Wafer transportation state detection method and device, front-end module and electronic equipment

Abstract

This application provides a wafer transport status detection method and apparatus, a front-end module, and electronic equipment, belonging to the field of wafer inspection technology. The method includes: acquiring the position timing data of a wafer scanning structure and the sensing signal collected by a sensor; calculating the real-time absolute coordinate position of the wafer scanning structure based on the position timing data; aligning the real-time absolute coordinate position with the timestamp information of the sensing signal; calculating the actual movement distance of the wafer scanning structure during the sensor's sensing of the target wafer and the actual sensing duration of the target wafer based on the time-aligned position data; determining whether the target wafer has a thickness anomaly based on the actual movement distance and the actual sensing duration; and if the target wafer has a thickness anomaly, detecting the anomaly type based on the time-domain waveform characteristics of the sensing signal. This application can improve the accuracy of thickness anomaly detection during wafer transport.

Description

Technical Field

[0001] This application belongs to the field of wafer inspection technology, and more specifically, relates to a wafer transportation status detection method and apparatus, front-end module, and electronic equipment. Background Technology

[0002] In semiconductor wafer manufacturing and transportation, wafer thickness consistency is a key parameter affecting the yield of subsequent processes. Therefore, real-time thickness monitoring of wafers during transportation is necessary. Current technologies typically employ fixed thickness sensors or optical inspection devices to measure wafer thickness. However, these solutions suffer from low accuracy and are susceptible to interference from factors such as sensor installation misalignment and environmental vibrations, leading to misjudgments or missed detections. Therefore, a comprehensive assessment of the wafer's condition during transportation is urgently needed. Summary of the Invention

[0003] The purpose of this application is to provide a wafer transportation status detection method and apparatus, front-end module, and electronic equipment to improve the detection accuracy of thickness anomalies during wafer transportation.

[0004] A first aspect of this application provides a wafer transport status detection method, including: The position timing data of the wafer scanning structure during the scanning of the target wafer and the sensing signals collected by the sensor are obtained. The position timing data is collected by the encoder in the wafer scanning structure. The sensor is set on the wafer scanning structure and moves with the wafer scanning structure. The real-time absolute coordinate position of the wafer scanning structure is calculated based on the position time sequence data; the real-time absolute coordinate position and the timestamp information of the sensing signal are time-aligned; based on the time-aligned position data, the first encoder position value corresponding to the first moment when the sensor starts to sense the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor ends to sense the edge of the target wafer are extracted. The difference between the position value of the second encoder and the position value of the first encoder is calculated to obtain the actual movement distance of the wafer scanning structure during the period when the sensor senses the target wafer; the time difference between the second moment and the first moment is calculated to obtain the actual sensing duration of the sensor on the target wafer; The actual travel distance is compared with the encoder standard travel distance range corresponding to the preset wafer standard thickness to obtain the first comparison result. The actual sensing time is compared with the sensor standard sensing time range corresponding to the preset wafer standard thickness to obtain the second comparison result. Based on the first comparison result and the second comparison result, it is determined whether the target wafer has a thickness abnormality. If the target wafer has a thickness anomaly, the anomaly type of the target wafer is detected based on the time-domain waveform characteristics of the sensing signal.

[0005] A second aspect of this application provides a wafer transport status detection device, comprising: The data acquisition unit is used to acquire the position timing data of the wafer scanning structure during the scanning of the target wafer and the sensing signals collected by the sensor. The position timing data is acquired by the encoder in the wafer scanning structure, and the sensor is set on the wafer scanning structure and moves with the wafer scanning structure. The data extraction unit is used to calculate the real-time absolute coordinate position of the wafer scanning structure based on the position time series data; to time-align the real-time absolute coordinate position and the timestamp information of the sensing signal; and to extract the first encoder position value corresponding to the first moment when the sensor starts to sense the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor stops sensing the edge of the target wafer based on the time-aligned position data. The data calculation unit is used to calculate the difference between the position value of the second encoder and the position value of the first encoder to obtain the actual movement distance of the wafer scanning structure during the period when the sensor senses the target wafer; and to calculate the time difference between the second moment and the first moment to obtain the actual sensing duration of the sensor on the target wafer. The first anomaly detection unit is used to compare the actual travel distance with the encoder standard travel distance range corresponding to the preset wafer standard thickness to obtain a first comparison result, compare the actual sensing time with the sensor standard sensing time range corresponding to the preset wafer standard thickness to obtain a second comparison result, and determine whether the target wafer has a thickness anomaly based on the first comparison result and the second comparison result. The second anomaly detection unit is used to detect the anomaly type of the target wafer based on the time-domain waveform characteristics of the sensing signal if the target wafer has a thickness anomaly.

[0006] A third aspect of this application provides a front-end module, including a wafer cassette, a wafer picking structure, a wafer inspection station, a wafer scanning structure, and a controller; the wafer picking structure is used to pick up qualified wafers from the wafer inspection station and put them into the wafer cassette, the wafer scanning structure is used to inspect the wafers on the wafer inspection station, and the controller is used to execute the steps of the above-described wafer transport status detection method.

[0007] A fourth aspect of this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that the processor executes the computer program to implement the steps of the wafer transport status detection method described above.

[0008] The beneficial effects of the wafer transport status detection method and apparatus, front-end module, and electronic equipment provided in this application are as follows: This application embodiment mounts a sensor on a movable wafer scanning structure, calculates real-time absolute coordinates by combining the position timing data collected by the encoder, and aligns the position timing data with the sensing signal collected by the sensor to convert wafer thickness measurement into high-precision encoder displacement detection. This detection method is suitable for online real-time detection requirements during wafer transportation, breaking through the limitation of fixed sensors that can only measure at fixed points. It can also offset the systematic error caused by sensor installation offset through absolute coordinate calibration, reduce the interference of environmental vibration on the detection results, and detect wafer thickness from two dimensions: actual movement distance and actual sensing time, thereby improving the accuracy of wafer thickness anomaly detection.

