Silicon wafer or wafer surface auxiliary focusing method in semiconductor detection process

Abstract

The invention discloses a silicon wafer or wafer surface auxiliary focusing method in a semiconductor detection process. The method comprises the following steps that a standard optical flat is placed above a microporous ceramic chuck to be adsorbed and fixed; obtaining reflected light spot signal intensity values of the standard optical flat at different positions; adjusting the levelness of the chuck according to the signal intensity values of the reflected light spots at different positions; black and white checkerboard mark sheet images at different positions are collected, corresponding transition pixel values are obtained, and it is analyzed that the adjusted levelness of the chuck meets set conditions; placing a silicon wafer or a wafer on a chuck meeting a set condition, and obtaining a focus mapping graph formed by height points; and drawing a scanning path, formulating a segmented midpoint auxiliary focusing strategy based on the scanning path, and performing auxiliary focusing on the surface of the silicon wafer or the wafer to obtain a clear image. According to the invention, high-precision, high-speed and low-cost auxiliary focusing can be realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor inspection technology, and more specifically to a method for assisting in focusing on the surface of a silicon wafer or crystal in a semiconductor inspection process. Background Technology

[0002] In semiconductor silicon wafer / wafer manufacturing, after a series of processes (such as wire cutting, grinding, etching, edge polishing, post-polishing cleaning, surface inspection, particle testing, argon annealing, coating, photolithography, etc.), due to factors such as high-temperature annealing, thin film layer stress, structural dimensions, process doping, crystal defects, etc., lattice mismatch or different coefficients of expansion between the film layer and the substrate can lead to tensile or compressive stress, causing the silicon wafer to warp and deform. At the same time, when the silicon wafer is formed into a wafer through photolithography and etching, the process of releasing thin film stress can also cause the wafer to warp and deform.

[0003] The aforementioned manufacturing process causes silicon wafers or chips to warp to varying degrees at different stages, affecting subsequent dicing, chip packaging, and functional testing, thus resulting in losses. To avoid this, silicon wafers or chips with significant warping need to be quickly rejected manually upon arrival. However, silicon wafers or chips with minor warping (<1mm) are difficult to judge manually, and even after being chucked, the surface of the wafer or chip still exhibits slight height fluctuations. Therefore, under the conditions of high magnification, high precision, and low depth of field testing, ensuring that the surface of the object being tested remains clearly imaged near the focal plane, and achieving high-precision detection and measurement of warped silicon wafers or chips, has become an urgent problem to be solved in the semiconductor silicon wafer / wafer manufacturing process.

[0004] To achieve high-precision inspection and measurement of warped silicon wafers or pavements, current technologies mainly include laser-based real-time focusing and image-based real-time focusing. Both methods require real-time adjustment of the Z-axis to keep the acquired image at the focal plane. Laser-based real-time focusing offers high accuracy but is expensive; image-based real-time focusing is less expensive but has lower accuracy and slower processing speed, making it unable to meet the high throughput requirements of increasingly demanding CT scans. Summary of the Invention

[0005] The purpose of this invention is to provide a method for assisted focusing of silicon wafer or crystal surface in semiconductor inspection processes, comprising the following steps: Step S1: Place the standard flat crystal on top of the microporous ceramic chuck, and use the ceramic microporous gas path built into the chuck to adsorb and fix the flat crystal; Step S2: Turn on the laser illumination module of the optical system device, adjust the chuck position multiple times based on the XY displacement platform, and obtain the reflected light spot signal intensity value of the standard flat crystal at different positions; Step S3: Set the intensity value error range, compare the intensity value of the reflected light spot signal at different positions with the intensity value error range, obtain the comparison result, and adjust the chuck levelness based on the comparison result; Step S4: Remove the standard flat crystal, place the black and white checkerboard marker on the chuck and fix it with adsorption, move the XY displacement platform, collect images of the black and white checkerboard marker at different positions, obtain the corresponding transition pixel values, and analyze whether the level of the adjusted chuck meets the set conditions. Step S5: Place the silicon wafer or crystal on a chuck that meets the set conditions, adjust the 3D point spectrum to the working distance based on the Z-axis linear motion module, move the XY displacement platform to perform point scanning, and obtain a focal mapping map composed of height points; Step S6: Draw the scanning path based on the focus map, formulate a segmented midpoint auxiliary focusing strategy based on the scanning path, and perform auxiliary focusing on the silicon wafer or wafer surface based on the segmented midpoint auxiliary focusing strategy to obtain a clear image.

