Camera synchronous triggering method, wafer detection system and computer program product

Abstract

The invention discloses a camera synchronous triggering method, a wafer detection system and a computer program product, and relates to the technical field of semiconductors. The method comprises the following steps: acquiring first target position information corresponding to an Nth target sampling time point of a scanning shaft in a motion table, wherein the motion table is used for bearing a wafer to be detected; on the basis of the first target position information, second target position information corresponding to the (N-1) th target sampling time point of the scanning axis and a corresponding target sampling time interval, calculating movement speed information of the scanning axis; based on the first target position information, the pixel size information and the second target position information, calculating to obtain a motion position deviation of the scanning axis; and on the basis of the movement position deviation, the pixel size information and the movement speed information, pulse triggering time of the time delay integral camera at the next moment is calculated, and a pulse triggering signal is output to the time delay integral camera when the pulse triggering time is reached. According to the embodiment of the invention, the synchronous triggering precision of the camera can be improved.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to a camera synchronization triggering method, a wafer detection system, and a computer program product. Background Art

[0002] Currently, most camera synchronization triggering devices in the semiconductor industry use scanning imaging. TDI (Time Delay Integration) line scan cameras are widely used in this industry. However, different processes have different performance requirements for inspection equipment, especially for graphic inspection equipment, which has even stricter inspection accuracy requirements, even at the level of hundreds of nanometers. This places very high demands on the image and motion stage's tracking. The triggering principle of existing TDI cameras is to set the corresponding line frequency of the TDI camera according to the speed of the motion stage to achieve TDI camera triggering. This method places very high demands on the uniformity of the motion stage's scanning axis speed. In theory, the scanning axis trigger interval must completely correspond to the pixel size to restore the true image one-to-one. However, if the speed uniformity is poor, the scanning axis trigger interval will be unstable, causing the generated image to be stretched or compressed, resulting in deviations in the positioning of detected defects.

[0003] There are two main approaches to TDI camera triggering technology: internal triggering and external triggering. However, internal triggering places very high demands on the speed uniformity of the motion stage's scanning axis, making it suitable only for process equipment without pattern detection or requiring low precision. External triggering, on the other hand, places high demands on the motion stage's drive controller and is also susceptible to position errors, hindering wafer inspection accuracy.

[0004] Based on this, the industry urgently needs a new camera synchronization triggering solution to effectively improve the current defect of TDI cameras in the scanning process, which has low synchronization triggering accuracy and cannot effectively guarantee wafer inspection accuracy. Summary of the Invention

[0005] The embodiments of the present application provide a camera synchronization triggering method, a wafer detection system and a computer program product, which can effectively improve the camera synchronization triggering accuracy, thereby effectively improving the wafer detection accuracy.

[0006] In a first aspect, an embodiment of the present application provides a camera synchronization triggering method, the camera synchronization triggering method comprising:

[0007] Obtaining first target position information of a scanning axis in a motion stage corresponding to an Nth target sampling time point, where the motion stage is used to carry a wafer to be measured, and N is a positive integer greater than or equal to 1;

[0008] Calculate the motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, where the target sampling time interval is the time interval between the Nth target sampling time point and the N-1th target sampling time point;

[0009] Calculating a motion position deviation of the scanning axis based on the first target position information, the pixel size information, and the second target position information;

[0010] Based on the motion position deviation, pixel size information and motion speed information, the pulse trigger time of the time delay integration camera at the next moment is calculated, and when the pulse trigger time is reached, a pulse trigger signal is output to the time delay integration camera.

[0011] In some possible implementations, calculating the motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval includes:

[0012] Calculating the difference between the first target position information and the second target position information to obtain position difference information;

[0013] The motion speed information is calculated based on the ratio between the position difference information and the target sampling time interval.

[0014] In some possible implementations, calculating the motion position deviation of the scanning axis based on the first target position information, the pixel size parameter, and the second target position information includes:

[0015] Calculating the sum of the second target position information and the pixel size information to obtain theoretical position information of the scanning axis;

[0016] The difference between the theoretical position information and the first target position information is calculated to obtain the motion position deviation.

[0017] In some possible implementations, calculating the next pulse trigger time of the time delay integration camera based on the motion position deviation, pixel size information, and motion speed information includes:

[0018] Calculate the sum of the motion position deviation and the pixel size information to obtain the corrected trigger position information;

[0019] The ratio between the trigger position information and the motion speed information is calculated to obtain the pulse trigger time.

[0020] In some possible implementations, after obtaining the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion stage, the camera synchronization triggering method further includes:

[0021] determining direction information of the time delay integration camera based on a positive or negative value of a difference between the first target position information and the second target position information;

[0022] When the pulse trigger time is reached, a pulse trigger signal is output to the time delay integration camera, including:

[0023] When the pulse trigger time is reached, a pulse trigger signal is output to the time delay integration camera based on the direction information.

[0024] In some possible implementations, before obtaining the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion stage, the camera synchronization triggering method further includes:

[0025] Obtaining a preset position compensation table, wherein the position compensation table includes a plurality of theoretical position information corresponding to a plurality of feature points, and a plurality of compensation information corresponding to the plurality of theoretical position information;

[0026] Before calculating the motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, the camera synchronization triggering method further includes:

[0027] Obtaining first initial position information of the scanning axis corresponding to the Nth target sampling time point and second initial position information corresponding to the N-1th target sampling time point;

[0028] Based on the position compensation table, the first initial position information is compensated to obtain the first target position information, and the second initial position information is compensated to obtain the second target position information.

[0029] In some possible implementations, compensating the first initial position information based on the position compensation table to obtain the first target position information, and compensating the second initial position information to obtain the second target position information includes:

[0030] Based on the position compensation table, first compensation information corresponding to the first initial position information and second compensation information corresponding to the second initial position information are obtained by performing piecewise interpolation processing on the plurality of feature points;

[0031] Based on the first compensation information, first target position information is obtained, and based on the second compensation information, second target position information is obtained.

[0032] In some possible implementations, based on the position compensation table, first compensation information corresponding to the first initial position information and second compensation information corresponding to the second initial position information are obtained by performing piecewise interpolation processing on multiple feature points, including:

[0033] Based on the position compensation table, a piecewise interpolation process is performed on the plurality of feature points by adopting a piecewise interpolation function relationship to obtain first compensation information and second compensation information;

[0034] The piecewise interpolation function relationships include:

[0035]

[0036] Among them, x is the initial position information to be compensated, F(x) is the compensation information corresponding to the initial position information x to be compensated, and x n is the theoretical position information of the nth feature point, x n+1 is the theoretical position information of the n+1th feature point, f(x n ) is the compensation information corresponding to the theoretical position information of the nth feature point, f(x n+1 ) is the compensation information corresponding to the theoretical position information of the n+1th feature point, x is located at x n to x n+1 within the range between.

[0037] In some possible implementations, the motion stage includes a drive controller that pre-stores a position compensation table. After obtaining first initial position information of the scanning axis corresponding to the Nth target sampling time point, the camera synchronization triggering method further includes:

[0038] The first initial position information is output to a driving controller in the motion stage, so that the driving controller compensates the first initial position information based on a position compensation table and drives the scanning axis to move according to the compensated first target position information.

