A method for assisting focusing on a surface of a silicon wafer or a wafer in a semiconductor detection process

Abstract

The application discloses a silicon wafer or wafer surface auxiliary focusing method in a semiconductor detection process, and comprises the following steps: placing a standard flat crystal on a microporous ceramic chuck for adsorption and fixation; acquiring the reflected light spot signal intensity values of the standard flat crystal at different positions; adjusting the chuck level according to the reflected light spot signal intensity values at different positions; collecting black-and-white chessboard pattern target image at different positions, acquiring corresponding transition pixel values, and analyzing the adjusted chuck level to see whether the adjusted chuck level meets the set condition; placing the silicon wafer or wafer on the chuck meeting the set condition, acquiring a focus mapping diagram composed of height points; drawing a scanning path, formulating a segmented midpoint auxiliary focusing strategy based on the scanning path, and performing auxiliary focusing on the silicon wafer or wafer surface to obtain clear imaging. The application can realize high-precision, high-speed and low-cost auxiliary focusing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor detection, in particular to a silicon wafer surface auxiliary focusing method in a semiconductor detection process. BACKGROUND

[0002] In the process of semiconductor silicon wafer, after a series of process flows (such as line cutting, grinding, etching, edge polishing, post-polishing cleaning, surface inspection, particle testing, argon annealing, film plating, and photolithography), due to the existence of high-temperature annealing, film layer stress, structure size, process doping, and crystal defects, the lattice mismatch or the different expansion coefficients between the film layer and the substrate cause tensile stress or compressive stress, resulting in the warping deformation of the silicon wafer; at the same time, when the silicon wafer is formed into a wafer after photolithography etching, the process of thin film stress release will cause the wafer to warp and deform.

[0003] The above process makes the silicon wafer or wafer warp and deform at different stages, affecting the subsequent slicing and cutting process, chip packaging and functional testing, and thus causing loss. In order to avoid the above situation, manual incoming inspection is required for the silicon wafer or wafer with large warping, but it is difficult for manual inspection to determine the silicon wafer or wafer with small warping (<1mm), and the surface of the silicon wafer or wafer after being adsorbed by the chuck still has small height fluctuations. Based on this, under the test conditions of high magnification, high precision and low depth of field, how to ensure that the measured object surface is always in the vicinity of the in-focus focal plane for clear imaging, and how to realize high-precision detection and measurement of the warped silicon wafer or wafer, have become problems that need to be solved in the process of manufacturing semiconductor silicon wafers / wafers.

[0004] In order to complete the high-precision detection and measurement of the warped silicon wafer or wafer, the current technology mainly includes laser real-time focusing and image real-time focusing. Both of the above two methods need to adjust the Z-axis in real time to make the collected image always in the focal plane position. The laser real-time focusing has high precision, but is expensive and has high cost; the image real-time focusing has low cost, but has low precision and slow running speed, and cannot meet the demand of high throughput as the CT requirement becomes higher and higher. SUMMARY

[0005] The purpose of the present application is to provide a silicon wafer surface auxiliary focusing method in a semiconductor detection process, which comprises the following steps:

[0006] Step S1: placing a standard flat crystal above a microporous ceramic chuck, and adsorbing and fixing the flat crystal through the ceramic microporous gas path built in the chuck;

[0007] Step S2: turning on the laser illumination module of the optical system device, adjusting the position of the chuck multiple times based on the XY displacement platform, and obtaining the reflected light spot signal intensity value of the standard flat crystal at different positions;

[0008] Step S3: setting an intensity value error interval, comparing the intensity values of the reflected light spots at different positions with the intensity value error interval to obtain a comparison result, and adjusting the chuck level based on the comparison result;

[0009] Step S4: removing the standard flat crystal, placing the black and white checkerboard sheet on the chuck and adsorbing and fixing it, moving the XY displacement platform, collecting images of the black and white checkerboard sheet at different positions, obtaining corresponding transition pixel values, and analyzing whether the adjusted chuck level meets the set condition;

[0010] Step S5: placing the silicon wafer or wafer on the chuck that meets the set condition, adjusting the 3D point spectrum to the working distance based on the Z-axis linear movement module, moving the XY displacement platform to perform point scanning, and obtaining a focus mapping graph composed of height points;

[0011] Step S6: drawing a scanning path based on the focus mapping graph, formulating a segmented midpoint auxiliary focusing strategy based on the scanning path, and performing auxiliary focusing on the surface of the silicon wafer or wafer based on the segmented midpoint auxiliary focusing strategy to obtain clear imaging.