[0006] In a preferred embodiment of the present invention, in step S2, when the XY displacement platform is moved to obtain the reflected light spot signal intensity values ​​at different positions of the standard flat crystal, the number of sampling points is greater than or equal to 5, and the sampling points are evenly distributed on the surface of the standard flat crystal, including the center position of the standard flat crystal and the surrounding edge area.

[0007] In a preferred embodiment of the present invention, the position of the chuck is adjusted based on the moving XY displacement platform so that the center of the standard flat crystal is located in the center of the imaging field of view. The laser spot is received and converted into a signal intensity value in real time. The XY displacement platform is moved multiple times to obtain the signal intensity values ​​at different positions of the standard flat crystal. The range is analyzed based on the signal intensity values ​​at different positions. The range is less than or equal to 1%. If the range is greater than 1%, the levelness of the chuck is adjusted.

[0008] In a preferred embodiment of the present invention, in step S5, when the XY displacement platform is moving to perform point scanning, a scanning matrix is ​​first constructed, and then the 3D point spectral sensor is guided to complete the point spectral sampling matrix based on the scanning matrix, thereby generating a point spectral scanning point cloud height map of the silicon wafer or wafer, and a focal mapping map is obtained based on the point spectral scanning point cloud height map.

[0009] In a preferred embodiment of the present invention, when constructing the scanning matrix, the number of rows and columns of the scanning matrix is ​​determined according to the diameter of the silicon wafer or crystal and the field of view of the objective lens, as follows: Set a silicon wafer or crystal with a diameter of 300 mm, and when using a 10X objective lens, set the scan matrix to 30×30 rows and columns; When using a 5X objective lens, the scan matrix is ​​set to 15×15 rows and columns;

[0010] When using a 2X objective lens, the scan matrix is ​​set to 8×8 rows and columns to ensure that the scan covers the entire surface of the silicon wafer or chip.

[0011] In a preferred embodiment of the present invention, in step S6, the scanning path is a zigzag scanning path; the segmented midpoint-assisted focusing strategy is specifically as follows: the midpoint of the Z-axis height between the start and end points of the first segment is taken as the moving and stopping position of the Z-axis motor of the first segment, the end point of the first segment is taken as the start point of the second segment, the midpoint of the Z-axis height between the start and end points of the second segment is taken as the moving and stopping position of the Z-axis motor of the second segment, and so on, the end point of the (N-1)th segment is taken as the start point of the Nth segment, and the midpoint of the Z-axis height between the start and end points of the Nth segment is calculated as the moving and stopping position of the Z-axis motor of the Nth segment, where N is a positive integer greater than 1.

[0012] In a preferred embodiment of the present invention, the optical system device in step S2 includes a camera, a tube lens, an objective lens, a bright field illumination source, a dark field illumination source, and a laser illumination module; the objective lens has a magnification of 2X, 5X, or 10X.

[0013] In a preferred embodiment of the present invention, in step S1, the chuck is provided with multiple ceramic microporous air passages. When the ceramic microporous air passages adsorb silicon wafers or wafers, the air pressure value of each microporous air passage is monitored in real time. The air pressure value of any two microporous air passages is calculated to obtain the air pressure difference. The air pressure difference is controlled within ±0.02MPa to ensure uniform force when the silicon wafers or wafers are adsorbed.

