Performance test method of laser ruler and computer equipment

Abstract

The invention provides a performance test method of a laser ruler and computer equipment. The performance test method of the laser ruler comprises the following steps: receiving a starting signal of a tested laser ruler; distance measurement position information fed back by the measured laser ruler is obtained, and the light intensity stability of the measured laser ruler is analyzed according to the distance measurement position information; driving the moving workpiece table carrying the semiconductor sample to move; and acquiring a feature mark image of the semiconductor sample by using an electron microscope, and analyzing the positioning precision and / or positioning repeatability of the measured laser ruler according to the feature mark image. According to the scheme, a comprehensive and efficient laser ruler performance testing scheme can be provided, the light intensity stability, the positioning precision and the positioning repeatability of the laser ruler are analyzed, the manual error can be effectively reduced through an automatic detection mode, and the testing efficiency and accuracy are improved; the comprehensive evaluation of the performances of different laser rulers is realized, different laser rulers are compatibly tested, and the cost can be reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a performance testing method and computer equipment for a laser ruler. Background Technology

[0002] Laser rulers, as precision measuring tools based on laser technology, have been widely used in the semiconductor industry due to their significant advantages such as high precision, non-contact measurement, and rapid measurement. In defect detection equipment, such as electron beam inspection equipment, the main function of a laser ruler is to perform closed-loop positioning with the workpiece stage. The closed-loop positioning system between the laser ruler and the workpiece stage mainly consists of four parts: a laser ruler measurement module, a workpiece stage drive module, a signal processing module, and a control center. Therefore, the performance requirements for laser rulers in defect detection equipment are extremely high.

[0003] Before applying different models of laser rulers to defect detection equipment, rigorous testing of various performance indicators of the laser rulers is required. The main testing aspects of laser rulers include: light intensity stability, positioning accuracy, and positioning repeatability. Currently, the primary method used for testing the light intensity stability, positioning accuracy, and positioning repeatability of laser rulers is the comparative testing method. This involves installing two sets of laser rulers or laser interferometers under identical tooling and environmental conditions. One set of laser rulers serves as the laser ruler under test, while the other set uses a higher-precision laser ruler for calibration, such as the Renishaw RLE20 laser ruler, or a laser interferometer, such as the Renishaw XL80 laser interferometer.

[0004] The disadvantages of using laser rulers for comparative testing are as follows: First, it is easily affected by different calibrated laser rulers. If a calibrated laser ruler that does not meet the performance standards is used for comparative testing with the laser ruler under test, the performance data of the laser ruler under test cannot be accurately obtained, leading to test failure. Second, the comparative testing method is not intuitive and is easily affected by data fluctuations. This is because this method can only obtain distance information by decomposing the signal fed back by the laser ruler, and then compare the distance information of the laser ruler under test and the calibrated laser ruler separately. However, the distance information is usually a fluctuating value, which cannot provide more accurate information about the accuracy of the laser ruler. Summary of the Invention

[0005] One objective of this invention is to solve the problem of inaccurate test data caused by the use of comparative testing methods, and to improve the efficiency and accuracy of laser ruler performance testing.

[0006] A further objective of this invention is to meet a variety of testing requirements and achieve a comprehensive evaluation of the performance of different laser rulers.

[0007] Specifically, the present invention provides a performance testing method for a laser ruler, comprising: receiving a start signal from the laser ruler under test; acquiring distance measurement position information fed back by the laser ruler under test, and analyzing the light intensity stability of the laser ruler under test based on the distance measurement position information; driving a moving workpiece stage carrying a semiconductor sample to move; and acquiring feature mark images of the semiconductor sample using an electron microscope, and analyzing the positioning accuracy and / or positioning repeatability of the laser ruler under test based on the feature mark images.

[0008] Optionally, the steps of acquiring the ranging position information fed back by the laser ruler under test and analyzing the light intensity stability of the laser ruler under test based on the ranging position information include: acquiring the ranging position information fed back by the laser ruler under test within a preset time period at a millisecond frequency through a data acquisition system; and evaluating the light intensity stability by calculating the fluctuation range and standard deviation of the ranging position information.