[0012] In a preferred embodiment of the present application, in step S2, when the XY displacement platform moves to obtain the reflected light spot signal intensity values at different positions of the standard flat crystal, the number of points taken is greater than or equal to 5, and the point positions are uniformly distributed on the surface of the standard flat crystal, including the central position and the peripheral edge region of the standard flat crystal.

[0013] In a preferred embodiment of the present application, the position of the chuck is adjusted based on the movement of 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 collected in real time and converted into a signal intensity value, the XY displacement platform is moved multiple times to obtain signal intensity values at different positions of the standard flat crystal, the range is analyzed according to the signal intensity values at different positions, and the range is less than or equal to 1%. If the range is greater than 1%, the level of the chuck is adjusted.

[0014] In a preferred embodiment of the present application, in step S5, when the XY displacement platform moves to perform point scanning, a scanning matrix is first constructed, then the 3D point spectrum sensor is guided to complete a point spectrum point matrix based on the scanning matrix, and a point spectrum scanning point cloud height graph of the silicon wafer or wafer is generated, and the focus mapping graph is obtained based on the point spectrum scanning point cloud height graph.

[0015] In a preferred embodiment of the present application, when the scanning matrix is constructed, the number of rows and columns of the scanning matrix is determined according to the diameter of the silicon wafer or wafer and the field of view range of the objective lens, and is specifically as follows:

[0016] When a silicon wafer or wafer with a diameter of 300 mm is used, the scanning matrix is set to 30x30 rows and columns when a 10X objective lens is used.

[0017] When a 5X objective lens is used, the scanning matrix is set to 15x15 rows and columns;

[0018] When a 2X objective lens is used, the scanning matrix is set to 8x8 rows and columns, ensuring that the scanning covers the entire surface of the silicon wafer or wafer.

[0019] In a preferred embodiment of the present application, in step S6, the scanning path is a zigzag scanning path; and the segmented midpoint auxiliary focusing strategy is specifically as follows: taking the midpoint of the Z-direction height between the starting point and the ending point of the first segment as the moving and stopping position of the Z-axis motor of the first segment, taking the ending point of the first segment as the starting point of the second segment, taking the midpoint of the Z-direction height between the starting point and the ending point of the second segment as the moving and stopping position of the Z-axis motor of the second segment, and so on, taking the ending point of the N-1th segment as the starting point of the Nth segment, and rolling calculating the midpoint of the Z-direction height between the starting point and the ending point of the Nth segment as the moving and stopping position of the Z-axis motor of the Nth segment, wherein N is a positive integer greater than 1.

[0020] In a preferred embodiment of the present application, in step S2, the optical system device includes a camera, a barrel lens, an objective lens, a bright field illumination light source, a dark field illumination light source and a laser illumination module; and the objective lens has a magnification of 2X, 5X or 10X.

[0021] In a preferred embodiment of the present application, in step S1, a plurality of ceramic microporous air paths are arranged on the chuck, and when the silicon wafer or wafer is adsorbed, the air pressure value of each microporous air path is monitored in real time, the air pressure values of any two microporous air paths are calculated by difference, an air pressure difference is obtained, and the air pressure difference is controlled within ±0.02 MPa, so that the silicon wafer or wafer is uniformly adsorbed.

[0022] Thanks to the above technical solution, the present application has the following advantages compared with the prior art:

[0023] On the basis of the horizontal chuck, the present application precisely controls each microporous air path to ensure that the silicon wafer / wafer is uniformly adsorbed; through the Z-axis linear movement module and the X and Y axis displacement platforms, 3D point spectrum focus mapping height data are obtained, so that each frame of image collected by the optical system is close to the normal focus focal plane, and high-precision, high-speed and low-cost auxiliary focusing is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A flowchart of a silicon wafer or wafer surface auxiliary focusing method in a semiconductor detection process provided by an embodiment of the present application is shown;