[0014] Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art: This invention, based on a horizontal chuck, precisely controls the air path of each micro-hole to ensure uniform adsorption of silicon wafers / crystals; through a Z-axis linear motion module and X and Y-axis displacement platforms, it acquires 3D point spectral focus mapping height data, so that each frame of image acquired by the optical system is close to the positive focal plane, achieving high-precision, high-speed and low-cost auxiliary focusing. Attached Figure Description

[0015] Figure 1 This invention provides a flowchart of a silicon wafer or crystal surface-assisted focusing method in a semiconductor inspection process. Figure 2 This shows a schematic diagram of the flat crystal and the black and white checkerboard marker provided in an embodiment of the present invention; Figure 3 A schematic diagram of the system device provided in an embodiment of the present invention is shown; Figure 4 This shows a schematic diagram of the front side of a silicon wafer or crystal provided in an embodiment of the present invention; Figure 5 A schematic diagram of warping provided in an embodiment of the present invention is shown; Figure 6A schematic diagram of the chuck provided in an embodiment of the present invention is shown; Figure 7 A schematic diagram of the micropores provided in an embodiment of the present invention is shown; Figure 8 This shows a schematic diagram of the objective lens depth of field provided in an embodiment of the present invention; Figure 9 This shows a schematic diagram of the objective lens depth-of-field parameters provided in an embodiment of the present invention; Figure 10 The field-of-view scanning matrix provided in the embodiments of the present invention is shown; Figure 11 The point spectrum sampling matrix provided in the embodiment of the present invention is shown; Figure 12 This displays a point cloud height map provided in an embodiment of the present invention; Figure 13 This displays a sparse point array diagram provided in an embodiment of the present invention; Figure 14 This shows a cross-sectional view of the wafer or silicon wafer morphology provided in an embodiment of the present invention; Figure 15 This shows a schematic diagram of the first segment midpoint-assisted focusing provided by an embodiment of the present invention; Figure 16 This shows a schematic diagram of the second segment midpoint-assisted focusing provided in an embodiment of the present invention; Figure 17 This shows a schematic diagram of midpoint-assisted focusing for the Nth segment provided in an embodiment of the present invention; Figure 18 This shows a zigzag scanning path diagram provided in an embodiment of the present invention; Figure 19 This shows a wafer image in a state without auxiliary focusing, as provided in an embodiment of the present invention; Figure 20 This shows a wafer image under assisted focusing conditions provided in an embodiment of the present invention; Figure 21 A schematic diagram of transition pixels provided in an embodiment of the present invention is shown. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] like Figure 1 As shown, this embodiment of the invention provides a method for assisted focusing on the surface of a silicon wafer or crystal in a semiconductor inspection process. The test procedure is detailed below: Step 1: Connect and start the PC software operation and control module. First, place the standard optical disc on top of the microporous ceramic chuck. The optical disc is adsorbed and fixed through the ceramic microporous air passage (micropore diameter is about 20 micrometers) built into the chuck.

[0020] Step 2: Move the XY displacement platform so that the center of the standard flat crystal placed above the chuck is in the center of the imaging field of view. Turn on the laser (wavelength: 785nm) illumination module of the optical system to receive and collect the laser spot in real time and convert it into a signal intensity value. Move the XY displacement platform again to obtain the signal intensity values ​​of the standard flat crystal at different positions. By adjusting the spiral set screw of the tilt adjustment module below the chuck multiple times, the range of signal intensity values ​​at different positions of the standard flat crystal is controlled within 1%.

[0021] Step 3: Remove the standard flat crystal, place the black and white checkerboard marker and fix it in place. Turn on the optical system and move the X and Y axis displacement platforms respectively to acquire images of the black and white checkerboard marker at different positions, and obtain the corresponding transition pixel values ​​(≤3 pixels). According to the algorithm detection principle, at least 3 transition pixels are needed to complete the feature boundary localization; the boundary grayscale of the real image will show a change from dark to light (from black to white), that is, a gradual S-shaped curve, rather than an ideal step curve, such as... Figure 21 As shown, the horizontal adjustment of the chuck platform is completed by using the above-mentioned standard flat crystal signal intensity value range, and the transition pixel value is obtained by using the black and white checkerboard marker to complete the horizontal confirmation of the chuck platform.

