Eccentricity compensation system for wafer transmission and wafer transmission equipment

Abstract

The utility model provides an eccentric compensation system for wafer transmission and wafer transmission equipment. The eccentric compensation system comprises a manipulator body, manipulator fingers, a target sensor, a first station, a second station, a calibration wafer, a target wafer and a manipulator controller, the target sensor is used for projecting target light beams; the manipulator controller is used for recording a first position polar coordinate, a second position polar coordinate, a third position polar coordinate and a fourth position polar coordinate when the manipulator finger triggers the state change of the target sensor twice when carrying the calibration wafer and the target wafer; determining a target polar coordinate based on the station polar coordinate of the second station, the wafer diameter, the first position polar coordinate, the second position polar coordinate, the third position polar coordinate and the fourth position polar coordinate; and based on the target polar coordinate, controlling the manipulator finger to carry the target wafer to a second station. According to the system, eccentric compensation can be carried out in the wafer transmission process, and the wafer transmission efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of general control or regulation system technology, and more particularly to an eccentricity compensation system and wafer transfer device for wafer transfer. Background Technology

[0002] In semiconductor chip manufacturing, the wafers are first transported from the wafer cassette (a container used to protect, transport, and store wafers, holding up to 25 wafers) to the processing station (e.g., station A) by an external wafer transport system. Then, a robotic arm inside the equipment moves the wafers from station A to the target station (e.g., station B) for inspection or manufacturing. Because there is a certain degree of misalignment between the wafers within the wafer cassette, the robotic arm deviates from the center of station A when transporting the wafers there. When transporting them from station A to station B, the wafer center deviates from the center of station B, thus affecting the inspection results or manufacturing quality. Therefore, correcting the wafer's positional deviation at station B is a critical problem that needs to be solved in semiconductor chip manufacturing. Utility Model Content

[0003] This application provides an eccentricity compensation system and a wafer transport device. It can perform eccentricity compensation during wafer transport, improving wafer transport efficiency. The technical solution is as follows:

[0004] According to one aspect of this application, an eccentricity compensation system for wafer transfer is provided. The eccentricity compensation system includes: a robot body, a robot finger, a target sensor, a first station, a second station, a calibration wafer, a target wafer, and a robot controller. The target sensor is located between the robot body and the first station. The target sensor is electrically connected to the robot controller, and the robot controller is electrically connected to the robot finger. The calibration wafer and the target wafer have the same wafer diameter.

[0005] A polar coordinate system is constructed with the center of the robotic arm body as the origin.

[0006] The target sensor is used to project a target beam, which is not parallel to the surface of the calibration wafer or the target wafer.

[0007] The robotic arm controller is used to pre-record the first and second polar coordinates of the center of the robotic arm finger when the target sensor is triggered to change state twice during the process of the robotic arm finger carrying the calibration wafer from the first station to the robotic arm body. The center of the calibration wafer coincides with the center of the finger.

[0008] The robotic arm fingers are used to move the target wafer from the first workstation to the second workstation;

[0009] During the process of the robotic arm finger moving the target wafer from the first workstation to the robotic arm body, the robotic arm controller is also used to record the third and fourth polar coordinates of the center of the robotic arm finger when the target sensor changes state twice;

[0010] The robotic arm controller is also used to determine the updated target polar coordinates of the robotic arm finger corresponding to the movement of the finger center based on the station polar coordinates of the second workstation, the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates;

[0011] The robotic arm controller is also used to control the robotic arm fingers to move the target wafer from the robotic arm body to the second workstation based on the target polar coordinates.

[0012] According to one aspect of this application, a wafer transport device is provided, which includes the aforementioned eccentricity compensation system.

[0013] The beneficial effects of the technical solutions provided in this application include at least the following:

[0014] By adding a target sensor between the first workstation and the robot body, the polar coordinate position of the robot finger's center is obtained when the target sensor's state changes twice during the transfer of a standard wafer (whose center may not coincide with the robot finger's center) from the first workstation to the robot body; and the polar coordinate position of the robot finger's center is obtained when the target sensor's state changes twice during the transfer of a target wafer (whose center may not coincide with the robot finger's center) from the first workstation to the robot body. This allows for the determination of the polar coordinate position of the robot finger's center based on the polar coordinate position of the standard wafer and the target wafer. The coordinate position is calculated, and the deviation is used to compensate for the original movement position of the robot's finger center (the polar coordinates of the second station), resulting in updated target polar coordinates. Finally, when the robot's finger extends to the second station, the target wafer can be transported according to the updated target polar coordinates. Because the deviation has been pre-compensated, the center of the target wafer transported to the second station can coincide with the center of the second station. Moreover, since the polar coordinates have been compensated and updated before the wafer is placed in the second station, the deviation of the wafer can be compensated while performing the wafer placement movement, eliminating the need for compensation movement after the wafer placement movement, thus improving the wafer transfer efficiency. Attached Figure Description

[0015] Further details, features, and advantages of this application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

[0016] Figure 1 This is a schematic diagram of the wafer eccentricity compensation method provided by related technologies;

[0017] Figure 2 This is a schematic diagram of the structure of an eccentricity compensation system provided in an embodiment of this application;

[0018] Figure 3 This is a top view schematic diagram of an exemplary embodiment of the present application, showing the change in sensor state triggered for the first time when a robotic arm finger moves a standard wafer from the first workstation.

[0019] Figure 4 This is a top view schematic diagram of an exemplary embodiment of the present application, showing a robotic arm finger moving a standard wafer from a first workstation and triggering a change in the sensor state again.

