Spiral scanning light intensity regulation and control method and device, wafer detection system and medium

Abstract

The invention discloses a spiral scanning light intensity adjustment and control method and device, a wafer detection system and a medium, and relates to the field of wafer detection. In the variable-speed scanning process, the light intensity of the illumination light source incident to the wafer is changed by changing the transmittance of the light intensity regulation and control module, so that a scattered light signal emitted by the wafer and received by the scanning camera is changed, and the target light intensity is greater than the initial light intensity in the accelerated scanning process; in the deceleration scanning process, the target light intensity is smaller than the initial light intensity; the scanning time and the target light intensity are in a negative correlation relationship, so that the gray value uniformity of the imaged image is ensured as far as possible, overexposure or wafer damage is avoided, and the safety and defect detection rate of the wafer are improved; secondly, different triggering conditions are set for the light intensity regulation and control module, so that the light intensity regulation and control module is flexibly triggered to regulate and control the light intensity; and thirdly, the transmittance of the light intensity adjustment and control module is controlled based on the current target light intensity determined by the mapping relation, so that the light intensity is accurately controlled, and the image quality is improved.

Description

Technical Field

[0001] The present application relates to the field of wafer detection, and particularly to a method and device for intensity control of spiral scanning, a wafer detection system, and a medium. Background Art

[0002] Wafer defect detection is crucial in semiconductor design, production, packaging, testing and other processes, and is the key to improving the production yield. To balance detection efficiency and detection accuracy, when detecting wafer defects, an ultra-high-resolution line scan camera is mostly used. The wafer is scanned by the line scan camera, and the generated images are segmented, coordinate-transformed, and stitched to restore the entire wafer picture. Combined with feature algorithm analysis, the defect detection of the entire wafer is finally realized. The conventional scheme uses a Z-shaped trajectory scan, that is, the wafer is scanned row by row, and after scanning one row, it changes to the next row until the entire wafer is scanned. Multiple links such as acceleration / constant speed / deceleration / stop / line change / error calibration may be involved in the row-by-row scanning process, resulting in generally low efficiency of wafer defect detection.

[0003] In order to improve the detection efficiency, in the related art, a spiral line is used to perform variable-speed scanning on the wafer. However, during the variable-speed scanning process, due to different accumulated illumination durations in local scanning areas, the gray values of the imaged images are uneven, and there may even be overexposure or damage to the wafer, seriously affecting the defect detection rate.

[0004] Therefore, it can be seen that during the variable-speed spiral line scanning process, how to improve the quality of the imaged images and ensure as much as possible that the wafer is not damaged to improve the accuracy of wafer defect detection is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The present application discloses a method and device for intensity control of spiral scanning, a wafer detection system, and a medium, which are used to solve the technical problem that during the variable-speed scanning process, the gray values of the imaged images are uneven, and there may even be overexposure or damage to the wafer, seriously affecting the defect detection rate.

[0006] In a first aspect, the present application provides a method for controlling the light intensity of spiral scanning, which is applied to a controller in a wafer inspection system; the wafer inspection system further includes a light intensity control module; a first input end of the light intensity control module is used to receive a light beam emitted by an illumination light source, and a second input end of the light intensity control module is connected to an output end of the controller; the light beam emitted from the output end of the light intensity control module is incident on the wafer surface. In this method, first, during the variable-speed scanning process, the light intensity of the illumination light source incident on the wafer is changed by changing the transmittance of the light intensity control module, thereby changing the scattered light signal emitted by the wafer received by the scanning camera. During the acceleration scanning process, the target light intensity is greater than the initial light intensity; during the deceleration scanning process, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity, which can ensure that the gray values of the imaging images are as uniform as possible, avoid overexposure or damage to the wafer, and improve the safety and defect detection rate of the wafer; second, the types of scanning parameters at least include the spiral trajectory radius or the scanning time. Under different types of scanning parameters, or under different types of scanning parameters and variable-speed scanning conditions, different trigger conditions are set for the light intensity control module, realizing flexible triggering of the light intensity control module to control the light intensity; third, according to the mapping relationship between the target light intensity, the scanning parameters and the initial light intensity at the starting position of the variable-speed scanning, the current target light intensity corresponding to the value of the current scanning parameter is determined, and then the transmittance of the light intensity control module is controlled according to the target light intensity, realizing more accurate control of the light intensity and improving the quality of the imaging image.

[0007] In a possible implementation manner, determining the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation includes: when it is detected that the type of the current scanning parameter is the spiral trajectory radius and the current scanning direction is from outside to inside, determining that the preset requirement to be met by the current scanning parameter is that the spiral trajectory radius is less than or equal to the radius of the variable-speed scanning starting position; when it is detected that the type of the current scanning parameter is the spiral trajectory radius and the current scanning direction is from inside to outside, determining that the preset requirement to be met by the current scanning parameter is that the spiral trajectory radius is greater than or equal to the radius of the variable-speed scanning starting position. In this method, different preset requirements are set for the scanning parameter of the spiral trajectory radius under different scanning directions (from outside to inside scanning or from inside to outside scanning). Since the light intensity control module is triggered to control the light intensity only when the spiral trajectory radius meets the preset requirements, accurate control of the light intensity control module is achieved; and in the case of scanning from outside to inside, the spiral trajectory radius is less than or equal to the radius of the variable-speed scanning starting position, triggering the light intensity control module, rather than the spiral trajectory radius being greater than the radius of the variable-speed scanning starting position triggering the light intensity control module, that is, not triggering the light intensity control module during the uniform scanning stage. Since the scattered light signals emitted by the wafer received by the scanning camera are the same during the uniform scanning stage, the gray values of the imaging images are uniform per se and do not require light intensity control. Only light intensity control is performed during the variable-speed scanning stage, improving the efficiency of ensuring the uniformity of the gray values of the images; similarly, in the case of scanning from inside to outside, the spiral trajectory radius is greater than or equal to the radius of the variable-speed scanning starting position, triggering the light intensity control module, also improving the efficiency of ensuring the uniformity of the gray values of the images. And in the case of scanning from outside to inside, as long as the spiral trajectory radius is less than or equal to the radius of the variable-speed scanning starting position, the light intensity control module can be triggered, realizing the control of the light intensity at any radius position less than or equal to the variable-speed scanning starting position, ensuring the uniformity of the gray values of the imaging images during the variable-speed scanning process; similarly, in the case of scanning from inside to outside, as long as the spiral trajectory radius is greater than or equal to the radius of the variable-speed scanning starting position, the light intensity control module can be triggered, realizing the control of the light intensity at any radius position greater than or equal to the variable-speed scanning starting position, ensuring the uniformity of the gray values of the imaging images during the variable-speed scanning process.