[0022] Step 4: Place the silicon wafer / crystal above the chuck, precisely control the gas path of each micropore to ensure that the silicon wafer / crystal is uniformly adsorbed; through the Z-axis linear movement module, precisely adjust the 3D point spectrum to the working distance, and move the XY displacement platform to perform point scanning to obtain a focal mapping map composed of height points.

[0023] Step 5: Based on the scanning path drawn by the focus map, formulate a segmented midpoint-assisted focusing strategy, and calculate the midpoint position corresponding to the start and end points of each segment in a rolling manner, so that each frame of image acquired by the optical system is close to the positive focal plane.

[0024] The above steps can be used to assist in focusing the silicon wafer / crystal surface, ultimately enabling defect detection and dimensional measurement of the silicon wafer / crystal.

[0025] Figure 19 , 20 The images show 10X wafer images with and without assisted focusing. Comparing the two images, it can be seen that the 10X wafer can be clearly imaged using the point spectrum assisted focusing strategy of this invention.

[0026] According to an embodiment of the present invention, in step S2, when the XY displacement platform is moved to obtain the reflected light spot signal intensity values ​​at different positions of the standard flat crystal, the number of sampling points is greater than or equal to 5, and the sampling points are evenly distributed on the surface of the standard flat crystal, including the center position of the standard flat crystal and the surrounding edge area.

[0027] According to an embodiment of the present invention, the position of the chuck is adjusted based on the moving XY displacement platform so that the center of the standard flat crystal is located in the center of the imaging field of view. The laser spot is received and converted into a signal intensity value in real time. The XY displacement platform is moved multiple times to obtain the signal intensity values ​​at different positions of the standard flat crystal. The range is analyzed based on the signal intensity values ​​at different positions. If the range is less than or equal to 1%, the chuck level is adjusted.

[0028] According to an embodiment of the present invention, in step S5, when the XY displacement platform is moved to perform point scanning, a scanning matrix is ​​first constructed, and then the 3D point spectral sensor is guided to complete the point spectral sampling matrix based on the scanning matrix, thereby generating a point spectral scanning point cloud height map of the silicon wafer or wafer, and a focal mapping map is obtained based on the point spectral scanning point cloud height map.

[0029] It should be noted that after undergoing a series of manufacturing processes, the warpage of silicon wafers / crystals is relatively gradual due to factors such as high-temperature annealing, thin-film layer stress, or stress release, and generally does not exhibit abrupt changes in critical regions. Standard wafer or silicon wafer specifications are 300mm in diameter and approximately 0.8mm in thickness. Figure 4 The image shown is a front view of the wafer. A warped silicon wafer or piezoelectric wafer exists; after testing, the corresponding 3D point cloud height diagram is shown below. Figure 5 As shown.

[0030] By precisely controlling the gas path of each micropore using a microporous ceramic chuck, uniform adsorption is achieved. At this point, the silicon wafer or crystal surface is relatively flat, typically with fluctuations of around 10 micrometers. For example... Figure 6 The diagram shown is of the chuck. Figure 7 This is a schematic diagram of a microaperture (20 micrometers in diameter). Due to variations in depth of focus across different magnification objectives, the corresponding depth-of-field diagram is shown below. Figure 8 As shown, common depth-of-field parameters for 2X / 5X / 10X objectives are as follows: Figure 9 As shown.

[0031] As mentioned above, after the silicon wafer / crystal is adsorbed by the microporous ceramic chuck, the fluctuation is typically around 10 micrometers. When the imaging field of view formed by the 10X objective lens is selected to construct the scanning matrix, the corresponding schematic diagram is shown below. Figure 10 As shown in the diagram. This scanning matrix is ​​used to guide the point spectral sensor in completing the point spectral acquisition matrix, and its corresponding schematic diagram is shown in the diagram. Figure 11 As shown; finally, a point cloud height map of the wafer or silicon wafer is generated using point spectral scanning, as shown. Figure 12 As shown.

