Method and device for detecting deviation position of wafer on mechanical arm and electronic equipment
By using a single sensor and a PLC controller in wafer offset detection, the rising and falling edges of the sensor signal are recorded, and the wafer offset is calculated. This solves the problems of high cost, low accuracy, and poor real-time performance in existing technologies, and achieves efficient and accurate wafer offset detection.
Patent Information
- Application Number
- CN202512033891.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-02-24
AI Technical Summary
Existing wafer offset detection technologies suffer from high hardware costs, complex installation, large computational load, poor real-time performance, and susceptibility to environmental interference, making it difficult to meet the high-efficiency requirements of semiconductor manufacturing.
By employing a single sensor combined with a digital laser sensor and a PLC controller, the offset of the wafer on the robotic arm is calculated by recording the rising and falling edges of the sensor signal, simplifying the inspection process and improving accuracy.
It significantly reduced testing costs, improved testing accuracy and real-time performance, simplified calibration and maintenance processes, and enhanced the stability and positioning accuracy of the robotic arm.
Smart Images
Figure CN121552448A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of sensor detection, and in particular to a method, apparatus, and electronic device for detecting the offset position of a wafer on a robotic arm. Background Technology
[0002] Currently, in semiconductor manufacturing processes, robotic arms are typically used to move wafers from transport chambers or workstations to various reaction chambers. During wafer handling, to prevent misalignment or damage during pick-up and drop, precise detection of wafer misalignment is crucial to avoid impacting the production process. Current technologies primarily rely on multi-sensor systems or vision systems for wafer misalignment detection. However, multi-sensor systems have high hardware costs and complex installation processes, while vision systems involve significant computational demands for image processing, resulting in long processing times and poor real-time performance. Summary of the Invention
[0003] In view of this, the purpose of the present invention is to provide a method, apparatus and electronic device for detecting the offset position of a wafer on a robotic arm, which can significantly reduce detection costs and improve detection accuracy.
[0004] In a first aspect, embodiments of the present invention provide a method for detecting the offset position of a wafer on a robotic arm. The method includes: during the extension and retraction movement of the robotic arm, using a fixed single sensor, performing reference detection processing on the position of a standard wafer that has not been offset when an edge trigger is generated, to obtain a first rising edge position and a first falling edge position, and determining a first chord length and a first vertical distance from the center of the wafer to the first chord length based on the first rising edge position and the first falling edge position; during the extension and retraction movement of the robotic arm, using a fixed single sensor, performing offset detection processing on the position of a wafer under test that has been offset when an edge trigger is generated, to obtain a second rising edge position and a first falling edge position. The rising edge position and the second falling edge position are determined, and based on the second rising edge position and the second falling edge position, the second chord length and the second vertical distance from the center of the circle to the second chord length are determined; the midpoint position of the first chord length and the second chord length are sent to the vertical offset calculation model to determine the first offset of the wafer under test; the first vertical distance and the second vertical distance are sent to the horizontal offset calculation model to determine the second offset of the wafer under test; and the first offset and the second offset are determined as the target offset detection results, wherein the first offset is the offset of the wafer under test in the extension direction of the robotic arm, and the second offset is the offset of the wafer under test perpendicular to the extension direction of the robotic arm.
[0005] In one embodiment, the step of performing reference detection processing on the position of an unoffset standard wafer when an edge trigger is generated using a fixed single sensor to obtain a first rising edge position and a first falling edge position includes: when performing reference detection processing on the unoffset standard wafer, determining the timestamp when the digital signal output by the single sensor changes from a first state to a second state as a first timestamp, and determining the timestamp when the digital signal changes from the second state back to the first state as a second timestamp; determining the first rising edge position based on the first timestamp and the encoder value of the robotic arm at the corresponding time, and determining the first falling edge position based on the second timestamp and the encoder value at the corresponding time.
[0006] In one embodiment, the step of determining the first chord length and the first vertical distance from the center of the circle to the first chord length based on the first rising edge position and the first falling edge position includes: determining the difference between the first falling edge position and the first rising edge position as the first chord length, and determining the square root of the difference between the square of half the wafer radius and the square of half the first chord length as the first vertical distance from the center of the circle to the first chord length.
[0007] In one embodiment, the step of using a fixed single sensor to perform offset detection processing on the position of a wafer under test with offset when an edge trigger is generated, and obtaining the second rising edge position and the second falling edge position, includes: when performing offset detection processing on the wafer under test with offset, determining the timestamp when the digital signal output by the single sensor changes from a first state to a second state as a third timestamp, and determining the timestamp when the digital signal changes from the second state back to the first state as a fourth timestamp; determining the second rising edge position based on the third timestamp and the encoder value of the robotic arm at the corresponding time, and determining the second falling edge position based on the fourth timestamp and the encoder value at the corresponding time.