[0008] In a possible implementation, obtaining the current radius of the helical trajectory includes: obtaining the current grating scale encoding information of the multi-axis displacement stage; determining the current radius of the helical trajectory corresponding to the current grating scale encoding information according to the pre-established correspondence between the grating scale encoding information of the multi-axis displacement stage and the radius of the helical trajectory. Compared with the method of directly measuring the trajectory radius, in the method provided in this application, by reading the current grating scale encoding information and according to the pre-established correspondence between the grating scale encoding information of the multi-axis displacement stage and the radius of the helical trajectory, the current radius of the helical trajectory can be determined without measurement, which improves the efficiency and accuracy of obtaining the current radius of the helical trajectory.

[0009] In a possible implementation, determining the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter includes: when it is detected that the type of the current scanning parameter is the scanning time, determining that the preset requirements to be met by the current scanning parameter are that the scanning time is greater than or equal to the preset time. In this method, the optical intensity modulation module is not triggered at all times during the variable-speed scanning process, but only when the scanning time is greater than the preset time. That is, when the scanning time is short, the optical intensity modulation module is not triggered, avoiding unnecessary optical intensity adjustment operations and reducing energy consumption.

[0010] In a possible implementation, obtaining the current scanning time includes: obtaining the current grating scale encoding information of the multi-axis displacement stage; determining the current radius of the helical trajectory corresponding to the current grating scale encoding information according to the pre-established correspondence between the grating scale encoding information of the multi-axis displacement stage and the radius of the helical trajectory; determining the current scanning time corresponding to the current radius of the helical trajectory according to the pre-established correspondence between the radius of the helical trajectory and the scanning time. It can be seen that the current scanning time is determined by this method.

[0011] In a possible implementation, the optical intensity modulation module is at least one of the following: a combination of a half-wave plate and a Brewster window component equipped with a motion motor; a combination of a half-wave plate and a polarization beam splitting cube equipped with a motion motor; a combination of a polarizing optical element and an analyzing optical element equipped with a motion motor; a variable attenuation sheet equipped with a motion motor; a combination of multiple fixed magnification attenuation sheets equipped with a motion motor; a liquid crystal component; or, a spatial light modulation component. By flexibly setting the optical intensity modulation module, various flexible ways of adjusting the optical intensity are obtained.

[0012] In a possible implementation manner, controlling the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity includes: when the light intensity modulation module is a combination of a half-wave plate equipped with a motion motor and a Brewster window component, obtaining a first transmittance response curve; wherein, the first transmittance response curve is used to characterize the corresponding relationship between the transmittance and the azimuth angle of the half-wave plate; determining the target transmittance according to the ratio between the current target light intensity and the light intensity of the illumination light source; determining the target azimuth angle of the half-wave plate when the target transmittance is determined according to the first transmittance response curve; controlling the azimuth angle of the half-wave plate to be the target azimuth angle so as to control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity. In this method, the adjustment of the light intensity is achieved by controlling the azimuth angle of the half-wave plate.

[0013] In a possible implementation manner, controlling the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity includes: when the light intensity modulation module is a liquid crystal component, obtaining a second transmittance response curve; wherein, the second transmittance response curve is used to characterize the corresponding relationship between the transmittance and the supply voltage of the liquid crystal component; determining the target transmittance according to the ratio between the current target light intensity and the light intensity of the illumination light source; determining the target supply voltage of the liquid crystal component when the target transmittance is determined according to the second transmittance response curve; controlling the supply voltage of the liquid crystal component to be the target supply voltage so as to control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity. In this method, the adjustment of the light intensity is achieved by adjusting the supply voltage of the liquid crystal component.

[0014] In a possible implementation manner, after controlling the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity, it further includes: determining whether the value of the current scanning parameter reaches a preset value; if so, determining that the scanning is completed, and controlling the light intensity modulation module to reset to the initial transmittance condition; if not, returning to detect whether the current scanning parameter meets the preset requirement, and when it is detected that the current scanning parameter meets the preset requirement, entering the step of determining the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter, and the initial light intensity at the variable-speed scanning starting position. In this method, after the value of the current scanning parameter reaches the preset value, it is determined that the scanning is completed, and the light intensity module is reset, ensuring that each adjustment starts from the same condition, which is convenient for the subsequent control of the scanning process; and when the value of the current scanning parameter does not reach the preset value, the current target light intensity is continuously determined to perform the adjustment of the light intensity, as much as possible ensuring the uniformity of the gray value of the imaging image during the entire process of variable-speed scanning.

[0015] In a possible implementation manner, the preset value is determined by the type of the scanning parameter, or by the type of the scanning parameter and the scanning direction. The flexible setting and reasonable setting of the preset value are realized.

[0016] In a possible implementation, the light intensity control method further includes: during the variable-speed spiral scanning, if it is detected that the current scanning parameters do not meet the preset requirements, controlling the transmittance of the light intensity control module to remain unchanged; or, during the constant-speed spiral scanning, controlling the transmittance of the light intensity control module to remain unchanged. This avoids unnecessary light intensity adjustment operations and reduces energy consumption.

[0017] In a possible implementation, the scanning direction is from outside to inside, the type of the current scanning parameter is the spiral trajectory radius, the time period of the constant-speed spiral scanning process is the time period within a preset duration since the start of the spiral scanning; during the variable-speed spiral scanning process, the constant angular velocity remains unchanged, and the start time of the variable-speed spiral scanning process is the time after the end time of the constant-speed spiral scanning process. According to the relationship between speed, angular velocity, and radius, scanning from outside to inside, first performing constant-speed scanning and then constant-angular-velocity scanning, avoiding the occurrence of an infinitely large angular velocity when continuously performing constant-speed scanning. The scanning direction is from inside to outside, the type of the current scanning parameter is the spiral trajectory radius, during the variable-speed spiral scanning process, the constant angular velocity remains unchanged, and the time period of the variable-speed spiral scanning is the time period within a preset duration since the start of the spiral scanning; the start time of the constant-speed spiral scanning process is the time after the end time of the variable-speed spiral scanning process. According to the relationship between speed, angular velocity, and radius, scanning from inside to outside, first performing constant-angular-velocity scanning and then constant-speed scanning, avoiding the occurrence of a relatively large speed when continuously performing constant-angular-velocity scanning.

