Wafer detection device and detection method

Abstract

The invention discloses a wafer detection device and method, the device comprises a base, a damping assembly and a device main body which are stacked in sequence, the device main body comprises a mounting frame, and a jacking assembly, a displacement rotation assembly, a code reading and edge searching assembly and a thickness measurement assembly which are arranged on the mounting frame; the displacement rotating assembly comprises a Y-axis movement mechanism and a rotating mechanism arranged on the Y-axis movement mechanism in a sliding mode, the Y-axis movement mechanism is provided with a first station and a second station, and the rotating mechanism can be switched between the two stations; the jacking assembly comprises a jacking driving mechanism of a first station and a material receiving disc, and the jacking driving mechanism drives the material receiving disc to ascend and descend along the Z axis and rotate around the theta axis. The center of the swing mechanism is provided with a bearing port for the receiving disc to pass through, and a bearing sucker group for bearing wafers is arranged in the port; the code reading edge searching assembly and the thickness measuring assembly are oppositely arranged on the upper side and the lower side of the first station and the second station respectively. The device integrates wafer edge searching, code reading and measuring steps, the automation degree of wafer detection is improved, and the detection efficiency and precision are improved.

Description

Technical Field

[0001] This invention relates to the field of wafer inspection technology, and particularly to a wafer inspection apparatus and inspection method. Background Technology

[0002] In semiconductor manufacturing processes, wafer quality inspection is a critical step in ensuring device performance and yield, involving various inspection items such as code reading, edge finding, and thickness measurement. Current technologies typically rely on multiple independent devices to complete wafer inspection step-by-step, or on single, less integrated devices for multiple positioning and transfers, resulting in cumbersome procedures and low efficiency. Furthermore, because wafers are inherently fragile and require extremely high cleanliness, frequent manual intervention or equipment vibration not only increases the risk of breakage but may also introduce contamination, impacting product yield.

[0003] Existing inspection devices often employ a separate design, with modules for code reading, edge finding, and thickness measurement distributed across different workstations. This necessitates multiple handling and positioning of the wafer between different stations, resulting in significant accumulated errors and difficulty in ensuring consistent positioning throughout the process. Furthermore, traditional equipment lacks effective vibration damping and height monitoring mechanisms, making it susceptible to decreased inspection accuracy or even wafer damage from external vibrations or minor equipment displacements. In terms of transmission and rotation control, some devices suffer from loose structures and susceptibility to eccentricity, further impacting the accuracy of wafer positioning and rotational edge finding.

[0004] Therefore, the purpose of this application is to design a highly integrated, highly automated and stable wafer inspection device and method that can realize the continuous execution of multiple inspection items, reduce intermediate transfer links, improve inspection efficiency and accuracy, and at the same time ensure the safety and cleanliness of the wafer during the inspection process. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention proposes a wafer inspection device and inspection method to solve the aforementioned technical problems.

[0006] According to the first aspect of this application, a wafer inspection device is proposed, comprising a base, a shock absorption assembly, and a device body stacked sequentially. The device body includes a mounting frame and a lifting assembly, a displacement rotation assembly, a code reading and edge finding assembly, and a thickness measurement assembly disposed on the mounting frame.

[0007] The displacement rotation assembly includes a Y-axis motion mechanism and a rotary mechanism slidably disposed thereon. The Y-axis motion mechanism is provided with a first station and a second station at intervals. The rotary mechanism switches between the first station and the second station along the Y-axis motion mechanism. The lifting assembly includes a lifting drive mechanism and a receiving tray placed at the first station. The lifting drive mechanism drives the receiving tray to move up and down along the Z-axis and rotate around the first θ-axis. The rotary mechanism has a bearing port at its center for the receiving tray to pass through, and the bearing port has a bearing chuck assembly for bearing the wafer. The rotary mechanism is configured to drive the wafer to rotate around the second θ-axis.

[0008] The code reading and edge finding component and the thickness measurement component are respectively set on the upper and lower sides of the first and second workstations.