[0009] In addition, after determining that the wafer has a thickness anomaly, this embodiment further detects the type of wafer anomaly based on the time-domain waveform characteristics of the sensing signal, enabling the differentiation of different wafer anomaly modes. Compared to existing technologies that can only output a binary result of "normal / abnormal", this embodiment can provide more granular wafer anomaly classification information, making the state assessment during wafer transportation more accurate. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic flowchart of a wafer transport status detection method provided in an embodiment of this application; Figure 2 This is a structural block diagram of a wafer transport status detection device provided in an embodiment of this application; Figure 3 This is a schematic block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0012] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0013] To make the objectives, technical solutions, and advantages of this application clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0014] This application is used in a wafer anomaly detection scenario. In this scenario, before the robotic arm picks up the wafer and places it into the wafer cassette, the wafer needs to be placed on a wafer inspection platform for thickness detection. Wafers that pass the thickness detection are placed into the wafer cassette by the robotic arm, while wafers that fail the thickness detection are placed in a recycling box. The thickness detection of the wafer on the wafer inspection platform is achieved through a wafer scanning structure.

[0015] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a wafer transport status detection method provided in an embodiment of this application. The method can be executed by a front-end module and includes: S101: Acquire the position timing data of the wafer scanning structure during the scanning of the target wafer and the sensing signal collected by the sensor. The position timing data is acquired by the encoder in the wafer scanning structure. The sensor is set on the wafer scanning structure and moves with the wafer scanning structure.

[0016] In this embodiment, the wafer scanning structure consists of a mechanical execution module with linear reciprocating translational motion degrees of freedom. It can uniformly scan the target wafer during wafer thickness measurement, enabling the encoder and sensor to acquire relevant data and detect wafer thickness anomalies. The wafer scanning process can be understood as follows: after the target wafer is positioned on the wafer inspection platform's positioning reference plane by a robotic arm for centering and posture fixation, the wafer scanning structure initiates its feed motion from the scanning origin until the sensor completely leaves the wafer's physical coverage area, completing the entire motion range. This process includes five time-series segments: an idle segment before scanning starts, a segment where the sensor enters the target wafer's edge, a segment where the sensor completely covers the wafer body, a segment where the sensor exits the target wafer's edge, and a idle segment at scanning termination. In this embodiment, the data range collected by the sensor is limited to the effective scanning range where the sensor detects wafer obstruction.

[0017] In this embodiment, the encoder can be an absolute encoder, mounted on the shaft end of the vertical lifting drive motor of the wafer scanning structure. The absolute encoder is coaxially connected to the main shaft of the drive motor. During the scanning process of the target wafer, the angular displacement of the motor main shaft can be quantized and encoded in real time by the absolute encoder to obtain position timing data. In this embodiment, the position timing data consists of a timing pairing data group composed of the absolute position code value of the encoder synchronously output by the absolute encoder during the vertical lifting scanning process of the wafer scanning structure and the corresponding sampling timestamp. The absolute position code value at each sampling moment is bound and stored with the timestamp at that moment.

[0018] In this embodiment, the sensor can be a photoelectric sensor. The sensing working surface of the photoelectric sensor is arranged facing the target wafer on the detection platform. Its sensing output level or analog amplitude changes stepwise depending on whether the light path is blocked by the wafer. Therefore, the thickness of the target wafer can be detected by the sensing signal collected by the sensor.

[0019] This embodiment acquires the position timing data of the wafer scanning structure in real time through an encoder, and simultaneously uses a sensor that moves synchronously with the wafer scanning structure to collect sensing signals, thereby achieving spatiotemporal synchronization of position information and detection signals, which can effectively improve the accuracy and reliability of wafer thickness anomaly detection.

[0020] S102: Calculate the real-time absolute coordinate position of the wafer scanning structure based on the position timing data; align the real-time absolute coordinate position with the timestamp information of the sensing signal, and extract the first encoder position value corresponding to the first moment when the sensor starts sensing the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor stops sensing the edge of the target wafer based on the time-aligned position data.

[0021] In this embodiment, the real-time absolute coordinate position is the real-time physical coordinate value of the wafer scanning structure during the vertical lifting process, which is obtained by converting the position time sequence data. The coordinates take the preset mechanical reference zero point of the wafer scanning structure as the origin and can be used to calculate the actual movement distance of the wafer scanning structure during the period when the sensor senses the target wafer.

[0022] In one embodiment, calculating the real-time absolute coordinate position of the wafer scanning structure based on positional timing data includes: The positional time-series data is decoded and converted to obtain binary absolute position values; Based on the encoder's resolution parameters and the mechanical transmission ratio of the wafer scanning structure, the binary absolute position value is converted into the physical coordinate value of the wafer scanning structure; The physical coordinate values ​​are smoothed and filtered to obtain the real-time absolute coordinate position of the wafer scanning structure.

[0023] In this embodiment, the binary absolute position value refers to the raw digital quantity output by the encoder after acquiring and converting the real-time spatial position of the wafer scanning structure. It is represented as a string of absolute position encoded data in binary form. The encoder's resolution parameter refers to the counting division corresponding to the minimum position change that the encoder can output or produce within a unit of physical motion. It is usually characterized by the increment of the binary absolute position value generated by the complete rotation of the encoder's motor shaft, with units of pulses per revolution or counts per revolution. The larger the binary count value corresponding to a unit rotation angle, the higher the spatial positioning accuracy. The mechanical transmission ratio refers to the proportional relationship between the rotational motion of the motor shaft and the linear displacement of the wafer scanning structure in the scanning direction.

[0024] In this embodiment, the binary absolute position value is converted into the physical coordinate value of the wafer scanning structure based on the encoder's resolution parameters and the mechanical transmission ratio of the wafer scanning structure, using the following formula: .