[0008] In one embodiment, the step of determining the second chord length and the second vertical distance from the center of the circle to the second chord length based on the second rising edge position and the second falling edge position includes: determining the difference between the second falling edge position and the second rising edge position as the second chord length, and determining the square root of the difference between the square of half the wafer radius and the square of half the second chord length as the second vertical distance from the center of the circle to the second chord length.
[0009] In one embodiment, the step of sending the midpoint position of the first chord length and the second chord length to the vertical offset calculation model to determine the first offset of the wafer under test includes: determining the first midpoint position as the sum of half the first chord length and the first rising edge position, or the difference between the first falling edge position and half the first chord length, wherein the first midpoint position is the position of the robotic arm at the perpendicular bisector from the center of the circle to the first chord length when the sensor is triggered; determining the second midpoint position as the sum of half the second chord length and the second rising edge position, or the difference between the second falling edge position and half the second chord length, wherein the second midpoint position is the position of the robotic arm at the perpendicular bisector from the center of the circle to the second chord length when the sensor is triggered; and determining the absolute value of the difference between the second midpoint position and the first midpoint position as the first offset.
[0010] In one embodiment, the step of sending a first vertical distance and a second vertical distance to a horizontal offset calculation model to determine a second offset of the wafer under test includes: determining the absolute value of the difference between the first vertical distance and the second vertical distance as the second offset.
[0011] Secondly, embodiments of the present invention also provide a device for detecting the offset position of a wafer on a robotic arm. The device includes: a reference detection module, which, during the extension and retraction movement of the robotic arm, performs reference detection processing on the position of a standard wafer that has not shifted when an edge trigger is generated using a fixed single sensor, obtaining a first rising edge position and a first falling edge position, and determining a first chord length and a first vertical distance from the center of the wafer to the first chord length based on the first rising edge position and the first falling edge position; and an offset detection module, which, during the extension and retraction movement of the robotic arm, performs offset detection processing on the position of a wafer under test that has shifted when an edge trigger is generated using a fixed single sensor, obtaining... The system moves to the second rising edge position and the second falling edge position, and determines the second chord length and the second vertical distance from the center of the circle to the second chord length based on the second rising edge position and the second falling edge position; the offset calculation module sends the midpoint position of the first chord length and the second chord length to the vertical offset calculation model to determine the first offset of the wafer under test, sends the first vertical distance and the second vertical distance to the horizontal offset calculation model to determine the second offset of the wafer under test, and determines the first offset and the second offset as the target offset detection result, wherein the first offset is the offset of the wafer under test in the extension direction of the robotic arm, and the second offset is the offset of the wafer under test perpendicular to the extension direction of the robotic arm.
[0012] Thirdly, embodiments of the present invention also provide an electronic device, including a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement any of the methods provided in the first aspect.
[0013] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions, which, when invoked and executed by a processor, cause the processor to implement any of the methods provided in the first aspect.
[0014] The embodiments of the present invention bring the following beneficial effects: This invention provides a method, apparatus, and electronic device for detecting the offset position of a wafer on a robotic arm. During the extension and retraction of the robotic arm, a fixed single sensor is used to perform baseline detection processing on the position of a standard wafer without offset when an edge trigger occurs, obtaining a first rising edge position and a first falling edge position. Based on the first rising edge position and the first falling edge position, a first chord length and a first vertical distance from the center of the circle to the first chord length are determined. Then, during the extension and retraction of the robotic arm, a fixed single sensor is used to perform offset detection processing on the position of a wafer under test with offset when an edge trigger occurs, obtaining a second rising edge position and a second falling edge position. Based on the second rising edge position and the second falling edge position, a second chord length and a second vertical distance from the center of the circle to the second chord length are determined. Finally, the midpoint position of the first chord length and the second chord length is sent to a vertical offset calculation model to determine the first offset of the wafer under test. The first vertical distance and the second vertical distance are sent to a horizontal offset calculation model to determine the second offset of the wafer under test. The first offset and the second offset are then used as the target offset detection result. This invention can significantly reduce detection costs and improve detection accuracy.
[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.