[0009] By adopting the above technical solution, the lifting drive mechanism drives the receiving tray to rise / fall along the Z-axis. The receiving tray picks up the wafer and rotates around the first θ-axis to search for and read the code. During the edge-searching and code-reading process, the edge-searching component is responsible for capturing edge images of the upper and lower surfaces of the wafer. After edge-searching is completed, the lifting drive mechanism first corrects the wafer in the X / θ direction, and then the Y-axis motion mechanism corrects the wafer in the Y direction. The lifting drive mechanism then drives the receiving tray to rotate the wafer to the code-reading position, and the edge-searching component reads the code information from the upper and lower surfaces of the wafer. After the edge detection is completed, the lifting drive mechanism descends along the Z-axis and transfers the wafer to the chuck assembly mounted on the rotary mechanism. The Y-axis motion mechanism drives the rotary mechanism to carry the wafer along the Y-axis to the second station. The rotary mechanism drives the wafer to rotate around the second θ-axis. At this time, the thickness measurement component measures the thickness at different positions of the wafer. After completing the thickness measurement step, the wafer moves back to the first station. At this time, the receiving tray rises again along the Z-axis, raising the wafer to the discharge height above the first station, completing all the inspection steps for one wafer.

[0010] Preferably, the lifting drive mechanism includes a lead screw spline shaft, a lifting base plate, a first Z-axis motor and a first θ-axis motor fixed on the lifting base plate, a receiving tray connected to the top of the lead screw spline shaft, and a receiving suction cup assembly on the top surface of the receiving tray; the lead screw spline shaft passes vertically through the lifting base plate, and the nut of the lead screw spline shaft is fixed on the connecting frame above the lifting base plate; the lead screw spline shaft is connected to a first pulley and a second pulley via splines below the lifting base plate and above the connecting frame, respectively; the output ends of the first Z-axis motor and the first θ-axis motor are respectively connected to the first pulley and the second pulley via a first belt and a second belt, respectively.

[0011] By adopting the above technical solution, the receiving tray adsorbs the wafer through the receiving suction cup group. The first Z-axis motor and the first θ-axis motor can drive the lead screw spline shaft to rotate individually or simultaneously through the synchronous belt. This can realize the action of Z-axis lifting alone and the first θ-axis rotating alone or while lifting and rotating. The number of motors working at the same time, the motor speed, and the direction of rotation can be controlled. The lead screw spline shaft can realize movement in different directions and different movement speeds.

[0012] A further preferred embodiment includes an X-axis correction mechanism and an X-axis base plate. The X-axis correction mechanism includes a pair of X-axis slide rails disposed on the X-axis base plate along the X-axis direction. The X-axis slider of the X-axis slide rail is connected to the bottom surface of the lifting base plate. The lifting base plate is also provided with an X-axis motor frame. The top of the X-axis motor frame has an outwardly extending extension plate. A first θ motor is fixed below the extension plate. An X-axis motor is provided at one end of the X-axis motor frame. The output end of the X-axis motor is coaxially connected to an X-axis lead screw along the X-axis direction. The nut side of the X-axis lead screw is connected to the top surface of the X-axis base plate.

[0013] By adopting the above technical solution, the lifting base plate can move relative to the X-axis base plate along the X-axis direction, thereby realizing the X-axis fine adjustment of the entire lifting mechanism. Specifically, the X-axis motor drives the X-axis lead screw to rotate, and its nut moves linearly along the X-axis direction. Since the side of the nut is connected to the top surface of the X-axis base plate, a relative displacement will occur between the X-axis base plate and the lifting base plate. By fixing the X-axis base plate to the inner bottom surface of the mounting frame, only the lifting base plate will produce relative displacement.

[0014] Preferably, the code reading edge finding component includes an upper code reading edge finding unit and a lower code reading edge finding unit that are staggered on the upper and lower sides of the first workstation. Both the upper and lower code reading edge finding units include a code reading mounting frame and a Z-axis correction module fixed thereon. An image acquisition module is slidably mounted on the Z-axis correction module, and a distance sensor is provided on one side of the image acquisition module. The Z-axis correction module is configured to drive the image acquisition module to move up and down along the Z-axis.

[0015] By adopting the above technical solution, the upper code reading and edge finding unit and the lower code reading and edge finding unit are distributed in an alternating manner. The distance between the image acquisition module and the wafer surface is determined by the ranging sensor, and then the Z-axis position of the image acquisition module is finely adjusted by the Z-axis correction module to ensure that the image acquisition module can clearly read the code and identify the edge of the wafer.