[0018] In a second aspect, the present application provides a wafer detection system, including a light intensity control module. The first input end of the light intensity control module is used to receive the light beam emitted by the illumination light source, and the second input end of the light intensity control module is connected to the output end of the controller; the light beam emitted from the output end of the light intensity control module is incident on the wafer surface;

[0019] The controller is configured to: obtain the current variable-speed scanning situation, the type of the current scanning parameter, and the value of the current scanning parameter; wherein, the variable-speed scanning situation includes at least the scanning direction and the starting position of the variable-speed scanning; the type of the scanning parameter includes at least the radius of the spiral trajectory or the scanning time; determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation, or determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter; when it is detected that the current scanning parameter meets the preset requirements, determine the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter, and the initial light intensity at the starting position of the variable-speed scanning; wherein, during the acceleration scanning process, the target light intensity is greater than the initial light intensity; during the deceleration scanning process, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity; control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity. This wafer detection system has the same or corresponding technical features as the light intensity modulation method for spiral scanning mentioned above, and the same effect.

[0020] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned light intensity modulation method for spiral scanning are implemented. It has the same or corresponding technical features as the light intensity modulation method for spiral scanning mentioned above, and the same effect.

[0021] In a fourth aspect, the present application provides a light intensity modulation device for spiral scanning, including: a memory for storing a computer program; a processor for implementing the steps of the above-mentioned light intensity modulation method for spiral scanning when executing the computer program. It has the same or corresponding technical features as the light intensity modulation method for spiral scanning mentioned above, and the same effect. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is an architecture diagram of a wafer detection system provided by an embodiment of the present application;

[0024] Figure 2 It is a flowchart of a light intensity modulation method for spiral scanning provided by Embodiment 1 of the present application;

[0025] Figure 3Schematic diagram of light intensity control triggered by scanning position provided in the second embodiment of the present application;

[0026] Figure 4 Transmittance response curve of a 1 / 2 wave plate + Brewster window light intensity control module provided in the second embodiment of the present application;

[0027] Figure 5 Flow chart of a method for light intensity control triggered by scanning position provided in the second embodiment of the present application;

[0028] Figure 6 Schematic diagram of light intensity control triggered by scanning time provided in the third embodiment of the present application;

[0029] Figure 7 Flow chart of a method for light intensity control triggered by scanning time provided in the third embodiment of the present application. Detailed implementation manners

[0030] The light intensity control method for spiral scanning provided by the present application is applied to the controller in the wafer detection system. Figure 1 Architecture diagram of a wafer detection system provided for the embodiment of the present application. As Figure 1 shown, the wafer detection system includes an illumination light source, a light intensity control module, a reflecting mirror, a wafer, a light energy recovery device, a collection system, a scanning camera, a motion control module, a multi-axis displacement stage (X moving stage, Z moving stage, θ rotating stage), and a controller. The first input end of the light intensity control module is used to receive the light beam emitted by the illumination light source, and the second input end of the light intensity control module is connected to the output end of the controller; the input end of the controller is connected to the displacement stage through the motion control module. The wafer is located on the multi-axis displacement stage. The light beam emitted from the output end of the light intensity control module is incident on the surface of the wafer; the illumination light source is used to generate laser light for illuminating the wafer. The light intensity control module is used to control the laser transmittance of the illumination light source. The collection system is used to collect the scattered light signal of the sample and transmit it to the scanning camera. The motion control module is used to plan the spiral trajectory and control the movement of the X-axis moving stage, Z-axis moving stage, and θ-axis rotating stage according to the preset trajectory, and at the same time generate a trigger pulse to trigger the scanning camera to take a picture. The scanning camera is used to receive the scattered light signal emitted by the wafer and acquire an image. In the present application, the controller performs the operation of light intensity control for spiral scanning.

[0031] Embodiment 1:

[0032] Figure 2 Flow chart of a method for light intensity control for spiral scanning provided in the first embodiment of the present application. As Figure 2 shown, the method includes:

[0033] S10: Obtain the current variable-speed scanning situation, the type of the current scanning parameter, and the value of the current scanning parameter; wherein, the variable-speed scanning situation includes at least the scanning direction and the starting position of the variable-speed scanning; the type of the scanning parameter includes at least the radius of the spiral trajectory or the scanning time;

[0034] S11: Determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation, or determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter;

[0035] S12: When it is detected that the current scanning parameter meets the preset requirements, determine the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter, and the initial light intensity at the starting position of the variable-speed scanning; wherein, during the acceleration scanning process, the target light intensity is greater than the initial light intensity; during the deceleration scanning process, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity;

[0036] S13: Control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity.

[0037] The motion control module is used to plan the spiral trajectory, control the movement of the X-axis moving stage, the Z-axis moving stage, and the θ-axis turntable according to the preset trajectory, and generate trigger pulses to trigger the scanning camera to take pictures, so as to realize the spiral scanning of the wafer. The variable-speed scanning includes acceleration scanning and deceleration scanning. The scanning direction includes scanning from the outer circle to the inner circle along the spiral trajectory (abbreviated as scanning from the outside to the inside), and scanning from the inner circle to the outer circle along the spiral trajectory (abbreviated as scanning from the inside to the outside). The starting position of the variable-speed scanning is determined according to the actual scanning scenario.

[0038] According to the relationship among speed, angular velocity and radius, in order to avoid the situation where the scanning from outside to inside is always a uniform scan, resulting in an infinitely large angular velocity. Here, scanning scenario one is proposed: the scanning direction is from outside to inside, the type of the current scanning parameter is the radius of the spiral trajectory, the time period of the uniform spiral scanning process is the time period within a preset duration since the start of the spiral scanning; during the variable-speed spiral scanning process, the constant angular velocity remains unchanged, and the start time of the variable-speed spiral scanning process is the time after the end time of the uniform spiral scanning process. That is, scanning scenario one: scanning from outside to inside, first uniform scanning, and then constant angular velocity scanning. In order to avoid the situation where the scanning from inside to outside is always a constant angular velocity scan, resulting in a relatively large speed. Here, scanning scenario two is proposed: the scanning direction is from inside to outside, the type of the current scanning parameter is the radius of the spiral trajectory, during the variable-speed spiral scanning process, the constant angular velocity remains unchanged, and the time period of the variable-speed spiral scanning is the time period within a preset duration since the start of the spiral scanning; the start time of the uniform spiral scanning process is the time after the end time of the variable-speed spiral scanning process. That is, scanning scenario two: scanning from inside to outside, first constant angular velocity scanning, and then uniform scanning.

