Deformation optimization method and system for AOI (Automatic Optic Inspection) of mask and medium
By establishing a deformation model of the relationship between lens focal length and clamping, the clamping state of the mask AOI inspection is optimized, which solves the problem of high false detection rate caused by mask deformation and improves inspection efficiency.
Patent Information
- Application Number
- CN202510784918.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-12
- Publication Date
- 2025-09-19
AI Technical Summary
During the mask AOI inspection process, the deformation of the mask's glass substrate causes an increase in the false detection rate and low inspection efficiency.
By establishing the relationship between the focus value of the scanning lens and the deformation variable and focal length value caused by the clamping relationship between the target mask, the deformation of the mask is judged, and the most appropriate hardware parameters are calculated through the parameter determination model. The clamping state is adjusted to optimize the deformation during scanning and reduce the false detection rate.
It reduces the false detection rate of AOI inspection, improves production efficiency, avoids the use of cumbersome optical interferometers and other equipment, and simplifies the inspection process.
Smart Images
Figure CN120668046A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of defect detection, and in particular to a deformation optimization method, system and medium for mask AOI detection. Background Art
[0002] A mask (also known as a photomask) is a precision pattern transfer template, a coated glass substrate containing precise electronic circuit images, used in the mass production of microelectronic products. Through high-precision photolithography, micro- and nanoscale circuit patterns are engraved onto the mask substrate to create the mask product. Automated Optical Inspection (AOI) equipment is a type of inspection equipment based on optical principles and machine vision technology, widely used in the electronics manufacturing industry. It uses a high-resolution camera to automatically scan the object being inspected, capturing images and comparing them with pre-set standard image data to detect various defects. AOI equipment is used for production process monitoring and quality control, capable of real-time detection of defects throughout the production process, promptly identifying and correcting problems and ensuring consistent product quality.
[0003] As a high-precision pattern transfer template, the quality of its pattern engraving directly affects the quality of mass-produced products in downstream industries. Therefore, it is particularly important to use AOI equipment to conduct strict defect inspection on the mask. Because the patterns engraved on the mask are relatively small, with line widths ranging from a few microns to tens of microns, the accuracy of the defect judgment results during AOI scanning is easily affected by the deformation of the glass substrate of the mask itself. When the deformation is too large, the number of defects judged by the scan will become very large, among which real defects and falsely judged defects are mixed together, and the excessive number makes it difficult to re-inspect and re-confirm the defect judgment. Therefore, minimizing and eliminating the deformation of the mask substrate during AOI scanning can effectively reduce the false detection rate, improve production efficiency, and better ensure the quality of the mask. Summary of the Invention
[0004] The technical problem to be solved by the present invention is that during the AOI inspection process of the mask, the false detection rate increases due to the influence of the deformation of the glass substrate of the mask itself, and the problem of low detection efficiency is significant. The purpose of the present invention is to provide a deformation optimization method, system and medium for AOI inspection of the mask. On the basis of traditional AOI inspection technology, the method is improved. By establishing a relationship between the deformation variable and the focal length value generated by the clamping relationship between the focus value of the scanning lens and the target mask, the deformation of the target mask is intuitively judged without the use of cumbersome optical interferometers and other equipment. At the same time, the most suitable hardware parameters are calculated through the parameter determination model and the deformation variable model, and the clamping state is improved by adjusting the hardware parameters to optimize the deformation during scanning, thereby reducing the AOI false detection rate and improving production efficiency.
[0005] The present invention is achieved through the following technical solutions: This solution provides a deformation optimization method for mask AOI inspection, including: During the AOI inspection of the target mask, the focal length data of the scanning lens along the moving direction of the clamping mechanism is collected; Draw a focal length deformation relationship diagram according to the focal length data; A safe deformation range is preset and the focal length deformation relationship curve in the focal length deformation relationship diagram is judged to be beyond the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, an optimization mechanism is activated to obtain the optimal clamping force and optimal clamping distance. Adjust the clamping mechanism to the optimal clamping force and optimal clamping distance.
[0006] A further optimization scheme is that the focal length deformation relationship diagram is drawn according to the focal length data; including the method: A coordinate system is constructed with the moving distance of the clamping mechanism as the x-axis and the focal length of the scanning lens as the y-axis; A focal length deformation relationship curve is drawn in the coordinate system based on the focal length data.