[0025] in, X Represents the physical coordinate values ​​of the wafer scan structure. H Represents the absolute binary position value. B R represents the single-turn displacement corresponding to the mechanical transmission ratio, and R represents the encoder resolution. In a wafer scanning structure, the mechanical transmission ratio is the ratio of the speed of the driving shaft (motor output shaft) where the encoder is located to the speed of the driven actuating shaft (such as a leadscrew). The physical meaning of this ratio is that the rotation of the driving shaft... i During one revolution, the driven actuation axis rotates exactly one revolution. The linear displacement generated by the wafer scanning structure during one revolution of the driven actuation axis is... The displacement per revolution corresponding to the mechanical transmission ratio. .

[0026] In this embodiment, smoothing filtering of the physical coordinate values ​​can effectively suppress the instantaneous fluctuations in physical coordinate values ​​caused by encoder quantization noise, mechanical transmission backlash, and high-frequency vibration, making the output real-time absolute coordinate position curve smooth and stable.

[0027] Because position timing data (acquired by the encoder) and sensing signals (acquired by the sensor), although recorded on the same timeline, are acquired independently by different hardware, they typically exhibit differences in sampling frequency, transmission delay, or clock skew. Therefore, it is necessary to time-align the real-time absolute coordinate position with the timestamp information of the sensing signals to facilitate subsequent processing based on the time-aligned position data. Without time alignment, directly matching based on their original timestamps will result in incorrect coordinate values ​​due to time misalignment. For example, the sensor may have actually detected the edge of the target wafer, but the encoder position before time alignment corresponds to a moment when it has not yet reached or has already passed the edge. This will distort the subsequently calculated actual travel distance, causing wafers with normal thickness to be misjudged as abnormal.

[0028] Therefore, in this embodiment, time alignment refers to correcting the time information of the real-time absolute coordinate position according to the timestamp information of the sensing signal. The purpose of time alignment is to synchronize the real-time absolute coordinate position with the sensing signal in time, ensuring that the extracted first encoder position value and second encoder position value can truly reflect the absolute coordinates of the target wafer edge at the moment the sensor senses it, thereby providing a reliable data basis for wafer thickness judgment and anomaly detection.

[0029] In one embodiment, if a rising edge and a falling edge are detected in the sensor's sensing signal during a single scan, the first encoder position value corresponding to the first moment when the sensor begins to sense the edge of the target wafer, and the second encoder position value corresponding to the second moment when the sensor ends to sense the edge of the target wafer, are extracted, including: The moment when the amplitude of the sensor's sensing signal first exceeds the effective threshold is recorded as the first moment, and the encoder position value corresponding to the first moment is extracted as the first encoder position value. The effective threshold is the minimum threshold that distinguishes between effective and invalid sensing signals. The moment when the amplitude of the sensor's sensing signal first falls below or equals the effective threshold is recorded as the second moment, and the encoder position value corresponding to the second moment is extracted as the second encoder position value.

[0030] In this embodiment, during a single scan, as the sensor gradually approaches, passes through, and eventually leaves the edge region of the target wafer, the sensor signal it collects sequentially exhibits a positive transition (rising edge) from the substrate noise level to the effective sensing amplitude and a negative transition (falling edge) from the effective sensing amplitude to the substrate noise level in the time domain. Moreover, during a single scan, there is only one effective sensing interval that goes from nothing to something and then back to nothing.

[0031] In the above scenario, the position values ​​of the first encoder and the second encoder can be determined based on the relationship between the amplitude of the sensor's sensed signal and the effective threshold. The effective threshold is a pre-calibrated minimum amplitude boundary used to distinguish between "invalid sensed signals" and "valid sensed signals" within the sensor's output amplitude range, and can be determined through multiple experiments.

[0032] During a single scan, if the amplitude of the sensor's sensing signal is greater than the effective threshold, it can be determined that the sensor is in the wafer physical sensing area; if the amplitude of the sensor's sensing signal is not greater than the effective threshold, it can be determined that the sensor is not in the wafer physical sensing area.

[0033] This embodiment determines the two edge positions of the target wafer by judging the rising and falling edges of the sensing signal based on a preset effective threshold. This method can eliminate the problem of false edge recognition caused by substrate noise and electromagnetic disturbance, and shorten the wafer detection time through lightweight computation.

[0034] In one embodiment, if at least two rising edges and at least two falling edges are detected in the sensor's sensing signal during a single scan, the extraction of the first encoder position value corresponding to the first moment when the sensor begins to sense the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor ends to sense the edge of the target wafer includes: The moment when the amplitude of the sensor's sensing signal first exceeds the effective threshold is recorded as the first moment, and the encoder position value corresponding to the first moment is extracted as the first encoder position value. The effective threshold is the minimum threshold that distinguishes between effective and invalid sensing signals. The moment when the amplitude of the sensor's sensing signal is last less than or equal to the effective threshold is recorded as the second moment, and the encoder position value corresponding to the second moment is extracted as the second encoder position value.

[0035] In this embodiment, during a single scan, the sensor's sensing of the target wafer does not maintain a continuous and effective single-peak pattern. Instead, it experiences at least two transitions (rising edges) from an ineffective sensing state to an effective sensing state, and at least two transitions (falling edges) from an effective sensing state back to an ineffective sensing state. This multi-edge phenomenon physically corresponds to the non-monotonic continuity of the target wafer's edge in the scanning direction—for example, the wafer may have notches, chipped edges, through cracks, surface-attached particles, or be tilted, causing the scanning path to cut in and out. It may also be caused by multiple wafers mounted on the same carrier. Because the effective and ineffective sensing states alternate, the sensor's sensing signal forms multiple effective pulse intervals in the time domain.