[0009] Optionally, the step of driving the moving stage carrying the semiconductor sample to move includes: controlling the moving stage to move the semiconductor sample, so that each reference point on the semiconductor sample moves sequentially to the test position corresponding to the target point. Multiple feature marks are pre-selected on the semiconductor sample as test points, and the test points include multiple reference points and one target point.

[0010] Optionally, the steps of acquiring feature marker images of semiconductor samples using an electron microscope and analyzing the positioning accuracy of the laser ruler under test based on the feature marker images include: acquiring images of the target point before movement and images of each reference point after movement using an electron microscope; calibrating the image of the target point before each movement; calculating the deviation between the image of the target point and the images of each reference point and repeatedly acquiring a preset number of sets of data; and calculating the average deviation of each reference point in the preset number of sets of data and analyzing the positioning accuracy based on the average deviation.

[0011] Optionally, the step of driving the moving stage carrying the semiconductor sample to move includes: controlling the moving stage to move the semiconductor sample, so that each reference point on the semiconductor sample moves to the test position corresponding to the target point multiple times, wherein multiple feature marks are pre-selected on the semiconductor sample as test points, and the test points include multiple reference points and one target point.

[0012] Optionally, the steps of acquiring feature marker images of semiconductor samples using an electron microscope and analyzing the positioning repeatability of the laser ruler under test based on the feature marker images include: acquiring images of the target point before movement and images of the reference point after movement using an electron microscope; calibrating the image of the target point before each movement; acquiring a preset number of images of each reference point before acquiring images of the next reference point; calculating the deviation between the first image acquired at each reference point and other images of that reference point; and calculating the average deviation of each reference point, and analyzing the positioning repeatability based on the average deviation.

[0013] Optionally, the step of driving the moving stage carrying the semiconductor sample to move includes: adjusting the drive motor of the moving stage by acquiring the analog signal fed back by the laser ruler under test, so that the moving stage moves to a specified position.

[0014] Optionally, after the step of acquiring feature marker images of semiconductor samples using an electron microscope, the method further includes: preprocessing the feature marker images by denoising and enhancing contrast; and identifying the image location and shape information of the feature markers using a feature extraction algorithm.

[0015] Optionally, after the step of analyzing the positioning accuracy and / or positioning repeatability of the laser ruler under test based on the feature-marked image, the method further includes: constructing an index system based on the test results of light intensity stability, positioning accuracy and positioning repeatability, assigning corresponding weights to each performance index, and calculating the comprehensive performance score of the laser ruler under test by weighted summation.

[0016] According to another aspect of the present invention, a computer device is also provided, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the performance testing method of the laser ruler described above.

[0017] The laser ruler performance testing method of the present invention receives the start signal of the laser ruler under test, acquires the distance measurement position information fed back by the laser ruler under test, analyzes the light intensity stability of the laser ruler under test based on the distance measurement position information, drives the moving workpiece stage carrying the semiconductor sample to move, uses an electron microscope to collect feature mark images of the semiconductor sample, and analyzes the positioning accuracy and / or positioning repeatability of the laser ruler under test based on the feature mark images. It can provide a comprehensive and efficient laser ruler performance testing scheme, analyze the light intensity stability, positioning accuracy and positioning repeatability of the laser ruler, and the automated detection method can effectively reduce human error and improve testing efficiency and accuracy.

[0018] Furthermore, the performance testing method for laser rulers of the present invention allows the workpiece stage to be adapted to different models of laser rulers, enabling it to meet various testing requirements on the same testing equipment, achieve comprehensive evaluation of the performance of different laser rulers, and be compatible with testing different laser rulers, thereby reducing costs. During the testing process, the actual working environment of the laser ruler is simulated, and various environmental factors are controlled to protect the test results from interference from the external environment, ensuring that the test results are true and reliable, and providing strong support for the performance optimization and application selection of laser rulers.