[0039] In order to flexibly control the light intensity, in this application, the light intensity can be controlled based on different scanning parameters. Specifically, the types of scanning parameters at least include the radius of the spiral trajectory (r) or the scanning time (t). When the selected scanning parameter is the radius of the spiral trajectory, the value of the current scanning parameter is the value of the radius of the spiral trajectory; when the selected scanning parameter is the scanning time, the value of the current scanning parameter is the value of the scanning time. When obtaining the value of the radius of the spiral trajectory, it can be obtained by direct measurement. However, there are problems such as low measurement efficiency and low measurement accuracy in direct measurement. Therefore, in practice, obtaining the current radius of the spiral trajectory includes: obtaining the current grating scale encoding information of the multi-axis displacement stage; determining the current radius of the spiral trajectory corresponding to the current grating scale encoding information according to the pre-established correspondence between the grating scale encoding information of the multi-axis displacement stage and the radius of the spiral trajectory. Reading the current grating scale encoding information and directly determining the current radius of the spiral trajectory according to the correspondence between the grating scale encoding information of the multi-axis displacement stage and the radius of the spiral trajectory, without measurement, improves the efficiency and accuracy of obtaining the current radius of the spiral trajectory. Similarly, when obtaining the current scanning time, the scanning time can be directly counted; in addition, when obtaining the current scanning time, it can also be obtained by obtaining the current grating scale encoding information of the multi-axis displacement stage; determining the current radius of the spiral trajectory corresponding to the current grating scale encoding information according to the pre-established correspondence between the grating scale encoding information of the multi-axis displacement stage and the radius of the spiral trajectory; determining the current scanning time corresponding to the current radius of the spiral trajectory according to the pre-established correspondence between the radius of the spiral trajectory and the scanning time. In practice, the method for obtaining the current scanning time can be flexibly selected.

[0040] To trigger the light intensity control module for regulation, in this application, the preset requirements to be met by the current scanning parameters are determined according to the type of the current scanning parameters and the current variable-speed scanning situation, or the preset requirements to be met by the current scanning parameters are determined according to the type of the current scanning parameters.

[0041] Specifically, determining the preset requirements to be met by the current scanning parameters according to the type of the current scanning parameters and the current variable-speed scanning situation includes:

[0042] When it is detected that the type of the current scanning parameter is the spiral trajectory radius and the current scanning direction is from outside to inside, it is determined that the preset requirement to be met by the current scanning parameter is that the spiral trajectory radius is less than or equal to the radius at the starting position of the variable-speed scanning;

[0043] When it is detected that the type of the current scanning parameter is the spiral trajectory radius and the current scanning direction is from inside to outside, it is determined that the preset requirement to be met by the current scanning parameter is that the spiral trajectory radius is greater than or equal to the radius at the starting position of the variable-speed scanning.

[0044] Assume that the radius at the starting position of the variable-speed scanning is represented by R0, and the spiral trajectory radius is r. Then, for scanning from outside to inside, when r ≤ R0, the light intensity control module is triggered for light intensity regulation. For scanning from inside to outside, when r ≥ R0, the light intensity control module is triggered for light intensity regulation. It should be noted that for scanning from outside to inside, if it is variable-speed scanning at the beginning, the maximum value of R0 is Rmax; if it is uniform scanning at the beginning and becomes variable-speed scanning during the process, the maximum value of R0 is a value less than Rmax. For scanning from inside to outside, if it is variable-speed scanning at the beginning, the minimum value of R0 is 0; if it is uniform scanning at the beginning and becomes variable-speed scanning during the process, the minimum value of R0 is greater than 0.

[0045] In addition to triggering the light intensity control module according to the spiral trajectory radius, the light intensity control can also be triggered according to the scanning time. Specifically, determining the preset requirements to be met by the current scanning parameters according to the type of the current scanning parameters includes: when it is detected that the type of the current scanning parameter is the scanning time, it is determined that the preset requirement to be met by the current scanning parameter is that the scanning time is greater than or equal to a preset time.

[0046] Assume that the preset time is t0, that is, when t ≥ t0, the light intensity control module is triggered for light intensity regulation.

[0047] To achieve accurate regulation of the light intensity, when it is detected that the current scanning parameters meet the preset requirements, the current target light intensity corresponding to the value of the current scanning parameters is determined according to the mapping relationship among the target light intensity, the scanning parameters, and the initial light intensity at the starting position of the variable-speed scanning.

[0048] It should be noted that the mapping relationship between the target light intensity, the scanning parameters, and the initial light intensity at the starting position of variable-speed scanning can be of various types, such as exponential / linear / logarithmic / polynomial / power functions, etc. For example, if the scanning parameter is r, the mapping relationship is a function with r as the variable; if the scanning parameter is t, the mapping relationship is a function with t as the variable. There is no limitation on the selected function, which is determined according to the specific scanning scenario. To ensure the uniformity of the gray values of the imaged image, in practice, during the acceleration scanning process, the target light intensity is greater than the initial light intensity; during the deceleration scanning process, the target light intensity is less than the initial light intensity; and the scanning time is negatively correlated with the target light intensity.

[0049] After determining the current target light intensity, in order to make the light intensity incident on the wafer be the current target light intensity through the regulation of the light intensity regulation module. In practice, specific control can be carried out according to the specific structure of the light intensity regulation module. Among them, the light intensity regulation module is at least one of the following:

[0050] A combination of a half-wave plate equipped with a motion motor and a Brewster window component;

[0051] A combination of a half-wave plate equipped with a motion motor and a polarization beam splitting cube;

[0052] A combination of a polarizing optical element equipped with a motion motor and an analyzing optical element;

[0053] A variable attenuation sheet equipped with a motion motor;

[0054] A combination of multiple fixed magnification attenuation sheets equipped with a motion motor;

[0055] A liquid crystal component;

[0056] Or, a spatial light modulation component.

[0057] Taking the light intensity regulation module as a combination of a half-wave plate equipped with a motion motor and a Brewster window component as an example, controlling the transmittance of the light intensity regulation module to be the transmittance corresponding to the current target light intensity includes:

[0058] Obtain a first transmittance response curve; wherein, the first transmittance response curve is used to characterize the corresponding relationship between the transmittance and the azimuth angle of the half-wave plate;

[0059] Determine the target transmittance according to the ratio between the current target light intensity and the light intensity of the illumination light source;

[0060] Determine the target azimuth angle of the half-wave plate when determining the target transmittance according to the first transmittance response curve;

[0061] Control the azimuth angle of the half-wave plate to be the target azimuth angle to control the transmittance of the light intensity regulation module to be the transmittance corresponding to the current target light intensity.