[0039] Based on the same inventive concept, in a second aspect, an embodiment of the present application provides a wafer inspection system, the wafer inspection system including a motion stage, a processor, and a time delay integration camera;

[0040] The motion stage is used to carry the wafer to be tested, and the scanning axis in the motion stage is used to control the movement of the wafer to be tested so that the surface of the wafer to be tested passes through the scanning area of the time delay integration camera line by line;

[0041] The processor is communicatively connected to the motion stage and the time delay integration camera, respectively, and is configured to execute the camera synchronization triggering method as described in any of the aforementioned embodiments of the present application;

[0042] The time delay integration camera is used to scan the wafer to be tested under the control of the pulse trigger signal of the processor.

[0043] In some possible implementations, the motion stage further includes a position encoder;

[0044] The position encoder is used to collect the initial position information of the scanning axis according to a preset sampling period and transmit the initial position information of the scanning axis to the processor.

[0045] In some possible implementations, the motion stage further includes a drive controller, which pre-stores a position compensation table, wherein the position compensation table includes a plurality of theoretical position information corresponding to a plurality of feature points, and a plurality of compensation information corresponding to the plurality of theoretical position information;

[0046] The processor is further configured to transmit initial position information of the scanning axis to the drive controller;

[0047] The drive controller is used to receive initial position information, compensate the initial position information based on a position compensation table, and drive the scanning axis to move according to target position information obtained by compensation.

[0048] Based on the same inventive concept, in a third aspect, an embodiment of the present application provides a camera synchronization triggering device, the camera synchronization triggering device comprising:

[0049] A first acquisition module is configured to acquire first target position information corresponding to an Nth target sampling time point of a scanning axis in a motion stage, where the motion stage is configured to carry a wafer to be measured, and N is a positive integer greater than or equal to 1;

[0050] a first calculation module, configured to calculate motion speed information of the scanning axis based on the first target position information, second target position information corresponding to the scanning axis at the N-1th target sampling time point, and a corresponding target sampling time interval, where the target sampling time interval is the time interval between the Nth target sampling time point and the N-1th target sampling time point;

[0051] A second calculation module is used to calculate the motion position deviation of the scanning axis based on the first target position information, the pixel size information and the second target position information;

[0052] The third calculation module is used to calculate the pulse trigger time of the time delay integration camera at the next moment based on the motion position deviation, pixel size information and motion speed information, and output a pulse trigger signal to the time delay integration camera when the pulse trigger time is reached.

[0053] In a fourth aspect, an embodiment of the present application provides a camera synchronization trigger device, the camera synchronization trigger device comprising:

[0054] a processor and a memory storing computer program instructions;

[0055] When the processor executes the computer program instructions, the camera synchronization triggering method provided in any one of the above-mentioned embodiments of the present application is implemented.

[0056] In a fifth aspect, an embodiment of the present application provides a computer storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, a camera synchronization triggering method as provided in any one of the above-mentioned embodiments of the present application is implemented.

[0057] In a sixth aspect, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes a camera synchronization triggering method as provided in any one of the above-mentioned embodiments of the present application.

[0058] From the above description, it can be seen that a camera synchronization triggering method, a wafer detection system and a computer program product in an embodiment of the present application calculate the motion speed information of the scanning axis through the first target position information, the second target position information and the target sampling time interval. Then, the motion position deviation is calculated based on the first target position information, the pixel size information and the second target position information. Finally, based on the motion position deviation, the pixel size information and the motion speed information, the pulse trigger time of the time delay integration camera at the next moment is calculated. In the embodiment of the present application, the motion position deviation of the above-mentioned scanning axis is introduced into the calculation of the pulse trigger time of the TDI camera at the next moment. In this way, by flexibly adjusting the pulse trigger time interval, the TDI camera can be triggered in advance or delayed according to the motion position deviation, thereby effectively eliminating the position accumulation error, effectively improving the camera synchronization trigger accuracy, and thus fully improving the wafer detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0060] Figure 1 1 is a schematic diagram of the architecture of a camera synchronization triggering method in the related art provided by an embodiment of the present application;

[0061] Figure 2 1 is a schematic diagram of the architecture of a camera synchronization triggering method in the related art provided by another embodiment of the present application;

[0062] Figure 3 This is a flowchart of a camera synchronization triggering method provided by an embodiment of the present application;

[0063] Figure 4This is a schematic diagram of compensation positions provided by an embodiment of the present application;

[0064] Figure 5 1 is a schematic diagram of the architecture of a camera synchronization triggering method provided in an embodiment of the present application;

[0065] Figure 6 1 is a schematic structural diagram of a wafer inspection system provided in one embodiment of the present application;

[0066] Figure 7 is a structural diagram of a wafer inspection system provided by another embodiment of the present application;

[0067] Figure 8 This is a structural diagram of a camera synchronization triggering device provided in one embodiment of the present application;

[0068] Figure 9 2 is a schematic structural diagram of a camera synchronization trigger device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0069] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating the examples of the present application.

[0070] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements.

[0071] It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned. They should be regarded as exemplary. Their purpose is only to illustrate the feasibility of implementing the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0072] As mentioned in the background technology section, there are currently two main implementation schemes for TDI camera triggering technology, namely TDI internal triggering and TDI external triggering.

[0073] Specifically, if Figure 1 As shown in the figure, in the TDI internal triggering method, a PC (Personal Computer) serves as the host computer. The host computer issues speed commands to the drive controller in the motion platform, calculates the TDI line frequency based on the relationship between the motion platform speed and the camera pixel size, and sends the line frequency command to the TDI camera to achieve real-time image acquisition. However, this solution has very high requirements for speed uniformity and is only suitable for process equipment without pattern detection or with low precision requirements (micrometer level). Therefore, this solution has the disadvantage of poor TDI camera synchronization triggering and low detection precision requirements.

[0074] See below Figure 2 In TDI external triggering mode, the motor controller acquires the scan axis position from the position encoder on the motion stage and outputs a set of RS422 differential signals to the RS422 through its internal Position Event Generator (PEG). The RS422 converts these RS422 differential signals into the pulse and direction signals required by the TDI camera. These signals are then input to the camera through its external trigger interface, ultimately achieving synchronous triggering of the TDI camera and the scan axis.

[0075] However, the aforementioned DI external triggering solution places high demands on the performance of the drive controller in the motion stage. Furthermore, there is a potential for discrepancy between the position information provided by the position encoder and the wafer surface position. Therefore, this approach still cannot effectively achieve TDI synchronous triggering, and wafer inspection accuracy cannot be effectively guaranteed.

[0076] Therefore, the current TDI internal triggering method places very high demands on the uniformity of the device's scanning axis speed, making it only suitable for process equipment without pattern detection or with low precision requirements. Meanwhile, the TDI external triggering method places high demands on the driver controller performance and is also affected by position errors, which can hinder wafer inspection accuracy. Therefore, the industry urgently needs a new camera synchronization triggering solution to address the current TDI camera's low synchronization triggering accuracy during the scanning process, which results in insufficient wafer inspection accuracy.

[0077] In view of the above, in order to solve the problems of the prior art, the embodiments of the present application provide a camera synchronization triggering method, a wafer inspection system and a computer program product. It should be noted that the embodiments provided in this application are not intended to limit the scope of the disclosure of this application.

[0078] The following first introduces the camera synchronization triggering method provided in the embodiment of the present application.

[0079] Figure 3 A flowchart of a camera synchronization triggering method provided by an embodiment of the present application is shown. This camera synchronization triggering method is applied to a processor, such as an FPGA (Field-Programmable Gate Array) with a phase-locked loop (PLL) function, to achieve highly synchronized signal phase output.