[0007] A further optimization scheme is to preset a safe deformation range and determine whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range; including the following method: Set the lower and upper focal length limits, and use the area between them as the safe deformation range; When the focal length deformation relationship curve is completely within the safe deformation range, it is determined that the current focal length deformation relationship curve does not exceed the safe deformation range; when any point of the focal length deformation relationship curve exceeds the safe deformation range, it is determined that the current focal length deformation relationship curve exceeds the safe deformation range.
[0008] A further optimization solution is that the method for obtaining the optimal clamping force and the optimal clamping distance includes: Sampling the target mask to obtain sampling focal length data, and calculating the shape variable of the target mask according to the shape variable model; A focal length deformation scatter plot is constructed based on the sampled focal length data and deformation variables, a linear regression equation of the target mask is solved using the least squares method, and a parameter determination model of the target mask is derived based on the linear regression equation; Perform multi-area sampling tests on the target mask to determine the fixed focal length and fixed clamping distance, which are then input into the parameter determination model to obtain the optimal clamping force. A multi-area sampling test is performed on the target mask to determine the fixed focal length and fixed clamping force, which are then input into the parameter determination model to obtain the optimal clamping distance.
[0009] A further optimization scheme is that the target mask is sampled to obtain sampling focal length data, and the deformation variable of the target mask is calculated according to the deformation variable model; including the method: Perform AOI scanning on the target mask to obtain multiple scanning strips, and record N sets of sampling focal length data along the scanning direction of the scanning lens; N>2; Substitute the sampled focal length data into the shape variable model to calculate N groups of shape variables :
[0010] Wherein, k represents the proportional coefficient, E represents the elastic modulus, h represents the thickness of the target mask, L represents the free end length; and F represents the clamping force.
[0011] A further optimization scheme is to perform a multi-area sampling test on the target mask to determine a fixed focal length and a fixed clamping distance, and input the fixed focal length and the fixed clamping distance into a parameter determination model to obtain an optimal clamping force; including the following method: The target mask is divided into an easily deformable area and an undeformable area, and a plurality of easily deformable sampling points are set in the easily deformable area; Focus each easily deformed sampling point and record the focal length value, and calculate the average focal length value of all easily deformed sampling points as the fixed focal length; At a fixed focal length, adjust the clamping force so that the pressure on the target mask is uniform, and record the clamping distance at this time as the fixed clamping distance; Substituting the fixed focal length and fixed clamping distance into the parameter determination model, the optimal clamping force is calculated:
[0012] in, represents initial focus; K represents the first coefficient; L represents the clamping distance; F represents the clamping force; and f represents the real-time focal length.
[0013] A further optimization scheme is to perform a multi-area sampling test on the target mask to determine a fixed focal length and a fixed clamping force, and input the fixed focal length and the fixed clamping force into a parameter determination model to obtain an optimal clamping distance; including the following method: Dividing the target mask into an easily deformable area and a non-deformable area, setting a plurality of easily deformable sampling points in the easily deformable area, and setting a plurality of non-deformable sampling points in the non-deformable area; With two horizontal clamps as a group, focus on each easily deformed sampling point and record the focal length value, calculate the average focal length value FX of all easily deformed sampling points; focus on each non-deformable sampling point and record the focal length value, calculate the average focal length value FX of all non-deformable sampling points. The average focal length value FM of the sampling points; the average of the average focal length value FX and the average focal length value FM is used as the fixed focal length; The optimal clamping force is used as the fixed clamping force; The fixed focal length and fixed clamping distance are substituted into the parameter determination model to calculate the optimal clamping force.
[0014] A further optimization solution is that the method of dividing the easily deformable area and the non-deformable area of the target mask includes: The area extending N distance inward from the edge of the target mask directly contacting the clamping mechanism is divided into the easily deformed area, and for the rectangular target mask, the area extending N / 2 distance to both sides of its shorter median line is divided into the easily deformed area.
[0015] This solution also provides a deformation optimization system for mask AOI inspection, which is characterized by being used to implement the above-mentioned deformation optimization method for mask AOI inspection; comprising: The acquisition module is used to collect the focal length data of the scanning lens along the moving direction of the clamping mechanism during the AOI inspection process of the mask; A drawing module, configured to draw a focal length deformation relationship diagram according to the focal length data; An optimization module is used to preset a safe deformation range and determine whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, an optimization mechanism is activated to obtain the optimal clamping force and optimal clamping distance; The adjustment module is used to adjust the clamping mechanism to an optimal clamping force and an optimal clamping distance.