[0020] Figure 5 This is a top view schematic diagram of wafer transfer deviation calculation provided in an exemplary embodiment of this application;

[0021] Explanation of icon numbers:

[0022] 10- Robotic arm body; 20- Center of the robotic arm body; 11- Robotic arm finger; 21- Center of the robotic arm finger; 12- Calibration wafer; 13- Target sensor; 14- First station; 22- Center of the first station; 15- Second station; 23- Center of the second station; 17- Direction in which the robotic arm finger retracts from the first station back to the robotic arm body; 24- Intersection of the transported wafer and the target beam projected by the target sensor. Detailed Implementation

[0023] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0024] It should be understood that the steps described in the embodiments of this application may be performed in different orders and / or in parallel. Furthermore, embodiments may include additional steps and / or omit the steps shown. The scope of this application is not limited in this respect.

[0025] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc., mentioned in this application are only used to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies. It should be noted that the modifications "a" and "a plurality" mentioned in this application are illustrative and not restrictive, and those skilled in the art should understand that unless explicitly indicated in the context, they should be understood as "one or more". The names of messages or information exchanged between multiple devices in the embodiments of this application are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0026] The present invention will now be described with reference to the accompanying drawings. The technical solutions provided by the embodiments of the present invention will be explained in detail through specific examples and application scenarios.

[0027] This addresses the issue of wafer center misalignment at target station B during the transfer of wafers from station A to station B. To correct this positional deviation, related technologies offer solutions such as... Figure 1 As shown, three regional laser sensors (sensor 1, sensor 2, and sensor 3) are arranged in the circumferential direction of the target station B. Their output values ​​are linearly proportional to the length of the sensor receiver that is blocked. First, the calibration wafer is accurately placed at the target station B. The robot controller calculates the coordinates (x, y, y) of the calibration center of the calibration wafer based on the output values ​​of the three regional laser sensors. c y c After the robotic arm handles the actual wafer (i.e., the target wafer) to the target station B, the robotic arm controller calculates the target center coordinates (x, y, x) of the actual wafer based on the output values ​​of three regional laser sensors. a y a The difference in coordinates between the calibrated center and the target center is the compensation amount. The robotic arm finger then performs a compensation movement based on the compensation amount to place the actual wafer in the correct position.

[0028] While the above method can calculate the deviation (or compensation amount) of the actual wafer at the target station B, it requires adding too many sensors to the target station B, which will occupy the space of the target station B. Moreover, the robotic arm can only calculate the compensation amount and perform the compensation movement after the actual wafer is transported to the target station B. The robotic arm cannot directly perform the compensation movement during the process of transporting the wafer from station A to the target station B. This causes the wafer placement movement and the compensation movement to be executed in series, which will also reduce the wafer transfer efficiency.

[0029] To address the cost and transmission efficiency issues associated with related technical deviation calculations, this application provides a novel eccentricity compensation system that eliminates the need for excessive sensors and space occupation at the target workstation B. Furthermore, it enables the combined execution of wafer placement and compensation movements, correcting wafer position deviations at the target workstation B without sacrificing transmission efficiency. Figure 2 This is a schematic diagram of the structure of an eccentricity compensation system provided in an embodiment of this application. Figure 2 As shown, the eccentricity compensation system includes a robot body 10, a robot finger 11, a calibration wafer 12, a target wafer, a target sensor 13, a first station 14, a second station 15, and a robot controller (not shown in the figure). The target sensor 13 is located between the robot body 10 and the first station 14; the target sensor 13 is electrically connected to the robot controller, and the robot controller is electrically connected to the robot finger 11. The calibration wafer 12 and the target wafer have the same wafer diameter.

[0030] It should be noted that during the actual transmission process, the target wafer replacement calibration wafer 12 is located on the robotic arm finger 11.

[0031] When the calibration wafer 12 is located at the first station, the calibration center of the calibration wafer 12 coincides with the center 22 of the first station 14 and also with the center of the finger of the robotic arm finger 11.

[0032] The first station 14 is equivalent to station A, and the second station 15 is equivalent to the target station B. The corresponding wafer handling process from station A to target station B is as follows: the robotic arm finger 11 extends to the first station 14 to pick up the wafer, the robotic arm finger 11 retracts to the robotic arm body 10 along direction 17, then turns to the second station 15, and finally extends to the second station 15 to place the wafer.

[0033] This application constructs a polar coordinate system or a rectangular coordinate system with the center 20 of the robot body 10 as the origin, for use in subsequent calculations of the target polar coordinates.

[0034] The target sensor 13 is an optical sensor used to project a target beam. This target beam is not parallel to the surface of the calibration wafer or the target wafer, so that the wafer along the retraction path of the robotic finger 11 from the first station 14 to the robotic body 10 will both block and unblock the target beam, thereby triggering a state change of the target sensor 13 twice. Optionally, the target sensor 13 can be a laser sensor or a fiber optic sensor, etc.

[0035] The robot controller is used to pre-record the first and second polar coordinates of the center of the robot finger 11 when the target sensor 13 is triggered twice during the process of the robot finger 11 moving the calibration wafer 12 from the first station 14 to the robot body 10. The calibration center of the calibration wafer 12 coincides with the center of the finger.

[0036] In this embodiment, a polar coordinate system is constructed with the center of the robot body as the origin. For example, with the first and second workstations fixed, the polar coordinates of the first workstation are known to be (R... A T A ), R A T represents the polar radius of the center of the first workstation in the polar coordinate system. A This represents the polar angle of the center of the first workstation in the polar coordinate system. The polar coordinates of the second workstation can be (R... B T B ), R B T represents the polar radius of the center of the second workstation in polar coordinates. B This represents the polar angle of the center of the second station in the polar coordinate system. Optionally, the polar coordinates of the first and second stations can be pre-recorded in the robot controller of the eccentricity compensation system.