[0080] like Figure 3 As shown, the camera synchronization triggering method includes the following steps:

[0081] S310, obtaining first target position information corresponding to the Nth target sampling time point of a scanning axis in a motion stage, where the motion stage is used to carry a wafer to be measured, and N is a positive integer greater than or equal to 1;

[0082] S320, calculating motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, where the target sampling time interval is the time interval between the Nth target sampling time point and the N-1th target sampling time point;

[0083] S330, calculating a motion position deviation of the scanning axis based on the first target position information, the pixel size information, and the second target position information;

[0084] S340 , calculating a pulse trigger time of the time delay integration camera at a next moment based on the motion position deviation, the pixel size information, and the motion speed information, and outputting a pulse trigger signal to the time delay integration camera when the pulse trigger time is reached.

[0085] From the above description, it can be seen that a camera synchronization triggering method of an embodiment of the present application calculates the motion speed information of the scanning axis through the first target position information, the second target position information and the target sampling time interval. Then, the motion position deviation is calculated based on the first target position information, the pixel size information and the second target position information. Finally, based on the motion position deviation, the pixel size information and the motion speed information, the pulse trigger time of the time delay integration camera at the next moment is calculated. In the embodiment of the present application, the motion position deviation of the above-mentioned scanning axis is introduced into the calculation of the pulse trigger time of the TDI camera at the next moment. In this way, by flexibly adjusting the pulse trigger time interval, the TDI camera can be triggered in advance or delayed according to the motion position deviation, thereby effectively eliminating the position accumulation error, effectively improving the camera synchronization trigger accuracy, and thus fully improving the wafer detection accuracy.

[0086] The specific implementation of the above steps 310 to 340 is described in detail below.

[0087] In S310 , the Nth target sampling point time may correspond to the Nth pulse triggering time point of the TDI camera.

[0088] In TDI camera scanning imaging, the motion stage is used to carry the wafer to be tested. The scanning axis in the motion stage is controlled by a motor and moves precisely according to the preset path and speed to ensure that the TDI camera can scan the wafer surface line by line and obtain high-quality images.

[0089] The motion stage is usually also equipped with a position encoder, which can be used to accurately measure and feedback the position information of the scanning axis in the motion stage. In this application, taking the linear motion of the scanning axis as an example, the position information fed back by the position encoder is in the form of a single coordinate (e.g., X coordinate).

[0090] In specific implementation, when obtaining the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion table, the initial position information output by the position encoder in the motion table at the Nth target sampling time point is received, and the above-mentioned first target position information is determined based on the initial position information.

[0091] It should be noted that the first target position information can be obtained by calibration based on the above-mentioned initial position information, or the first target position information can also be directly the initial position information, and this application does not make a strict limitation here.

[0092] In S320 , the second target position information corresponding to the N−1th target sampling time point of the scanning axis may be acquired in the previous data collection and stored in the processor.

[0093] The N-1th target sampling point time may correspond to the N-1th pulse triggering time point of the TDI camera.

[0094] The target sampling interval is the interval between the Nth target sampling time point and the N-1th target sampling time point. During the TDI camera's continuous triggering and scanning process, this target sampling interval may not be a fixed value due to factors such as the inability to achieve completely uniform scanning axis speed.

[0095] For example, the time interval between the first target sampling time point and the second target sampling time point is 0.015 ms, and the time interval between the second target sampling time point and the third target sampling time point is 0.013 ms.

[0096] In a specific implementation, after the first target position information is acquired, the movement speed information of the scanning axis is calculated based on the first target position information, the second target position information and the target sampling time interval.

[0097] For example, the displacement of the scanning axis is calculated based on the first target position information and the second target position information, and the motion position information is then calculated using the displacement and the target sampling time interval. The specific mathematical calculation method is not elaborated here. For example, if the actual motion of the scanning axis is considered to be non-uniform, a motion model or acceleration can be used to describe the motion speed of the scanning axis.

[0098] In some other examples, the first target position information, the second target position information or the target sampling time interval may be subjected to data preprocessing (eg, filtering or smoothing to reduce noise), and then the motion speed information may be calculated based on the preprocessed data.

[0099] It's important to note that during actual scan axis motion, the position encoder collects scan axis position information at a frequency of, for example, 500kHz. This 500kHz acquisition frequency is significantly greater than the frequency at which the first target position information is acquired. In other words, between two TDI camera triggers—that is, between the Nth target sampling time point and the N-1th target sampling time point—the position encoder may have collected scan axis position data many times.

[0100] As an optional embodiment, the motion speed information of the scanning axis is calculated based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, including:

[0101] Calculating the difference between the first target position information and the second target position information to obtain position difference information;

[0102] The motion speed information is calculated based on the ratio between the position difference information and the target sampling time interval.

[0103] In specific implementation, although the scanning axis of the motion stage cannot achieve completely uniform motion, its general motion situation can still be regarded as uniform motion to facilitate the rapid calculation of motion speed information.

[0104] Based on this, by calculating the difference between the first and second target position information, the position difference information of the scanning axis between the two pulse triggering moments is obtained. Then, by dividing the position difference information by the target sampling time interval, the motion speed information can be quickly calculated to achieve effective monitoring of the motion axis speed.

[0105] In this embodiment, the motion velocity information is calculated using a uniform scanning axis processing method. Compared to the complex velocity calculation method for non-uniform motion, the motion velocity information calculation method used in this embodiment is more direct and simple, and can quickly determine the motion velocity information during logical operations, effectively saving computational effort and eliminating the need for significant processor logic resources.

[0106] In S330, the pixel size information can be understood as the actual physical distance corresponding to each pixel, and this parameter can be pre-inputted by an external device (such as a host computer PC). In one example, the pixel size information is 250 nm.

[0107] It should be noted that, in combination with an actual TDI camera scanning method, when the scanning axis speed is completely uniform, the distance between the second target position information and the first target position information is one pixel size information.

[0108] However, since the actual movement of the scanning axis is affected by many factors such as the mechanical accuracy of the equipment and external environmental conditions, the distance between the second target position information and the first target position information is likely to deviate from the size of one pixel.

[0109] Based on this, in a specific implementation, logical operations can be performed on the first target position information, pixel size information, and second target position information using corresponding mathematical methods to calculate the motion position deviation of the scanning axis. This motion position deviation can be used to subsequently implement motion axis position tracking and compensation.

[0110] In some examples, before calculating the motion position deviation of the scanning axis, filtering or smoothing can be used to reduce the noise of the first target position information, the second target position information or the pixel size information, and then the processed data can be used to calculate the motion position deviation. This is not strictly limited here.

[0111] As an optional embodiment, calculating the motion position deviation of the scanning axis based on the first target position information, the pixel size parameter, and the second target position information includes:

[0112] Calculating the sum of the second target position information and the pixel size information to obtain theoretical position information of the scanning axis;

[0113] The difference between the theoretical position information and the first target position information is calculated to obtain the motion position deviation.

[0114] Specifically, if the scan axis reaches the second target position at N-1 target sampling time points, the theoretical position of the first target position at the next target sampling point is the second target position plus one pixel size. However, due to speed uniformity, the actual first target position at N target sampling time points may not be the theoretical position, but may deviate from it.