[0016] Preferably, the rotary mechanism includes a bearing plate, a second θ motor, and a rotating unit. The second θ motor is mounted on a base at one corner of the lower surface of the bearing plate, and its output end is connected upward to an θ pulley. The rotating unit includes a toothed steel ring and a collar. The bearing plate has an opening in the middle for the collar to be inserted, and the inner ring of the collar fits onto the upper part of the toothed steel ring. The inner ring of the toothed steel ring forms a bearing opening. The outer toothed surface of the toothed steel ring is connected to the θ pulley via an θ synchronous belt below the bearing plate.

[0017] By adopting the above technical solution, the carrier plate is responsible for connecting with the Y-axis motion mechanism. Only when it is in the first working position will the lifting drive mechanism drive the receiving tray to rise and fall along the Z-axis. When it is in the first working position, the receiving tray will pass through the carrier port when it rises to pick up the wafer. After the receiving tray picks up the wafer, it will descend to perform edge finding and perform X / θ direction correction on the wafer. After the correction is completed, the wafer can be handed over to the carrier suction cup group, and the Y-axis motion mechanism will perform Y direction correction before the code reading work is performed.

[0018] Further preferably, it also includes at least one tensioning unit, which includes a fixed plate, a rotating shaft vertically disposed on the bottom surface of the fixed plate, and a tensioning wheel rotatably connected to the rotating shaft. The top surface of the fixed plate is connected to the bottom surface of the bearing plate. The tensioning wheel and the θ pulley are located at the same horizontal height, and the θ pulley abuts against the back of the θ synchronous belt. The bottom surface of the toothed steel ring is also provided with at least one anti-eccentricity baffle.

[0019] By adopting the above technical solution, the tensioning unit is used to tension the θ synchronous belt. With the anti-eccentric baffle on the bottom surface of the toothed steel ring, the θ synchronous belt can be effectively prevented from falling off the toothed steel ring during transmission, thus ensuring the transmission efficiency and stability of the rotary mechanism during rotation.

[0020] Preferably, the Y-axis motion mechanism includes a pair of Y-axis slide rails arranged on the two inner sides of the mounting frame along the Y-axis direction. At least two Y-axis sliders are provided on the Y-axis slide rails, and the top surface of the Y-axis sliders is connected to the bottom surface of the rotary mechanism. A Y-motor frame is provided below one of the Y-axis slide rails. A Y-axis motor is provided at one end of the Y-motor frame. The output end of the Y-axis motor is coaxially connected to a Y-axis lead screw along the Y direction. The other end of the Y-axis lead screw is rotatably mounted on the Y-motor frame, and the nut of the Y-axis lead screw is connected to the bottom of a Y-axis slider.

[0021] By adopting the above technical solution, the Y-motor frame is fixed on the mounting frame. The Y-axis motor drives the Y-axis lead screw to rotate, which in turn drives its nut to move along the Y-axis direction. Since the nut is connected to a Y-axis slider, this Y-axis slider will also move synchronously. All Y-axis sliders are connected to the bottom surface of the rotary mechanism, specifically to the bottom surface of the support plate. Therefore, when a Y-axis slider is driven, the support plate will drive all Y-axis sliders to move along the Y-axis direction, realizing the switching of the rotary mechanism between the first and second workstations. The lifting drive mechanism and the rotary mechanism are respectively responsible for driving the wafer to rotate around the first θ-axis and the second θ-axis at the first and second workstations.

[0022] Preferably, the thickness measurement component includes an upper measurement unit and a lower measurement unit symmetrically arranged on the upper and lower sides of the second station; both the upper and lower measurement units include a measurement head and a controller, the controller being electrically connected to the measurement head, and the controller being used to analyze and report the data collected by the measurement head; it also includes an upper mounting plate and a lower mounting base, the upper measurement unit being fixed above the mounting frame by the upper mounting plate, and the lower measurement unit being fixed to the inner bottom surface of the mounting frame by the lower mounting base.

[0023] By adopting the above technical solution, when the wafer is in the second station, the upper measurement unit and the lower measurement unit measure the distance from the two measurement heads to the wafer surface, respectively. The controller analyzes and reports the relevant data, and calculates the wafer thickness by combining the distance between the two measurement heads.

[0024] Preferably, the shock absorption assembly includes several shock absorbers and a height detector. The shock absorber includes a mounting base and a movable connecting end respectively connected to the top surface of the base and the bottom surface of the mounting frame. The height detector includes a mounting plate and a slit sheet metal respectively connected to the mounting base and the movable connecting end. The mounting plate is provided with a first sensor and a second sensor. The first sensor faces the second sensor and forms a detection gap. The slit sheet metal vertically downwards into the detection gap, and a detection slit is formed on the slit sheet metal corresponding to the sensing areas of the first sensor and the second sensor.