[0037] based on Figure 2The eccentricity compensation system shown depicts the wafer transfer process from the first station to the second station as follows: the robotic arm's finger picks up the wafer from the first station, retracts its body, turns towards the second station, and finally places the wafer at the second station. When the robotic arm's finger picks up the wafer at the first station, its center coincides with the center of the first station; similarly, when placing the wafer at the second station, its center also coincides with the center of the second station. However, during actual transfer, the wafer's center may deviate from the center of the first station. This deviation causes the wafer's center to also deviate from the center of the robotic arm's finger after being picked up, and consequently, when placed at the second station, its center also deviates from the center of the second station. In other words, this deviation of the wafer's center from the center of the robotic arm's finger is the root cause of the wafer's eccentricity at the second station.

[0038] Considering the possibility of wafer deviation from the target workstation, this application provides a novel deviation compensation approach: by adding a target sensor between the first workstation and the robot body, the target sensor projects a target beam that is not parallel to the transmitted wafer, thereby obtaining the polar coordinate position of the robot's finger center when the target sensor's state changes twice during the transfer of a standard wafer (whose center coincides with the center of the robot's finger) from the first workstation to the robot body; and obtaining the polar coordinate position of the robot's finger center when the target wafer (whose center may not coincide with the center of the robot's finger) is transferred from the first workstation to the robot body. When the target sensor's state changes twice during the transfer of the calibrated wafer to the robot body, the polar coordinates of the robot's finger center are recorded. Based on the polar coordinates of the standard wafer and the target wafer, the deviation is calculated to compensate for the original movement of the robot's finger center (the polar coordinates of the second workstation), resulting in updated target polar coordinates. Finally, when the robot's finger reaches the second workstation, the target wafer can be transferred according to the updated target polar coordinates. Because the deviation has been pre-compensated, the wafer center of the target wafer transferred to the second workstation coincides with the workstation center. Based on this deviation compensation approach, one possible implementation involves first acquiring the first and second polar coordinates recorded during the robot's finger transfer of the calibrated wafer from the first workstation to the robot body. These first and second polar coordinates represent the polar coordinates of the robot's finger center during the two state changes triggered by the target sensor during wafer transfer, with the calibration center of the calibrated wafer coinciding with the center of the robot's finger.

[0039] The method for obtaining the first and second polar coordinates can be as follows: With the target sensor projecting a target beam, a calibration wafer is accurately placed on the robotic finger. The robotic finger is then controlled to retract from the first station along a first direction, where the first direction is the direction from the center of the first station to the center of the robotic body. During the retraction process, the calibration wafer initially blocks the target beam projected by the target sensor, triggering a change in the target sensor's state. The target sensor then sends a first state change signal to the robotic controller. Upon receiving the first state change signal, the robotic controller records the first polar coordinate of the finger's center at this moment as (R...). C1 T A The robotic arm finger continues to retract along the first direction, and the calibration wafer continues to block the target sensor until the target sensor is unblocked, triggering a change in the target sensor's state. The target sensor then sends a second state change signal to the robotic arm controller. Upon receiving the second state change signal, the robotic arm controller records the polar coordinates of the second position of the robotic arm finger's center at this moment as (R...). C2 T A ).

[0040] Please refer to Figure 3 This is a top view schematic diagram of an exemplary embodiment of this application, showing the initial triggering of a sensor state change as a robotic arm finger moves a standard wafer from a first workstation. Figure 3 As shown, a calibration wafer 12 is accurately placed on the robotic finger 11 and retracted from the center 22 of the first station 14 along direction 17. When the calibration wafer 12 first blocks the target sensor 13, triggering a change in its state, the robotic arm control system records the polar coordinates of the center 21 of the robotic finger as (R... C1 T A Point 24 is the intersection of the circumference of the calibrated wafer 12 and the beam projected by the target sensor 13.

[0041] Please refer to Figure 4 This is a top view schematic diagram of an exemplary embodiment of this application, showing a robotic arm finger moving a standard wafer from a first workstation and triggering a change in the sensor state. (See diagram below.) Figure 4 As shown, the robotic finger 11 continues to retract along direction 17, and the calibration wafer 12 continues to block the target sensor 13. When the target sensor 13 is unblocked, the target sensor 13 is triggered to change its state again. At this time, the robotic arm controller records the polar coordinates of the finger center 21 of the robotic finger 11 as (R... C2 T A Point 24 on calibration wafer 12 has moved to point 25 (R). S2 T S2Point 24 is the intersection of the circumference of the calibrated wafer 12 and the beam projected by the target sensor 13.

[0042] Optionally, the first and second polar coordinates can be pre-tested and stored in the robot controller. During the subsequent actual handling of the target wafer, the first and second polar coordinates can be directly obtained.

[0043] It should be noted that the diameter of the calibration wafer and the target wafer must be the same; if the diameter of the wafer transported by the eccentricity compensation system changes, a new calibration wafer needs to be selected, and the new first position polar coordinates and second position polar coordinates need to be tested.

[0044] Optionally, Figure 2 23 is the center of the second station of the second station 15, and 24 is the intersection of the transported wafer and the target beam.

[0045] The robotic arm finger 11 is used to move the target wafer from the first station 14 to the second station 15 under the control of the robotic arm controller.

[0046] During the process of the robotic arm finger moving the target wafer from the first station 14 to the robotic arm body 10, the robotic arm controller is also used to record the third and fourth polar coordinates of the center of the robotic arm finger 11 when the target sensor 13 changes state twice.