[0115] Based on this, in this embodiment, the sum of the second target position information and the pixel size information is first calculated to obtain the theoretical position information of the scanning axis. Next, the difference between the theoretical position information and the first target position information is calculated to obtain the motion position deviation of the scanning axis from the N-1th target sampling time point to the Nth target sampling time point.

[0116] In one example, for a pixel size of 250 nm, the interval between the first target position and the second target position is 249 nm. In this case, there is a 1 nm motion deviation between the 250 nm pixel size and the 249 nm interval. This indicates that the scan axis's motion speed is not completely uniform. Between two TDI camera triggers, the scan axis's position interval is less than one pixel size, resulting in a 1 nm motion deviation. This motion deviation can be used to adjust the next TDI camera trigger time.

[0117] In this embodiment, by performing a difference calculation based on the position interval between two adjacent trigger times and the theoretical pixel size information, the motion position deviation caused by the uneven motion speed of the scanning axis during this period can be quickly determined. This motion position deviation calculation method is simple and direct, eliminating the large amount of processor logic resources and processor performance requirements required by other complex processing methods.

[0118] In S340, the theoretical movement distance of the scanning axis between two consecutive trigger times of the TDI camera is one pixel. However, since the actual scanning axis movement speed is affected by various factors such as the mechanical accuracy of the equipment and external environmental conditions, movement position deviation may occur.

[0119] Based on this, in order to improve the row-by-row detection accuracy of the TDI camera on the wafer to be tested, after calculating the above-mentioned motion position deviation and the above-mentioned motion speed information respectively, the pulse trigger time of the time delay integration camera at the next moment is calculated based on the motion position deviation, pixel size information and motion speed information.

[0120] In one example, the position information after deviation compensation is calculated based on the motion position deviation and pixel size information. The motion time required for the scanning axis is then calculated based on this position information and the motion speed information. The motion position deviation can be positive or negative. If it is positive, the position needs to be increased based on the pixel size information. If it is negative, the position needs to be decreased based on the pixel size information to obtain the corrected trigger position information.

[0121] It should be noted that the specific position increase or decrease value can be determined according to the size of the motion position deviation, or can also be determined by a preset fixed increase or decrease value, which is not strictly limited here.

[0122] Next, after obtaining the corrected trigger position information based on the motion position deviation, assuming that the subsequent scanning axis continues to move according to the motion speed information, the corrected trigger position information is divided by the motion speed information to obtain the pulse trigger time of the time delay integration camera at the next moment.

[0123] Alternatively, the motion speed information of the scanning axis in the next period can be predicted by combining multiple motion speed information from earlier times through establishing a motion model, and then the corrected trigger position information is divided by the predicted motion speed information to obtain the pulse trigger time of the time delay integration camera at the next moment. This application does not make strict restrictions here.

[0124] Finally, once the next pulse trigger time is calculated, the processor uses a high-precision timer for timing and real-time monitoring. When the pulse trigger time is reached, it outputs a pulse trigger signal to the TDI external trigger interface provided by the time delay integration camera. This pulse trigger signal is an electrical signal that controls the exposure of the TDI camera. When the pulse trigger signal reaches the TDI camera, the camera begins exposure and captures an image of the corresponding area.

[0125] In this step, when calculating the pulse trigger time of the TDI camera at the next moment, the motion position deviation generated in the previous trigger time interval is compensated. By flexibly adjusting the pulse trigger time interval, the TDI camera can be triggered early or late according to the motion position deviation, thereby ensuring that the exposure of the TDI camera is precisely synchronized with the movement of the scanning axis.

[0126] In this way, the gradual accumulation of motion position deviations under multiple trigger time intervals is effectively avoided, which leads to large deviations in the TDI camera scanning, thereby causing the image generated by the imaging of the wafer to be tested to be stretched or compressed, resulting in large deviations in the detected defect positioning.

[0127] As an optional embodiment, the pulse triggering time of the time delay integration camera at the next moment is calculated based on the motion position deviation, pixel size information, and motion speed information, including:

[0128] Calculate the sum of the motion position deviation and the pixel size information to obtain the corrected trigger position information;

[0129] The ratio between the trigger position information and the motion speed information is calculated to obtain the pulse trigger time.

[0130] This embodiment provides a concise and efficient method for calculating the pulse trigger time. Specifically, the corrected trigger position information is obtained by directly adding the motion position deviation to the pixel size information. Furthermore, considering that the scanning axis typically has a small rate of change in speed during motion, it is assumed that the scanning axis continues to move at the same speed information as the previous phase in the next phase. Finally, the corrected trigger position information is divided by the motion speed information to quickly and efficiently calculate the next pulse trigger time of the time delay integration camera.

[0131] In one example, the pixel size is 250nm, the position deviation is 1nm, and the scanning axis's speed in the previous stage is 500mm / s, or 5×10^8nm / s. The resulting pulse trigger time is calculated as [(250+1) / 5×10^8] seconds. This allows for immediate compensation for the position deviation during the previous trigger interval, effectively eliminating accumulated position errors and improving position trigger accuracy.

[0132] In this embodiment, by directly adding the motion position deviation to the pixel size information, the corrected trigger position information can be quickly obtained. The pulse trigger time is then calculated by assuming that the scan axis continues to move at the same speed as the previous phase in the next phase. This simple and direct method for calculating the pulse trigger time eliminates the significant processor resource usage and performance requirements associated with other complex processing methods.

[0133] As an optional embodiment, after obtaining the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion stage, the camera synchronization triggering method further includes:

[0134] determining direction information of the time delay integration camera based on a positive or negative value of a difference between the first target position information and the second target position information;

[0135] When the pulse trigger time is reached, a pulse trigger signal is output to the time delay integration camera, including:

[0136] When the pulse trigger time is reached, a pulse trigger signal is output to the time delay integration camera based on the direction information.

[0137] In this embodiment, to ensure that the exposure of the TDI camera is consistent with the movement direction of the motion stage, the direction information of the time delay integration camera is also determined to facilitate accurate image acquisition. This direction information of the time delay integration camera can be used to determine the accumulation direction of the image data.

[0138] In a specific implementation, the sign of the difference between the first target position information and the second target position information is calculated. If the position difference is positive, the TDI camera's scanning direction is determined to be positive. If the position difference is negative, the TDI camera's scanning direction is determined to be negative. Next, when the pulse trigger time is reached, the polarity of the pulse signal is adjusted based on the direction information, and the direction-corrected pulse trigger signal is output to the time delay integration camera.

[0139] In this way, the exposure of the TDI camera can be effectively ensured to be consistent with the movement direction of the motion stage, so that the exposure signal of the TDI camera can be correctly accumulated, thereby improving the wafer image acquisition and detection accuracy and avoiding image blur or misalignment caused by incorrect direction.

[0140] As an optional embodiment, before obtaining the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion stage, the camera synchronization triggering method further includes:

[0141] Obtaining a preset position compensation table, wherein the position compensation table includes a plurality of theoretical position information corresponding to a plurality of feature points, and a plurality of compensation information corresponding to the plurality of theoretical position information;

[0142] Before calculating the motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, the camera synchronization triggering method further includes:

[0143] Obtaining first initial position information of the scanning axis corresponding to the Nth target sampling time point and second initial position information corresponding to the N-1th target sampling time point;

[0144] Based on the position compensation table, the first initial position information is compensated to obtain the first target position information, and the second initial position information is compensated to obtain the second target position information.