[0036] In the aforementioned multi-edge scenario, regardless of the number of alternations between valid and invalid sensing states, the moment corresponding to the first identified sensing signal amplitude exceeding the valid threshold is taken as the first moment, and the first encoder position value is extracted based on the position information corresponding to this first moment. Similarly, regardless of the number of alternations between valid and invalid sensing states, the moment corresponding to the last identified sensing signal amplitude being less than or equal to the valid threshold is taken as the second moment, and the second encoder position value is extracted based on the position information corresponding to this second moment.

[0037] This embodiment addresses complex scenarios involving multiple edges, such as wafers with notches, chipped edges, cracks, tilting, or multiple wafers. It determines the start and end positions of the target wafer edge using the first rising edge and the last falling edge, respectively. Regardless of how many times the rising and falling edge signals alternate, it can accurately capture the overall boundary range of the target wafer in the scanning direction, effectively avoiding edge positioning deviations caused by local defects or interference from multiple wafers, and improving the robustness of detection under complex conditions.

[0038] S103: Calculate the difference between the position value of the second encoder and the position value of the first encoder to obtain the actual movement distance of the wafer scanning structure during the period when the sensor senses the target wafer; calculate the time difference between the second moment and the first moment to obtain the actual sensing time of the sensor on the target wafer.

[0039] In this embodiment, the actual travel distance is not the standard thickness of the target wafer, but rather the measured thickness of the target wafer calculated by the encoder within the sensor's sensing range. The actual travel distance reflects the encoder coordinate system distance between the sensing incident boundary and the sensing exit boundary as the sensor scan line passes through the wafer body. This distance may include the wafer body, the wafer tilt projection component, and the union span of multiple sensing areas caused by defects or foreign objects. Therefore, this measured thickness is a comprehensive geometric characteristic that can be used to detect whether the wafer thickness is normal.

[0040] In this embodiment, the wafer scanning structure moves at a constant speed when the sensor scans the target wafer.

[0041] This embodiment compares the actual travel distance with the standard thickness of the wafer to directly determine whether the wafer thickness is within the normal range. In addition, it can also perform cross-validation by combining the actual sensing time to effectively identify abnormal wafers and improve the accuracy of wafer thickness anomaly detection.

[0042] S104: Compare the actual travel distance with the encoder standard travel distance range corresponding to the preset wafer standard thickness to obtain a first comparison result; compare the actual sensing time with the sensor standard sensing time range corresponding to the preset wafer standard thickness to obtain a second comparison result; and determine whether the target wafer has a thickness abnormality based on the first comparison result and the second comparison result.

[0043] In this embodiment, the standard wafer thickness refers to the nominal physical thickness of the wafer along the sensor detection direction under ideal conditions of no warping, no tilting, and single-wafer transportation. This nominal value is a predetermined known parameter. Different types of wafers correspond to different standard thicknesses.

[0044] The standard stroke range of an encoder refers to the range of positional changes that the encoder should produce from sensing the leading edge of the wafer to leaving the trailing edge of the wafer when the sensor is scanned in a fixed mounting posture.

[0045] Specifically, the standard travel range of this encoder is determined as follows: The sensor moves with the wafer scanning structure, and its sensing area corresponds to a detection window of a certain length in space. When the wafer thickness is the standard thickness, from the time the sensor is first blocked by the wafer edge to the time it is completely unblocked, the first distance actually traveled by the wafer scanning structure in the scanning direction is determined based on the standard thickness and the detection geometry; the detection geometry includes the spatial configuration parameters of the sensor relative to the wafer. Using the first distance as the center, upper and lower limits are set to obtain the standard travel range of the encoder.

[0046] In this embodiment, the spatial configuration parameters of the sensor relative to the wafer include the size of the sensor spot in space, the incident angle between the beam axis and the tangent on the wafer surface, and the scanning motion direction (wafer thickness direction) of the sensor driven by the wafer scanning structure. If the first distance is L, the standard stroke range of the encoder can be 0.99L~1.01L.

[0047] In this embodiment, determining the first distance actually traveled by the wafer scanning structure in the scanning direction based on the standard thickness and the detection geometry includes: calculating the first distance according to the following formula: ; Where L is the first distance and T is the standard wafer thickness. S The effective feature size of the sensor spot is parallel to the wafer normal direction. The angle of incidence is the distance between the beam axis and the tangent on the wafer surface.

[0048] In this embodiment, traditional calibration methods often ignore the influence of the spatial span of the light spot on the start and end times of occlusion, which can easily cause a fixed system deviation in the encoder's reference stroke. This solution uses the effective feature size of the light spot parallel to the wafer normal as an independent calculation parameter, and includes the additional scanning displacement caused by the light spot occlusion in the first distance to compensate for the timing stroke error caused by the sensing window width, so that the reference value of the encoder's standard stroke range is closer to the true displacement value of the entire occlusion scanning process.

[0049] The standard sensing duration range refers to the range of time from triggering to disappearing of the sensor sensing signal within the scan stroke corresponding to the encoder's standard stroke range, based on the preset scan speed of the wafer scanning structure.

[0050] In one embodiment, determining whether a target wafer has a thickness anomaly based on a first comparison result and a second comparison result includes: If the actual travel distance is greater than the upper limit of the encoder's standard travel range, and the actual sensing time is greater than the upper limit of the sensor's standard sensing time range, then the thickness of the target wafer is determined to be greater than the standard thickness. If the actual travel distance is less than the lower limit of the encoder's standard travel range, and the actual sensing time is less than the lower limit of the sensor's standard sensing time range, then the thickness of the target wafer is determined to be less than the standard thickness.

[0051] In this embodiment, the relationship between the target wafer thickness and the standard thickness is determined based on two dimensions: actual travel distance and actual sensing duration. This is to avoid misjudgments caused by accidental jumps in travel measurement or factors other than thickness. Only when both "increased actual travel distance" and "increased actual sensing duration" occur simultaneously, or both "decreased actual travel distance" and "decreased actual sensing duration" occur simultaneously, can it be concluded that the wafer thickness anomaly is reasonable in both spatial and temporal dimensions. If the actual travel distance is too large, but the actual sensing duration is normal or too short, this violates the laws of physical kinematics and is most likely due to electrical interference from the encoder generating invalid pulses, rather than wafer thickening. Therefore, judging based on both actual travel distance and actual sensing duration can avoid such false alarms.