[0047] Similar to acquiring the first and second polar coordinate positions corresponding to the standard wafer, during the process of moving the target wafer from the first station to the second station by the robotic arm finger, the robotic arm controller will also record the third and fourth polar coordinate positions acquired during the process of the robotic arm finger moving the target wafer from the first station to the robotic arm body. The third and fourth polar coordinate positions are the polar coordinate positions of the center of the robotic arm finger when the target sensor is triggered to change state twice during the process of moving the target wafer.

[0048] To avoid introducing other variables, it is necessary to ensure that the diameter of the target wafer is the same as that of the calibration wafer. Whether the target wafer deviates from the center of the robotic hand's finger is unknown.

[0049] The robot controller is also used to determine the target polar coordinates of the updated robot finger 11 corresponding to the movement of the finger center, based on the station polar coordinates of the second station 15, the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates.

[0050] Since the first and second polar coordinates of the standard wafer are pre-acquired, if the target wafer does not deviate from the center of the robotic finger while the target sensor position remains unchanged, the third and fourth polar coordinates of the target wafer should be close to the first and second polar coordinates of the standard wafer. Otherwise, there is a deviation. Based on this deviation, the amount of deviation can be calculated and compensated for to the original target position of the robotic finger – the polar coordinates of the second station – to obtain the updated target polar coordinates. This allows the robotic finger to be directly controlled to move towards the updated target polar coordinates to correct the deviation. In one possible implementation, the robotic controller is also used to determine the updated target polar coordinates of the robotic finger's center movement based on the polar coordinates of the second station, the wafer diameter, the first, second, third, and fourth polar coordinates.

[0051] The robot controller is also used to control the robot fingers to move the target wafer from the robot body 10 to the second station 15 based on the target polar coordinates.

[0052] Because the deviation can be calculated and compensated during the retraction of the target wafer from the first station to the robot body, and the final target polar coordinate value of the robot finger's movement is updated, the robot controller can control the robot finger to place the target wafer at the second station based on the target polar coordinates, thereby correcting any potential eccentricity issues at the second station. Furthermore, since the polar coordinates are updated before the wafer is placed at the second station, the wafer deviation can be compensated for during the placement movement, eliminating the need for subsequent compensation movements and improving wafer transfer efficiency.

[0053] In summary, this application provides a novel eccentricity compensation system: by adding a target sensor between the first workstation and the robot body, the system records the polar coordinate position of the robot finger's corresponding finger center when the target sensor's state changes twice during the transfer of a standard wafer (whose wafer center may not coincide with the robot finger's finger center) from the first workstation to the robot body; and records the polar coordinate position of the robot finger's corresponding finger center when the target sensor's state changes twice during the transfer of a target wafer (whose wafer center may not coincide with the robot finger's finger center, resulting in deviation) from the first workstation to the robot body, thereby adjusting the system based on the polar coordinate position of the standard wafer. The coordinate position and the polar coordinate position corresponding to the target wafer are used to calculate the deviation to compensate for the original movement position of the robot's finger center (the polar coordinates of the second station), resulting in updated target polar coordinates. Finally, when the robot's finger extends to the second station, the target wafer can be transported according to the updated target polar coordinates. Because the deviation has been pre-compensated, the center of the target wafer transported to the second station can coincide with the center of the second station. Moreover, since the polar coordinate compensation and update have been performed before the wafer is placed in the second station, the wafer deviation can be compensated while performing the wafer placement movement, eliminating the need for compensation movement after the wafer placement movement, thus improving the wafer transfer efficiency.

[0054] Through reasoning and analysis, the operational relationships between the first polar coordinate position, the second polar coordinate position, the third polar coordinate position, the fourth polar coordinate position, the wafer diameter, and the deviation value are obtained. After calculating the deviation value, the robot controller can determine the updated target coordinates for the robot finger movement based on the deviation value and the working coordinates of the second station. This embodiment is based on... Figure 2 The eccentricity compensation system shown focuses on how the robot controller determines the updated target polar coordinates.

[0055] The method for obtaining the third and fourth polar coordinates can be as follows: The robotic arm finger retracts from the first workstation along a first direction (the direction from the center of the first workstation to the center of the robotic arm itself). During the retraction process, the target wafer initially blocks the target beam projected by the target sensor, triggering a change in the target sensor's state. The target sensor then sends a first state change signal to the robotic arm controller. Upon receiving the first state change signal, the robotic arm controller records the third polar coordinate of the center of the robotic arm finger at this moment as (R...). C3 T AThe robotic arm's finger continues to retract along the first direction, and the target wafer continues to block the target sensor until the target sensor is unblocked, triggering a change in the target sensor's state. The target sensor then sends a second state change signal to the robotic arm controller. Upon receiving the second state change signal, the robotic arm controller records the polar coordinates of the fourth position corresponding to the center of the robotic arm's finger at this time as (R...). C4 T A In other words, when the target beam projected by the target sensor is first blocked during the process of the robotic arm finger moving the target wafer from the first station to the robotic arm body, the target sensor is also used to send a first state change signal to the robotic arm controller. The robotic arm controller is also used to record the third polar coordinate of the center of the corresponding finger when it receives the first state change signal. When the target beam projected by the target sensor is unblocked during the process of the robotic arm finger moving the target wafer from the first station to the robotic arm body, the target sensor is also used to send a second state change signal to the robotic arm controller. The robotic arm controller is also used to record the fourth polar coordinate of the center of the corresponding finger when it receives the second state change signal.