[0145] The actual position of a motion stage's scanning axis is typically sampled using a position encoder within the stage. However, due to mechanical errors and component wear within the stage's transmission system, and the limited resolution of the position encoder, the position reported by the encoder may differ from the actual position. Inaccurate position information collected initially can affect the accuracy of subsequent pulse trigger timing calculations, thereby compromising camera image quality.

[0146] Therefore, in this embodiment, a preset position compensation table is obtained in advance to compensate for the position information fed back by the position encoder. In one example, in the preparation stage of the early compensation table, for example Figure 4 As shown, a wafer standard film including multiple feature points is photographed by a camera to obtain the actual position information (x1, y1), (x2, y2) ... (xn, yn) of the feature points in the standard film by optical detection means.

[0147] In addition, the moving table carries the wafer standard and controls the scanning axis to move. The position encoder collects the scanning axis information at this stage, combines the coordinate information collected by the scanning axis and the theoretical position information (x'1, y'1), (x'2, y'2)...(x'n, y'n) of the characteristic points of the standard film according to theoretical calculation.

[0148] By comparing the above-mentioned actual position information (x1, y1), (x2, y2)…(xn, yn) and the theoretical position information (x'1, y'1), (x'2, y'2)…(x'n, y'n), and calculating the coordinate difference between the actual position information and the theoretical position information, multiple error values (△x1, △y1), (△x2, △y2)…(△xn, △yn) corresponding to multiple theoretical position information can be calculated.

[0149] In this way, based on the plurality of theoretical position information corresponding to the plurality of feature points and the plurality of compensation information corresponding to the plurality of theoretical position information, the position compensation table is constructed and sent to the processor in advance through the host computer.

[0150] It should be noted that multiple compensation information can be, for example, multiple error values (△x1, △y1), (△x2, △y2)…(△xn, △yn) corresponding to multiple theoretical position information, or the actual position information (x1, y1), (x2, y2)…(xn, yn) of the feature points in the standard film measured by the aforementioned optical detection means. This application does not impose strict restrictions here.

[0151] It should also be noted that the above method for obtaining the position compensation table is merely an example. In other possible embodiments, taking into account the linear motion of the scanning axis, the actual position information of multiple feature points on the standard film measured by optical detection is x1, x2, ..., xn, and the theoretical position information of the multiple feature points is x'1, x'2, ..., x'n. By calculating the coordinate difference between the actual position information and the theoretical position information, the multiple error values corresponding to the multiple theoretical position information are obtained as △x1, △x2, ..., △xn.

[0152] In this case, the above-mentioned multiple compensation information can be multiple error values △x1, △x2, ..., △xn, or can be actual position information x1, x2, ..., xn of multiple feature points, which is not strictly limited here.

[0153] After obtaining the position compensation table, after obtaining the first initial position information sampled by the position encoder, the first initial position information can be compensated using the position compensation table to obtain the first target position information after position calibration. Furthermore, after obtaining the second initial position information sampled by the position encoder, the second initial position information can be compensated using the position compensation table to obtain the second target position information after position calibration.

[0154] In this way, the position information collected by the position encoder is compensated through the above-mentioned position compensation table, so that the position information used in subsequent calculations is more accurate, which helps to improve the synchronization of TDI camera triggering, thereby helping to improve wafer detection accuracy.

[0155] As an optional embodiment, based on the position compensation table, compensating the first initial position information to obtain the first target position information, and compensating the second initial position information to obtain the second target position information, includes:

[0156] Based on the position compensation table, first compensation information corresponding to the first initial position information and second compensation information corresponding to the second initial position information are obtained by performing piecewise interpolation processing on the plurality of feature points;

[0157] Based on the first compensation information, first target position information is obtained, and based on the second compensation information, second target position information is obtained.

[0158] In specific implementations, compensation information corresponding to the initial position information is obtained by performing piecewise interpolation on multiple feature points. This piecewise interpolation method can be linear or nonlinear. The choice of piecewise interpolation method can be determined based on the specific needs of the actual application and is not strictly limited here. During piecewise interpolation, interpolation is performed within the theoretical position information interval of two adjacent feature points, which helps to improve the accuracy of the compensation information corresponding to the determined initial position information and the overall position compensation efficiency.

[0159] After determining the first compensation information corresponding to the first initial position information, the first target position information is obtained based on the first compensation information. After determining the second compensation information corresponding to the second initial position information, the second target position information is obtained based on the second compensation information.

[0160] In one example, using multiple compensation information as multiple error values corresponding to multiple feature points, a first error value corresponding to the first initial position information and a second error value corresponding to the second initial position information are obtained by performing piecewise interpolation on the multiple feature points. The first target position information is obtained by calculating the sum of the first error value and the first initial position information, and the second target position information is obtained by calculating the sum of the second compensation information and the second initial position information.

[0161] In another example, taking multiple compensation information as multiple actual position information corresponding to multiple feature points as an example, by performing segmented interpolation processing on the multiple feature points, the first actual position information corresponding to the first initial position information and the second actual position information corresponding to the second initial position information are obtained. The first actual position information can be used as the first target position information, and the second actual position information can be used as the second target position information.

[0162] In this embodiment, segmented interpolation of multiple feature points based on the position compensation table effectively improves the accuracy of the compensation information corresponding to the determined initial position information and the overall position compensation efficiency. This facilitates more efficient position information correction, thereby improving the overall TDI camera triggering efficiency.

[0163] It should be noted that the compensation time of the first initial position information may be different from the compensation time of the second initial position information. In view of the actual order of collecting the initial position information, the compensation time of the second initial position information may be earlier than the compensation time of the first initial position information.

[0164] Furthermore, in other feasible embodiments, when compensating the initial position information based on the position compensation table, an actual corrected position curve for the feature points can also be constructed using the position compensation table. For example, the actual corrected position curve can be drawn based on the actual position information corresponding to multiple feature points. Thus, by mapping the initial position information to the actual corrected position curve, the corresponding target position information can be directly obtained.

[0165] As an optional embodiment, based on the position compensation table, first compensation information corresponding to the first initial position information and second compensation information corresponding to the second initial position information are obtained by performing piecewise interpolation processing on multiple feature points, including:

[0166] Based on the position compensation table, a piecewise interpolation process is performed on the plurality of feature points by adopting a piecewise interpolation function relationship to obtain first compensation information and second compensation information;

[0167] The piecewise interpolation function relationships include:

[0168]

[0169] In formula (1), x is the initial position information to be compensated, F(x) is the compensation information corresponding to the initial position information x to be compensated, and x n is the theoretical position information of the nth feature point, x n+1 is the theoretical position information of the n+1th feature point, f(x n ) is the compensation information corresponding to the theoretical position information of the nth feature point, f(x n+1 ) is the compensation information corresponding to the theoretical position information of the n+1th feature point, x is located at x n to x n+1 within the range between.

[0170] In this embodiment, based on the aforementioned piecewise interpolation function relationship, a specific piecewise interpolation calculation method is provided, which can efficiently and accurately determine the compensation information corresponding to the initial position information. In the aforementioned piecewise interpolation function relationship, F(x) is the compensation information corresponding to the initial position information x to be compensated. This compensation information can be, for example, the aforementioned error value or the aforementioned actual position information. The initial position information x to be compensated can be, for example, the aforementioned first initial position information or the second initial position information.

[0171] In a specific example, taking the compensation information as the aforementioned error value, there are adjacent first and second feature points among the multiple feature points, and the theoretical position information x of the first feature point is n For example 1, the theoretical position information x of the second feature point n+1 For example, the initial position information x to be compensated is 1.5. The error value f(x n) is 0.1, the error value of the second feature point f(x n+1 ) is 0.9.