[0025] By adopting the above technical solution, the shock absorber is used to reduce the vibration of the main body of the device, thereby reducing the impact of external vibration on the main body of the device and ensuring the stability of wafer inspection. At the same time, a height detector is set up. The sensing areas of the first sensor and the second sensor will interact with each other. When the detection slit is exactly in line with the sensing areas of the first sensor and the second sensor, they can interact normally. When the height of the main body of the device changes, the slit sheet metal will be displaced vertically with the movable connection end, causing the position of the detection slit to change. At this time, the interaction between the first sensor and the second sensor is interrupted, and the corresponding signal is output. The control program of the device stops, preventing wafer breakage during handover due to abnormal height of the main body of the device.

[0026] According to a second aspect of this application, a wafer inspection method is proposed, implemented using any of the above-mentioned apparatus, comprising:

[0027] S1: The lifting drive mechanism rises along the Z-axis and picks up the wafer. The lifting drive mechanism carries the wafer down to the preset edge-finding and code-reading height at the first station.

[0028] S2: The lifting drive mechanism drives the wafer to rotate around the first θ axis, and the upper code reading and edge finding unit and the lower code reading and edge finding unit capture images of the wafer's edges;

[0029] S3: Fit the calculation of the actual center of the wafer, determine the deviation of the wafer center, the lifting drive mechanism corrects the wafer in the X and / or θ directions, the lifting drive mechanism descends and transfers the wafer to the carrier suction cup group of the displacement rotation component, and the Y-axis motion mechanism of the displacement rotation component corrects the wafer in the Y-axis direction.

[0030] S4: Correction complete. The lifting drive mechanism drives the wafer to rise and rotates around the first θ axis to the code reading position. The upper code reading edge finding unit and the lower code reading edge finding unit capture and identify the code information on the wafer surface.

[0031] S5: After code reading is completed, the lifting drive mechanism descends along the Z-axis and transfers the wafer to the carrier chuck assembly. The Y-axis motion mechanism carries the wafer to the second station. The rotary mechanism drives the wafer to rotate around the second θ-axis. The upper and lower measurement units measure the thickness of the wafer at different positions.

[0032] S6: Measurement completed. The Y-axis motion mechanism carries the wafer to the first station. The lifting drive mechanism rises to adsorb the wafer and moves to the discharge height above the first station to complete the discharge.

[0033] By adopting the above technical solution, this method can achieve a high degree of automation in the three steps of wafer code reading, edge finding, and thickness measurement. From receiving the wafer from the receiving tray to the first θ motor of the lifting drive mechanism driving the wafer to rotate and find the edge, when the center deviation of the wafer is too large, the position of the wafer needs to be finely adjusted and corrected. Finally, the edge finding operation is completed. At this time, the wafer is rotated to the code reading position, and the code information on the wafer surface is further photographed and identified by OCR. After the code reading is completed, the wafer is automatically controlled to the second station, where the upper measurement unit and the lower measurement unit measure the thickness of the wafer. Thus, all three steps are completed. This method has high detection accuracy and can effectively avoid the phenomenon of defective wafers being mixed with good wafers due to low detection accuracy during the unloading process.

[0034] Compared with the prior art, the beneficial effects of this application are as follows:

[0035] The wafer inspection device of this application adopts a stacked structure, integrating functional components such as lifting, displacement rotation, code reading and edge finding, and thickness measurement. Relying on the Y-axis motion mechanism and its rotation mechanism, as well as the X / Z / θ coordination of the lifting device, it realizes automated switching of wafers between the first and second workstations. It works with the lifting component to complete wafer pick-up, handover, and unloading, without human intervention throughout the process. This improves inspection efficiency and avoids contamination from human contact, meeting high cleanliness requirements. Through bidirectional image acquisition and center deviation correction of the code reading and edge finding component, combined with bidirectional vector measurement of the thickness measurement component, the accuracy of wafer edge positioning, code recognition, and thickness detection is greatly improved. The vibration damping component effectively reduces external vibration interference, the tensioning unit and anti-eccentric structure ensure transmission stability, and the height detector can promptly warn of abnormalities to prevent wafer breakage. The overall structure is compact and reliable in operation, adapting to the multiple requirements of high efficiency, accuracy, and safety in wafer inspection in large-scale production. Attached Figure Description