[0052] S105: If the target wafer has a thickness anomaly, the anomaly type of the target wafer is detected based on the time-domain waveform characteristics of the sensing signal.

[0053] In one embodiment, when the target wafer exhibits a thickness anomaly, the anomaly type can be classified based on the time-domain waveform characteristics of the sensing signal. When the target wafer does not exhibit a thickness anomaly, it indicates that the wafer can proceed with subsequent processing normally, and no further anomaly type detection is required. The time-domain waveform characteristics in this embodiment include signal edge transition characteristics and signal amplitude variation characteristics. In this embodiment, under ideal conditions where the target wafer has a standard thickness, a flat surface, and no tilt, when the sensor scans along the normal direction across the wafer edge, the process of the light spot transitioning from partial obstruction to full obstruction, and then gradually unobstructed, is smooth, monotonous, and symmetrical. Correspondingly, the time-domain waveform of the sensing signal presents as a single, regularly shaped pulse.

[0054] When a wafer exhibits localized notches, edge chipping, bulges, or double-wafer overlap anomalies, the time-domain waveform will show non-monotonic jumps, short-duration glitches, or step-like transitions at the signal edges, rather than a single smooth slope. Especially when a wafer exhibits double-wafer overlap anomalies, the time-domain waveform characteristics are not single-peaked but show obvious bimodal characteristics. Therefore, this embodiment can detect the anomaly type of the target wafer based on the time-domain waveform characteristics of the sensed signal, and promptly screen out abnormal wafers.

[0055] As can be seen from the above, this embodiment of the application mounts the sensor on a movable wafer scanning structure, calculates the real-time absolute coordinates by combining the position timing data collected by the encoder, and aligns the position timing data with the sensing signal collected by the sensor in time, transforming wafer thickness measurement into high-precision encoder displacement detection. This detection method not only meets the online real-time detection requirements during wafer transportation, breaking through the limitations of fixed sensors that can only measure at fixed points, but also offsets the systematic errors caused by sensor installation offset through absolute coordinate calibration, reduces the interference of environmental vibration on the detection results, and detects wafer thickness from two dimensions: actual travel distance and actual sensing time, thus improving the accuracy of wafer thickness anomaly detection. In addition, after determining that there is a thickness anomaly in the wafer, this embodiment of the application further detects the type of wafer anomaly based on the time-domain waveform characteristics of the sensing signal, which can distinguish different wafer anomaly modes. Compared with the prior art, which can only output a binary result of "normal / abnormal", this embodiment of the application can provide more granular wafer anomaly classification information, making the state assessment during wafer transportation more accurate.

[0056] In one embodiment of this application, detecting the anomaly type of a target wafer based on the time-domain waveform characteristics of an inductive signal includes: In response to the target wafer's thickness being greater than the standard thickness, the target wafer is determined to be either an anomaly of multiple wafer overlap or a wafer warping anomaly based on the signal edge transition characteristics. In response to the target wafer's thickness being less than the standard thickness, the target wafer is determined to be either a thin-film anomaly or a wafer fragment anomaly based on the characteristics of the signal amplitude variation.

[0057] Edge transition characteristics include the slope of the rising edge of the sensed signal, the slope of the falling edge, and the total number of edge transitions; In one embodiment, distinguishing a target wafer from a multi-wafer overlap anomaly or a wafer warping anomaly based on signal edge transition characteristics includes: Calculate the absolute values ​​of the rising edge slope and the falling edge slope of the induced signal; If the total number of edge transitions is equal to 2N, then the target wafer is determined to have a multi-wafer overlap anomaly, where N is an integer greater than or equal to 2; If the total number of edge transitions is equal to 2, the absolute value of the rising edge slope is greater than the upper limit of the standard wafer edge slope range, and the absolute value of the falling edge slope is greater than the upper limit of the standard wafer edge slope range, then the target wafer is determined to have a wafer warping anomaly. If the total number of edge transitions is equal to 2, the absolute value of the rising edge slope is less than the lower limit of the standard wafer edge slope range, or the absolute value of the falling edge slope is less than the lower limit of the standard wafer edge slope range, then the target wafer is determined to have a wafer warping anomaly.

[0058] This embodiment uses the number of edge transitions of the sensing signal as the primary judgment criterion and the absolute value of the edge slope as the secondary judgment criterion, which can effectively distinguish between two types of anomalies: multi-wafer overlap and wafer warping. First, the total number of complete edge transitions of the sensing signal during the sensor's scan of the wafer is counted. If the total number of transitions is 2N and N is an integer greater than or equal to 2, it indicates that the scanning path has passed through the edges of N wafers in sequence. Each wafer corresponds to a set of rising and falling edges, which can be used to determine that the target wafer has a multi-wafer overlap anomaly. If the total number of transitions is 2, it means that the object being tested is still a single wafer. At this time, it is necessary to further calculate the absolute values ​​of the rising and falling edge slopes of the sensing signal and compare them with the edge slope range of a standard wafer. When the absolute values ​​of both the rising and falling edge slopes are greater than the upper limit of the standard range, or the absolute value of any edge slope is less than the lower limit of the standard range, it indicates that the thickness transition profile of the wafer edge has deviated from the normal shape of a flat wafer, which can be used to determine that the target wafer has a wafer warping anomaly.

[0059] In this embodiment, the signal amplitude variation characteristics include the fluctuation amount of the signal amplitude and the effective blocking ratio. The effective blocking ratio refers to the proportion of the cumulative time during which the signal amplitude remains above the effective threshold within the effective sensing time interval of the sensor on the target wafer, relative to the total duration of that effective sensing time interval.