[0062] Taking the light intensity control module as the liquid crystal component as an example, controlling the transmittance of the light intensity control module to be the transmittance corresponding to the current target light intensity includes:

[0063] Obtaining a second transmittance response curve; wherein, the second transmittance response curve is used to characterize the corresponding relationship between the transmittance and the supply voltage of the liquid crystal component;

[0064] Determining the target transmittance according to the ratio between the current target light intensity and the light intensity of the illumination light source;

[0065] Determining the target supply voltage of the liquid crystal component when determining the target transmittance according to the second transmittance response curve;

[0066] Controlling the supply voltage of the liquid crystal component to be the target supply voltage to control the transmittance of the light intensity control module to be the transmittance corresponding to the current target light intensity.

[0067] The above process realizes that the light intensity incident on the wafer is the current target light intensity by regulating the transmittance of the light intensity control module, thereby ensuring the uniformity of the gray value of the imaging image. Further, during the process of spiral scanning light intensity control, it is possible to judge whether the scanning is completed. To facilitate the user to understand the scanning process, specifically, after controlling the transmittance of the light intensity control module to be the transmittance corresponding to the current target light intensity, it further includes:

[0068] Judging whether the value of the current scanning parameter reaches a preset value;

[0069] If so, determining that the scanning is completed and controlling the light intensity control module to reset to the initial transmittance working condition;

[0070] If not, returning to detect whether the current scanning parameter meets the preset requirements, and when it is detected that the current scanning parameter meets the preset requirements, entering the step of determining the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter and the initial light intensity at the starting position of the variable-speed scanning.

[0071] Among them, the preset value is determined by the type of the scanning parameter, or by the type of the scanning parameter and the scanning direction. For example, if the type of the scanning parameter is the radius of the spiral trajectory and the scanning direction is from the outside to the inside, the preset value is 0; if the scanning direction is from the inside to the outside, the preset value is Rmax. If the type of the scanning parameter is the scanning time, the preset value is the total scanning time length ( ). After determining that the scanning is completed, resetting the light intensity module ensures that each adjustment starts from the same working condition, facilitating the subsequent regulation of the scanning process; and after the value of the current scanning parameter does not reach the preset value, continuing to determine the current target light intensity and performing the regulation of the light intensity, as much as possible ensuring the uniformity of the gray value of the imaging image during the entire process of variable-speed scanning.

[0072] During the above process, the light intensity is regulated. In practice, to avoid unnecessary light intensity adjustment operations and reduce energy consumption, the light intensity regulation method for spiral scanning further includes:

[0073] During the variable-speed spiral scan, if it is detected that the current scan parameters do not meet the preset requirements, the transmittance of the light intensity regulation module is controlled to remain unchanged;

[0074] Or, during the uniform-speed spiral scan, the transmittance of the light intensity regulation module is controlled to remain unchanged.

[0075] When scanning from the outside to the inside, when r > R0, it is considered that r does not meet the preset requirements, and the light intensity regulation module will not be triggered for light intensity regulation. When scanning from the inside to the outside, when r < R0, it is considered that r does not meet the preset requirements, and the light intensity regulation module will not be triggered for light intensity regulation. When t < t0, it is considered that t does not meet the preset requirements, and the light intensity regulation module will not be triggered for light intensity regulation. Ways to prevent the light intensity regulation module from performing light intensity regulation: such as keeping the azimuth angle of the half-wave plate unchanged and keeping the supply voltage of the liquid crystal component unchanged.

[0076] During the variable-speed scan, the light intensity of the illumination light source incident on the wafer is changed by changing the transmittance of the light intensity regulation module, thereby changing the scattered light signal emitted by the wafer received by the scanning camera. During the acceleration scan, the target light intensity is greater than the initial light intensity; during the deceleration scan, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity, which can ensure that the gray values of the imaged images are as uniform as possible, avoid overexposure or damage to the wafer, and improve the safety and defect detection rate of the wafer; secondly, the types of scan parameters at least include the spiral trajectory radius or the scanning time. Under different types of scan parameters, or under different types of scan parameters and variable-speed scan conditions, different trigger conditions are set for the light intensity regulation module to flexibly trigger the light intensity regulation module to regulate the light intensity; thirdly, according to the mapping relationship between the target light intensity, the scan parameters and the initial light intensity at the starting position of the variable-speed scan, the current target light intensity corresponding to the value of the current scan parameters is determined, and then the transmittance of the light intensity regulation module is controlled according to this target light intensity, achieving relatively accurate control of the light intensity and improving the quality of the imaged images.

[0077] To enable those skilled in the art to better understand the light intensity regulation method for spiral scanning of the present application, the above method will be described below with reference to two specific embodiments of regulating the light intensity based on the spiral trajectory radius and regulating the light intensity based on the scanning time.

[0078] Embodiment 2:

[0079] The main system architecture of this embodiment is consistent with that of the first embodiment and will not be elaborated here. The motion control module is used to plan the multi-axis moving stage to perform a spiral motion with a combination of constant linear velocity and constant angular velocity. Specifically, the spiral scans from the edge of the wafer towards the center, and the spiral trajectory goes through at least but not limited to two stages of constant linear velocity and constant angular velocity (in practice, there can also be a combination of multiple stages such as an acceleration stage, constant linear velocity, constant angular velocity, and deceleration stage). Figure 3 FIG. is a schematic diagram of light intensity control triggered based on the scanning position provided by the second embodiment of the present application. The scanning position is reflected by the radius of the spiral trajectory. Scanning from the outside to the inside, it successively includes a constant linear velocity stage and a constant angular velocity stage. As Figure 3 shown, at the constant angular velocity stage, the light intensity control module is triggered at the R0 position. It should be noted that during the trajectory planning process, the constant linear velocity can be switched to the constant angular velocity at any specified radius. The controller reads the grating scale encoding information of the multi-axis displacement stage at a certain period (for example: polling once every 1ms) to obtain the scanning radius r information of the current spiral trajectory. In this embodiment, the controller is built-in with a distance comparator for comparing the size relationship between the current scanning radius r of the spiral and the preset radius R0 in real time. When the read scanning radius r > R0, the controller does not trigger the light intensity control module to work, that is, the light intensity remains unchanged; when the read scanning radius r ≤ R0, the controller triggers the light intensity control module to attenuate the light intensity with a distance-related function.