[0036] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. Other embodiments and many anticipated advantages of the embodiments will be readily recognized as they become better understood through reference to the following detailed description. Other features, objects, and advantages of this application will become more apparent from reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 This is a schematic diagram of the wafer inspection device according to an embodiment of this application;

[0038] Figure 2 This is an exploded view of the lifting drive mechanism structure according to a specific embodiment of this application;

[0039] Figure 3 This is a schematic diagram of the installation of the X-axis correction mechanism according to a specific embodiment of this application;

[0040] Figure 4 This is a schematic diagram of the cooperation between the rotary mechanism and the Y-axis motion mechanism according to a specific embodiment of this application;

[0041] Figure 5 This is a bottom structural view of the rotary mechanism according to a specific embodiment of this application;

[0042] Figure 6 This is a schematic diagram of the installation of the code reading edge finding component and the thickness measurement component according to a specific embodiment of this application;

[0043] Figure 7 This is a schematic diagram of the code reading and edge finding unit structure according to a specific embodiment of this application;

[0044] Figure 8 This is a schematic diagram of the calibration of a thickness measurement component according to a specific embodiment of this application;

[0045] Figure 9 This is a schematic diagram of the shock-absorbing component structure according to a specific embodiment of the application;

[0046] Figure 10 This is a schematic diagram of the shock absorber and height detector working together according to a specific embodiment of this application;

[0047] Figure 11 This is a flowchart of the detection method according to an embodiment of this application;

[0048] Figure 12 This is a schematic diagram of the calibration principle according to a specific embodiment of this application.

[0049] The meaning of each number in the diagram:

[0050] 01. Base, 02. Vibration damping assembly, 03. Main body of the device, 04. Mounting frame, 05. Lifting assembly, 06. Displacement and rotation assembly, 07. Code reading and edge finding assembly, 08. Thickness measurement assembly, 09. Y-axis motion mechanism, 10. Rotary mechanism, 11. Lifting drive mechanism, 12. Receiving tray, 13. Bearing port, 14. Wafer, 15. Bearing suction cup assembly, 16. Lead screw spline shaft, 17. Lifting base plate, 18. First Z-axis motor, 19. First θ-axis motor, 10. Receiving suction cup. 20. Disc assembly 21. Connecting frame 22. First pulley 23. Second pulley 24. First belt 25. Second belt 26. Transmission guard plate 27. Pressure roller 28. Displacement detection plate 29. X-axis correction mechanism 20. X-axis base plate 30. X-axis slide rail 31. X-axis slider 32. X-motor frame 33. Extension plate 34. X-axis motor 35. X-axis lead screw 36. Connecting block 37. Connecting plate 38. Bearing plate 39. Second theta motor 40. Theta belt 41. Wheel, Toothed Steel Ring; 42. Shaft Collar; 43. Theodolite Synchronous Belt; 44. Fixing Plate; 45. Tensioning Wheel; 46. Anti-eccentricity Baffle; 47. Y-axis Slide Rail; 48. Y-axis Slider; 49. Y-motor Frame; 50. Y-axis Motor; 51. Y-axis Lead Screw; 52. Dust-free Cable Chain; 53. Upper Code Reading and Edge Finding Unit; 54. Lower Code Reading and Edge Finding Unit; 55. Code Reading Mounting Bracket; 56. Module Housing; 57. Camera; 58. Lens; 59. Distance Sensor; 60. Second Z-axis Motor 61. Z-axis motor frame; 62. Z-axis lead screw; 63. Upper measuring unit; 64. Lower measuring unit; 65. Measuring head; 66. Controller; 67. Upper mounting plate; 68. Lower mounting base; 69. First marker block; 70. Second marker block; 71. Third marker block; 72. Shock absorber; 73. Height detector; 74. Mounting base; 75. Movable connection end; 76. Mounting plate; 77. Slit sheet metal; 78. First sensor; 79. Second sensor; 80. Detection slit; 81. Detailed Implementation

[0051] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0052] 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.

[0053] According to the first aspect of this application, a wafer inspection device is proposed. Figure 1 A schematic diagram of a wafer inspection apparatus according to an embodiment of this application is shown, as follows: Figure 1 As shown, the device includes a base 01, a shock absorption assembly 02 and a device body 03 stacked in sequence. The device body 03 includes a mounting frame 04 and a lifting assembly 05, a displacement rotation assembly 06, a code reading and edge finding assembly 07 and a thickness measuring assembly 08 disposed on the mounting frame 04.