[0019] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0020] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic diagram of a performance testing method for a laser ruler according to an embodiment of the present invention; Figure 2 This is a partial structural schematic diagram of a test device for a laser ruler performance testing method according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the analysis of light intensity stability in a laser ruler performance testing method according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the test points of a semiconductor sample in a laser ruler performance testing method according to an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the analysis of positioning accuracy in a performance testing method for a laser ruler according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the analysis of positioning repeatability in a performance testing method for a laser ruler according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a computer program product according to an embodiment of the present invention; Figure 8 This is a schematic diagram of a computer-readable storage medium according to an embodiment of the present invention; and Figure 9 This is a schematic diagram of a computer device according to an embodiment of the present invention. Detailed Implementation

[0021] This embodiment provides a performance testing method for laser rulers, which can provide a comprehensive and efficient laser ruler performance testing solution, analyze the light intensity stability, positioning accuracy and positioning repeatability of laser rulers, and the automated testing method can effectively reduce human error and improve testing efficiency and accuracy. Figure 1 This is a schematic diagram of a performance testing method for a laser ruler according to an embodiment of the present invention. Figure 2 This is a partial structural schematic diagram of a test device for a laser ruler performance testing method according to an embodiment of the present invention. Figure 1 As shown, the performance testing method for the laser ruler in this embodiment generally includes: Step S102: Receive the start signal from the laser ruler under test; Step S104: Obtain the ranging position information fed back by the laser ruler under test, and analyze the light intensity stability of the laser ruler under test based on the ranging position information. Step S106: Drive the moving workpiece stage carrying the semiconductor sample to move; Step S108: Use electron microscope 110 to acquire feature marker images of semiconductor samples, and analyze the positioning accuracy and / or positioning repeatability of the laser ruler under test based on the feature marker images.

[0022] In a preferred embodiment, step S106, which involves moving the stage carrying the semiconductor sample, may specifically include: adjusting the drive motor of the stage by acquiring the analog signal fed back by the laser ruler under test, so that the stage moves to a designated position.

[0023] After acquiring the feature marker image of the semiconductor sample using the electron microscope 110 in step S108, the process may further include: preprocessing the feature marker image by denoising and enhancing contrast; and identifying the image location and shape information of the feature markers using a feature extraction algorithm.

[0024] After step S108 analyzes the positioning accuracy and / or positioning repeatability of the laser ruler under test based on the feature marker image, the following may be included: constructing an index system based on the test results of light intensity stability, positioning accuracy and positioning repeatability, assigning corresponding weights to each performance index, and calculating the comprehensive performance score of the laser ruler under test by weighted summation.

[0025] The testing procedures for the positioning repeatability and accuracy of the laser ruler under test involve a closed-loop control setup. The laser ruler under test is used as the core component of the closed-loop control of the moving workpiece stage, and its measurement data serves as the primary basis for the stage's position feedback. When the stage needs to be moved, a command is sent to the laser ruler according to the preset target position. The laser ruler measures the change in distance between itself and the reference mirror, providing real-time image position information of the stage. Based on the feedback data from the laser ruler, the drive motor of the stage is continuously adjusted to ensure precise movement to the designated position. Simultaneously, to ensure the stability and accuracy of the closed-loop control, an advanced Proportional-Integral-Derivative (PID) control algorithm is employed to optimize and adjust the control parameters, reducing system response time and overshoot.

[0026] In one specific embodiment, the moving workpiece stage is repeatedly moved to multiple designated positions. After each movement, an electron microscope 110 is triggered to photograph the feature marks on the semiconductor sample. The electron microscope 110 has a resolution down to the nanometer level, enabling it to clearly capture the details of the feature marks. The captured images are transmitted to a computer and analyzed using a specially developed image processing algorithm. The algorithm first preprocesses the images, including noise reduction and contrast enhancement, to improve image quality. Then, a feature extraction algorithm identifies the image position and shape information of the feature marks in each image. Finally, the image position information of the feature marks in different images is compared to calculate the offset of the feature marks. By performing statistical analysis on the offsets obtained from multiple measurements, such as calculating the average and standard deviation, the positioning repeatability and positioning accuracy of the measured laser ruler are determined.

[0027] In a preferred embodiment, the test results of the laser ruler's light intensity stability, positioning repeatability, and positioning accuracy can be comprehensively analyzed to construct a comprehensive index system for evaluating the performance of the laser ruler. Specifically, different performance indicators can be assigned corresponding weights based on their importance. The more important the performance indicator, the greater its corresponding weight can be set.