[0080] The distance-related attenuation function can be an exponential / linear / logarithmic / polynomial / power function with the radius r as a variable, for example: , , , or , where is the optical power of the initial light intensity, and the letters a, b, c, and d are all natural constants. In this embodiment, a third-order polynomial function is preferably used as the light intensity attenuation function. The hardware structure of the light intensity control module includes but is not limited to: a combination of a half-wave plate and a Brewster window component equipped with a motion motor, a combination of a half-wave plate and a polarization beam splitting cube equipped with a motion motor, a combination of a polarizing optical element and an analyzing optical element equipped with a motion motor, a variable attenuation sheet equipped with a motion motor, a combination of multiple fixed magnification attenuation sheets equipped with a motion motor, a liquid crystal component, a spatial light modulation component, and other components with the ability to adjust the light intensity transmittance. In this embodiment, a combination of a half-wave plate and a Brewster window equipped with a rotating motor is preferably used. Its principle is to change the polarization state of the incident light by rotating the azimuth angle of the half-wave plate, and combine the partial or total reflection characteristics of the S polarization component and the P polarization component of the incident light by the Brewster window to achieve the adjustment of the beam transmittance. The transmittance response curve of the half-wave plate at different azimuth angles is as Figure 4 shown.Figure 4 This is the transmittance response curve of a 1 / 2 wave plate + Brewster window light intensity control module provided in the second embodiment of the present application. The abscissa represents the azimuth angle of the 1 / 2 wave plate, and the ordinate represents the transmittance. Specifically, the controller directly controls the azimuth angle of the 1 / 2 wave plate according to the r-related attenuation function and the transmittance response curve of the light intensity control module to achieve the adjustment of the light intensity transmittance during the spiral scan.

[0081] Figure 5 This is a flowchart of a method for triggering light intensity control based on the scanning position provided in the second embodiment of the present application. As Figure 5 shown, the method includes:

[0082] S14: Scan from the outer circle to the inner circle according to the preset spiral trajectory, and the controller reads the trajectory radius r in real time;

[0083] S15: Determine whether the trajectory r ≤ R0, where R0 is a preset arbitrarily specified radius; if not, go to step S16: if so, go to step S17;

[0084] S16: The light intensity of the illumination source remains unchanged;

[0085] S17: The controller adjusts the transmittance of the light intensity control module according to the control logic of the r-related function;

[0086] S18: Determine whether r is equal to 0; if not, return to step S17; if so, go to step S19;

[0087] S19: Complete the scan, and the light intensity control module returns to the initial transmittance condition.

[0088] Specifically, step 1: Perform a spiral scan on the wafer, with the scan radius from the outer circle to the inner circle. The controller reads the scan trajectory radius r of the motion control module in real time and compares it with a preset arbitrarily specified radius R0 (0 < R0 < Rmax, where Rmax is the radius of the outermost circle);

[0089] Step 2: When the trajectory radius r > R0, the light intensity of the illumination source remains unchanged;

[0090] Step 3: When the trajectory radius r ≤ R0, the controller adjusts the transmittance of the light intensity control module according to the position trigger control logic (transmittance curve formula) to achieve light intensity control; the transmittance curve can include but is not limited to exponential / linear / logarithmic / polynomial formulas with the radius r as a variable (for example: ), where 0 ≤ r ≤ R0, a is a constant greater than 0, is the constant angular velocity; for another example: the polynomial fitting formula , where a, b, c, d are constant terms, etc.);

[0091] Step 4: When the trajectory radius r = 0, the scanning is completed, and the controller controls the light intensity modulation module to restore to the initial transmittance condition.

[0092] In this embodiment, when the multi-axis displacement stage performs variable-speed scanning according to the preset helix, the controller reads the helix scanning radius information in real time and compares it with the preset specified R0. When r > R0, the light intensity remains unchanged; when the helix trajectory radius r ≤ R0, the light intensity control module is triggered to adjust the light intensity transmittance with an r-related attenuation function, realizing the closed-loop control of the light intensity. During the wafer defect detection process, the problem of overexposure of the light intensity in a local area caused by the variable-speed scanning of the helix can be effectively solved, improving the safety and defect detection rate of the wafer.

[0093] Embodiment Three:

[0094] The main system architecture of this embodiment is the same as that of Embodiment One and will not be described in detail here. In Embodiment Two, the light intensity modulation is triggered based on the scanning position, while in this embodiment, the light intensity modulation is triggered based on the scanning time. The motion control module plans the multi-axis moving stage to perform a combined helix motion of constant linear velocity and constant angular velocity, scanning from the edge of the wafer towards the center. Different from Embodiment Two, in this embodiment, the controller reads the grating scale encoding information of the multi-axis displacement stage at a certain period (for example: polling once every 1 ms), establishes the relationship curve between the scanning radius r and the scanning time t of the current helix trajectory, and pre-stores it in the controller; in addition, the controller is built-in with a time comparator, and any t0 moment greater than or equal to 0 can be preset as the time stamp to trigger the controller to change the transmittance of the light intensity modulation module. Figure 6 It is a schematic diagram of light intensity modulation triggered based on the scanning time provided by Embodiment Three of this application. As Figure 6 shown, when t < t0, the light intensity remains unchanged; when t ≥ t0, the light intensity modulation is performed. Specifically, when the multi-axis moving stage starts the helix scan, the controller starts to accumulate the scanning time t and compares the accumulated scanning time t with t0 in real time. When the accumulated scanning time t of the helix < t0, the controller does not trigger the light intensity modulation module to work, that is, the light intensity remains unchanged; when the accumulated scanning time t of the helix ≥ t0, the controller triggers the light intensity modulation module to attenuate the light intensity with a distance-time related function.

[0095] The time-related attenuation function can be an exponential / linear / logarithmic / polynomial / power function with the time t as a variable, such as , , , or etc. Among them, is the optical power of the initial light intensity, and the letters a, b, c, and d are natural constants. In this embodiment, the controller preferably uses a time-dependent polynomial function of the third or fourth order as the light intensity attenuation function, changes the polarization state of the incident light through the azimuth angle of the half-wave plate, and combines the partial or total reflection characteristics of the S-polarized component and the P-polarized component in the incident light by the Brewster window to achieve beam transmittance adjustment. For the transmittance curve, specifically refer to the one in Embodiment 2 Figure 4 .

[0096] Figure 7 is a flowchart of a method for light intensity control based on scan time trigger provided in Embodiment 3 of this application. As Figure 7 shown, the method includes:

[0097] S20: Scan from the outer circle to the inner circle according to a preset spiral trajectory, and the controller reads the scan time t in real time;

[0098] S21: Determine whether the time t≥t0, where t0 is a preset arbitrary specified moment; if not, then enter step S22: if so, then enter step S23;

[0099] S22: The light intensity of the illumination light source remains unchanged;

[0100] S23: The controller adjusts the transmittance of the light intensity control module according to the control logic of the t-related function;

[0101] S24: Determine whether t is equal to ; if not, then return to step S23; if so, then enter step S25;

[0102] S25: Complete the scan, and the light intensity control module returns to the initial transmittance working condition.