[0016] The present solution also provides a computer-readable medium having a computer program stored thereon. The computer program is executed by a processor to implement the above-mentioned deformation optimization method for mask AOI inspection.
[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention provides a deformation optimization method, system, and medium for AOI inspection of a mask. Based on traditional mask AOI inspection technology, the method is improved by establishing a relationship between the focus value of the scanning lens and the deformation variable and focal length value caused by the clamping relationship between the target mask, so as to intuitively judge the deformation of the target mask without using cumbersome equipment such as optical interferometers. At the same time, the most appropriate hardware parameters are calculated through a parameter determination model and a deformation variable model. By adjusting the hardware parameters and improving the clamping state, the deformation during scanning is optimized, thereby reducing the AOI false detection rate and improving production efficiency.
[0018] 2. The present invention provides a deformation optimization method, system and medium for mask AOI detection; the most appropriate hardware parameters are calculated through a parameter determination model and a deformation variable model, and the hardware parameters of the clamping mechanism are adjusted to improve the clamping state to optimize the deformation of the target mask during scanning, thereby reducing the AOI false detection rate and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings: Figure 1 This is a flow chart of the deformation optimization method for mask AOI inspection; Figure 2 Schematic diagram of the focal length deformation relationship curve; Figure 3 Schematic diagram of mask assembly; Figure 4 is the focal length deformation relationship scatter plot; Figure 5 This is a sampling diagram of easy-to-deform points and difficult-to-deform points; In the attached figure: 1-Holder block; 2-target mask. DETAILED DESCRIPTION
[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.
[0021] The glass substrate of the mask is very thin, ranging from a few millimeters to more than ten millimeters. During AOI scanning, it is clamped by the holder block in the clamping mechanism. The weight of the mask and the clamping force of the holder block cause the mask to deform. Measuring small deformations typically requires the use of a laser interferometer, which requires calibration of the optical environment. This is a cumbersome process and not suitable for detection during scanning. Because deformation can cause changes in the focal length of the camera, the method proposed in this invention can use the camera's focal length to determine deformation and calculate the deformation amount. See the following examples for details.
[0022] Example 1 This embodiment provides a deformation optimization method for mask AOI detection, such as Figure 1 Shown, including: Step 1: During the AOI inspection of the target mask, the focal length data of the scanning lens along the moving direction of the clamping mechanism is collected; Step 2: Draw a focal length deformation relationship diagram based on the focal length data; this step specifically includes the following method: S21, constructing a coordinate system with the moving distance of the clamping mechanism as the x-axis and the focal length of the scanning lens as the y-axis; S22, based on the focal length data, draws a focal length deformation relationship curve in the coordinate system. When the target mask is scanned by the AOI equipment, the lens is constantly focusing on the mask in real time. The focal lengths along the moving direction of the Holder block are plotted one by one on the Cartesian coordinate system and connected into a line to clearly show the deformation condition. Figure 2 shown.
[0023] Step 3: Preset a safe deformation range and determine whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, activate the optimization mechanism to obtain the optimal clamping force and optimal clamping distance; In step three, the method of presetting a safe deformation range and determining whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range includes: Set the lower and upper focal length limits, and use the area between them as the safe deformation range; When the focal length deformation relationship curve is completely within the safe deformation range, it is determined that the current focal length deformation relationship curve does not exceed the safe deformation range; when any point of the focal length deformation relationship curve exceeds the safe deformation range, it is determined that the current focal length deformation relationship curve exceeds the safe deformation range.
[0024] Figure 2 Many parts of the focal length deformation relationship curve in the figure have exceeded the safe deformation range (the two horizontal straight lines in the figure). The mask assembly diagram is shown in Figure 3As shown, the target reticle 2 is clamped by the Holder blocks 1 on either side of the reticle's edge. Uneven or excessive force can cause deformation of the target reticle's flatness plane perpendicular to the reticle surface. Due to the stress, the target reticle can sag inward or bulge outward. The lens focuses perpendicular to the target reticle surface. The focal length at sharp focus provides information about the reticle's flatness, or in other words, its deformation. Because the change in focal length is positively correlated with the magnitude of deformation, the focal length can be used to represent the deformation by deriving a relationship between focal length and deformation. This focal length can then be used to calculate the required hardware parameters (i.e., the optimal clamping force and distance).