[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of a wafer offset detection system on a robotic arm, provided in an embodiment of the present invention. Figure 2 A flowchart illustrating a method for detecting the offset position of a wafer on a robotic arm, provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a wafer offset detection method provided in an embodiment of the present invention; Figure 4 A schematic diagram of an un-offset wafer entering a light beam, provided as an embodiment of the present invention; Figure 5 This is a schematic diagram of an un-offset wafer leaving a light beam, provided as an embodiment of the present invention; Figure 6 A schematic diagram illustrating an offset wafer entering a light beam, provided as an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating a method of offsetting a wafer away from a light beam, as provided in an embodiment of the present invention. Figure 8 This is a schematic diagram illustrating the remaining offset state of a wafer according to an embodiment of the present invention; Figure 9 This is a schematic diagram of another wafer offset state provided in an embodiment of the present invention; Figure 10 A schematic diagram of a device for detecting the offset position of a wafer on a robotic arm, provided in an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0020] Currently, in the wafer handling process, to avoid the impact of wafer offset or damage on the production process and to improve the accuracy of wafer placement, an offset detection system is needed to detect the offset of the wafer center point in real time to facilitate subsequent production steps. However, existing wafer offset detection solutions have the following problems: 1. Low motor positioning accuracy. Most wafer handling robotic arms on the market are driven by servo motors. However, the use of servo motors requires the addition of an additional reducer. Due to the influence of mechanical structure and friction, the stability and positioning accuracy of the arm during operation are relatively poor.
[0021] 2. Numerous sensors. The detection system employs multiple sensors, significantly increasing the system's hardware costs. Furthermore, the installation of these multiple sensors requires precise planning of their positions and angles, which not only complicates the installation process but also occupies considerable equipment space.
[0022] 3. Large data processing volume. Both visual image processing and multi-point triangulation require the analysis and calculation of a large amount of collected data. This results in long data processing time, poor system real-time performance, and difficulty in meeting the high-efficiency requirements for wafer handling and inspection in semiconductor manufacturing.
[0023] 4. Susceptible to environmental interference. The detection performance of vision systems and some photoelectric sensors is easily affected by environmental factors. For example, dust in the production environment can adhere to the sensor or wafer surface, affecting the accuracy of data acquisition; changes in light can also interfere with the image acquisition and processing of the vision system, leading to increased detection errors.
[0024] 5. Difficult calibration and maintenance. Multiple sensors require precise calibration to ensure the consistency and accuracy of the detection data. The calibration process is cumbersome and consumes a lot of time and manpower. Furthermore, if a sensor deviates during subsequent use, all related sensors need to be recalibrated during maintenance, which is difficult and costly.
[0025] Based on this, the wafer offset detection method, apparatus and electronic equipment provided by the present invention can significantly reduce detection costs and improve detection accuracy.
[0026] To facilitate understanding of this embodiment, a method for detecting the offset position of a wafer on a robotic arm, as disclosed in this embodiment of the invention, will first be described in detail. This method is applied to a detection system for the offset position of a wafer on a robotic arm. To facilitate understanding of the detection system for the offset position of a wafer on a robotic arm, this embodiment of the invention provides a schematic diagram of the structure of such a system, as shown below. Figure 1 As shown, it includes: a PLC controller, a high-speed signal input module, a digital laser sensor (high responsiveness, high precision, and ultra-small spot size), a robotic arm, a direct drive motor, and a direct drive motor controller.
[0027] This detection system uses a PLC as the controller, employs a high-speed digital input module and a set of retroreflective digital laser sensors (ultra-small spot size). During operation, the sensor laser probe is mounted vertically along the trajectory of the robotic arm towards the target chamber or workstation, ensuring that when the robotic arm carrying the wafer located at its center point passes the sensor, the sensor spot illuminates the area with a significant change in the wafer's edge slope. At the instant the robotic arm carrying the wafer passes (or leaves) the sensor, the sensor spot is blocked (or the blocking disappears) by the wafer edge, corresponding to the rising and falling edges of the sensor's input DI signal, respectively. The wafer is placed at the center point of the robotic arm, ensuring the wafer's center point coincides with the arm's center point. The arm is extended or retracted to pass the sensor, and the arm's position values at the rising and falling edges of the sensor are recorded as reference values. The wafer's center point is then shifted, and the robotic arm is extended or retracted, recording the arm's position at the rising and falling edges of the sensor. Using a specific algorithm, the offset of the wafer's center point in the arm's extension / retraction direction can be calculated. and offset perpendicular to the stretching direction Since this offset detection method mainly relies on the position of the robotic arm carrying the wafer trigger sensor to calculate the offset, it places certain requirements on the stability and positioning accuracy of the robotic arm during operation, the responsiveness of the sensor, the responsiveness of the signal acquisition module, and the control system.
[0028] The aforementioned system, employing a high-precision, high-response, and ultra-small spot digital laser sensor, significantly improves data acquisition accuracy, thereby reducing errors in offset calculation. The equipment mentioned in this detection system (direct-drive motor, digital laser sensor, high-speed signal acquisition module) is configured with the PLC under the same control network, directly controlled by the PLC (the motor controller can be adjusted to match the PLC's task cycle), further enhancing the system's responsiveness, stability, and detection accuracy. Furthermore, this system requires no additional detection equipment; only a set of retroreflective digital laser sensors, along with a high-speed signal input module and PLC, are needed to detect wafer center point offset. Compared to traditional vision inspection systems and other offset detection systems, this significantly reduces costs and improves detection accuracy.