[0056] Please refer to Figure 5 This is a top view schematic diagram of wafer transfer deviation calculation provided in an exemplary embodiment of this application. Figure 5 As shown, with the center 20 of the robot body 10 as the origin, during the target wafer transfer process, the robot finger 11 picks up a target wafer 16 from the first station 14 and retracts along direction 17. The robot controller records the polar coordinates of the center of the robot finger when the target sensor state changes twice, and the target wafer 16 triggers the polar coordinates of the center of the robot finger as (R... C3 T A ) and (R C4 T A When the target sensor 13 changes state for the second time, point 24 on the target wafer 16 moves to point 27 (R). S3 T S3 Point 24 is the intersection of the circumference of the target wafer 16 and the beam projected by the target sensor 13.

[0057] Optionally, in order to ensure that the two points (points 24 and 27) on the circumference of the target wafer involved in the center calculation, and the two points (points 24 and 25) on the circumference of the calibration wafer are not two points passing through the center, the deployment position of the target sensor needs to be located to the left or right of the line connecting the center of the robot body and the center of the first workstation, and the vertical distance from the line needs to be at least less than half the diameter of the wafer.

[0058] Optionally, when the robot controller determines the target polar coordinates for the updated movement of the robot finger's center based on the station polar coordinates of the second workstation, the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates, it is also specifically used to perform the following steps:

[0059] 1. Based on the wafer diameter, the first polar coordinate, the second polar coordinate, the third polar coordinate, and the fourth polar coordinate, determine the first deviation value between the target center and the calibration center of the target wafer in the rectangular coordinate system.

[0060] In an exemplary example, the relationship between the first deviation value obtained through reasoning and the wafer diameter, the first polar coordinate, the second polar coordinate, the third polar coordinate, and the fourth polar coordinate can be shown in Equation (1):

[0061]

[0062] Where, Δx A Δy represents the deviation of the x-coordinate in a rectangular coordinate system. A This represents the deviation value of the ordinate in a rectangular coordinate system, with the center of the robot body as the origin. (R) C1 T A (R) represents the first position polar coordinates. C2 T A (R) represents the second position polar coordinates. C3 T A (R) represents the polar coordinates of the third position. C4 T A (x) represents the fourth polar coordinate, and D represents the diameter of the target wafer; c y c (x) represents the rectangular coordinates of the center of the calibration circle on the calibration wafer. a y a ) represents the rectangular coordinates of the center of the target circle of the target wafer.

[0063] As shown in formula (1), after obtaining the polar coordinates of the first, second, third, and fourth positions, and the wafer diameter, these coordinates can be substituted into formula (1) to calculate the deviation between the target center of the target wafer and the calibration center of the calibration wafer in the rectangular coordinate system. Optionally, to improve the accuracy of the deviation determination, it is necessary to ensure that the wafer planes of the standard wafer and the target wafer are parallel to the transmission plane of the robotic hand finger.

[0064] The reasoning behind formula (1) is as follows: First, based on two points on the circumference of the calibration wafer, determine the rectangular coordinates of the center of the calibration circle of the calibration wafer. Then, based on two points on the circumference of the target wafer, determine the rectangular coordinates of the center of the target circle of the target wafer. Finally, take the difference between the two rectangular coordinates and deduce the formula for calculating the final deviation value. In an exemplary example, the robot controller is also used to execute steps A to C when executing step one.

[0065] Step A: Based on the wafer diameter, the first polar coordinates, and the second polar coordinates, determine the first rectangular coordinates of the calibration circle center.

[0066] Depend on Figure 3 and Figure 4 It can be seen that when the calibration wafer first triggers the change in the target sensor's state, the circumference of the calibration wafer intersects with the target beam projected by the target sensor at point 24. When the target sensor is unblocked, the target sensor's state changes again upon triggering, at which point 24 on the calibration wafer 12 moves to point 25. Assume the polar coordinates of intersection point 24 are (R... S1 T S1 (This intersection point 24 is also the polar coordinate position of the target sensor); the polar coordinates of point 25 are (R S2 T S2 ). The polar coordinates of intersection point 24 (R) S1 T S1 Convert the coordinates of point 25 to rectangular coordinates (x1, y1); convert the polar coordinates of point 25 to (R). S2 T S2 The coordinates are converted to rectangular coordinates (x2, y2), and combined with the wafer diameter D, the rectangular coordinates of the calibration center 26 of the calibration wafer are calculated as (xc, yc):

[0067]

[0068] Where (xc, yc) are the rectangular coordinates of the center of the calibration wafer, (x1, y1) are the rectangular coordinates of the intersection point of the calibration wafer and the target beam projected by the target sensor, and (x2, y2) are the rectangular coordinates of the point to which the intersection point moves when the obstruction is removed. C1 T A (R) represents the first position polar coordinates. C2 T A ) represents the second polar coordinate, and D represents the diameter of the calibrated wafer.

[0069] It should be noted that (x1, y1) and (x2, y2) in formula (2) are unknown and will cancel each other out in subsequent calculations, so there is no need to know the specific coordinate values.

[0070] Step B: Based on the wafer diameter, the third polar coordinate, and the fourth polar coordinate, determine the second rectangular coordinate of the target circle's center.

[0071] Similar to the process of calculating the rectangular coordinates of the center of the calibration circle corresponding to the calibration wafer, such as... Figure 5 As shown, the robot controller records the polar coordinates of the center 21 of the robot's finger when the target sensor state changes twice after the target wafer 16 is triggered. C3 T A ) and (R C4 T A When the target sensor state changes for the second time, intersection 24 on target wafer 16 moves to point 27 (R). S3 T S3 The intersection point of the circumference of the target wafer 16 and the beam projected by the target sensor 13 is point 24 (R). S1 T S1 ). The polar coordinates of intersection point 24 (R) S1 T S1 Convert the coordinates of point 27 to rectangular coordinates (x1, y1); convert the polar coordinates of point 27 to (R). S3 T S3 The coordinates are converted to rectangular coordinates (x3, y3), and combined with the wafer diameter D, the rectangular coordinates of the target wafer's center 28 are calculated as (x3, y3). a y a ):

[0072]

[0073] Among them, (x a y a (x1, y1) represents the rectangular coordinates of the center of the target wafer, (x3, y3) represents the rectangular coordinates of the intersection point of the target wafer and the target beam projected by the target sensor, and (x3, y3) represents the rectangular coordinates of the point to which the intersection point moves when the obstruction is removed. C3 T A (R) represents the polar coordinates of the third position. C4 T A ) represents the fourth polar coordinate, and D represents the diameter of the target wafer.