[0025] Force analysis reveals that the target mask is subjected to clamping forces on both sides, and deformation perpendicular to the mask surface is caused by internal stress within the target mask. The target mask is very thin, and its edges are fixed by clamps to prevent movement and rotation. This deformation satisfies the thin plate bending model with rigid boundary conditions. The amount of deformation perpendicular to the mask surface, bending inward or outward, is called deflection. When the target mask thickness is much smaller than the target mask height and width, the small deflection thin plate theory is satisfied. In this embodiment, the glass substrate material of the target mask is quartz glass. Under these clamping conditions, the mask deforms elastically, which conforms to Hooke's law. Therefore, (F represents the clamping force, E represents the elastic modulus, represents the shape variable); When the target mask satisfies the small deflection thin plate theory, the tangible variable model is:
[0026] k represents the proportional coefficient, E represents the elastic modulus, h represents the thickness of the target mask, L represents the free end length, and F represents the clamping force. In this embodiment, E of the quartz material is 72GPA, the glass thickness h is a known constant, and the free end length L, i.e., the left and right distance of the Holder block, is a measurable constant. When the boundary condition is a rigid constraint, , then .
[0027] It is known that the change in focal length f is positively correlated with the deformation of the glass substrate (target mask) and satisfies the normal distribution. Multiple glass substrates of the same size can be used to collect multiple deformation variables in the case of clamping and scanning. and the focal length value corresponding to one , constructing Figure 4 The focal length deformation relationship scatter plot is shown (concave deformation on the left and convex deformation on the right), and then the linear regression equation is established as: , the slope A can be obtained by using the least squares method, and then we can get:
[0028]
[0029]
[0030] make , K is the first coefficient, which is a constant calculated by the extra calculation, then:
[0031] in ,F, The third variable can be obtained by controlling two of the variables.
[0032] The specific parameter determination models are: ; This allows you to set the appropriate focal length and clamping distance L to determine the most appropriate clamping force F; or set the appropriate focal length and the clamping force F to determine the most suitable Holder distance L.
[0033] Specifically, the method for obtaining the optimal clamping force and the optimal clamping distance includes: S31, sampling the target mask to obtain sampling focal length data, and calculating the deformation variable of the target mask according to the deformation variable model; this step specifically includes the following method: Perform AOI scanning on the target mask to obtain multiple scanning strips, and record N sets of sampling focal length data along the scanning direction of the scanning lens; N>2; Substitute the sampled focal length data into the shape variable model to calculate N groups of shape variables :
[0034] Wherein, k represents the proportional coefficient, E represents the elastic modulus, h represents the thickness of the target mask, L represents the free end length; and F represents the clamping force.
[0035] S32, constructing a focal length deformation scatter plot based on the sampled focal length data and the deformation variable, solving a linear regression equation of the target mask based on a least squares method, and deriving a parameter determination model of the target mask based on the linear regression equation; S33, performing a multi-area sampling test on the target mask to determine a fixed focal length and a fixed clamping distance, inputting the fixed focal length and the fixed clamping distance into a parameter determination model to obtain an optimal clamping force; this step specifically includes the following method: S331, such as Figure 5As shown, the target reticle is divided into an easily deformable region and a non-deformable region, with multiple easily deformable sampling points set in the easily deformable region. The area extending inward from the edge of the target reticle directly in contact with the clamping mechanism for a distance N is divided into the easily deformable region. For a rectangular target reticle, the area extending N / 2 to either side of its shorter median line is also divided into the easily deformable region. The remaining area is the non-deformable region. Generally, the area near the direct contact force between the glass substrate and the clamp and the middle part of the glass substrate are prone to deformation, while the part of the glass substrate away from the clamp and not near the central bending area is generally not prone to deformation.
[0036] S332, focusing each easily deformed sampling point and recording the focal length value, and calculating the average focal length value of all easily deformed sampling points as the fixed focal length; S333, at a fixed focal length, adjusting the clamping force so that the pressure on the target mask is uniform, and recording the clamping distance at this time as the fixed clamping distance; S334, substituting the fixed focal length and the fixed clamping distance into the parameter determination model to calculate the optimal clamping force.
[0037] The clamps of AOI equipment are typically driven by pneumatic cylinders or motors. The clamping force F applied by the clamps can be adjusted by adjusting the cylinder pressure and motor power. Therefore, focusing samples are taken from all deformation points near the clamps to calculate the average focal length, which serves as a standard for adjusting the clamping force of all clamps (i.e., fixing the focal length) to achieve uniform pressure on the glass sheet. Finally, the fixed focal length and fixed clamping distance are substituted into the parameter determination model to calculate the optimal clamping force.