[0028] Based on the indicator system and weights, the comprehensive performance score of each tested laser ruler model can be calculated. By weighted summation, the light intensity stability score, positioning repeatability score, and positioning accuracy score of each tested laser ruler are calculated to obtain the comprehensive performance score. A higher comprehensive performance score indicates better overall performance of the tested laser ruler.

[0029] Based on comprehensive performance scores, different models of laser rulers can be ranked, providing users with a comprehensive and objective reference when selecting a laser ruler. The ranking results detail the performance scores for each laser ruler across various indicators and the overall performance score, allowing users to clearly understand the performance differences between different laser rulers and thus choose the most suitable one based on their needs.

[0030] Figure 2 Partial structure of the test equipment for the performance testing method of the laser ruler applicable to this embodiment is shown. In fact, the overall structure of the test equipment may include: an electron microscope 110, a moving workpiece stage, a controller, the laser ruler under test, and an environmental chamber. Figure 2 An electron microscope 110 is shown, and the moving stages include an X-axis moving stage 131 and a Y-axis moving stage 132. Furthermore, Figure 2 Also shown are a stage 120 on a moving workpiece stage for carrying semiconductor samples, an X-axis reflector 141 and a Y-axis reflector 142 on the moving workpiece stage, and an X-axis fixture 151 and a Y-axis fixture 152 for mounting the probe of the laser ruler under test.

[0031] The electron microscope 110 can be used to capture images of feature markings on semiconductor samples. In a preferred embodiment, the electron microscope 110 can meet the requirements for nanometer-precision imaging of feature markings on semiconductor samples. It has good optical performance, which can effectively reduce aberrations and distortions, ensuring the clarity and accuracy of the captured images. The camera of the electron microscope 110 can be connected to a computer via a high-speed data transmission cable to achieve rapid transmission of image data.

[0032] The moving stage meets high-precision requirements, supporting semiconductor samples and enabling the electron microscope 110 to collect feature marks at different locations on the samples through its own movement. In a preferred embodiment, the main body of the moving stage can be made of high-strength aluminum alloy, providing good stability and resistance to deformation. A series of precision mounting slots and positioning holes can be designed on the surface of the moving stage for mounting different types of reference mirrors. These reference mirrors are tightly connected to the moving stage via high-precision positioning pins and fastening bolts, ensuring no displacement during testing.

[0033] For securing semiconductor samples, a combination of vacuum adsorption and mechanical grippers can be used. A vacuum adsorption chamber is installed inside the moving stage, which, connected to an external vacuum pump, generates negative pressure in the area where the semiconductor sample is placed, firmly adsorbing the sample onto the moving stage. Simultaneously, adjustable mechanical grippers are equipped at the edge of the moving stage to further secure the semiconductor sample, preventing it from shaking or shifting during testing.

[0034] The controller can be an integrated drive and control unit, used to acquire the signal fed back by the laser ruler under test, form a closed loop with the movement of the moving workpiece stage, and drive the moving workpiece stage to a designated position. In a preferred embodiment, the integrated drive and control controller has multiple analog input channels and digital input / output channels, capable of accurately acquiring the analog signal fed back by the laser ruler under test. It can also drive the moving workpiece stage to move to the designated position.

[0035] The laser ruler under test, acting as a ranging module, can transmit distance information to the integrated drive and control controller, thus forming a complete closed loop with the moving workpiece stage. In a preferred embodiment, the laser ruler under test can be of different models, and the laser ruler probe can be mounted on a fixture that is compatible with different laser ruler probes. The light spot of the laser ruler under test can hit a reflector on the moving workpiece stage, thereby realizing the ranging function and feeding back the acquired signal to the integrated drive and control controller.