[0074] It should be noted that (x1, y1) and (x3, y3) in formula (3) are unknown and will cancel each other out in subsequent calculations, so there is no need to know the specific coordinate values.

[0075] Moreover, when determining the target center according to formula (3), since only two points on the circumference and the diameter are known, there may be two centers that are calculated. Therefore, there are "+" and "-" in formula (3).

[0076] Step C: Based on the first and second rectangular coordinates, determine the first deviation value between the target circle center and the calibration circle center in the rectangular coordinate system.

[0077] After determining the first rectangular coordinates of the calibration center and the second rectangular coordinates of the target center, the difference between the two rectangular coordinates can be used to obtain the deviation value between the target center and the calibration center in the rectangular coordinate system, which is also known as formula (1). According to formula (1), the difference can cancel out the unknown parameters such as (x1, y1), (x2, y2) and (x3, y3). The deduction formula of the deviation value is only related to the polar coordinates of the first position, the second position, the third position, the fourth position, and the wafer diameter.

[0078] Since formula (3) calculates two center points, the deviation value obtained after the difference should also be two sets of deviation values. Therefore, it is necessary to select the most suitable deviation value (that is, select the correct center point of the target wafer). The corresponding robot controller is also used to execute steps C1 to C3 when executing step C.

[0079] Step C1: Determine two sets of candidate deviation values ​​based on the first and second rectangular coordinates.

[0080] Step C2: Determine whether the two sets of candidate deviation values ​​meet the preset threshold conditions.

[0081] Step C3: The candidate deviation value that meets the preset threshold condition is determined as the first deviation value between the target circle center and the calibration circle center in the rectangular coordinate system.

[0082] Substituting the polar coordinates of the first, second, third, and fourth positions, along with the wafer diameter, into formula (1), two sets of candidate deviation values ​​can be calculated. That is, based on the first and second rectangular coordinates, two sets of candidate deviation values ​​can be determined. To select a suitable deviation value and determine whether the deviation value can be corrected, a preset threshold condition is set, which is Δx. A 2 +Δy A 2 <(D) 2 / 4, where Δx A The x-coordinate, Δy, represents the calculated candidate deviation values. A The vertical axis represents the candidate deviation value, and D represents the wafer diameter. This involves determining the relationship between the sum of the squares of the horizontal and vertical axes of the candidate deviation value and the square of the quarter-wafer diameter. If the sum is less than the sum of the squares of the horizontal and vertical axes, the candidate deviation value meets a preset threshold condition; if it is greater than or equal to the sum of the squares, it does not meet the preset threshold condition. The candidate deviation value that meets the preset threshold condition is then determined as the first deviation value between the target circle center and the calibration circle center in a Cartesian coordinate system.

[0083] Optionally, if there are no candidate deviation values ​​that meet the preset threshold conditions, a prompt indicating that the deviation is too large will be output directly, and the robotic arm fingers will be controlled to stop transporting the target wafer, indicating that manual intervention is required and the deviation can no longer be automatically corrected.

[0084] Step 2: Based on the first deviation value and the station polar coordinates, determine the target polar coordinates of the updated robotic arm finger corresponding to the finger center movement.

[0085] After calculating the first deviation value, the target polar coordinates are corrected based on the original transport endpoint (the polar coordinates of the second station) to obtain the updated target polar coordinates, so that the robot controller can continue to transport the target wafer based on the target polar coordinates.

[0086] Since the first deviation value is a center deviation determined in the first direction (the direction of the line connecting the center of the robot body and the center of the first workstation), and the polar coordinates of the workstation to be corrected are located in the second direction (the direction of the line connecting the center of the robot body and the center of the second workstation), if it is necessary to correct the polar coordinates of the workstation based on the first deviation value, the first deviation value needs to be converted into a deviation value in the second direction first, and then the polar coordinates of the workstation can be corrected based on the converted deviation value. Therefore, in an exemplary example, when the robot controller executes step two, it is also specifically used to execute steps D to F.

[0087] Step D: Determine the target rotation matrix for rotating the finger center of the robotic arm from the first direction to the second direction. The first direction is the line connecting the body center and the center of the first workstation, and the second direction is the line connecting the body center and the center of the second workstation.

[0088] Based on the geometric relationship between the first deviation value and the second deviation value, a target rotation matrix for rotating the finger center of the robotic hand from the first direction to the second direction can be constructed. For example, the target rotation matrix can be shown in formula (4):

[0089]

[0090] Among them, (T) B -T A ) represents the rotation angle, which is the angle between the second direction and the first direction.

[0091] Step E: Based on the first deviation value and the target rotation matrix, determine the second deviation value in the second direction.

[0092] After obtaining the target rotation matrix, the second deviation value in the second direction can be obtained based on the first deviation value and the target rotation matrix. For example, the relationship between the second deviation value, the first deviation value, and the target rotation matrix can be shown in formula (5):

[0093]

[0094] Among them, (Δx) A Δy) represents the first deviation value, (Δx) B Δy B ) indicates the second deviation value. Represents the target rotation matrix, (T) B -T A () indicates the rotation angle.