[0054] The displacement rotation assembly 06 includes a Y-axis motion mechanism 09 and a rotary mechanism 10 slidably disposed thereon. The Y-axis motion mechanism 09 is provided with a first station and a second station at intervals. The rotary mechanism 10 switches between the first station and the second station along the Y-axis motion mechanism 09. The lifting assembly 05 includes a lifting drive mechanism 11 and a receiving tray 12 disposed at the first station. The lifting drive mechanism 11 drives the receiving tray 12 to move up and down along the Z-axis and rotate around the first θ-axis. The rotary mechanism 10 has a bearing port 13 at its center for the receiving tray 12 to pass through, and the bearing port 13 has a bearing suction cup assembly 15 for bearing the wafer 14. The rotary mechanism 10 is configured to drive the wafer 14 to rotate around the second θ-axis.

[0055] The code reading and edge finding component 07 and the thickness measurement component 08 are respectively positioned on the upper and lower sides of the first and second workstations.

[0056] Specifically, when the rotary mechanism 10 is directly above the receiving tray 12, it is in the first working position. When the rotary mechanism 10 carries the wafer 14 along the Y-axis motion mechanism 09, and the edge of the wafer 14 enters the gap between the thickness measurement components 08 on the upper and lower sides, it is in the second working position.

[0057] The lifting drive mechanism 11 drives the receiving tray 12 to rise / fall along the Z-axis, thereby moving the wafer 14 from the height of the robotic arm (not shown in the figure) in the upper material preparation area to the edge-finding height above the first station. The receiving tray 12 picks up the wafer 14 and rotates around the first θ-axis to find and read the edge. During the edge-finding and reading process, the edge-finding component 07 is responsible for capturing edge images of the upper and lower surfaces of the wafer 14. After the edge finding is completed, the lifting drive mechanism 11 first corrects the wafer 14 in the X / θ direction, and then the Y-axis motion mechanism 09 corrects the wafer 14 in the Y direction. The lifting drive mechanism then rotates the wafer 14 to the reading position. The code reading and edge finding component 07 reads the code information on the upper and lower surfaces of the wafer 14. After completing the code reading and edge finding, the rotary mechanism 10 carries the wafer 14 to the second station along the Y-axis. The rotary mechanism 10 drives the wafer 14 to rotate around the second θ-axis. At this time, the thickness measurement component 08 measures the thickness of the wafer 14 at different positions. After completing the thickness measurement step, the wafer 14 moves back to the first station. At this time, the receiving tray 12 rises again along the Z-axis, raising the wafer 14 to the discharge height above the first station (the height of the robot arm). The wafer 14 is then handed back to the robot arm, completing all the detection steps for one wafer 14.

[0058] Figure 2 An exploded view of the lifting drive mechanism structure according to a specific embodiment of this application is shown, as follows: Figure 1-2 As shown, the lifting drive mechanism 11 includes a lead screw spline shaft 16, a lifting base plate 17, a first Z-axis motor 18 and a first θ-axis motor 19 fixed on the lifting base plate 17, and a receiving tray 12 connected to the top of the lead screw spline shaft 16. The top surface of the receiving tray 12 is also provided with a receiving suction cup assembly 20. Specifically, both the bearing suction cup assembly 15 and the receiving suction cup assembly 20 include several vacuum suction cups. The lead screw spline shaft 16 vertically passes through the lifting base plate 17, and the nut of the lead screw spline shaft 16 is fixed to the connecting frame 21 above the lifting base plate 17. Specifically, the lead screw spline shaft 16 is provided with two nuts. Each nut is connected to the top and bottom of the connecting frame 21 respectively; the lead screw spline shaft 16 is connected to the first pulley 22 and the second pulley 23 via splines below the lifting base plate 17 and above the connecting frame 21 respectively; the output ends of the first Z-axis motor 18 and the first θ motor 19 are connected to the first pulley 22 and the second pulley 23 via the first belt 24 and the second belt 25 respectively; the second belt 25 is additionally provided with a tensioning roller 27; and a transmission guard plate 26 is provided above the second pulley 23 and the second belt 25 to protect the second pulley 23 and the second belt 25.