[0103] Specifically, step 1: Perform a spiral scan on the wafer, with the scan radius from the outer circle to the inner circle. The controller statistically records the trajectory scan time t in real time and compares it with a preset arbitrary moment t0 (0 < t0 < , is the total time required to complete the trajectory);

[0104] Step 2: When the spiral scan time t < t0, keep the initial light intensity unchanged;

[0105] Step 3: When the scan time t≥t0, the controller adjusts the transmittance of the light intensity control module according to the time-related function and control logic (transmittance curve formula) to achieve light intensity control; the transmittance curve formula can include but is not limited to: exponential / linear / logarithmic / polynomial formula with time t as the variable (for example: , where a is a constant term greater than 0);

[0106] Step 4: When t = , the scanning is completed, and the controller controls the light intensity modulation module to restore to the initial transmittance condition.

[0107] It should be noted that the time can be directly counted. Taking the scanning time t as a variable avoids frequent polling of the grating scale coding position information of the multi-axis displacement stage, effectively reducing the position deviation caused by polling delay, and has higher timeliness and accuracy in terms of light intensity modulation accuracy.

[0108] In this embodiment, when the multi-axis displacement stage performs variable-speed scanning according to the preset helix, the controller accumulates the time information of the helix scanning and compares it with the preset specified t0 moment. When t < t0, the light intensity remains unchanged; when the scanning time t ≥ t0, the light intensity control module is triggered to adjust the light intensity transmittance with a t-related attenuation function, realizing the closed-loop control of the light intensity. During the wafer defect detection process, it can effectively solve the problem of overexposure of the light intensity in a local area caused by variable-speed scanning of the helix, improving the safety and defect detection rate of the wafer. At the same time, it efficiently solves the problem of position error in light intensity control caused by position polling delay.

[0109] Embodiment 4:

[0110] A method for modulating light intensity by spiral scanning is described above. This embodiment also provides a wafer detection system, including a light intensity modulation module. The first input end of the light intensity modulation module is used to receive the light beam emitted by the illumination light source, and the second input end of the light intensity modulation module is connected to the output end of the controller; the light beam emitted from the output end of the light intensity modulation module is incident on the wafer surface;

[0111] The controller is used to: obtain the current variable-speed scanning situation, the type of the current scanning parameter, and the value of the current scanning parameter; wherein, the variable-speed scanning situation includes at least the scanning direction and the starting position of the variable-speed scanning; the type of the scanning parameter includes at least the helix trajectory radius or the scanning time; determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation, or determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter; when it is detected that the current scanning parameter meets the preset requirements, determine the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter, and the initial light intensity at the starting position of the variable-speed scanning; wherein, during the acceleration scanning process, the target light intensity is greater than the initial light intensity; during the deceleration scanning process, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity; control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity.

[0112] The wafer detection system provided in this embodiment has the same or corresponding technical features as the intensity modulation method of spiral scanning described above. The embodiments of the intensity modulation method of spiral scanning have been described in detail above, and the embodiments of the wafer detection system will not be elaborated here, and it has the same beneficial effects as the intensity modulation method of spiral scanning mentioned above.

[0113] An embodiment of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned intensity modulation method of spiral scanning are implemented.

[0114] It can be understood that if the method in the above embodiments is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs that can store program codes.

[0115] The computer-readable storage medium provided by the present application includes the above-mentioned intensity modulation method of spiral scanning, and the effect is the same as above.

[0116] An embodiment of the present application also provides an intensity modulation device for spiral scanning, including:

[0117] A memory for storing a computer program;

[0118] A processor for implementing the steps of the above-mentioned intensity modulation method of spiral scanning when executing the computer program.

[0119] Among them, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented in at least one hardware form of a digital signal processor (DSP), a field-programmable gate array (FPGA), or a programmable logic array (PLA). The processor may also include a main processor and a coprocessor. The main processor is a processor used to process data in the wake state, also known as the central processing unit (CPU); the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor may be integrated with a graphics processing unit (GPU), and the GPU is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor may further include an artificial intelligence (AI) processor, and the AI processor is used to process computational operations related to machine learning.

[0120] The memory may include one or more computer-readable storage media, and the computer-readable storage media may be non-transitory. The memory may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash storage devices. In this embodiment, the memory is at least used to store the following computer programs. After the computer programs are loaded and executed by the processor, the relevant steps of the spiral scanning light intensity control method disclosed in the foregoing embodiments can be implemented. In addition, the resources stored in the memory may also include an operating system and data, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system may include Windows, Unix, Linux, etc. The data may include, but is not limited to, the data involved in the spiral scanning light intensity control method mentioned above.

[0121] The spiral scanning light intensity control device provided in this embodiment includes a memory and a processor. When the processor executes the program stored in the memory, the following method can be implemented: the spiral scanning light intensity control method, and the effect is the same as above.

[0122] The above-mentioned preferred embodiments further elaborate on the purpose, technical solution, and advantages of the present application. It should be understood that the above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for controlling light intensity by spiral scanning, characterized in that A controller applied to a wafer detection system; the wafer detection system further includes a light intensity control module; a first input end of the light intensity control module is used to receive a light beam emitted by an illumination light source, and a second input end of the light intensity control module is connected to an output end of the controller; the light beam emitted from the output end of the light intensity control module is incident on the wafer surface; the method includes: Obtain the current variable-speed scanning situation, the type of the current scanning parameter, and the value of the current scanning parameter; wherein, the variable-speed scanning situation at least includes a scanning direction and a variable-speed scanning starting position; the type of the scanning parameter at least includes a spiral trajectory radius or a scanning time; Determine a preset requirement to be satisfied by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation, or determine a preset requirement to be satisfied by the current scanning parameter according to the type of the current scanning parameter; When it is detected that the current scanning parameter meets the preset requirement, determine a current target light intensity corresponding to the value of the current scanning parameter according to a mapping relationship between a target light intensity, the scanning parameter, and an initial light intensity at the variable-speed scanning starting position; wherein, during an acceleration scanning process, the target light intensity is greater than the initial light intensity; during a deceleration scanning process, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity; Control the transmittance of the light intensity control module to be the transmittance corresponding to the current target light intensity.

2. The light intensity modulation method of spiral scanning according to claim 1, wherein The determining the preset requirement to be satisfied by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation includes: When it is detected that the type of the current scanning parameter is a spiral trajectory radius and the current scanning direction is from outside to inside, determine that the preset requirement to be satisfied by the current scanning parameter is that the spiral trajectory radius is less than or equal to the radius at the variable-speed scanning starting position; When it is detected that the type of the current scanning parameter is a spiral trajectory radius and the current scanning direction is from inside to outside, determine that the preset requirement to be satisfied by the current scanning parameter is that the spiral trajectory radius is greater than or equal to the radius at the variable-speed scanning starting position.