[0036] In a preferred embodiment, the environmental chamber can achieve constant temperature, constant humidity, and constant pressure. The environmental chamber can employ a double-layer insulation structure, filled internally with high-performance insulation material to reduce the influence of external ambient temperature. Temperature control is achieved through a high-precision heating wire and a refrigeration compressor, coupled with a temperature sensor to monitor the ambient temperature in real time, keeping temperature fluctuations within ±0.1℃. Humidity regulation relies on an ultrasonic humidifier and dehumidifier, automatically adjusting the ambient humidity based on data feedback from a humidity sensor, maintaining it within ±2% of the set value. Pressure control utilizes an air pump and pressure regulating valve, combined with a pressure sensor, to ensure the ambient pressure remains stable at ±0.01% of standard atmospheric pressure.

[0037] Figure 3 This is a schematic diagram illustrating the analysis of light intensity stability in a laser ruler performance testing method according to an embodiment of the present invention. Figure 3 As shown, the step of analyzing light intensity stability in the performance testing method of the laser ruler in this embodiment may include: Step S302: Receive the start signal from the laser ruler under test; Step S304: The distance measurement position information fed back by the laser ruler under test within a preset time period is collected by the data acquisition system at a millisecond frequency. Step S306: Drive the motion stage carrying the semiconductor sample to move.

[0038] It should be noted that, in the process of analyzing the light intensity stability of the laser ruler under test in this embodiment, the moving workpiece stage can first be placed in the environmental chamber and fixed in the designated position by machining parts to ensure that it does not shift during the test. Then, different models of laser rulers under test are installed sequentially on the test area and connected to the data acquisition system.

[0039] Under constant temperature, humidity, and pressure conditions, the laser ruler under test is activated and put into operation. During the data acquisition process, the data acquisition system samples data at a millisecond frequency to ensure that minute changes in the position of the laser ruler under test are captured. In a preferred embodiment, the data acquisition system collects the ranging position information fed back by the laser ruler under test over 2 hours and 8 hours. This is because factors such as air turbulence and temperature can easily affect the laser emitter during the 2-hour and 8-hour operation of the laser ruler under test, causing the ranging position to drift. Therefore, the ranging position information during these two operating periods is the primary reference.

[0040] In addition, environmental parameters can be recorded at regular intervals, such as every 10 minutes, while simultaneously checking the equipment's operational status to ensure the continuity and stability of the testing process. Finally, the collected data is analyzed and processed, and the stability of the measured laser ruler's light intensity is evaluated by calculating parameters such as the fluctuation range and standard deviation of the ranging position information. Specifically, the smaller the fluctuation range and standard deviation of the ranging position information, the better the stability of the measured laser ruler's light intensity is considered.

[0041] Multiple feature markers can be pre-selected on the semiconductor sample as test points, including multiple reference points and one target point. Figure 4 This is a schematic diagram of the test points of a semiconductor sample in a laser ruler performance testing method according to an embodiment of the present invention. Figure 4 As shown, the test points of the semiconductor sample may include: A, M, D, G, J, B, E, H, and K. Where A is the target point, and M, D, G, J, B, E, H, and K are reference points. Furthermore, M, D, G, and J can be considered as the outer ring reference points, and B, E, H, and K as the inner ring reference points.

[0042] Figure 5 This is a schematic diagram illustrating the analysis of positioning accuracy in a laser ruler performance testing method according to an embodiment of the present invention. Figure 5 As shown, the step of analyzing positioning accuracy in the performance testing method of the laser ruler in this embodiment may include: Step S502: Receive the start signal from the laser ruler under test; Step S504: Control the moving workpiece stage to move the semiconductor sample, so that each reference point on the semiconductor sample moves sequentially to the test position corresponding to the target point. Step S506: The electron microscope 110 acquires images of the target point before movement and images of each reference point after movement. The image of the target point is calibrated before each movement. Step S508: Calculate the deviation between the image of the target point and the images of each reference point, and repeatedly collect a preset number of sets of data; Step S510: Calculate the average deviation of each reference point in the preset group of data, and analyze the positioning accuracy based on the average deviation.

[0043] It should be noted that the test position corresponding to the target point in step S504 refers to the area directly below the electron microscope 110. Figure 4 For example, the test position corresponding to target point A. In step S506, calibrating the image of the target point before each movement means moving the target point back to the test position, acquiring an image of the target point, and calibrating it using the image acquired before the initial movement.