[0032] By using point spectral scanning of the point cloud height map, one row is extracted to generate a sparse point array map of the wafer or silicon wafer. Specifically, to facilitate the illustration of the cross-sectional morphology of the wafer or silicon wafer, [the following is used]. Figure 11 From the constructed point spectrum sampling matrix, one row is randomly extracted to generate a sparse point array map of the wafer or silicon chip, as an example. Figure 13 As shown; connecting adjacent points yields a cross-section of a continuous wafer or silicon wafer morphology, such as... Figure 14 As shown.

[0033] In the actual implementation of this application, it is necessary to... Figure 11 Each row of the constructed point spectrum sampling matrix is ​​extracted to generate a sparse point array map of the wafer or silicon wafer; then, adjacent points are connected to obtain a cross-section of the continuous wafer or silicon wafer morphology for each row, and then... Figure 15 , Figure 16 and Figure 17 The segmented midpoint-assisted focusing strategy shown ultimately achieves high-precision and high-speed assisted focusing that is both "capable of keeping up" and "accurately aligned".

[0034] According to an embodiment of the present invention, when constructing the scanning matrix, the number of rows and columns of the scanning matrix is ​​determined based on the diameter of the silicon wafer or crystal and the field of view of the objective lens, as follows: Set a silicon wafer or crystal with a diameter of 300 mm, and when using a 10X objective lens, set the scan matrix to 30×30 rows and columns; When using a 5X objective lens, the scan matrix is ​​set to 15×15 rows and columns; When using a 2X objective lens, the scan matrix is ​​set to 8×8 rows and columns to ensure that the scan covers the entire surface of the silicon wafer or chip.

[0035] According to an embodiment of the present invention, in step S6, the scanning path is a zigzag scanning path; the segmented midpoint-assisted focusing strategy is as follows: the midpoint of the Z-axis height between the start and end points of the first segment is taken as the moving and stopping position of the Z-axis motor of the first segment, the end point of the first segment is taken as the start point of the second segment, the midpoint of the Z-axis height between the start and end points of the second segment is taken as the moving and stopping position of the Z-axis motor of the second segment, and so on, the end point of the (N-1)th segment is taken as the start point of the Nth segment, and the midpoint of the Z-axis height between the start and end points of the Nth segment is calculated in a rolling manner as the moving and stopping position of the Z-axis motor of the Nth segment, where N is a positive integer greater than 1.

[0036] It should be noted that the point cloud height map generated from the point spectrum acquisition point matrix (refer to...) Figure 11 This serves as a reference data point for Z-axis auxiliary focusing. The scanning path of the silicon wafer or crystal is a zigzag scan, such as... Figure 18 As shown. Before scanning each silicon wafer or piezoelectric wafer, a point cloud height map is first imported. Simultaneously, the illumination and imaging systems are activated, along with the X, Y, and Z-axis displacement platforms beneath the microporous ceramic chuck. Using... Figure 15 , Figure 16 and Figure 17 The segmented midpoint-assisted focusing strategy shown ultimately achieves high-precision and high-speed assisted focusing that is both "capable of keeping up" and "accurately aligned".

[0037] Furthermore, since the time required for the X-axis movement is greater than the focusing response time of the Z-axis motor, achieving high-precision and high-speed assisted focusing requires adhering to the principle of "keeping up and accurately focusing": (1) Keep up: This means that the time required for the ΔX stroke movement is greater than the focusing response time of the Z-axis motor, ensuring that the Z-axis focusing is completed during the movement.

[0038] (2) Accuracy: This means that during the process of shooting with an area array, each frame of the image is close to the focal plane, so that the image is always in a clear state during the shooting process.