[0029] based on Figure 1 The diagram shows a structural schematic of a wafer offset detection system on a robotic arm. This invention provides a detailed description of the method for detecting wafer offset on a robotic arm. (See also...) Figure 2 The diagram shows a flowchart of a method for detecting the offset position of a wafer on a robotic arm. The method mainly includes the following steps S202 to S206: In step S202, during the extension and retraction movement of the robotic arm, a fixed single sensor is used to perform reference detection processing on the position of the unoffset standard wafer when the edge trigger is generated, to obtain the first rising edge position and the first falling edge position, and based on the first rising edge position and the first falling edge position, the first chord length and the first vertical distance from the center of the circle to the first chord length are determined.
[0030] In one embodiment, in the above scheme, the sensor is fixed, and the position of the laser beam it emits is fixed in space. The wafer is lifted by a robotic arm and passes through the laser beam at a constant speed. During recording, instead of marking specific points on the wafer and sending signals by geometric points, the chord length is deduced by recording the time of signal jumps (corresponding to the arm position), and then the center offset is calculated.
[0031] Step S204: During the extension and retraction movement of the robotic arm, the offset detection processing is performed on the position of the wafer under test with offset when the edge trigger is generated by a fixed single sensor to obtain the second rising edge position and the second falling edge position. Based on the second rising edge position and the second falling edge position, the second chord length and the second vertical distance from the center of the circle to the second chord length are determined.
[0032] In one embodiment, the offset detection process is the same as the calibration process described above, and this method can be used to detect wafer offset in any direction. Therefore, it is not necessary to pre-determine the offset direction of the wafer and then use different strategies to measure the offset. The measurement scheme of the present invention is a universal detection method.
[0033] Step S206: The midpoint position of the first chord length and the second chord length is sent to the vertical offset calculation model to determine the first offset of the wafer under test. The first vertical distance and the second vertical distance are sent to the horizontal offset calculation model to determine the second offset of the wafer under test. The first offset and the second offset are determined as the target offset detection results. The first offset is the offset of the wafer under test in the extension and retraction direction of the robotic arm, and the second offset is the offset of the wafer under test perpendicular to the extension and retraction direction of the robotic arm.
[0034] In one implementation, 100 sets of data were collected by detecting the offset δX of the center point in the X direction. Analysis of the data revealed that the average value of δX was 0.046581356, and MAX(δX) - MIN(δX) = 0.049293876 - 0.042912965 = 0.006380911, indicating high detection accuracy and good practicality. Similarly, 200 sets of data were collected for detecting the offset δY of the center point in the Y direction. Analysis of the data showed that the average value of δX was 0.090532953, and MAX(δY) - MIN(δY) = 0.095366791 - 0.081825452 = 0.013541339, demonstrating high detection accuracy and strong practicality.
[0035] The wafer offset detection method on the robotic arm provided in this embodiment of the invention uses a direct drive motor to drive the robotic arm, eliminating the need for an additional reducer device. This eliminates gaps, resonances, and positioning errors introduced by other components, and improves motion stability and positioning accuracy by one level compared to a general servo motor.
[0036] Furthermore, the use of a single sensor significantly reduces costs. Currently, most wafer offset detection solutions on the market use sensors or vision systems, and the equipment is basically a multi-cavity structure. Using a single-sensor detection method can greatly reduce costs.
[0037] The detection method provided in this invention also has the advantages of high timeliness and simple calibration and maintenance. Due to the use of high-response sensors and the integration of the algorithm into the controller, it can monitor wafer offset in real time and allow the control system to respond quickly to the equipment. A single set of sensors only requires simple mode settings to perform normal detection work. Existing technologies use multiple sensors and vision systems. The detection accuracy of the vision system can be affected by factors such as lighting or camera cleanliness. Precise calibration is required between multiple sensors to ensure the consistency and accuracy of the detection data. The calibration process is cumbersome, consuming a lot of time and manpower. Furthermore, if a sensor deviates during subsequent use, all related sensors need to be recalibrated during maintenance, resulting in high maintenance difficulty and cost.