[0044] In one specific embodiment, the semiconductor sample is a wafer, and the feature markers are die structures on the wafer. Figure 4 The following example illustrates the specific method of image acquisition in this embodiment: Images are acquired sequentially at the following points: Adie, Mdie, Adie, calibrated Adie, Ddie, Adie, calibrated Adie, Gdie, Adie, calibrated Adie, Jdie, Adie, calibrated Adie, Bdie, Adie, calibrated Adie, Edie, Adie, calibrated Adie, Hdie, Adie, calibrated Adie, Kdie, Adie. Here, Adie refers to the image acquired when the target point A is located at the test position, i.e., below the electron microscope 110; Mdie refers to the image acquired when the reference point M is located at the test position, i.e., below the electron microscope 110, and so on.

[0045] After acquiring images in the above order, the deviations between Adie and Mdie, Ddie, Gdie, Jdie, Bdie, Edie, Hdie, and Kdie can be calculated. In one specific embodiment, the preset number of groups can be 10, meaning that 10 images can be acquired in the above order and the deviations calculated to obtain 10 sets of deviation data. Each set of deviation data includes the deviations between Adie and Mdie, Ddie, Gdie, Jdie, Bdie, Edie, Hdie, and Kdie. Finally, the positioning accuracy can be analyzed by calculating the average deviation of each reference point.

[0046] It should be noted that the smaller the average deviation of a single reference point and the more similar the average deviations of all reference points, the better the positioning accuracy of the laser ruler being measured. The specific values ​​of the preset number of groups mentioned above are merely illustrative and not intended to limit the invention. In other embodiments, other values ​​can be set according to actual circumstances.

[0047] Figure 6 This is a schematic diagram illustrating the analysis of positioning repeatability in a laser ruler performance testing method according to an embodiment of the present invention. Figure 6As shown, the step of analyzing positioning repeatability in the performance testing method of the laser ruler in this embodiment may include: Step S602: Receive the start signal from the laser ruler under test; Step S604: Control the moving workpiece stage to move the semiconductor sample, so that each reference point on the semiconductor sample moves to the test position corresponding to the target point multiple times. Step S606: The electron microscope 110 acquires images of the target point before movement and the reference point after movement. Before each movement, the images of the target point are calibrated. After acquiring a preset number of images of each reference point, the images of the next reference point are acquired. Step S608: Calculate the deviation between the first image acquired at each reference point and other images at that reference point; Step S610: Calculate the average deviation of each reference point and analyze the positioning repeatability based on the average deviation.

[0048] It should be noted that the test position corresponding to the target point in step S604 refers to the area directly below the electron microscope 110. Figure 4 For example, the test position corresponding to target point A. In step S606, calibrating the image of the target point before each movement means moving the target point back to the test position, acquiring an image of the target point, and calibrating it using the image acquired before the initial movement.

[0049] In one specific embodiment, the semiconductor sample is a wafer, and the feature markers are die structures on the wafer; the preset number of sheets can be 10. Figure 4 Taking the test points shown as an example, the specific method of image acquisition in this embodiment is as follows: Images are acquired sequentially as follows: Adie, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie, after calibration, Mdie, Adie. Here, Adie refers to the image acquired when the target point A is located at the test position, i.e., below the electron microscope 110; Mdie refers to the image acquired when the reference point M is located at the test position, i.e., below the electron microscope 110, and so on.

[0050] After acquiring 10 Mdie images, the deviation of the first Mdie image can be calculated as a baseline to compare it with the others. Finally, the repeatability of the localization can be analyzed by calculating the average deviation of the baseline point M. The other baseline points can be calculated using the same image acquisition order and calculation method as baseline point M, resulting in the average deviation of all baseline points. In fact, a similar method can be used to calculate the average deviation of the target point A.

[0051] It should be noted that the smaller the average deviation of a single reference point, the more similar the average deviations of all reference points, and the better the positioning repeatability of the measured laser ruler. The specific values ​​of the preset number of sheets mentioned above are merely illustrative and not intended to limit the invention. In other embodiments, other values ​​can be set according to actual circumstances.

