage 100. When the relative distance is within the error tolerance range, the center correction is completed. After the correction is completed, the wafer 120 is carried to the probe station equipment for testing.

[0045] In summary, in this solution, the wafer 120 is transported and placed on the wafer stage 100 by the robot 130, and concentric positioning is performed by the area matching sensor 140, the mobile robot 130 and the rotating wafer stage 100, so that the wafer 120 to be tested is preliminarily concentrically positioned on the upper part, thereby reducing the calibration time of the wafer 120 and improving the efficiency of the product to be tested. Of course, this solution is also suitable for relatively transparent silicon carbide products.

[0046] In the description of this specification, the description with reference to the terms "one embodiment, some embodiments, illustrative embodiments, examples, specific examples or some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0047] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A wafer concentric positioning device, characterized in that: include: A wafer loading mechanism, comprising a wafer loading platform (100) and a rotating motor (110), wherein the wafer loading platform (100) is used to place a wafer (120), and the rotating motor (110) is used to drive the wafer loading platform (100) to rotate; a loading mechanism, arranged on one side of the wafer carrier (100), comprising a mechanical arm (130), wherein the mechanical arm (130) is used to carry the wafer (120) and place it on the wafer carrier (100); A collection and fitting mechanism is arranged on the other side of the wafer stage (100), the collection and fitting mechanism comprising an area matching sensor (140) and a controller, the area matching sensor (140) being used to collect light values ​​when the wafer (120) rotates through a detection area, and the controller being used to fit the wafer (120) and obtain the center position of the wafer (120).

2. A wafer concentric positioning device according to claim 1, characterized in that: The wafer carrier mechanism further comprises a lifting component (150) for driving the wafer carrier stage (100) to rise and fall.

3. A wafer concentric positioning device according to claim 1, characterized in that: The wafer carrier (100) is provided with a vacuum suction hole for adsorbing the wafer (120), and the vacuum suction hole is connected to a vacuum device.

4. The wafer concentric positioning device according to claim 1, characterized in that: The loading mechanism also includes a loading platform (160) and a lifting motor (170). The loading platform (160) is provided with a material box (180) for placing the wafer (120). The lifting motor (170) is used to drive the loading platform (160) to rise and fall. The robot arm (130) can enter the material box (180) and take out the wafer (120) in the material box (180).

5. A wafer concentric positioning device according to claim 4, characterized in that: The loading mechanism also includes a synchronous belt (190) for driving the mechanical arm (130) to move back and forth between the loading platform (160) and the wafer carrier (100).

6. The wafer concentric positioning device according to claim 4, characterized in that: A photoelectric sensor is provided at the bottom of the material loading platform (160), and the photoelectric sensor is used to detect the material box (180).

7. The wafer concentric positioning device according to claim 4, characterized in that: A pair of laser sensors (200) are provided on the side of the loading platform (160), and the laser sensors (200) are used to detect the stacking height of the wafers.

8. The wafer concentric positioning device according to claim 1, characterized in that: The mechanical arm (130) is provided with a vacuum suction head for sucking the wafer (120), and the vacuum suction head is connected to a vacuum device.

9. The wafer concentric positioning device according to claim 1, characterized in that: The acquisition fitting mechanism comprises a C-shaped bracket (210), the area matching sensor (140) is relatively arranged at the upper and lower ends of the C-shaped bracket (210), and the wafer (120) passes between the upper and lower ends of the C-shaped bracket (210) when rotating.

10. A wafer concentric positioning method, characterized in that: A wafer concentric positioning device as claimed in any one of claims 1 to 9, comprising the following steps: S100, the robotic arm (130) moves the wafer (120) onto the wafer carrier (100); S200, the rotating motor (110) drives the wafer stage (100) to rotate, and the area-based radiation sensor (140) collects light values ​​when the wafer (120) rotates and passes through the detection area; S300, the controller fits the collected light value points into a circle and obtains the position of the center of the circle, and calculates the relative distance between the center of the fitted circle and the center of the slide stage (100); S400, rotating the wafer carrier (100) in cooperation with the mobile mechanical arm (130) to compensate for position deviation between the wafer (120) and the center of the wafer carrier (100); S500, re-fitting the center of the compensated wafer (120), and recalculating the relative distance between the center of the fitted circle and the center of the wafer carrier (100); when the relative distance is within the allowable error range, the center correction is completed.

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