[0025] Figure 2 A flat crystal and black and white chessboard pattern sample diagram provided by an embodiment of the present application is shown;

[0026] Figure 3 A system device diagram provided by an embodiment of the present application is shown;

[0027] Figure 4 A schematic diagram of a front surface of a silicon wafer or wafer is shown according to an embodiment of the present application;

[0028] Figure 5 A schematic diagram of warping is shown according to an embodiment of the present application;

[0029] Figure 6 A schematic diagram of a chuck is shown according to an embodiment of the present application;

[0030] Figure 7 A schematic diagram of a micro-hole is shown according to an embodiment of the present application;

[0031] Figure 8 A schematic diagram of an objective lens depth of field is shown according to an embodiment of the present application;

[0032] Figure 9 A schematic diagram of an objective lens depth of field parameter is shown according to an embodiment of the present application;

[0033] Figure 10 A field of view scanning matrix is shown according to an embodiment of the present application;

[0034] Figure 11 A point spectrum point taking matrix is shown according to an embodiment of the present application;

[0035] Figure 12 A point cloud height map is shown according to an embodiment of the present application;

[0036] Figure 13 A sparse point column map is shown according to an embodiment of the present application;

[0037] Figure 14 A wafer or silicon wafer topography cross-sectional view is shown according to an embodiment of the present application;

[0038] Figure 15 A schematic diagram of a first segment midpoint auxiliary focusing is shown according to an embodiment of the present application;

[0039] Figure 16 A schematic diagram of a second segment midpoint auxiliary focusing is shown according to an embodiment of the present application;

[0040] Figure 17 A schematic diagram of an Nth segment midpoint auxiliary focusing is shown according to an embodiment of the present application;

[0041] Figure 18 A zigzag scanning path diagram is shown according to an embodiment of the present application;

[0042] Figure 19 A wafer image in an auxiliary focusing-free state is shown according to an embodiment of the present application;

[0043] Figure 20A wafer image in an auxiliary focusing state provided by an embodiment of the application is shown;

[0044] Figure 21 A transition pixel schematic diagram provided by an embodiment of the application is shown. DETAILED DESCRIPTION

[0045] In order for those skilled in the art to better understand the scheme of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0046] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, device, product or apparatus that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or apparatuses.

[0047] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0048] As Figure 1 shown, an auxiliary focusing method for a silicon wafer or wafer surface in a semiconductor detection process is provided, and the test process is described in detail as follows:

[0049] Step 1: Connect the PC software operation and control module, first place the standard flat crystal above the microporous ceramic chuck, and realize the adsorption and fixation of the flat crystal through the ceramic microporous air path (microporous diameter about 20 microns) built in the chuck.

[0050] Step 2: Move the XY displacement platform so that the center of the standard flat crystal placed above the chuck is located in the center of the imaging field of view, turn on the laser (wavelength: 785 nm) illumination module of the optical system device, real-time receive and collect the laser spot and convert it into signal intensity value; again, move the XY displacement platform to obtain the signal intensity value at different positions of the standard flat crystal, and adjust the screw jacks of the tilt adjustment module below the chuck for multiple times so that the range of the signal intensity values at different positions of the standard flat crystal is controlled within 1%.

[0051] Third step: remove the standard flat crystal, place the black and white chessboard pattern and adsorb and fix, turn on the optical system device, move the X and Y axis displacement platform respectively, collect the images of the black and white chessboard pattern at different positions, and obtain the corresponding transition pixel value (requirement ≤3 pixels). According to the algorithm detection principle, at least 3 transition pixels are required to complete the feature boundary positioning; the boundary gray scale of the real image will change from dark to light (from black to white), that is, a gradual S-shaped curve, not an ideal step curve, as shown in the figure. The horizontal adjustment of the chuck platform is completed by the above-mentioned standard flat crystal signal intensity value range, and the transition pixel value is obtained by using the black and white chessboard pattern to complete the horizontal confirmation of the chuck platform. Figure 21

[0052] Fourth step: place the silicon wafer / crystal on the chuck, accurately control each micro-pore gas path, and ensure that the silicon wafer / crystal is uniformly adsorbed; accurately adjust the 3D point spectrum to the working distance through the Z-axis linear movement module, and move the XY displacement platform to take points for scanning, and obtain the focus mapping composed of height points.