[0052] In summary, the laser ruler performance testing method of this embodiment is mechanically adaptable to various laser ruler testing fixtures; it forms a closed-loop control by combining the laser ruler feedback signal with the motion of the workpiece stage, and then evaluates the performance of the laser ruler by combining the image results of the electron microscope 110; this method can avoid inconsistencies and inaccuracies in laser ruler test evaluation results due to different benchmark laser rulers and different test reference values; this method can eliminate the interference of environmental factors on laser ruler test results; and image analysis can improve the accuracy to the nanometer level.

[0053] The testing equipment is compatible with various laser scales, reducing costs. Image analysis provides more intuitive and accurate repeatability and precision, better aligning with the practical applications of semiconductor testing equipment. Automated image acquisition and analysis reduce human error and improve testing efficiency. Constant temperature, humidity, and pressure environmental control protects test results from external interference. Closed-loop control, using a laser scale-driven workpiece stage for positioning, better suits the operating mode of semiconductor testing equipment, facilitating the selection and optimization of laser scales for semiconductor testing.

[0054] This embodiment also provides a computer program product, a computer-readable storage medium, and a computer device. Figure 7 This is a schematic diagram of a computer program product 500 according to an embodiment of the present invention. Figure 8 This is a schematic diagram of a computer-readable storage medium 300 according to an embodiment of the present invention. Figure 9 This is a schematic diagram of a computer device 400 according to an embodiment of the present invention.

[0055] Computer program product 500 includes computer program 310, which, when executed by processor 410, implements any of the aforementioned laser ruler performance testing methods. Computer-readable storage medium 300 stores the aforementioned computer program 310 thereon, which, when executed by processor 410, implements any of the aforementioned laser ruler performance testing methods. Computer device 400 may include memory 420, processor 410, and computer program 310 stored in memory 420 and running on processor 410, wherein processor 410, when executing computer program 310, implements any of the aforementioned laser ruler performance testing methods.

[0056] The computer program 310 used to perform the operations of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, status setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages ​​and procedural programming languages.

[0057] Computer program 310 may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0058] In some embodiments, in order to perform aspects of the present invention, electronic circuits including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs) or programmable logic arrays (PLAs) can execute computer-readable program instructions to personalize the electronic circuits by utilizing state information of computer-readable program instructions.

[0059] For the purposes of this embodiment, computer program product 500 is a related product containing computer program 310. For the purposes of this embodiment, computer-readable storage medium 300 is a tangible device capable of holding and storing computer program 310, and can be any device capable of containing, storing, communicating, propagating or transmitting computer program 310 for use by or in conjunction with an instruction execution system, apparatus or device.

[0060] More specific examples (a non-exhaustive list) of computer-readable storage media 300 include the following: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable optical disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, and any suitable combination of the foregoing.

[0061] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any machine-readable storage medium for use by, or in conjunction with, instruction execution systems, apparatuses or devices (such as computer-based systems, processor-based systems or other systems that can fetch and execute instructions from, or instruction execution systems, apparatuses or devices).

[0062] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system.

[0063] Computer device 400 can be, for example, a server, desktop computer, laptop computer, tablet computer, or smartphone. In some examples, computer device 400 can be a cloud computing node. Computer device 400 can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., that perform specific tasks or implement specific abstract data types. Computer device 400 can be implemented in a distributed cloud computing environment where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can reside on local or remote computing system storage media, including storage devices.

[0064] Computer device 400 may include a processor 410 adapted to execute stored instructions and a memory 420 that provides temporary storage space for the operation of instructions during operation. The processor 410 may be a single-core processor, a multi-core processor, a computing cluster, or any other configuration. The memory 420 may include random access memory (RAM), read-only memory, flash memory, or any other suitable storage system.

[0065] The processor 410 can be connected via a system interconnect (e.g., PCI, PCI-Express, etc.) to an I / O interface (input / output interface) suitable for connecting the computer device 400 to one or more I / O devices (input / output devices). I / O devices may include, for example, a keyboard and indicating devices, where indicating devices may include a touchpad or touchscreen, etc. I / O devices may be built into the computer device 400 or may be external devices connected to the computing device.