[0095] Step F: Based on the second deviation value and the station polar coordinates, determine the target polar coordinates of the updated robotic arm finger corresponding to the finger center movement.

[0096] After obtaining the second deviation value in the second direction, the updated target polar coordinates can be determined based on the second deviation value and the original station polar coordinates. For example, the relationship between the target polar coordinates, the station polar coordinates, and the second deviation value can be shown in formula (6):

[0097]

[0098] Among them, (Δx) B Δy B ) represents the second deviation value, (R' B T' B (R) represents the updated target polar coordinates. B T B ) represents the original polar coordinates of the workstation.

[0099] Step 3: Based on the target polar coordinates, control the robotic arm fingers to move the target wafer from the robotic arm body to the second workstation.

[0100] Since the target polar coordinates have been calculated during the process of the robotic arm fingers retracting the target wafer from the first station to the robotic arm body, the subsequent robotic arm controller can control the robotic arm fingers to rotate from the first direction to the second direction, and then the robotic arm body extends to the second station, so as to place the target wafer after reaching the target polar coordinates, thereby completing the transfer of the target wafer from the first station to the second station.

[0101] It should be noted that the process of moving the target wafer and the process of moving the calibration wafer from the first station back to the center of the robot body are similar (e.g., Figure 4As shown), the third and fourth polar coordinates are obtained during this process and used to calculate the updated target polar coordinates. After calculating the target polar coordinates, the robot controller can continue to control the robot finger 11 to continue carrying the target wafer back to the center 20 of the robot body 10, and then continue to control the robot finger 11 to rotate along direction 18, and then extend along direction 19 to the second station to reach the target polar coordinate point (R'). B T' B Place the target wafer and complete the transfer of the target wafer from station A to station B.

[0102] In this embodiment, a method for calculating the deviation value and the updated target polar coordinates is provided through geometric reasoning. This allows the corrected target polar coordinates to be determined based on the known polar coordinates of the first, second, third, fourth, and fifth positions, the workstation polar coordinates, and the wafer diameter. This enables the updating of the final movement position of the robotic arm's fingers during wafer transfer, improving wafer transfer efficiency while ensuring the accurate movement of the target wafer to the second workstation.

[0103] An exemplary embodiment of this application also provides a wafer transfer device, which includes the eccentricity compensation system provided in the embodiments of this application. The eccentricity compensation system includes: a robot body, a robot finger, a target sensor, a first station, a second station, a calibration wafer, a target wafer, and a robot controller. The target sensor is located between the robot body and the first station, and is electrically connected to the robot controller. The robot controller is electrically connected to the robot finger, and the calibration wafer and the target wafer have the same wafer diameter.

[0104] A polar coordinate system is constructed with the center of the robotic arm body as the origin.

[0105] The target sensor is used to project a target beam, which is not parallel to the surface of the calibration wafer or the target wafer.

[0106] The robotic arm controller is used to pre-record the first and second polar coordinates of the center of the robotic arm finger when the target sensor is triggered to change state twice during the process of the robotic arm finger carrying the calibration wafer from the first station to the robotic arm body. The center of the calibration wafer coincides with the center of the finger.

[0107] The robotic arm fingers are used to move the target wafer from the first workstation to the second workstation;

[0108] During the process of the robotic arm finger moving the target wafer from the first workstation to the robotic arm body, the robotic arm controller is also used to record the third and fourth polar coordinates of the center of the robotic arm finger when the target sensor changes state twice;

[0109] The robotic arm controller is also used to determine the updated target polar coordinates of the robotic arm finger corresponding to the movement of the finger center based on the station polar coordinates of the second workstation, the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates;

[0110] The robotic arm controller is also used to control the robotic arm fingers to move the target wafer from the robotic arm body to the second workstation based on the target polar coordinates.

[0111] Optionally, if the target light beam projected by the target sensor is first blocked during the process of the robotic arm finger carrying the target wafer from the first workstation to the robotic arm body, the target sensor is further configured to send a first state change signal to the robotic arm controller, and the robotic arm controller is further configured to record the third position polar coordinates of the center of the corresponding finger of the robotic arm finger when the first state change signal is received;

[0112] When the target beam projected by the target sensor is removed during the process of the robotic arm finger moving the target wafer from the first station to the robotic arm body, the target sensor is further configured to send a second state change signal to the robotic arm controller, and the robotic arm controller is further configured to record the fourth position polar coordinates corresponding to the center of the robotic arm finger when receiving the second state change signal.

[0113] Optionally, the target sensor is located to the left or right of the line connecting the center of the robot body and the center of the first workstation.

[0114] Optionally, the target sensor is an optical sensor.

[0115] Optionally, the wafer plane of the target wafer is parallel to the transmission plane of the robotic finger.

[0116] Optionally, the robotic arm controller is further configured to:

[0117] Based on the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates, determine the first deviation value between the target center of the target wafer and the calibration center in the rectangular coordinate system;

[0118] Based on the first deviation value and the workstation polar coordinates, the updated target polar coordinates of the robotic arm finger corresponding to the movement of the finger center are determined.

[0119] Optionally, the robotic arm controller is further configured to:

[0120] Based on the wafer diameter, the first position polar coordinates, and the second position polar coordinates, determine the first rectangular coordinates of the calibration circle center;

[0121] Based on the wafer diameter, the third polar coordinate, and the fourth polar coordinate, determine the second rectangular coordinate of the target circle center;

[0122] Based on the first rectangular coordinates and the second rectangular coordinates, the first deviation value between the target circle center and the calibration circle center in the rectangular coordinate system is determined.