[0059] Furthermore, a vertical displacement detection plate 28 is provided on one side of the connecting frame 21. The displacement detection plate 28 is provided with several limit switches / sensors corresponding to the lower part of the lead screw spline shaft 16, which are used to output the displacement distance of the lead screw spline shaft 16.

[0060] Specifically, it also includes an X-axis correction mechanism 29 and an X-axis base plate 30. The lifting base plate 17 is connected to the X-axis base plate 30, and the X-axis base plate 30 is connected to the inner bottom surface of the mounting frame 04. The bottom surface of the mounting frame 04 and the X-axis base plate 30 are the same, both having openings to accommodate the movement of each component of the lifting mechanism along the X-axis direction.

[0061] The receiving tray 12 adsorbs the wafer 14 through the receiving suction cup group 20. The first Z-axis motor 18 and the first θ-axis motor 19 can drive the lead screw spline shaft 16 individually or simultaneously through the synchronous belt. Since the nut of the lead screw spline shaft 16 is fixed, the Z-axis can be raised and lowered individually and the first θ-axis can be rotated individually or simultaneously. The number of motors working at the same time, the motor speed, and the direction of rotation can be controlled. The lead screw spline shaft 16 can achieve movement in different directions and different movement speeds.

[0062] Figure 3 A schematic diagram of the installation of the X-axis correction mechanism according to a specific embodiment of this application is shown, such as... Figure 1-3 As shown, the X-axis correction mechanism 29 includes a pair of X-axis slide rails 31 arranged along the X-axis direction on the X-axis base plate 30. The X-axis slider 32 of the X-axis slide rail 31 is connected to the bottom surface of the lifting base plate 17. The lifting base plate 17 is also provided with an X motor frame 33. The top of the X motor frame 33 has an outwardly extending extension plate 34. The first θ motor 19 is fixed below the extension plate 34. One end of the X motor frame 33 is provided with an X-axis motor 35. The output end of the X-axis motor 35 is coaxially connected to the X-axis lead screw 36 along the X direction. The nut side of the X-axis lead screw 36 is connected to the top surface of the X-axis base plate 30. Specifically, its nut is connected to a connecting block 37. The side of the connecting block 37 is connected to a vertical connecting plate 38. The bottom surface of the connecting plate 38 is connected to the top surface of the X-axis base plate 30.

[0063] The lifting base plate 17 can move relative to the X-axis base plate 30 along the X-axis direction, thereby realizing the fine adjustment of the entire lifting assembly 05 in the X-axis direction. Specifically, the X-axis motor 35 drives the X-axis lead screw 36 to rotate, and its nut moves linearly along the X-axis direction. Since the side of the nut is connected to the top surface of the X-axis base plate 30, a relative displacement will occur between the X-axis base plate 30 and the lifting base plate 17. By fixing the X-axis base plate 30 to the inner bottom surface of the mounting frame 04, only the lifting base plate 17 will produce a relative displacement in the X direction.

[0064] Figure 4 A schematic diagram of the cooperation between the rotary mechanism and the Y-axis motion mechanism according to a specific embodiment of this application is shown. Figure 5 A bottom structural view of the slewing mechanism according to a specific embodiment of this application is shown, as follows: Figure 1-5As shown, the rotary mechanism 10 includes a support plate 39, a second θ motor 40, and a rotating unit. The second θ motor 40 is mounted on a base at one corner of the lower surface of the support plate 39, and the output end of the second θ motor 40 is connected upward to the θ pulley 41. The rotating unit includes a toothed steel ring 42 and a collar 43. The support plate 39 has an opening in the middle for the collar 43 to be inserted, and the inner ring of the collar 43 fits onto the upper part of the toothed steel ring 42. The inner ring of the toothed steel ring 42 forms a bearing opening 13. The outer tooth surface of the toothed steel ring 42 is connected to the θ pulley 41 via an θ synchronous belt 44 below the support plate 39.

[0065] The carrier plate 39 is responsible for connecting to the Y-axis motion mechanism 09. When it is in the first working position, the lifting drive mechanism 11 will drive the receiving tray 12 to rise and fall along the Z-axis and rotate around the first θ-axis. At this time, the second θ motor 40 does not work. When it is in the second working position, the second θ motor 40 drives the toothed steel ring 42 to rotate through the synchronous belt, which further drives the wafer 14 to rotate. The rotation center at this time is the second θ-axis. When it is in the first working position, the receiving tray 12 will pass through the center of the carrier port 13 when it rises to pick up the wafer 14. After the receiving tray 12 picks up the wafer 14, it will descend to find the edge and perform X / θ direction correction on the wafer 14. After the correction is completed, the wafer 14 can be handed over to the carrier suction cup group 15, and the Y-axis motion mechanism 09 will perform Y direction correction before the code reading work is performed.