[0172] Substituting the above parameter values into equation (1), the error value F(x) corresponding to the initial position information x to be compensated is calculated to be 0.5. Thus, after using the above piecewise interpolation function to calculate the error value corresponding to the initial position information x, the initial position information 1.5 is added to the error value 0.5 to obtain the target position information corresponding to the initial position information, which is 2.

[0173] In another specific example, taking the compensation information as the aforementioned actual position information, there are adjacent first and second feature points among the multiple feature points, and the theoretical position information x of the first feature point is n For example 1, the theoretical position information x of the second feature point n+1 For example, the initial position information x to be compensated is 1.5. The actual position information f(x n ) is 1.1, the actual position information of the second feature point f(x n+1 ) is 2.9.

[0174] Substituting the above parameter values into formula (1), the actual position information F(x) corresponding to the initial position information x to be compensated is calculated to be 2. In this way, after the actual position information corresponding to the initial position information x is calculated using the above piecewise interpolation function, the actual position information is used as the target position information, and the target position information corresponding to the initial position information is obtained as 2.

[0175] As an optional embodiment, the motion stage includes a drive controller that pre-stores a position compensation table; after obtaining first initial position information of the scanning axis corresponding to the Nth target sampling time point, the camera synchronization triggering method further includes:

[0176] The first initial position information is output to a driving controller in the motion stage, so that the driving controller compensates the first initial position information based on a position compensation table and drives the scanning axis to move according to the compensated first target position information.

[0177] In practical motion control, the motion stage includes a drive controller. As its core component, the drive controller receives scan axis position information from a position encoder and generates drive signals based on an internal control algorithm to control and adjust the scan axis's motion. Therefore, the drive controller's ability to achieve precise drive control is crucial for synchronizing the scan axis's motion position with the TDI camera's pulse trigger position.

[0178] Based on this, in this embodiment, the aforementioned position compensation table is also provided to the drive controller. After the processor receives the first initial position information fed back by the position encoder, the processor directly outputs this first initial position information to the drive controller. The drive controller compensates the first initial position information according to the internally stored position compensation table and, based on the compensated first target position information, performs more precise drive control of the scan axis.

[0179] In this embodiment, the drive controller continuously adjusts the scan axis position through position feedback and position compensation, thereby helping the final scan axis trajectory approach the ideal position trajectory. This embodiment effectively reduces the impact of mechanical errors, environmental factors, and measurement errors on position feedback, improves the positioning accuracy of the scan axis position information, and further enhances the synchronization between the scan axis motion position and the TDI camera pulse trigger position.

[0180] It should be understood that the above-mentioned specific compensation method for the initial position information based on the position compensation table can be found in the corresponding description part of the aforementioned embodiment. For the sake of brevity, this application will not go into details here.

[0181] It should be added that, in combination with actual application scenarios, the data output interface of the position encoder is connected to the processor, and the position encoder feeds back the collected initial position information to the processor through its data output interface, and the processor then forwards the received initial position information to the drive controller.

[0182] In this way, for a position encoder that only includes a single data output interface, the position encoder no longer needs to provide an additional interface to the drive controller, and can also achieve position feedback to the drive controller, thereby reducing the replacement cost caused by upgrading the position encoder in the motion table.

[0183] In addition, in some possible embodiments, the processor may also send the compensated first target position information to the drive controller to avoid the compensation calculation workload within the drive controller.

[0184] To facilitate understanding of the camera synchronization triggering method provided by the above embodiment, the above method is described below using a specific scenario embodiment. Figure 5 Schematic diagram of the camera synchronization triggering method provided in one embodiment of the present application.

[0185] The application scenario of this embodiment may be: a scanning detection scenario of a wafer to be tested.

[0186] like Figure 5As shown, taking an FPGA with a phase-locked loop (PLL) function as an example, the host computer 1 can be used to provide pixel size information 6 and a position compensation table 7 to the FPGA 5. The motion stage 2 is used to support the wafer to be tested. The motion stage 2 includes a scanning axis, a position encoder 3, and a drive controller 4. The position encoder 3 is used to collect the initial position information of the scanning axis and transmit this initial position information to the FPGA 5. Its sampling period is, for example, 500K. The drive controller 4 is used to drive and control the movement of the scanning axis.

[0187] FPGA 5 also includes a data collector 8, segmented interpolation compensation 9, motion speed information 10, pulse trigger time 11, and pulse trigger signal 12. These components can be considered functional modules implemented by the programming logic within FPGA 5. These functional modules are described below using a specific example.

[0188] In a specific example, the position encoder 3 transmits the first initial position information collected at the Nth target sampling time point to the data collector 8 in the FPGA 5. After receiving the first initial position information, the data collector 8 transmits the first initial position information to the segmented interpolation compensation 9 and the drive controller 4 in the motion stage 2. The drive controller 4 stores a position compensation table internally, which can compensate for the first initial position information, thereby achieving precise positioning of the scanning axis.

[0189] After receiving the first initial position information, the segmented interpolation compensation 9 calls the position compensation table 7 to perform segmented interpolation processing to obtain the first compensation information corresponding to the first initial position information. Then, based on the first compensation information, it determines the corrected first target position information. Then, it transmits the first target position information to the motion speed information 10.

[0190] After receiving the first target position information, the motion speed information processor 10 calculates the difference between the first target position information and the second target position information corresponding to the N-1th target sampling time point to obtain position difference information. The motion speed information is then calculated based on the ratio between the position difference signal and the target sampling time interval. The motion speed information, the first target position information, and the second target position information are then transmitted to the pulse trigger time processor 11.

[0191] The second target position information may be compensated based on the second initial position information collected at the N-1th target sampling time point. The target sampling interval is the time interval between the Nth target sampling time point and the N-1th target sampling time point. The N-1th target sampling time point may correspond to the N-1th pulse trigger time point of the TDI camera 13, and the Nth target sampling time point may correspond to the Nth pulse trigger time point of the TDI camera 13.

[0192] The pulse trigger timer 11 calculates the theoretical position of the scanning axis by summing the second target position information and the pixel size information. It then calculates the difference between the theoretical position information and the first target position information to obtain the motion position deviation. Next, it calculates the sum of the motion position deviation and the pixel size information to obtain the corrected trigger position information. The ratio of this corrected trigger position information to the motion speed information is then calculated to determine the next pulse trigger time for the TDI camera 13. Furthermore, the pulse trigger timer 11 determines the direction of the TDI camera 13 based on the sign of the difference between the first and second target position information.

[0193] Pulse trigger timer 11 transmits the calculated pulse trigger time and direction information to pulse trigger signal 12. Pulse trigger signal 12 performs timing. When the pulse trigger time is reached, it outputs a pulse trigger signal to TDI camera 13 via the TDI external trigger interface provided by TDI camera 13, thereby achieving high synchronization between the triggering of TDI camera 13 and the movement of the scanning axis.

[0194] The camera triggering method provided in this scenario embodiment is a position-triggered TDI scanning method. In this embodiment, the trigger position information is corrected by calculating the motion position deviation. The corrected trigger position information and motion speed information are then used to calculate the next pulse trigger time for the TDI camera. By flexibly adjusting the pulse trigger interval, the TDI camera can be triggered early or late based on the motion position deviation, effectively eliminating cumulative position errors and improving position triggering accuracy. This helps ensure precise synchronization between the TDI camera's exposure and the movement of the scanning axis, thereby significantly enhancing wafer inspection accuracy.