[0053] Fifth step: based on the scanning path drawn by the focus mapping, a segmented midpoint auxiliary focusing strategy is formulated, the positions of the intermediate points corresponding to the start points and end points of each segment are calculated, so that each frame of image obtained by the optical system is close to the paraxial focal plane.

[0054] Through the above steps, the auxiliary focusing on the surface of the silicon wafer / crystal can be completed, and finally the defect detection and size measurement of the silicon wafer / crystal can be realized.

[0055] Figure 19 、 20 The 10X wafer images under the conditions of not starting the auxiliary focusing and starting the auxiliary focusing are shown in FIGS. 10 and 11 respectively. It can be seen from the comparison of the two images that the 10X wafer can be clearly imaged by using the point spectrum auxiliary focusing strategy of the present application.

[0056] According to the embodiment of the present application, in step S2, when the XY displacement platform moves to obtain the reflection 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 point positions are uniformly distributed on the surface of the standard flat crystal, and the sampling point positions include the central position and the peripheral edge region of the standard flat crystal.

[0057] According to the embodiment of the present application, the XY displacement platform is moved to adjust the position of the chuck, so that the center of the standard flat crystal is located in the center of the imaging field of view, the laser spot is collected in real time and converted into signal intensity value, 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 according to the signal intensity values at different positions, and if the range is greater than 1%, the levelness of the chuck is adjusted.

[0058] ​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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] In the actual implementation of this application, it is necessary to... Figure 11The point spectrum point matrix constructed is extracted from each row to generate a sparse point column graph of the wafer or silicon wafer; then, adjacent points are connected to obtain a cross section of the wafer or silicon wafer morphology with continuity, and then a segmented midpoint auxiliary focusing strategy shown in Figure 15 、 Figure 16 and Figure 17 is used to finally realize high-precision and high-speed auxiliary focusing.

[0064] According to the embodiment of the present application, 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 wafer and the field of view of the objective lens, and is specifically as follows:

[0065] When a silicon wafer or wafer with a diameter of 300 mm is set, when a 10X objective lens is used, the scanning matrix is set to 30x30 rows and columns;

[0066] When a 5X objective lens is used, the scanning matrix is set to 15x15 rows and columns;

[0067] When a 2X objective lens is used, the scanning matrix is set to 8x8 rows and columns, to ensure that the scanning covers the entire surface of the silicon wafer or wafer.

[0068] According to the embodiment of the present application, in step S6, the scanning path is a zigzag scanning path; the segmented midpoint auxiliary focusing strategy is specifically as follows: the midpoint of the Z-direction height between the starting point and the ending point of the first segment is taken as the moving and stopping position of the Z-axis motor of the first segment, the ending point of the first segment is taken as the starting point of the second segment, the midpoint of the Z-direction height between the starting point and the ending point 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 ending point position of the N-1 segment is taken as the starting point position of the N segment, and the midpoint of the Z-direction height between the starting point and the ending point of the N segment is calculated and taken as the moving and stopping position of the Z-axis motor of the N segment, where N is a positive integer greater than 1.

[0069] It should be noted that the point cloud height map generated by the point spectrum point matrix (see Figure 11 ) is taken as the reference data point for Z-direction auxiliary focusing. The scanning path of the silicon wafer or wafer is a zigzag scanning path, as shown in Figure 18 Before scanning each silicon wafer or wafer, first import the point cloud height map, and turn on the illumination system and the imaging system, and also turn on the X, Y displacement platform and the Z-axis displacement module below the microporous ceramic chuck. A segmented midpoint auxiliary focusing strategy shown in Figure 15 、 Figure 16 and Figure 17 is used to finally realize high-precision and high-speed auxiliary focusing.

[0070] Further, since the time consumed by the movement of the delta X stroke is greater than the focusing response time of the Z-axis motor, in order to realize high-precision and high-speed auxiliary focusing, the principle of "keeping up and being accurate" needs to be followed:

[0071] (1) Keeping up: that is, the time consumed by the movement of the delta X stroke is greater than the focusing response time of the Z-axis motor, so as to ensure that the Z-direction focusing is completed during the movement.