[0038] S34, performing a multi-area sampling test on the target mask to determine a fixed focal length and a fixed clamping force, and inputting the fixed focal length and the fixed clamping force into a parameter determination model to obtain an optimal clamping distance.
[0039] This step specifically includes the following methods: S341, dividing the target mask into an easily deformable area and a non-deformable area, setting a plurality of easily deformable sampling points in the easily deformable area, and setting a plurality of non-deformable sampling points in the non-deformable area; S342: Using two horizontal clamps as a group, focus each easily deformed sampling point and record the focal length, and calculate the average focal length FX of all easily deformed sampling points; focus each non-deformed sampling point and record the focal length, and calculate the average focal length FM of all non-deformed sampling points; and use the average of the average focal length FX and the average focal length FM as the fixed focal length; Specifically, first select all points horizontal to the clamp. Since the clamping force is in the horizontal direction, the focus of deformation improvement is on the horizontal direction. Take two horizontal clamps as a group, and average the focal length values of all points that are easily deformed in the horizontal direction to obtain the average value of the easily deformed focal length of multiple groups. 、 … , and then average all groups to get (n is the number of groups); then focus all the selected points on the glass substrate that are not easily deformed and average all the focal length values to get FM; finally, the best whole-plate focus value can be obtained from FX and FM, FM .
[0040] S343, taking the optimal clamping force as the fixed clamping force; S344: Substitute the fixed focal length and the fixed clamping distance into the parameter determination model to calculate the optimal clamping force.
[0041] Step 4: Adjust the clamping mechanism to the optimal clamping force and optimal clamping distance.
[0042] Example 2 This embodiment provides a deformation optimization system for mask AOI inspection, which is used to implement the deformation optimization method for mask AOI inspection described in Example 1; the system includes: The acquisition module is used to collect the focal length data of the scanning lens along the moving direction of the clamping mechanism during the AOI inspection process of the mask; A drawing module, configured to draw a focal length deformation relationship diagram according to the focal length data; An optimization module is used to preset a safe deformation range and determine whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, an optimization mechanism is activated to obtain the optimal clamping force and optimal clamping distance; The adjustment module is used to adjust the clamping mechanism to an optimal clamping force and an optimal clamping distance.
[0043] Example 3 This embodiment provides a computer-readable medium having a computer program stored thereon. The computer program is executed by a processor to implement the deformation optimization method for mask AOI inspection as described in Example 1. Specifically, the following steps are performed: Step 1: During the AOI inspection of the target mask, the focal length data of the scanning lens along the moving direction of the clamping mechanism is collected; Step 2: drawing a focal length deformation relationship diagram according to the focal length data; Step 3: Preset a safe deformation range and determine whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, activate the optimization mechanism to obtain the optimal clamping force and optimal clamping distance; Step 4: Adjust the clamping mechanism to the optimal clamping force and optimal clamping distance.
[0044] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A deformation optimization method for mask AOI inspection, characterized in that: include: During the AOI inspection of the target mask, the focal length data of the scanning lens along the moving direction of the clamping mechanism is collected; Draw a focal length deformation relationship diagram according to the focal length data; A safe deformation range is preset and the focal length deformation relationship curve in the focal length deformation relationship diagram is judged to be beyond the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, an optimization mechanism is activated to obtain the optimal clamping force and optimal clamping distance. Adjust the clamping mechanism to the optimal clamping force and optimal clamping distance.
2. The deformation optimization method for mask AOI inspection according to claim 1, characterized in that: said drawing of a focal length deformation relationship diagram according to said focal length data; Includes methods: A coordinate system is constructed with the moving distance of the clamping mechanism as the x-axis and the focal length of the scanning lens as the y-axis; A focal length deformation relationship curve is drawn in the coordinate system based on the focal length data.
3. The deformation optimization method for mask AOI inspection according to claim 2, characterized in that: The preset safe deformation range and determining whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range; Includes methods: Set the lower and upper focal length limits, and use the area between them as the safe deformation range; When the focal length deformation relationship curve is completely within the safe deformation range, it is determined that the current focal length deformation relationship curve does not exceed the safe deformation range; When any point of the focal length deformation relationship curve exceeds the safe deformation range, it is determined that the current focal length deformation relationship curve exceeds the safe deformation range.