[0039] The surface fluctuations of the wafer or silicon wafer are generally stable, without any critical high-low jumps. During multi-frame image acquisition, the Z-axis fluctuations are small. At this time, the ΔX motion stroke can be expanded to ensure that the time required for the ΔX motion is greater than the focusing response time of the Z-axis motor. This ensures that the motor can complete the Z-axis movement within this stroke range.

[0040] According to an embodiment of the present invention, the optical system device in step S2 includes a camera, a tube lens, an objective lens, a bright field illumination source, a dark field illumination source, and a laser illumination module; the objective lens magnification is 2X, 5X, or 10X.

[0041] According to an embodiment of the present invention, in step S1, the chuck is provided with multiple ceramic microporous air channels. When the ceramic microporous air channels adsorb silicon wafers or wafers, the air pressure value of each microporous air channel is monitored in real time. The air pressure value of any two microporous air channels is calculated to obtain the air pressure difference. The air pressure difference is controlled within ±0.02MPa to ensure uniform force when the silicon wafers or wafers are adsorbed.

[0042] This invention first projects a laser beam onto a standard optical plane using the laser illumination module in the optical system to level the chuck. Then, the bright-field illumination source of the optical system is activated, reflecting the light through a beam splitter onto a black-and-white checkerboard grid. The light is then reflected back to the cylindrical lens via a mirror, ultimately achieving image formation on the target surface of the CMOS camera, thus reconfirming the chuck's level. Based on the leveled chuck, a silicon wafer or crystal is placed on top of it. Each micro-orifice gas path is precisely controlled to ensure uniform adsorption of the wafer / crystal. The Z-axis linear module is moved to precisely adjust the 3D point spectrum to the working distance. The X and Y-axis displacement platforms are moved to perform point scanning, acquiring a focal mapping map composed of height points. A segmented midpoint-assisted focusing strategy is developed, and the midpoint positions corresponding to the start and end points of each segment are calculated. The optical system and XY displacement platforms are activated again to ensure that each frame acquired by the optical system is close to the focal plane, ultimately achieving defect detection and dimensional measurement of the silicon wafer / crystal. This invention achieves high-precision, high-speed, and low-cost assisted focusing. For 10X microscope objectives, the focusing accuracy can reach 1 / 2 objective depth of field (about 4 micrometers), which can meet the requirements for real-time scanning and online inspection and measurement of silicon wafers / crystals.

[0043] A schematic diagram of the system device of the present invention is shown below. Figure 3 As shown. The device includes a microporous ceramic chuck device (including a tilt adjustment module), a chuck leveling fixture (standard flat crystal, black and white checkerboard grid), an XY displacement platform, a Z-axis linear motion module, a 3D point spectrum-assisted focusing system, an optical system device (including a camera, tube lens, objective lens, bright field illumination source, dark field illumination source and laser illumination module), and a PC software motion control module.

[0044] In summary, this invention, based on a horizontal chuck, precisely controls the air path of each micro-hole to ensure uniform adsorption of silicon wafers / crystals; through a Z-axis linear motion module and X and Y-axis displacement platforms, it acquires 3D point spectral focus mapping height data, so that each frame of image acquired by the optical system is close to the positive focal plane, achieving high-precision, high-speed and low-cost auxiliary focusing.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for assisted focusing on the surface of a silicon wafer or crystal in a semiconductor inspection process, characterized in that, Includes the following steps: Step S1: Place the standard flat crystal on top of the microporous ceramic chuck, and use the ceramic microporous gas path built into the chuck to adsorb and fix the flat crystal; Step S2: Turn on the laser illumination module of the optical system device, adjust the chuck position multiple times based on the XY displacement platform, and obtain the reflected light spot signal intensity value of the standard flat crystal at different positions; Step S3: Set the intensity value error range, compare the intensity value of the reflected light spot signal at different positions with the intensity value error range, obtain the comparison result, and adjust the chuck levelness based on the comparison result; Step S4: Remove the standard flat crystal, place the black and white checkerboard marker on the chuck and fix it with adsorption, move the XY displacement platform, collect images of the black and white checkerboard marker at different positions, obtain the corresponding transition pixel values, and analyze whether the level of the adjusted chuck meets the set conditions. Step S5: Place the silicon wafer or crystal on a chuck that meets the set conditions, adjust the 3D point spectrum to the working distance based on the Z-axis linear motion module, move the XY displacement platform to perform point scanning, and obtain a focal mapping map composed of height points; Step S6: Draw the scanning path based on the focus map, formulate a segmented midpoint auxiliary focusing strategy based on the scanning path, and perform auxiliary focusing on the silicon wafer or wafer surface based on the segmented midpoint auxiliary focusing strategy to obtain a clear image.

2. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 1, characterized in that, In step S2, when moving the XY displacement platform to obtain the reflected light spot signal intensity values ​​at different positions of the standard flat crystal, the number of sampling points is greater than or equal to 5, and the sampling points are evenly distributed on the surface of the standard flat crystal, including the center position of the standard flat crystal and the surrounding edge areas.

3. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 2, characterized in that, The position of the chuck is adjusted based on the XY displacement platform so that the center of the standard flat crystal is located in the center of the imaging field of view. The laser spot is received and converted into a signal intensity value in real time. The XY displacement platform is moved multiple times to obtain the signal intensity values ​​at different positions of the standard flat crystal. The range is analyzed based on the signal intensity values ​​at different positions. The range is less than or equal to 1%. If the range is greater than 1%, the levelness of the chuck is adjusted.

4. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 3, characterized in that, In step S5, when the XY displacement platform is moving to perform point scanning, a scanning matrix is ​​first constructed, and then the 3D point spectral sensor is guided to complete the point spectral sampling matrix based on the scanning matrix, thereby generating a point spectral scanning point cloud height map of the silicon wafer or wafer, and obtaining a focal mapping map based on the point spectral scanning point cloud height map.

5. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 4, characterized in that, When constructing the scan matrix, the number of rows and columns is determined based on the diameter of the silicon wafer or crystal and the field of view of the objective lens, as follows: Set a silicon wafer or crystal with a diameter of 300 mm, and when using a 10X objective lens, set the scan matrix to 30×30 rows and columns; When using a 5X objective lens, the scan matrix is ​​set to 15×15 rows and columns; When using a 2X objective lens, the scan matrix is ​​set to 8×8 rows and columns to ensure that the scan covers the entire surface of the silicon wafer or chip.

6. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 5, characterized in that, In step S6, the scanning path is a zigzag scanning path; the segmented midpoint-assisted focusing strategy is as follows: the midpoint of the Z-axis height between the start and end points of the first segment is taken as the moving and stopping position of the Z-axis motor of the first segment, the end point of the first segment is taken as the start point of the second segment, the midpoint of the Z-axis height between the start and end points of the second segment is taken as the moving and stopping position of the Z-axis motor of the second segment, and so on, the end point of the (N-1)th segment is taken as the start point of the Nth segment, and the midpoint of the Z-axis height between the start and end points of the Nth segment is calculated as the moving and stopping position of the Z-axis motor of the Nth segment, where N is a positive integer greater than 1.

7. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 1, characterized in that, The optical system device described in step S2 includes a camera, a tube lens, an objective lens, a bright field illumination source, a dark field illumination source, and a laser illumination module; the objective lens has a magnification of 2X, 5X, or 10X.

8. The silicon wafer or crystal surface-assisted focusing method in the semiconductor detection process as described in claim 1, characterized in that, In step S1, the chuck is equipped with multiple ceramic microporous air channels. When the ceramic microporous air channels adsorb silicon wafers or wafers, the air pressure value of each microporous air channel is monitored in real time. The air pressure value of any two microporous air channels is calculated to obtain the air pressure difference. The air pressure difference is controlled within ±0.02MPa to ensure that the silicon wafers or wafers are subjected to uniform force during adsorption.

Images