[0072] (2) Being accurate: that is, during the execution of the area array snapshot process, each frame of image obtained is close to the in-focus position, so as to realize that the image is in a clear state at all times during the execution of the shooting process.

[0073] The overall wafer or silicon wafer surface fluctuation is relatively stable, and there is no high-low jump in the critical region. During the multi-frame image acquisition process, the Z-direction fluctuation is small, so the delta X movement stroke can be expanded, the time consumed by the movement of the delta X stroke is greater than the focusing response time of the Z-axis motor, and then the motor can complete the Z-direction movement within the stroke range.

[0074] According to the embodiment of the present application, the optical system device in step S2 includes a camera, a barrel lens, an objective lens, a bright field illumination light source, a dark field illumination light source and a laser illumination module; the objective lens has a magnification of 2X, 5X or 10X.

[0075] According to the embodiment of the present application, in step S1, a plurality of ceramic micro-hole air paths are arranged on the chuck, and the air pressure value of each micro-hole air path is monitored in real time when the silicon wafer or wafer is adsorbed, the air pressure values of any two micro-hole air paths are calculated by difference, the air pressure difference is obtained, and the air pressure difference is controlled within ±0.02MPa, so that the silicon wafer or wafer is adsorbed uniformly.

[0076] The application first projects laser to a standard flat crystal through a laser illumination module in an optical system device, completes the chuck horizontal adjustment, enables the bright field illumination light source of the optical system device, reflects the objective lens to the black and white chessboard pattern sheet through the beam splitter, and then reflects back to the cylindrical mirror through the mirror surface, finally reaches the CMOS camera target surface imaging, and completes the chuck horizontal confirmation again. On the basis of the horizontal chuck, the silicon wafer or wafer is placed above the chuck, the micro-hole air path is accurately controlled, the silicon wafer / wafer is uniformly adsorbed, the Z-axis linear module is moved, the 3D point spectrum is accurately adjusted to the working distance, the X and Y axis displacement platforms are moved respectively to take points and scan, the focus mapping diagram composed of height points is obtained, the segmented midpoint auxiliary focusing strategy is formulated, and the positions of the intermediate points corresponding to the start and end points of each segment are calculated. The optical system device and the XY displacement platform are used again, so that each frame of image obtained by the optical system is close to the normal focus focal plane, and finally the defect detection and size measurement of the silicon wafer / wafer are realized. The application scheme can realize high-precision, high-speed and low-cost auxiliary focusing. For a 10X microscope objective, the focusing accuracy can reach 1 / 2 of the objective depth of field (about 4 microns), which can meet the real-time scanning and online detection and measurement of the silicon wafer / wafer.

[0077] The system device schematic diagram of the application is shown in Figure 3 The device includes a micro-hole ceramic chuck device (including an inclination adjustment module), a chuck horizontal adjustment jig (a standard flat crystal and a black and white chessboard pattern sheet), an XY displacement platform, a Z-axis linear movement module, a 3D point spectrum auxiliary focusing system, an optical system device (including a camera, a cylindrical mirror, an objective lens, a bright field illumination light source, a dark field illumination light source and a laser illumination module), and a PC software operation and control module.

[0078] In summary, on the basis of the horizontal chuck, the micro-hole air path is accurately controlled, the silicon wafer / wafer is uniformly adsorbed, the Z-axis linear movement module and the X and Y axis displacement platforms are used to obtain the 3D point spectrum focus mapping diagram height data, so that each frame of image collected by the optical system is close to the normal focus focal plane, and high-precision, high-speed and low-cost auxiliary focusing is realized.

[0079] The technical features of the above embodiments can be combined in any way, and in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as the scope disclosed in the application.