4. The deformation optimization method for mask AOI inspection according to claim 1, characterized in that: The method for obtaining the optimal clamping force and the optimal clamping distance includes: Sampling the target mask to obtain sampling focal length data, and calculating the shape variable of the target mask according to the shape variable model; A focal length deformation scatter plot is constructed based on the sampled focal length data and deformation variables, a linear regression equation of the target mask is solved using the least squares method, and a parameter determination model of the target mask is derived based on the linear regression equation; Perform multi-area sampling tests on the target mask to determine the fixed focal length and fixed clamping distance, which are then input into the parameter determination model to obtain the optimal clamping force. A multi-area sampling test is performed on the target mask to determine the fixed focal length and fixed clamping force, which are then input into the parameter determination model to obtain the optimal clamping distance.
5. The deformation optimization method for mask AOI inspection according to claim 4, characterized in that: The target mask is sampled to obtain sampling focal length data, and the deformation variable of the target mask is calculated according to the deformation variable model; including: method: Perform AOI scanning on the target mask to obtain multiple scanning strips, and record N sets of sampling focal length data along the scanning direction of the scanning lens; N>2; Substitute the sampled focal length data into the shape variable model to calculate N groups of shape variables : Wherein, k represents the proportional coefficient, E represents the elastic modulus, h represents the thickness of the target mask, L represents the free end length; and F represents the clamping force.
6. The deformation optimization method for mask AOI inspection according to claim 4, characterized in that: The method comprises: performing a multi-area sampling test on the target mask to determine a fixed focal length and a fixed clamping distance, inputting the fixed focal length and the fixed clamping distance into a parameter determination model to obtain an optimal clamping force; including: method: The target mask is divided into an easily deformable area and an undeformable area, and a plurality of easily deformable sampling points are set in the easily deformable area; Focus each easily deformed sampling point and record the focal length value, and calculate the average focal length value of all easily deformed sampling points as the fixed focal length; At a fixed focal length, adjust the clamping force so that the pressure on the target mask is uniform, and record the clamping distance at this time as the fixed clamping distance; Substituting the fixed focal length and fixed clamping distance into the parameter determination model, the optimal clamping force is calculated: in, represents initial focus; K represents the first coefficient; L represents the clamping distance; F represents the clamping force; and f represents the real-time focal length.
7. The deformation optimization method for mask AOI inspection according to claim 6, characterized in that: The multi-area sampling test is performed on the target mask to determine the fixed focal length and the fixed clamping force, and the fixed focal length and the fixed clamping force are input into the parameter determination model to obtain the optimal clamping distance; Includes methods: Dividing the target mask into an easily deformable area and a non-deformable area, setting a plurality of easily deformable sampling points in the easily deformable area, and setting a plurality of non-deformable sampling points in the non-deformable area; With two horizontal clamps as a group, focus on each easily deformed sampling point and record the focal length value, calculate the average focal length value FX of all easily deformed sampling points; focus on each non-deformable sampling point and record the focal length value, calculate the average focal length value FX of all non-deformable sampling points. The average focal length value FM of the sampling points; the average of the average focal length value FX and the average focal length value FM is used as the fixed focal length; The optimal clamping force is used as the fixed clamping force; The fixed focal length and fixed clamping distance are substituted into the parameter determination model to calculate the optimal clamping force.
8. The deformation optimization method for mask AOI inspection according to claim 6 or 7, characterized in that: The method of dividing the easily deformable area and the non-deformable area of the target mask includes: The area extending N distance inward from the edge of the target mask directly contacting the clamping mechanism is divided into the easily deformed area, and for the rectangular target mask, the area extending N / 2 distance to both sides of its shorter median line is divided into the easily deformed area.
9. A deformation optimization system for mask AOI inspection, characterized in that: A deformation optimization method for implementing a mask AOI inspection according to any one of claims 1 to 8; comprising: The acquisition module is used to collect the focal length data of the scanning lens along the moving direction of the clamping mechanism during the AOI inspection process of the mask; A drawing module, configured to draw a focal length deformation relationship diagram according to the focal length data; An optimization module is used to preset a safe deformation range and determine whether the focal length deformation relationship curve in the focal length deformation relationship diagram exceeds the safe deformation range. When the focal length deformation relationship curve exceeds the safe deformation range, an optimization mechanism is activated to obtain the optimal clamping force and optimal clamping distance; The adjustment module is used to adjust the clamping mechanism to an optimal clamping force and an optimal clamping distance.
10. A computer-readable medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the deformation optimization method for mask AOI inspection according to any one of claims 1 to 7.