[0123] Optionally, the robotic arm controller is further configured to:

[0124] Based on the first rectangular coordinate and the second rectangular coordinate, two sets of candidate deviation values ​​are determined;

[0125] Determine whether the two sets of candidate deviation values ​​meet the preset threshold condition;

[0126] The candidate deviation value that meets the preset threshold condition is determined as the first deviation value between the target circle center and the calibration circle center in the rectangular coordinate system.

[0127] Optionally, the robotic arm controller is further configured to:

[0128] Determine the target rotation matrix for rotating the finger center of the robotic hand from the first direction to the second direction, wherein the first direction is the line direction connecting the body center and the first workstation center corresponding to the first workstation, and the second direction is the line direction connecting the body center and the second workstation center corresponding to the second workstation.

[0129] Based on the first deviation value and the target rotation matrix, a second deviation value is determined in the second direction;

[0130] Based on the second deviation value and the workstation polar coordinates, the updated target polar coordinates of the robotic hand finger corresponding to the movement of the finger center are determined.

Claims

1. An eccentricity compensation system for wafer transmission, characterized in that, The eccentricity compensation system includes: a robot body, a robot finger, a target sensor, a first station, a second station, a calibration wafer, a target wafer, and a robot controller. The target sensor is located between the robot body and the first station. The target sensor is electrically connected to the robot controller, and the robot controller is electrically connected to the robot finger. The calibration wafer and the target wafer have the same wafer diameter. A polar coordinate system is constructed with the center of the robotic arm body as the origin. The target sensor is used to project a target beam, which is not parallel to the surface of the calibration wafer or the target wafer. The robotic arm controller is used to pre-record the first and second polar coordinates of the center of the robotic arm finger when the target sensor is triggered to change state twice during the process of the robotic arm finger carrying the calibration wafer from the first station to the robotic arm body. The center of the calibration wafer coincides with the center of the finger. The robotic arm fingers are used to move the target wafer from the first workstation to the second workstation; During the process of the robotic arm finger moving the target wafer from the first workstation to the robotic arm body, the robotic arm controller is also used to record the third and fourth polar coordinates of the center of the robotic arm finger when the target sensor changes state twice; The robotic arm controller is also used to determine the updated target polar coordinates of the robotic arm finger corresponding to the movement of the finger center based on the station polar coordinates of the second workstation, the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates; The robotic arm controller is also used to control the robotic arm fingers to move the target wafer from the robotic arm body to the second workstation based on the target polar coordinates.

2. The eccentricity compensation system according to claim 1, characterized in that, In the event that the target light beam projected by the target sensor is first blocked by the robotic arm finger during the process of the robotic arm finger moving the target wafer from the first workstation to the robotic arm body, the target sensor is also used to send a first state change signal to the robotic arm controller, and the robotic arm controller is also used to record the third position polar coordinates of the center of the robotic arm finger when the first state change signal is received; When the target beam projected by the target sensor is removed during the process of the robotic arm finger moving the target wafer from the first station to the robotic arm body, the target sensor is further configured to send a second state change signal to the robotic arm controller, and the robotic arm controller is further configured to record the fourth position polar coordinates corresponding to the center of the robotic arm finger when receiving the second state change signal.

3. The eccentricity compensation system according to claim 1, characterized in that, The target sensor is located to the left or right of the line connecting the center of the robot body and the center of the first workstation.

4. The eccentricity compensation system according to claim 1, characterized in that, The target sensor is an optical sensor.

5. The eccentricity compensation system according to claim 1, characterized in that, The wafer plane of the target wafer is parallel to the transmission plane of the robotic hand finger.

6. The eccentricity compensation system according to any one of claims 1 to 5, characterized in that, The robotic arm controller is also used for: Based on the wafer diameter, the first position polar coordinates, the second position polar coordinates, the third position polar coordinates, and the fourth position polar coordinates, determine the first deviation value between the target center of the target wafer and the calibration center in the rectangular coordinate system; Based on the first deviation value and the workstation polar coordinates, the updated target polar coordinates of the robotic arm finger corresponding to the movement of the finger center are determined.

7. The eccentricity compensation system according to claim 6, characterized in that, The robotic arm controller is also used for: Based on the wafer diameter, the first position polar coordinates, and the second position polar coordinates, determine the first rectangular coordinates of the calibration circle center; Based on the wafer diameter, the third polar coordinate, and the fourth polar coordinate, determine the second rectangular coordinate of the target circle center; Based on the first rectangular coordinates and the second rectangular coordinates, the first deviation value between the target circle center and the calibration circle center in the rectangular coordinate system is determined.

8. The eccentricity compensation system according to claim 7, characterized in that, The robotic arm controller is also used for: Based on the first rectangular coordinate and the second rectangular coordinate, two sets of candidate deviation values ​​are determined; Determine whether the two sets of candidate deviation values ​​meet the preset threshold condition; The candidate deviation value that meets the preset threshold condition is determined as the first deviation value between the target circle center and the calibration circle center in the rectangular coordinate system.

9. The eccentricity compensation system according to claim 6, characterized in that, The robotic arm controller is also used for: Determine the target rotation matrix for rotating the finger center of the robotic hand from a first direction to a second direction, wherein the first direction is the line direction connecting the body center and the center of the first workstation corresponding to the first workstation, and the second direction is the line direction connecting the body center and the center of the second workstation corresponding to the second workstation. Based on the first deviation value and the target rotation matrix, a second deviation value is determined in the second direction; Based on the second deviation value and the workstation polar coordinates, the updated target polar coordinates of the robotic hand finger corresponding to the movement of the finger center are determined.

10. A wafer transmission device, characterized in that, The wafer transfer device includes the eccentricity compensation system according to any one of claims 1-9.

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