[0038] See Figure 3 The diagram shows a wafer offset detection method. The sensor is installed at a position where the slope of the wafer edge changes significantly. At the same time, the installation of the sensor laser probe requires that the light spot be perpendicular to the wafer and that when the wafer passes the probe, the path (i.e., chord length) of the light spot on the wafer is parallel to the diameter of the wafer center point in the stretching direction. Taking the wafer offset as an example of offset to the upper right of the center point, the present invention also provides an implementation method for wafer offset detection, as detailed in (1) to (3) below: (1) Detection of unoffset wafers (calibration reference value): When performing reference detection processing on unoffset standard wafers, the timestamp when the digital signal output by the single sensor changes from the first state to the second state is determined as the first timestamp, and the timestamp when the digital signal changes from the second state back to the first state is determined as the second timestamp. Then, based on the first timestamp and the encoder value of the robotic arm at the corresponding time, the position of the first rising edge is determined, and based on the second timestamp and the encoder value at the corresponding time, the position of the first falling edge is determined. Finally, the difference between the position of the first falling edge and the position of the first rising edge is determined as the first chord length, and the square root of the difference between the square of half the wafer radius and the square of half the first chord length is determined as the first vertical distance from the center of the circle to the first chord length.
[0039] In one implementation, see Figure 4 A schematic diagram of an un-offset wafer entering a light beam is shown. Figure 5 The diagram shows an un-offset wafer leaving the light beam: Figure 4 The motion change process is as follows: the robotic arm is in the starting position, the wafer has not yet entered the range of the sensor's laser beam, then the robotic arm moves at a constant speed in the positive Y-axis direction (extending direction), the upper edge A of the wafer contacts the laser beam for the first time, the sensor is blocked, the output signal has a rising edge jump, and the controller records the position of the arm at this moment, namely YA (first rising edge position).
[0040] Figure 5 The motion process is as follows: the arm extends and the wafer leaves the laser beam. First, the arm continues to extend until the entire wafer passes through the laser beam. Then, the arm continues to extend at a constant speed from the lower edge point a of the wafer. When it leaves the laser beam, the beam recovers, and the sensor output signal changes to a falling edge. The controller records the position of the arm at this moment, namely Ya (the position of the first falling edge). At this point, the extension motion ends.
[0041] Specifically, data calibration is performed on the unoffset wafer, and the collected / calculated data is recorded as a reference value to calculate the offset δX in the X direction and the offset δY in the Y direction when the wafer center point shifts. The robotic arm carries the wafer located at the center of the arm and extends along the sensor direction at a constant speed. The controller records the sensor's rising edge position YA and falling edge position Ya, with the chord length: L1 = Aa = Ya - YA.
[0042] During the retraction motion, the sensor's rising edge position is Ya, and its falling edge position is YA. The chord length is L1 = aA = Ya - YA. With the motor center as the origin, the Y-axis is defined by the direction of the robotic arm's extension / retraction, and the X-axis is defined by the direction perpendicular to the extension / retraction. When the robotic arm extends in the Y-direction, the perpendicular distance from the center O of the wafer O to the chord length L1 is... The point B, where the center O is perpendicular to the chord length L1, triggers the sensor to determine the position of the robotic arm. (Arm out) or (Arm retracts).
[0043] (2) Detection of offset wafer (offset to the upper right of the center point): When performing offset detection processing on the wafer under test with offset, the timestamp when the digital signal output by the single sensor jumps from the first state to the second state is determined as the third timestamp, and the timestamp when the digital signal jumps from the second state back to the first state is determined as the fourth timestamp. Then, based on the third timestamp and the encoder value of the robotic arm at the corresponding time, the position of the second rising edge is determined, and based on the fourth timestamp and the encoder value at the corresponding time, the position of the second falling edge is determined. Finally, the difference between the position of the second falling edge and the position of the second rising edge is determined as the second chord length, and the square root of the difference between the square of half the wafer radius and the square of half the second chord length is determined as the second vertical distance from the center of the circle to the second chord length.
[0044] In one implementation, see Figure 6 The diagram shown illustrates a method for offsetting a wafer into a light beam. Figure 7 The diagram illustrates a method for offsetting a wafer away from a light beam. A robotic arm carries the offset wafer and extends it at a constant speed along the sensor direction. The controller records the sensor's rising edge position YA', falling edge position Ya', and chord length. .
[0045] During the retraction motion, the sensor's rising edge position Ya', falling edge position YA', and chord length are... .
[0046] Then, taking the center of the motor as the origin, and the direction of the robotic arm's extension and retraction as the Y-axis, and the direction perpendicular to the extension and retraction as the X-axis, when the robotic arm extends in the Y-direction, the perpendicular distance from the center O' of the wafer O' to the chord length L2 is... The point C, where the center O' is perpendicular to the chord length, triggers the sensor to determine the position of the robotic arm at that moment. (Arm out) or (Arm retracts).