[0060] Determining whether a target wafer exhibits thin-film anomalies or wafer fragmentation anomalies based on signal amplitude variation characteristics includes: If the fluctuation of the signal amplitude is less than the preset threshold and the effective obstruction ratio is less than the preset proportion, the target wafer is determined to be a wafer anomaly; if the fluctuation of the signal amplitude is not less than the preset threshold, the target wafer is determined to be a wafer fragment anomaly.

[0061] As can be seen from the above, when the wafer is relatively thick, this embodiment can utilize the total number of edge transitions and slope characteristics to not only distinguish between multiple overlapping wafers and warping anomalies, but also quantify the number of overlapping wafers. When the wafer is relatively thin, this embodiment can utilize amplitude fluctuation and effective occlusion ratio to effectively distinguish between thin wafers and fragmentation anomalies. Compared to single threshold determination, this embodiment, based on multi-dimensional features of time-domain waveforms, can identify different types of wafer thickness anomalies, significantly improving the accuracy of wafer thickness detection and reducing the risk of false detections and missed detections.

[0062] Corresponding to the wafer transport status detection method in the above embodiment, Figure 2 This is a structural block diagram of a wafer transport status detection device provided in one embodiment of this application. For ease of explanation, only the parts relevant to the embodiment of this application are shown. References Figure 2 The wafer transport status detection device 20 includes: a data acquisition unit 21, a data extraction unit 22, a data calculation unit 23, a first anomaly detection unit 24, and a second anomaly detection unit 25.

[0063] The data acquisition unit 21 is used to acquire the position timing data of the wafer scanning structure during the scanning of the target wafer and the sensing signal collected by the sensor. The position timing data is acquired by the encoder in the wafer scanning structure, and the sensor is set on the wafer scanning structure and moves with the wafer scanning structure. Data extraction unit 22 is used to calculate the real-time absolute coordinate position of the wafer scanning structure based on position time series data; to time-align the real-time absolute coordinate position and the timestamp information of the sensing signal; and to extract the first encoder position value corresponding to the first moment when the sensor starts sensing the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor stops sensing the edge of the target wafer based on the time-aligned position data. Data calculation unit 23 is used to calculate the difference between the position value of the second encoder and the position value of the first encoder to obtain the actual movement distance of the wafer scanning structure during the period when the sensor senses the target wafer; and to calculate the time difference between the second moment and the first moment to obtain the actual sensing duration of the sensor on the target wafer. The first anomaly detection unit 24 is used to compare the actual travel distance with the encoder standard travel distance range corresponding to the preset wafer standard thickness to obtain a first comparison result, compare the actual sensing time with the sensor standard sensing time range corresponding to the preset wafer standard thickness to obtain a second comparison result, and determine whether the target wafer has a thickness anomaly based on the first comparison result and the second comparison result. The second anomaly detection unit 25 is used to detect the anomaly type of the target wafer based on the time-domain waveform characteristics of the sensing signal if the target wafer has a thickness anomaly.

[0064] In one embodiment of this application, when calculating the real-time absolute coordinate position of the wafer scanning structure based on position timing data, the data extraction unit 22 is specifically used for: The positional time-series data is decoded and converted to obtain binary absolute position values; Based on the encoder's resolution parameters and the mechanical transmission ratio of the wafer scanning structure, the binary absolute position value is converted into the physical coordinate value of the wafer scanning structure; The physical coordinate values ​​are smoothed and filtered to obtain the real-time absolute coordinate position of the wafer scanning structure.

[0065] In one embodiment of this application, if a rising edge and a falling edge are detected in the sensor's sensing signal during a single scan, the data extraction unit 22 is specifically used for: The moment when the amplitude of the sensor's sensing signal first exceeds the effective threshold is recorded as the first moment, and the encoder position value corresponding to the first moment is extracted as the first encoder position value. The effective threshold is the minimum threshold that distinguishes between effective and invalid sensing signals. The moment when the amplitude of the sensor's sensing signal first falls below or equals the effective threshold is recorded as the second moment, and the encoder position value corresponding to the second moment is extracted as the second encoder position value.

[0066] In one embodiment of this application, if at least two rising edges and two falling edges are detected in the sensor's sensing signal during a single scan, the data extraction unit 22 is specifically used for: The moment when the amplitude of the sensor's sensing signal first exceeds the effective threshold is recorded as the first moment, and the encoder position value corresponding to the first moment is extracted as the first encoder position value. The effective threshold is the minimum threshold that distinguishes between effective and invalid sensing signals. The moment when the amplitude of the sensor's sensing signal is last less than or equal to the effective threshold is recorded as the second moment, and the encoder position value corresponding to the second moment is extracted as the second encoder position value.

[0067] In one embodiment of this application, the first anomaly detection unit 24 is specifically used for: If the actual travel distance is greater than the upper limit of the encoder's standard travel range, and the actual sensing time is greater than the upper limit of the sensor's standard sensing time range, then the thickness of the target wafer is determined to be greater than the standard thickness. If the actual travel distance is less than the lower limit of the encoder's standard travel range, and the actual sensing time is less than the lower limit of the sensor's standard sensing time range, then the thickness of the target wafer is determined to be less than the standard thickness.

[0068] In one embodiment of this application, the time-domain waveform features include signal edge transition features and signal amplitude variation features; the second anomaly detection unit 25 is specifically used for: In response to the target wafer's thickness being greater than the standard thickness, the target wafer is determined to be either an anomaly of multiple wafer overlap or a wafer warping anomaly based on the signal edge transition characteristics. In response to the target wafer's thickness being less than the standard thickness, the target wafer is determined to be either a thin-film anomaly or a wafer fragment anomaly based on the characteristics of the signal amplitude variation.