3. The light intensity modulation method for spiral scanning according to claim 2, characterized in that, Obtaining the current spiral trajectory radius includes: Obtain the current grating scale encoding information of the multi-axis displacement stage; Determine the current spiral trajectory radius corresponding to the current grating scale encoding information according to a pre-established correspondence relationship between the grating scale encoding information of the multi-axis displacement stage and the spiral trajectory radius.

4. The light intensity modulation method of spiral scanning according to claim 1, characterized in that, The determining the preset requirement to be satisfied by the current scanning parameter according to the type of the current scanning parameter includes: When it is detected that the type of the current scanning parameter is a scanning time, determine that the preset requirement to be satisfied by the current scanning parameter is that the scanning time is greater than or equal to a preset time.

5. The light intensity modulation method by spiral scanning according to claim 4, characterized in that, Obtaining the current scanning time includes: Obtain the current grating scale encoding information of the multi-axis displacement stage; Determine the current spiral trajectory radius corresponding to the current grating scale encoding information according to a pre-established correspondence relationship between the grating scale encoding information of the multi-axis displacement stage and the spiral trajectory radius; Determine the current scanning time corresponding to the current spiral trajectory radius according to a pre-established correspondence relationship between the spiral trajectory radius and the scanning time.

6. The light intensity modulation method for spiral scanning according to any one of claims 1 to 5, characterized in that, The light intensity control module is at least one of the following: A combination of a half-wave plate and a Brewster window component equipped with a motion motor; Combination of a 1 / 2 wave plate equipped with a motion motor and a polarization beam splitting cube; Combination of a polarizing optical element and an analyzing optical element equipped with a motion motor; Variable attenuator equipped with a motion motor; Combination of multiple fixed magnification attenuators equipped with a motion motor; Liquid crystal component; Or, a spatial light modulation component.

7. The light intensity modulation method of spiral scanning according to claim 6, characterized in that, The controlling the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity includes: In the case where the light intensity modulation module is a combination of a 1 / 2 wave plate equipped with a motion motor and a Brewster window component, obtaining a first transmittance response curve; wherein, the first transmittance response curve is used to characterize the corresponding relationship between the transmittance and the azimuth angle of the 1 / 2 wave plate; Determining a target transmittance according to the ratio between the current target light intensity and the light intensity of the illumination light source; Determining the target azimuth angle of the 1 / 2 wave plate when the target transmittance is determined according to the first transmittance response curve; Controlling the azimuth angle of the 1 / 2 wave plate to be the target azimuth angle so as to control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity.

8. The optical intensity modulation method by spiral scanning according to claim 6, characterized in that, The controlling the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity includes: In the case where the light intensity modulation module is a liquid crystal component, obtaining a second transmittance response curve; wherein, the second transmittance response curve is used to characterize the corresponding relationship between the transmittance and the supply voltage of the liquid crystal component; Determining a target transmittance according to the ratio between the current target light intensity and the light intensity of the illumination light source; Determining the target supply voltage of the liquid crystal component when the target transmittance is determined according to the second transmittance response curve; Controlling the supply voltage of the liquid crystal component to be the target supply voltage so as to control the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity.

9. The light intensity modulation method of spiral scanning according to claim 6, characterized in that, After the controlling the transmittance of the light intensity modulation module to be the transmittance corresponding to the current target light intensity, it further includes: Judging whether the value of the current scanning parameter reaches a preset value; If so, determining that the scanning is completed, and controlling the light intensity modulation module to reset to the initial transmittance condition; If not, returning to detect whether the current scanning parameter meets the preset requirement, and in the case where it is detected that the current scanning parameter meets the preset requirement, entering the step of determining the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter and the initial light intensity at the starting position of the variable speed scanning.

10. The light intensity modulation method by spiral scanning according to claim 9, characterized in that, The preset value is determined by the type of the scanning parameter, or by the type of the scanning parameter and the scanning direction.

11. The optical intensity modulation method by spiral scanning according to claim 6, characterized in that, The method further includes: During the variable speed spiral scanning, if it is detected that the current scanning parameter does not meet the preset requirement, controlling the transmittance of the light intensity modulation module to remain unchanged; Or, during the uniform speed spiral scanning, controlling the transmittance of the light intensity modulation module to remain unchanged.

12. The light intensity modulation method by spiral scanning according to claim 11, characterized in that, The scanning direction is from the outside to the inside, the type of the current scanning parameter is the spiral trajectory radius, and the time period of the uniform speed spiral scanning process is the time period within a preset duration since the start of the spiral scanning. During the variable-speed spiral scan, the constant angular velocity remains unchanged, and the start time of the variable-speed spiral scan is after the end time of the uniform-speed spiral scan; Or, the scanning direction is from the inside to the outside, the type of the current scanning parameter is the spiral trajectory radius, during the variable-speed spiral scan, the constant angular velocity remains unchanged, and the time period of the variable-speed spiral scan is the time period within a preset duration since the start of the spiral scan; The start time of the uniform-speed spiral scan is after the end time of the variable-speed spiral scan.

13. A wafer detection system, characterized in that, It includes a light intensity control module. The first input end of the light intensity control module is used to receive the light beam emitted by the illumination light source, and the second input end of the light intensity control module is connected to the output end of the controller; the light beam emitted from the output end of the light intensity control module is incident on the wafer surface; The controller is configured to: obtain the current variable-speed scanning situation, the type of the current scanning parameter, and the value of the current scanning parameter; wherein, the variable-speed scanning situation at least includes the scanning direction and the variable-speed scanning starting position; the type of the scanning parameter at least includes the spiral trajectory radius or the scanning time; determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter and the current variable-speed scanning situation, or determine the preset requirements to be met by the current scanning parameter according to the type of the current scanning parameter; when it is detected that the current scanning parameter meets the preset requirements, determine the current target light intensity corresponding to the value of the current scanning parameter according to the mapping relationship between the target light intensity, the scanning parameter, and the initial light intensity at the variable-speed scanning starting position; wherein, during the acceleration scan, the target light intensity is greater than the initial light intensity; during the deceleration scan, the target light intensity is less than the initial light intensity; the scanning time is negatively correlated with the target light intensity; control the transmittance of the light intensity control module to be the transmittance corresponding to the current target light intensity.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the light intensity control method for spiral scan according to any one of claims 1 to 12 are implemented.

15. A light intensity control device for spiral scanning, characterized in that, It includes: A memory for storing a computer program; A processor for implementing the steps of the light intensity control method for spiral scan according to any one of claims 1 to 12 when executing the computer program.

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