[0047] (3) Wafer offset calculation: First, the sum of half the first chord length and the first rising edge position, or the difference between the first falling edge position and half the first chord length, is determined as the first midpoint position. The sum of half the second chord length and the second rising edge position, or the difference between the second falling edge position and half the second chord length, is determined as the second midpoint position. Then, the absolute value of the difference between the second midpoint position and the first midpoint position is determined as the first offset. Finally, the absolute value of the difference between the first vertical distance and the second vertical distance is determined as the second offset. The first midpoint position is the position of the robotic arm when the sensor is triggered, which is the perpendicular bisector from the center of the circle to the first chord length. The second midpoint position is the position of the robotic arm when the sensor is triggered, which is the perpendicular bisector from the center of the circle to the second chord length.
[0048] In other words, the offset of the wafer center point in the Y direction (i.e., the first offset) is: When the robotic arm extends:
[0049] During the retraction movement of the robotic arm:
[0050] The offset of the wafer center point in the X direction (i.e., the second offset) is: δX=|D1-D2| In one embodiment, in addition to the aforementioned offset to the upper right of the center point, the wafer can also be offset to the lower right or to the upper left, see [link to relevant documentation]. Figure 8 The diagram shows a schematic of the remaining offset state of a wafer. In addition, other possible states include... Figure 9 The schematic diagram of another wafer offset state shows the wafer offset relative to the center point on the robotic arm to the lower right, upper left, lower left, directly below, directly above, directly left, and directly right. The offset calculation process is the same as the calculation method for the wafer offset to the upper right of the center point.
[0051] In summary, this invention provides a device structure design for wafer position offset detection using a single sensor, including the sensor's installation method at locations with significant slope changes on the wafer edge, simplifying the system structure and reducing costs. By employing a one-stop communication topology, it achieves high real-time performance and high responsiveness of the control system. Based on the direct signal connection between the sensor, robotic arm controller, and control system, including the offset detection algorithm directly embedded within the controller, it significantly improves offset detection efficiency and enables real-time, rapid responses to offset situations. Furthermore, existing technologies use multiple sensors or vision systems, which involve complex vision system debugging and require precise calibration between multiple sensors to ensure the consistency and accuracy of detection data. This calibration process is cumbersome, requiring significant time, manpower, and cost. In contrast, the debugging / calibration process of this invention is simpler, with lower maintenance difficulty and cost.
[0052] Regarding the wafer offset detection method provided in the foregoing embodiments, this invention provides a wafer offset detection device on a robotic arm. (See attached image.) Figure 10 The diagram shows a structural schematic of a device for detecting the offset position of a wafer on a robotic arm. The device includes the following parts: The reference detection module 1002, during the extension and retraction movement of the robotic arm, uses a fixed single sensor to perform reference detection processing on the position of the unoffset standard wafer when the edge trigger is generated, to obtain the first rising edge position and the first falling edge position, and based on the first rising edge position and the first falling edge position, determines the first chord length and the first vertical distance from the center of the circle to the first chord length. The offset detection module 1004, during the extension and retraction movement of the robotic arm, uses a fixed single sensor to perform offset detection processing on the position of the wafer under test with offset when the edge trigger is generated, to obtain the second rising edge position and the second falling edge position, and based on the second rising edge position and the second falling edge position, to determine the second chord length and the second vertical distance from the center of the circle to the second chord length. The offset calculation module 1006 sends the midpoint position of the first chord length and the second chord length to the vertical offset calculation model to determine the first offset of the wafer under test, and sends the first vertical distance and the second vertical distance to the horizontal offset calculation model to determine the second offset of the wafer under test. The first offset and the second offset are determined as the target offset detection results. The first offset is the offset of the wafer under test in the extension direction of the robotic arm, and the second offset is the offset of the wafer under test perpendicular to the extension direction of the robotic arm.
[0053] The wafer offset detection device provided in this application embodiment can significantly reduce detection costs and improve detection accuracy.
[0054] In one embodiment, when performing a reference detection process using a fixed single sensor to determine the position of an unoffset standard wafer at the moment of edge triggering, and obtaining the first rising edge position and the first falling edge position, the reference detection module 1002 is further configured to: determine the timestamp when the digital signal output by the single sensor changes from a first state to a second state as the first timestamp, and determine the timestamp when the digital signal changes from the second state back to the first state as the second timestamp; determine the first rising edge position based on the first timestamp and the encoder value of the robotic arm at the corresponding time, and determine the first falling edge position based on the second timestamp and the encoder value at the corresponding time.
[0055] In one embodiment, when performing the step of determining the first chord length and the first vertical distance from the center of the circle to the first chord length based on the first rising edge position and the first falling edge position, the reference detection module 1002 is further configured to: determine the difference between the first falling edge position and the first rising edge position as the first chord length, and determine the square root of the difference between the square of half the wafer radius and the square of half the first chord length as the first vertical distance from the center of the circle to the first chord length.