[0069] In one embodiment of this application, the edge transition characteristics include the slope of the rising edge of the sensing signal, the slope of the falling edge, and the total number of edge transitions; the second anomaly detection unit 25, when distinguishing between a target wafer as a multi-wafer overlap anomaly or a wafer warping anomaly based on the signal edge transition characteristics, is specifically used for: Calculate the absolute values ​​of the rising edge slope and the falling edge slope of the induced signal; If the total number of edge transitions is equal to 2N, then the target wafer is determined to have a multi-wafer overlap anomaly, where N is an integer greater than or equal to 2; If the total number of edge transitions is equal to 2, the absolute value of the rising edge slope is greater than the upper limit of the standard wafer edge slope range, and the absolute value of the falling edge slope is greater than the upper limit of the standard wafer edge slope range, then it is determined that the target wafer has multiple overlapping anomalies, and the number of overlapping wafers is calculated based on the ratio of the absolute value of the rising edge slope to the average value of the standard wafer edge slope. If the total number of edge transitions is equal to 2, the absolute value of the rising edge slope is less than the lower limit of the standard wafer edge slope range, or the absolute value of the falling edge slope is less than the lower limit of the standard wafer edge slope range, then the target wafer is determined to have a wafer warping anomaly.

[0070] Another embodiment of this application provides a front-end module, including a wafer cassette, a wafer picking structure, a wafer inspection station, a wafer scanning structure, and a controller; the wafer picking structure is used to pick up qualified wafers from the wafer inspection station and put them into the wafer cassette, the wafer scanning structure is used to inspect the wafers on the wafer inspection station, and the controller is used to execute the steps of the above-described wafer transport status detection method.

[0071] See Figure 3 , Figure 3 This is a schematic block diagram of an electronic device provided according to an embodiment of this application. Figure 3The electronic device 300 in this embodiment may include one or more processors 301, one or more input devices 302, one or more output devices 303, and one or more memories 304. The processors 301, input devices 302, output devices 303, and memories 304 communicate with each other via a communication bus 305. The memories 304 store computer programs, including program instructions. The processors 301 execute the program instructions stored in the memories 304. Specifically, the processors 301 are configured to invoke the program instructions to perform the functions of the units in the above-described device embodiments, for example... Figure 2 The functions of the data acquisition unit 21, data extraction unit 22, data calculation unit 23, first anomaly detection unit 24, and second anomaly detection unit 25 shown are illustrated.

[0072] It should be understood that, in the embodiments of this application, the processor 301 may be a central processing unit (CPU), but it may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0073] Input device 302 may include a touchpad, a fingerprint sensor (for collecting the user's fingerprint information and fingerprint orientation information), a microphone, etc., and output device 303 may include a display (LCD, etc.), a speaker, etc.

[0074] The memory 304 may include read-only memory and random access memory, and provides instructions and data to the processor 301. A portion of the memory 304 may also include non-volatile random access memory. For example, the memory 304 may also store device type information.

[0075] In specific implementations, the processor 301, input device 302, and output device 303 described in the embodiments of this application can execute the implementation method described in the wafer transport status detection method provided in the embodiments of this application, or they can execute the implementation method of the electronic device described in the embodiments of this application, which will not be repeated here.

[0076] In another embodiment of this application, a computer-readable storage medium is provided. This computer-readable storage medium stores a computer program, which includes program instructions. When executed by a processor, the program instructions implement all or part of the processes in the methods described above. Alternatively, the computer program can instruct related hardware to complete the process. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include any entity or device capable of carrying computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0077] The computer-readable storage medium can be an internal storage unit of the electronic device in any of the foregoing embodiments, such as a hard disk or memory of the electronic device. The computer-readable storage medium can also be an external storage device of the electronic device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the electronic device. Furthermore, the computer-readable storage medium can include both internal and external storage units of the electronic device. The computer-readable storage medium is used to store computer programs and other programs and data required by the electronic device. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0078] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0079] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the electronic devices and units described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0080] In the several embodiments provided in this application, it should be understood that the disclosed electronic devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces or units, or it may be an electrical, mechanical, or other form of connection.

[0081] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of this application, depending on actual needs.

[0082] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0083] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for detecting the transport status of a wafer, characterized in that, include: The position timing data of the wafer scanning structure during the scanning of the target wafer and the sensing signals collected by the sensor are acquired. The position timing data is acquired by the encoder in the wafer scanning structure, and the sensor is set on the wafer scanning structure and moves with the wafer scanning structure. Calculate the real-time absolute coordinate position of the wafer scanning structure based on the aforementioned position timing data; The real-time absolute coordinate position and the timestamp information of the sensing signal are time-aligned, and the first encoder position value corresponding to the first moment when the sensor starts to sense the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor ends to sense the edge of the target wafer are extracted based on the time-aligned position data. The difference between the second encoder position value and the first encoder position value is calculated to obtain the actual movement distance of the wafer scanning structure during the sensor sensing the target wafer; Calculate the time difference between the second moment and the first moment to obtain the actual sensing duration of the sensor on the target wafer; The actual travel distance is compared with the encoder standard travel range corresponding to the preset wafer standard thickness to obtain a first comparison result. The actual sensing time is compared with the sensor standard sensing time range corresponding to the preset wafer standard thickness to obtain a second comparison result. Based on the first comparison result and the second comparison result, it is determined whether the target wafer has a thickness abnormality. If the target wafer has a thickness anomaly, the anomaly type of the target wafer is detected based on the time-domain waveform characteristics of the sensing signal.

2. The wafer transport status detection method as described in claim 1, characterized in that, The calculation of the real-time absolute coordinate position of the wafer scanning structure based on the position timing data includes: The location time-series data is decoded and converted to obtain binary absolute location values; Based on the encoder's resolution parameters and the mechanical transmission ratio of the wafer scanning structure, the binary absolute position value is converted into the physical coordinate value of the wafer scanning structure; The physical coordinate values ​​are smoothed and filtered to obtain the real-time absolute coordinate position of the wafer scanning structure.