[0066] The processor 410 may also be linked via a system interconnect to a display interface suitable for connecting the computer device 400 to a display device. The display device may include a display screen as a built-in component of the computer device 400. The display device may also include an external computer monitor, television, or projector connected to the computer device 400. Furthermore, a network interface controller (NIC) may be adapted to connect the computer device 400 to a network via a system interconnect. In some embodiments, the NIC may use any suitable interface or protocol (such as an Internet Minicomputer System Interface) to transmit data. The network may be a cellular network, a radio network, a wide area network (WAN), a local area network (LAN), or the Internet, etc. Remote devices may connect to the computing device via the network.

[0067] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A performance testing method for a laser ruler, comprising: Receive the start signal from the laser ruler being measured; Obtain the ranging position information fed back by the laser ruler under test, and analyze the light intensity stability of the laser ruler under test based on the ranging position information; Drive the moving stage carrying the semiconductor sample to move; as well as The semiconductor sample is captured using an electron microscope to obtain characteristic marker images, and the positioning accuracy and / or positioning repeatability of the laser ruler under test are analyzed based on the characteristic marker images.

2. The method according to claim 1, wherein the step of obtaining the ranging position information fed back by the laser ruler under test, and analyzing the light intensity stability of the laser ruler under test based on the ranging position information includes: The data acquisition system collects the ranging position information fed back by the laser ruler under test within a preset time period at a millisecond frequency; as well as The stability of the light intensity is evaluated by calculating the fluctuation range and standard deviation of the ranging location information.

3. The method according to claim 1, wherein the step of driving the moving stage carrying the semiconductor sample to move comprises: The motion stage is controlled to move the semiconductor sample, so that each reference point on the semiconductor sample moves sequentially to the test position corresponding to the target point. Multiple feature marks are pre-selected on the semiconductor sample as test points, and the test points include multiple reference points and one target point.

4. The method according to claim 3, wherein the step of acquiring a feature marker image of the semiconductor sample using an electron microscope and analyzing the positioning accuracy of the laser ruler under test based on the feature marker image includes: Images of the target point before movement and images of each reference point after movement are acquired using the electron microscope. The images of the target point are calibrated before each movement. Calculate the deviation between the image of the target point and the images of each reference point, and repeatedly collect a preset number of data sets; as well as Calculate the average deviation of each reference point in the preset number of data sets, and analyze the positioning accuracy based on the average deviation.

5. The method of claim 1, wherein the step of driving the moving stage carrying the semiconductor sample to move comprises: The motion stage is controlled to move the semiconductor sample, so that each reference point on the semiconductor sample moves to the test position corresponding to the target point multiple times. Multiple feature marks are pre-selected on the semiconductor sample as test points, and the test points include multiple reference points and one target point.

6. The method according to claim 5, wherein the step of acquiring a feature marker image of the semiconductor sample using an electron microscope and analyzing the positioning repeatability of the laser ruler under test based on the feature marker image includes: The electron microscope is used to acquire images of the target point before movement and images of the reference point after movement. Before each movement, the images of the target point are calibrated. After acquiring a preset number of images of each reference point, the next reference point is acquired. Calculate the deviation between the first image acquired at each reference point and other images at that reference point; as well as Calculate the average deviation of each of the reference points, and analyze the positioning repeatability based on the average deviation.

7. The method of claim 1, wherein the step of driving the moving stage carrying the semiconductor sample to move comprises: By collecting the analog signal fed back by the laser ruler under test, the drive motor of the moving workpiece stage is adjusted to move the moving workpiece stage to the designated position.

8. The method of claim 1, further comprising, after the step of acquiring a feature marker image of the semiconductor sample using an electron microscope: The feature-marked image is preprocessed to remove noise and enhance contrast; as well as Image location and shape information of feature markers are identified through feature extraction algorithms.

9. The method of claim 1, further comprising, after the step of analyzing the positioning accuracy and / or positioning repeatability of the laser ruler under test based on the feature marker image: An index system is constructed based on the test results of the light intensity stability, the positioning accuracy, and the positioning repeatability. Each performance index is assigned a corresponding weight, and the comprehensive performance score of the laser ruler under test is calculated by weighted summation.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the performance testing method for a laser ruler according to any one of claims 1 to 9.

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