[0195] On the other hand, by setting a position compensation table within the FPGA, the FPGA can compensate for the initial position information collected by the position encoder based on this position compensation table, making the position information used in subsequent calculations more accurate, helping to improve the synchronization of TDI camera triggering and, therefore, wafer inspection accuracy. By performing position compensation within the drive controller, the drive controller can adjust the scan axis motion position in real time based on the compensated position information, thereby improving the positioning accuracy of the scan axis position information. This can further improve the synchronization of the scan axis motion position and the TDI camera pulse trigger position, which also helps to fully improve wafer inspection accuracy.

[0196] In addition, this scenario embodiment uses an FPGA with a phase-locked loop function. The FPGA can keep the phase of the output signal consistent with the phase of the input signal based on the phase-locked loop, and can achieve highly synchronized signal phase output, which also helps to ensure the precise synchronization of the exposure of the TDI camera and the movement of the scanning axis.

[0197] Based on the same inventive concept, the embodiment of the present application also provides a wafer detection system, such as Figure 6 As shown, Figure 6 1 is a schematic structural diagram of a wafer inspection system 100 provided in one embodiment of the present application;

[0198] The wafer inspection system 100 includes a motion stage 10, a processor 20 and a time delay integration camera 30;

[0199] The motion stage 10 is used to carry the wafer to be tested, and the scanning axis in the motion stage 10 is used to control the movement of the wafer to be tested so that the surface of the wafer to be tested passes through the scanning area of the time delay integration camera 30 line by line;

[0200] The processor 20 is in communication with the motion stage 10 and the time delay integration camera 30, respectively, and is configured to execute the camera synchronization triggering method as described in any of the aforementioned embodiments of the present application;

[0201] The time delay integration camera 30 / TDI camera 30 is used to scan the wafer to be tested under the control of the pulse trigger signal of the processor 20 .

[0202] It should be understood that the wafer detection system 100 provided in the embodiment of the present application has the function of implementing each step in the phase synchronization triggering method provided in the above method embodiment and can achieve its corresponding technical effects. For the sake of concise description, it will not be repeated here.

[0203] It should be noted that the wafer inspection system 100 provided in the embodiment of the present application may include more than one TDI camera 30. In other words, the processor 20 has multiple external pulse signal output interfaces, which can be used to trigger multiple TDI cameras 30.

[0204] In one example, the processor 20 can simultaneously trigger three TDI cameras 30 with pulse signals, thereby significantly improving the utilization of the processor 20 resources in a wafer inspection environment. This multi-output processor 20 helps reduce the actual cost of wafer inspection.

[0205] As an optional embodiment, the motion stage 10 further includes a position encoder;

[0206] The position encoder is used to collect the initial position information of the scanning axis according to a preset sampling period, and transmit the initial position information of the scanning axis to the processor 20.

[0207] In one example, the position encoder may be a SinCos type or other types, and the preset sampling period corresponding to the position encoder is, for example, 500K.

[0208] As an optional embodiment, the preset sampling period of the position encoder is greater than the clock period inside the processor 20. In this way, the data acquisition frequency of the position encoder is much lower than the internal clock signal frequency of the processor 20, which also helps to improve the synchronization triggering accuracy.

[0209] As an optional embodiment, the motion stage 10 further includes a drive controller, which pre-stores a position compensation table, wherein the position compensation table includes a plurality of theoretical position information corresponding to a plurality of feature points, and a plurality of compensation information corresponding to the plurality of theoretical position information;

[0210] The processor 20 is further configured to transmit the initial position information of the scanning axis to the drive controller;

[0211] The drive controller is used to receive initial position information, compensate the initial position information based on a position compensation table, and drive the scanning axis to move according to target position information obtained by compensation.

[0212] As an optional embodiment, the processor 20 includes a field programmable gate array with a phase-locked loop function.

[0213] In this embodiment, an FPGA with a phase-locked loop (PLL) function is used to ensure trigger accuracy from a hardware perspective. Leveraging the PLL's phase tracking capability, the FPGA uses the output signal of an object velocity sensor (such as a position encoder) as the PLL's reference input. A phase detector (PD) detects the phase difference between the velocity signal and the charge transfer clock. A loop filter (LF) then adjusts the output frequency of the voltage-controlled oscillator (VCO). Ultimately, this achieves highly synchronized signal phase output, helping to ensure precise synchronization between the TDI camera's exposure and the movement of the scanning axis.

[0214] As an optional embodiment, Figure 7 As shown, Figure 7 FIG2 is a schematic structural diagram of a wafer inspection system 100 provided in another embodiment of the present application; the wafer inspection system 100 further includes a host computer 40; the host computer 40 is communicatively connected to the processor 20 and is configured to transmit the position compensation table and / or pixel size information to the processor 20. The host computer 40 is, for example, a personal computer (PC).

[0215] Based on the camera synchronization triggering method provided in the above embodiment, for the same inventive concept, the present application also provides a camera synchronization triggering device corresponding to the above camera synchronization triggering method. Figure 8 A detailed introduction to the camera synchronization trigger device.

[0216] Figure 8A schematic structural diagram of a camera synchronization triggering device provided in one embodiment of the present application is shown. Figure 3 The camera synchronization triggering device 800 shown includes:

[0217] A first acquisition module 810 is configured to acquire first target position information corresponding to the Nth target sampling time point of a scanning axis in a motion stage, where the motion stage is configured to carry a wafer to be measured, and N is a positive integer greater than or equal to 1;

[0218] A first calculation module 820 is configured to calculate the motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, where the target sampling time interval is the time interval between the Nth target sampling time point and the N-1th target sampling time point;

[0219] A second calculation module 830 is configured to calculate a motion position deviation of the scanning axis based on the first target position information, the pixel size information, and the second target position information;

[0220] The third calculation module 840 is used to calculate the pulse trigger time of the time delay integration camera at the next moment based on the motion position deviation, pixel size information and motion speed information, and output a pulse trigger signal to the time delay integration camera when the pulse trigger time is reached.

[0221] It should be understood that the camera synchronization trigger device provided in the embodiment of the present application has the function of implementing each step in the phase synchronization trigger method provided in the above method embodiment and can achieve its corresponding technical effects. For the sake of concise description, it will not be repeated here.

[0222] Based on the camera synchronization triggering method provided in the above embodiment, for the same inventive concept, the present application also provides a wafer detection device corresponding to the above camera synchronization triggering method. Figure 9 This section provides a detailed introduction to camera synchronization triggering devices.

[0223] See below Figure 9 , Figure 9 2 is a schematic structural diagram of a camera synchronization trigger device provided in one embodiment of the present application.

[0224] The camera synchronization triggering device may include a processor 901 and a memory 902 storing computer program instructions.

[0225] Specifically, the processor 901 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0226] The memory 902 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 902 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 902 may include removable or non-removable (or fixed) media. Where appropriate, the memory 902 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 902 is a non-volatile solid-state memory.

[0227] The memory may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical or other physical / tangible memory storage devices. Thus, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0228] The processor 901 reads and executes computer program instructions stored in the memory 902 to implement any one of the camera synchronization triggering methods in the above embodiments.