[0056] In one embodiment, when performing offset detection processing on the position of the offset wafer under test at the time of edge triggering using a fixed single sensor to obtain the second rising edge position and the second falling edge position, the offset detection module 1004 is further configured to: determine the timestamp when the digital signal output by the single sensor changes from the first state to the second state as the third timestamp, and determine the timestamp when the digital signal changes from the second state back to the first state as the fourth timestamp; determine the second rising edge position based on the third timestamp and the encoder value of the robotic arm at the corresponding time, and determine the second falling edge position based on the fourth timestamp and the encoder value at the corresponding time.
[0057] In one embodiment, when performing the step of determining the second chord length and the second vertical distance from the center of the circle to the second chord length based on the second rising edge position and the second falling edge position, the offset detection module 1004 is further configured to: determine the difference between the second falling edge position and the second rising edge position as the second chord length, and determine the square root of the difference between the square of half the wafer radius and the square of half the second chord length as the second vertical distance from the center of the circle to the second chord length.
[0058] In one embodiment, when performing the step of sending the midpoint position of the first chord length and the second chord length to the vertical offset calculation model to determine the first offset of the wafer under test, the offset calculation module 1006 is further configured to: determine the first midpoint position as the sum of half of the first chord length and the first rising edge position, or the difference between the first falling edge position and half of the first chord length, wherein the first midpoint position is the position of the robotic arm at the point where the center of the circle is perpendicular to the first chord length when the sensor is triggered; determine the second midpoint position as the sum of half of the second chord length and the second rising edge position, or the difference between the second falling edge position and half of the second chord length, wherein the second midpoint position is the position of the robotic arm at the point where the center of the circle is perpendicular to the second chord length when the sensor is triggered; and determine the first offset as the absolute value of the difference between the second midpoint position and the first midpoint position.
[0059] In one embodiment, when performing the step of sending the first vertical distance and the second vertical distance to the horizontal offset calculation model to determine the second offset of the wafer to be measured, the offset calculation module 1006 is further configured to: determine the absolute value of the difference between the first vertical distance and the second vertical distance as the second offset.
[0060] The device provided in this embodiment of the invention has the same implementation principle and technical effect as the aforementioned method embodiment. For the sake of brevity, any parts not mentioned in the device embodiment can be referred to the corresponding content in the aforementioned method embodiment.
[0061] This invention provides an electronic device, specifically, the electronic device includes a processor and a storage device; the storage device stores a computer program, and the computer program, when run by the processor, executes the method described in any of the above embodiments.
[0062] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The electronic device 100 includes: a processor 110, a memory 111, a bus 112, and a communication interface 113. The processor 110, the communication interface 113, and the memory 111 are connected through the bus 112. The processor 110 is used to execute executable modules, such as computer programs, stored in the memory 111.
[0063] The memory 111 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 113 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc.
[0064] Bus 112 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 11 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.
[0065] The memory 111 is used to store programs. After receiving an execution instruction, the processor 110 executes the program. The method executed by the device for defining the flow process disclosed in any of the foregoing embodiments of the present invention can be applied to the processor 110 or implemented by the processor 110.
[0066] Processor 110 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 110 or by instructions in software form. Processor 110 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software module can reside in a mature storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory 111, and processor 110 reads the information in memory 111 and, in conjunction with its hardware, completes the steps of the above method.
[0067] The computer program product of the readable storage medium provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the foregoing method embodiments. For specific implementation, please refer to the foregoing method embodiments, which will not be repeated here.
[0068] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, electronic device, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0069] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A method for detecting the offset position of a wafer on a robotic arm, characterized in that, The method includes: During the extension and retraction motion of the robotic arm, a fixed single sensor is used to perform reference detection processing on the position of the standard wafer that has not been offset when the edge is triggered, to obtain the first rising edge position and the first falling edge position, and based on the first rising edge position and the first falling edge position, the first chord length and the first vertical distance from the center of the circle to the first chord length are determined. During the extension and retraction motion of the robotic arm, a fixed single sensor is used to detect the offset of the wafer under test when the edge is triggered, and the second rising edge position and the second falling edge position are obtained. Based on the second rising edge position and the second falling edge position, the second chord length and the second vertical distance from the center of the circle to the second chord length are determined. The midpoint positions of the first chord length and the second chord length are sent to the vertical offset calculation model to determine the first offset of the wafer under test. The first vertical distance and the second vertical distance are sent to the horizontal offset calculation model to determine the second offset of the wafer under test. The first offset and the second offset are determined as the target offset detection results. The first offset is the offset of the wafer under test in the extension direction of the robotic arm, and the second offset is the offset of the wafer under test perpendicular to the extension direction of the robotic arm.