[0080] The above is only a specific implementation of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the application, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for assisting focusing on a surface of a silicon wafer or a wafer in a semiconductor detection process, characterized in that, The method comprises the following steps: Step S1: placing a standard flat crystal above a microporous ceramic chuck, and adsorbing and fixing the flat crystal through a ceramic microporous air path built in the chuck; Step S2: turning on a laser illumination module of an optical system device, adjusting the position of the chuck multiple times based on an XY displacement platform, and obtaining signal intensity values of reflected light spots of the standard flat crystal at different positions; Step S3: setting an intensity value error interval, comparing the signal intensity values of the reflected light spots at different positions with the intensity value error interval, obtaining a comparison result, and adjusting the levelness of the chuck based on the comparison result; Step S4: removing the standard flat crystal, placing a black-and-white checkerboard pattern sheet on the chuck and adsorbing and fixing it, moving the XY displacement platform, collecting images of the black-and-white checkerboard pattern sheet at different positions, obtaining corresponding transition pixel values, and analyzing whether the adjusted levelness of the chuck meets a set condition; Step S5: placing a silicon wafer or a wafer on the chuck that meets the set condition, adjusting a 3D point spectrum to a working distance based on a Z-axis linear movement module, moving the XY displacement platform to perform point scanning, and obtaining a focus mapping diagram composed of height points; In step S6, the scanning path is a zigzag scanning path, and the segmented midpoint auxiliary focusing strategy is specifically as follows: taking the midpoint of the Z-direction height between the starting point and the ending point of a first segment as the movement and stop position of a Z-axis motor of the first segment, taking the ending point of the first segment as the starting point of a second segment, taking the midpoint of the Z-direction height between the starting point and the ending point of the second segment as the movement and stop position of a Z-axis motor of the second segment, and taking the ending point of an N-1th segment as the starting point of an Nth segment, and rolling the midpoint of the Z-direction height between the starting point and the ending point of the Nth segment as the movement and stop position of a Z-axis motor of the Nth segment, where N is a positive integer greater than 1. In step S2, when the XY displacement platform is moved to obtain signal intensity values of reflected light spots of the standard flat crystal at different positions, the number of sampling points is greater than or equal to 5, and the sampling points are uniformly distributed on the surface of the standard flat crystal, and the sampling points include a central position and a peripheral edge region of the standard flat crystal.

2. The method of claim 1, wherein the method is used for a semiconductor inspection process. The XY displacement platform is moved to adjust the position of the chuck, so that the center of the standard flat crystal is located in the center of the imaging field of view, the laser light spot is collected in real time and converted into a signal intensity value, the XY displacement platform is moved multiple times to obtain signal intensity values of the standard flat crystal at different positions, and the range is analyzed according to the signal intensity values at different positions. If the range is greater than 1%, the levelness of the chuck is adjusted.

3. The method of claim 2, wherein the method is used for a semiconductor inspection process, and the surface of the silicon wafer or wafer is a surface of a wafer or a wafer during a process of the semiconductor inspection process. In step S5, when the XY displacement platform is moved for point scanning, a scanning matrix is first constructed, then the 3D point spectrum sensor is guided to complete a point spectrum sampling matrix based on the scanning matrix, and a point spectrum scanning point cloud height map of the silicon wafer or the wafer is generated, and the focus mapping diagram is obtained based on the point spectrum scanning point cloud height map.

4. The method of claim 3, wherein the step of detecting the surface of the wafer or the wafer surface is performed by a semiconductor inspection process. When the scanning matrix is constructed, the number of rows and columns of the scanning matrix is determined according to the diameter of the silicon wafer or the wafer and the field of view range of the objective lens, and is specifically as follows:

5. The method of claim 4, wherein the step of detecting the surface of the wafer or the wafer surface is performed by a semiconductor inspection process. ​ The silicon wafer or wafer with a diameter of 300 mm is set, and the scanning matrix is set to 30*30 rows and columns when a 10X objective lens is used; When a 5X objective lens is used, the scanning matrix is set to 15*15 rows and columns; When a 2X objective lens is used, the scanning matrix is set to 8*8 rows and columns, ensuring that the scanning covers the entire surface of the silicon wafer or wafer.

6. 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 in step S2 includes a camera, a barrel lens, an objective lens, a bright field illumination light source, a dark field illumination light source and a laser illumination module; the objective lens has a magnification of 2X, 5X or 10X.

7. 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, a plurality of ceramic microporous air paths are arranged on the chuck, and the air pressure value of each microporous air path is monitored in real time when the silicon wafer or wafer is adsorbed, the air pressure values of any two microporous air paths are calculated by difference, the air pressure difference is obtained, and the air pressure difference is controlled within ±0.02 MPa, so that the silicon wafer or wafer is adsorbed uniformly.

Images