[0229] In one example, the data camera synchronization trigger device may further include a communication interface 903 and a bus 910. Figure 9 As shown, the processor 901 , the memory 902 , and the communication interface 903 are connected via a bus 910 and communicate with each other.

[0230] The communication interface 903 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0231] Bus 910 includes hardware, software, or both that couples components of the camera synchronization trigger device to each other. By way of example, and not limitation, a bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industrial Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, bus 910 may include one or more buses. Although the embodiments of the present application describe and illustrate specific buses, the present application contemplates any suitable bus or interconnect.

[0232] The camera synchronization triggering device executes the camera synchronization triggering method in the embodiment of the present application, thereby realizing the camera synchronization triggering method described in the embodiment of the present application.

[0233] In addition, in conjunction with the camera synchronization triggering method in the above embodiments, embodiments of the present application may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any of the camera synchronization triggering methods in the above embodiments is implemented.

[0234] Based on the camera synchronization triggering method in the above-mentioned embodiment, an embodiment of the present application provides a computer program product. When the instructions in the computer program product are executed by the processor of an electronic device, the electronic device executes the camera synchronization triggering method provided in any one of the above-mentioned embodiments of the present application.

[0235] It should be understood that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated. Those skilled in the art can make various changes, modifications, and additions, or change the order of the steps after understanding the spirit of the present application.

[0236] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0237] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps. In other words, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0238] Aspects of the present disclosure have been described above with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It is also understood that each box in the block diagram and / or flowchart and the combination of the boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0239] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. A camera synchronization triggering method, characterized in that: The method comprises: Obtaining first target position information of a scanning axis in a motion stage corresponding to an Nth target sampling time point, wherein the motion stage is used to carry a wafer to be measured, where N is a positive integer greater than or equal to 1; Calculate the motion speed information of the scanning axis based on the first target position information, the second target position information of the scanning axis corresponding to the N-1th target sampling time point, and the corresponding target sampling time interval, where the target sampling time interval is the time interval between the Nth target sampling time point and the N-1th target sampling time point; Calculating a motion position deviation of the scanning axis based on the first target position information, the pixel size information, and the second target position information; Based on the motion position deviation, the pixel size information, and the motion speed information, a pulse trigger time of a time delay integration camera at a next moment is calculated, and when the pulse trigger time is reached, a pulse trigger signal is output to the time delay integration camera.

2. The method according to claim 1, characterized in that The calculating the movement speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval includes: Calculating a difference between the first target position information and the second target position information to obtain position difference information; The motion speed information is calculated based on the ratio between the position difference information and the target sampling time interval.

3. The method according to claim 1, characterized in that The calculating the motion position deviation of the scanning axis based on the first target position information, the pixel size parameter, and the second target position information includes: Calculating a sum of the second target position information and the pixel size information to obtain theoretical position information of the scanning axis; The difference between the theoretical position information and the first target position information is calculated to obtain the motion position deviation.

4. The method according to claim 1, wherein The calculating the pulse triggering time of the time delay integration camera at the next moment based on the motion position deviation, the pixel size information, and the motion speed information includes: Calculating a sum of the motion position deviation and the pixel size information to obtain corrected trigger position information; The ratio between the trigger position information and the motion speed information is calculated to obtain the pulse trigger time.

5. The method according to claim 1, characterized in that After acquiring the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion stage, the method further includes: determining direction information of the time delay integration camera based on a positive or negative value of a difference between the first target position information and the second target position information; When the pulse trigger time is reached, outputting a pulse trigger signal to the time delay integration camera includes: When the pulse trigger time is reached, the pulse trigger signal is output to the time delay integration camera based on the direction information.

6. The method according to claim 1, characterized in that Before acquiring the first target position information corresponding to the Nth target sampling time point of the scanning axis in the motion stage, the method further includes: Obtaining a preset position compensation table, wherein the position compensation table includes a plurality of theoretical position information corresponding to a plurality of feature points and a plurality of compensation information corresponding to the plurality of theoretical position information; Before calculating the motion speed information of the scanning axis based on the first target position information, the second target position information corresponding to the scanning axis at the N-1th target sampling time point, and the corresponding target sampling time interval, the method further includes: Acquire first initial position information of the scanning axis corresponding to the Nth target sampling time point and second initial position information corresponding to the N-1th target sampling time point; Based on the position compensation table, the first initial position information is compensated to obtain the first target position information, and the second initial position information is compensated to obtain the second target position information.

7. The method according to claim 6, characterized in that The compensating the first initial position information based on the position compensation table to obtain the first target position information, and compensating the second initial position information to obtain the second target position information, includes: Based on the position compensation table, obtaining first compensation information corresponding to the first initial position information and second compensation information corresponding to the second initial position information by performing piecewise interpolation processing on the multiple feature points; The first target position information is obtained based on the first compensation information, and the second target position information is obtained based on the second compensation information.

8. The method according to claim 7, characterized in that The obtaining, based on the position compensation table, first compensation information corresponding to the first initial position information and second compensation information corresponding to the second initial position information by performing piecewise interpolation processing on the plurality of feature points, includes: Based on the position compensation table, performing piecewise interpolation processing on the plurality of feature points by adopting a piecewise interpolation function relationship to obtain the first compensation information and the second compensation information; The piecewise interpolation function relationship includes: Among them, x is the initial position information to be compensated, F(x) is the compensation information corresponding to the initial position information x to be compensated, and x n is the theoretical position information of the nth feature point, x n+1 is the theoretical position information of the n+1th feature point, f(x n ) is the compensation information corresponding to the theoretical position information of the nth feature point, f(x n+1 ) is the compensation information corresponding to the theoretical position information of the n+1th feature point, x is located at x n to x n+1 within the range between.

9. The method according to any one of claims 6 to 8, characterized in that: The motion stage includes a drive controller that pre-stores the position compensation table; after obtaining the first initial position information of the scanning axis corresponding to the Nth target sampling time point, the method further includes: The first initial position information is output to a drive controller in the motion stage, so that the drive controller compensates the first initial position information based on the position compensation table and drives the scanning axis to move according to the compensated first target position information.

10. A wafer inspection system, characterized in that: The system includes a motion stage, a processor, and a time delay integration camera; The motion stage is used to carry the wafer to be tested, and the scanning axis in the motion stage is used to control the movement of the wafer to be tested so that the surface of the wafer to be tested passes through the scanning area of the time delay integration camera line by line; The processor is communicatively connected to the motion stage and the time delay integration camera, respectively, and is configured to execute the camera synchronization triggering method according to any one of claims 1 to 9; The time-delayed integration camera is used to scan the wafer to be tested under the control of the pulse trigger signal of the processor.

11. The wafer inspection system according to claim 10, wherein: The motion stage also includes a position encoder; The position encoder is used to collect initial position information of the scanning axis according to a preset sampling period, and transmit the initial position information of the scanning axis to the processor.

12. The wafer inspection system according to claim 11, wherein: The motion stage further includes a drive controller, wherein the drive controller pre-stores a position compensation table, wherein the position compensation table includes a plurality of theoretical position information corresponding to a plurality of feature points and a plurality of compensation information corresponding to the plurality of theoretical position information; The processor is further configured to transmit the initial position information of the scanning axis to the drive controller; The drive controller is used to receive the initial position information, compensate the initial position information based on the position compensation table, and drive the scanning axis to move according to the target position information obtained by compensation.

13. A computer program product, characterized in that When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device performs the camera synchronization triggering method according to any one of claims 1 to 9.

Images