3. The wafer transport status detection method as described in claim 1, characterized in that, If, during a single scan, the sensor's sensing signal is detected to have both a rising edge and a falling edge, then the first encoder position value corresponding to the first moment when the sensor begins to sense the target wafer edge, and the second encoder position value corresponding to the second moment when the sensor ends to sense the target wafer edge, are extracted, including: The moment when the amplitude of the sensor's sensing signal first exceeds the effective threshold is recorded as the first moment, and the encoder position value corresponding to the first moment is extracted as the first encoder position value. The effective threshold is the minimum threshold for distinguishing between effective and invalid sensing signals. The moment when the amplitude of the sensor's sensing signal first becomes less than or equal to the effective threshold is recorded as the second moment, and the encoder position value corresponding to the second moment is extracted as the second encoder position value.

4. The wafer transport status detection method as described in claim 1, characterized in that, If, during a single scan, the sensor's sensing signal is detected to have at least two rising edges and two falling edges, then the first encoder position value corresponding to the first moment when the sensor begins to sense the target wafer edge and the second encoder position value corresponding to the second moment when the sensor ends to sense the target wafer edge are extracted, including: The moment when the amplitude of the sensor's sensing signal first exceeds the effective threshold is recorded as the first moment, and the encoder position value corresponding to the first moment is extracted as the first encoder position value. The effective threshold is the minimum threshold for distinguishing between effective and invalid sensing signals. The moment when the amplitude of the sensor's sensing signal is last less than or equal to the effective threshold is recorded as the second moment, and the encoder position value corresponding to the second moment is extracted as the second encoder position value.

5. The wafer transport status detection method as described in claim 1, characterized in that, The step of determining whether the target wafer has a thickness anomaly based on the first comparison result and the second comparison result includes: If the actual travel distance is greater than the upper limit of the encoder's standard travel range, and the actual sensing time is greater than the upper limit of the sensor's standard sensing time range, then the thickness of the target wafer is determined to be greater than the standard thickness. If the actual travel distance is less than the lower limit of the encoder's standard travel range, and the actual sensing time is less than the lower limit of the sensor's standard sensing time range, then the thickness of the target wafer is determined to be less than the standard thickness.

6. The wafer transport status detection method as described in claim 5, characterized in that, The time-domain waveform features include signal edge transition features and signal amplitude variation features; The detection of anomaly types in the target wafer based on the time-domain waveform characteristics of the sensed signal includes: In response to the target wafer's thickness being greater than the standard thickness, the target wafer is determined to be either an anomaly of multiple wafer overlap or a wafer warping anomaly based on the signal edge transition characteristics. In response to the target wafer's thickness being less than the standard thickness, the target wafer is determined to be either a thin-film anomaly or a wafer fragment anomaly based on the signal amplitude variation characteristics.

7. The wafer transport status detection method as described in claim 6, characterized in that, The edge transition characteristics include the slope of the rising edge of the sensing signal, the slope of the falling edge, and the total number of edge transitions. The method of distinguishing the target wafer as having multiple overlapping anomalies or wafer warping anomalies based on the signal edge transition characteristics includes: Calculate the absolute value of the rising edge slope and the absolute value of the falling edge slope of the sensing signal; If the total number of edge transitions is equal to 2N, then the target wafer is determined to have a multi-wafer overlap anomaly, where N is an integer greater than or equal to 2; If the total number of edge transitions is equal to 2, the absolute value of the rising edge slope is greater than the upper limit of the standard wafer edge slope range, and the absolute value of the falling edge slope is greater than the upper limit of the standard wafer edge slope range, then the target wafer is determined to have a wafer warping anomaly. If the total number of edge transitions is equal to 2, the absolute value of the rising edge slope is less than the lower limit of the standard wafer edge slope range, or the absolute value of the falling edge slope is less than the lower limit of the standard wafer edge slope range, then the target wafer is determined to have a wafer warping anomaly.

8. A wafer transport status detection device, characterized in that, include: The data acquisition unit is used to acquire the position timing data of the wafer scanning structure during the scanning of the target wafer and the sensing signals collected by the sensor. The position timing data is acquired by the encoder in the wafer scanning structure, and the sensor is set on the wafer scanning structure and moves with the wafer scanning structure. The data extraction unit is used to calculate the real-time absolute coordinate position of the wafer scanning structure based on the location time series data; The real-time absolute coordinate position and the timestamp information of the sensing signal are time-aligned, and the first encoder position value corresponding to the first moment when the sensor starts to sense the edge of the target wafer and the second encoder position value corresponding to the second moment when the sensor ends to sense the edge of the target wafer are extracted based on the time-aligned position data. The data calculation unit is used to calculate the difference between the position value of the second encoder and the position value of the first encoder to obtain the actual movement of the wafer scanning structure during the sensor sensing the target wafer; Calculate the time difference between the second moment and the first moment to obtain the actual sensing duration of the sensor on the target wafer; The first anomaly detection unit is used to compare the actual travel distance with the encoder standard travel distance range corresponding to the preset wafer standard thickness to obtain a first comparison result, compare the actual sensing time with the sensor standard sensing time range corresponding to the preset wafer standard thickness to obtain a second comparison result, and determine whether the target wafer has a thickness anomaly based on the first comparison result and the second comparison result. The second anomaly detection unit is used to detect the anomaly type of the target wafer based on the time-domain waveform characteristics of the sensing signal if the target wafer has a thickness anomaly.

9. A front-end module, characterized in that, The method includes a wafer cassette, a wafer picking structure, a wafer inspection station, a wafer scanning structure, and a controller; the wafer picking structure is used to pick up qualified wafers from the wafer inspection station and place them into the wafer cassette; the wafer scanning structure is used to inspect the wafers on the wafer inspection station; and the controller is used to execute the steps of the method as described in any one of claims 1 to 7.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 7.

Images