2. The method for detecting the offset position of a wafer on a robotic arm according to claim 1, characterized in that, The step of using a fixed single sensor to perform reference detection processing on the position of the unoffset standard wafer at the time of edge triggering to obtain the first rising edge position and the first falling edge position includes: When performing reference inspection processing on a standard wafer that has not been offset, the timestamp when the digital signal output by the single sensor changes from the first state to the second state is determined as the first timestamp, and the timestamp when the digital signal changes from the second state back to the first state is determined as the second timestamp. The position of the first rising edge is determined based on the first timestamp and the encoder value of the robotic arm at the corresponding time, and the position of the first falling edge is determined based on the second timestamp and the encoder value at the corresponding time.
3. The method for detecting the offset position of a wafer on a robotic arm according to claim 1, characterized in that, The step of determining the first chord length and the first vertical distance from the center of the circle to the first chord length based on the first rising edge position and the first falling edge position includes: The difference between the first falling edge position and the first rising edge position is determined as the first chord length, and the square root of the difference between the square of half the wafer radius and the square of half the first chord length is determined as the first vertical distance from the center of the circle to the first chord length.
4. The method for detecting the offset position of a wafer on a robotic arm according to claim 1, characterized in that, The step of using a fixed single sensor to detect the offset of the wafer under test at the point of edge triggering, and obtaining the second rising edge position and the second falling edge position, includes: When performing offset detection processing on a wafer under test with an offset, the timestamp when the digital signal output by the single sensor changes from the first state to the second state is determined as the third timestamp, and the timestamp when the digital signal changes from the second state back to the first state is determined as the fourth timestamp. The position of the second rising edge is determined based on the third timestamp and the encoder value of the robotic arm at the corresponding time, and the position of the second falling edge is determined based on the fourth timestamp and the encoder value at the corresponding time.
5. The method for detecting the offset position of a wafer on a robotic arm according to claim 1, characterized in that, The step of determining the second chord length and the second vertical distance from the center of the circle to the second chord length based on the second rising edge position and the second falling edge position includes: The difference between the second falling edge position and the second rising edge position is determined as the second chord length, and the square root of the difference between the square of half the wafer radius and the square of half the second chord length is determined as the second vertical distance from the center of the circle to the second chord length.
6. The method for detecting the offset position of a wafer on a robotic arm according to claim 1, characterized in that, The step of sending the midpoint position of the first chord length and the second chord length to the vertical offset calculation model to determine the first offset of the wafer under test includes: The first midpoint position is determined by the sum of half the first chord length and the first rising edge position, or the difference between the first falling edge position and half the first chord length. The first midpoint position is the position of the robotic arm when the sensor is triggered, which is the perpendicular bisector from the center of the circle to the first chord length. The second midpoint position is determined by the sum of half the second chord length and the second rising edge position, or the difference between the second falling edge position and half the second chord length. The second midpoint position is the position of the robotic arm when the sensor is triggered, which is the perpendicular bisector from the center of the circle to the second chord length. The absolute value of the difference between the second midpoint position and the first midpoint position is determined as the first offset.
7. The method for detecting the offset position of a wafer on a robotic arm according to claim 1, characterized in that, The step of sending the first vertical distance and the second vertical distance to the horizontal offset calculation model to determine the second offset of the wafer under test includes: The absolute value of the difference between the first vertical distance and the second vertical distance is determined as the second offset.
8. A device for detecting the offset position of a wafer on a robotic arm, characterized in that, The device includes: The reference detection module, during the extension and retraction movement of the robotic arm, uses a fixed single sensor to perform reference detection processing on the position of the unoffset standard wafer when the edge trigger is generated, to obtain the first rising edge position and the first falling edge position, and based on the first rising edge position and the first falling edge position, determines the first chord length and the first vertical distance from the center of the circle to the first chord length. The offset detection module uses a fixed single sensor to detect the offset of the wafer under test when an edge trigger occurs during the extension and retraction movement of the robotic arm. It obtains the second rising edge position and the second falling edge position, and determines the second chord length and the second vertical distance from the center of the circle to the second chord length based on the second rising edge position and the second falling edge position. The offset calculation module sends the midpoint position of the first chord length and the second chord length to the vertical offset calculation model to determine the first offset of the wafer under test, and sends the first vertical distance and the second vertical distance to the horizontal offset calculation model to determine the second offset of the wafer under test. The first offset and the second offset are determined as the target offset detection result, wherein the first offset is the offset of the wafer under test in the extension direction of the robotic arm, and the second offset is the offset of the wafer under test perpendicular to the extension direction of the robotic arm.
9. An electronic device, characterized in that, The method includes a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement the method of any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when invoked and executed by a processor, cause the processor to perform the method according to any one of claims 1 to 7.