[0066] Further preferably, it also includes at least one tensioning unit, which includes a fixed plate 45, a rotating shaft vertically disposed on the bottom surface of the fixed plate 45, and a tensioning wheel 46 rotatably connected to the rotating shaft. The top surface of the fixed plate 45 is connected to the bottom surface of the bearing plate 39. The tensioning wheel 46 and the θ pulley 41 are located at the same horizontal height, and the θ pulley 41 abuts against the back of the θ synchronous belt 44. The bottom surface of the toothed steel ring 42 is also provided with at least one anti-eccentricity baffle 47.

[0067] The tensioning unit is used to tension the θ synchronous belt 44. With the help of several anti-eccentric baffles 47 on the bottom surface of the toothed steel ring 42, the θ synchronous belt 44 can be effectively prevented from falling off the toothed steel ring 42 during transmission, thus ensuring the transmission efficiency and stability of the rotary mechanism 10 when it rotates.

[0068] Preferably, the Y-axis motion mechanism 09 includes a pair of Y-axis slide rails 48 arranged on the two inner sides of the mounting frame 04 along the Y-axis direction. At least two Y-axis sliders 49 are provided on the Y-axis slide rails 48. The top surface of the Y-axis sliders 49 is connected to the bottom surface of the rotary mechanism 10. A Y-motor frame 50 is provided below one side of the Y-axis slide rail 48. A Y-axis motor 51 is provided at one end of the Y-motor frame 50. The output end of the Y-axis motor 51 is coaxially connected to a Y-axis lead screw 52 along the Y direction. The other end of the Y-axis lead screw 52 is rotatably mounted on the Y-motor frame 50, and the nut of the Y-axis lead screw 52 is connected to the bottom of a Y-axis slider 49.

[0069] Specifically, a dust-free cable chain 53 is installed below a Y-axis slider 49 on the other side of the Y-axis guide rail to provide power to the components on the rotary mechanism 10.

[0070] The Y-motor frame 50 is fixed to the side of the mounting frame 04. The Y-axis motor 51 drives the Y-axis lead screw 52 to rotate, which in turn drives its nut to move along the Y-axis direction. Since the nut is connected to a Y-axis slider 49, this Y-axis slider 49 will also move synchronously. All Y-axis sliders 49 are connected to the bottom surface of the rotary mechanism 10, specifically to the bottom surface of the support plate 39. Therefore, when a Y-axis slider 49 is driven, the support plate 39 will drive all Y-axis sliders 49 to move along the Y-axis direction, realizing the switching of the rotary mechanism 10 between the first station and the second station. The lifting drive mechanism 11 and the rotary mechanism 10 are respectively responsible for driving the wafer 14 to rotate around the first θ-axis and the second θ-axis at the first station and the second station.

[0071] Figure 6 This diagram illustrates the installation of the code reading edge finding component and the thickness measurement component according to a specific embodiment of this application. Figure 7 A schematic diagram of the code reading and edge finding unit structure according to a specific embodiment of this application is shown, as follows: Figure 1-7 As shown, the code reading edge finding component 07 includes an upper code reading edge finding unit 54 and a lower code reading edge finding unit 55 staggered on the upper and lower sides of the first workstation, and the upper code reading edge finding unit 54 and the lower code reading edge finding unit 55 are respectively arranged along the X-axis and Y-axis directions; both the upper code reading edge finding unit 54 and the lower code reading edge finding unit 55 include a code reading mounting bracket 56 and a Z-axis correction module fixed thereon, and an image acquisition module is slidably arranged on the Z-axis correction module. The image acquisition module includes a module housing 57 and a camera 5 inside thereon. 8 and lens 59, and a ranging sensor 60 is provided on one side of the module housing 57. The Z-axis correction module is configured to drive the image acquisition module to move up and down along the Z-axis. The Z-axis correction module includes a second Z-axis motor 61, a Z-axis motor frame 62 and a Z-axis lead screw 63. The Z-axis motor frame 62 is fixed on the code reader mounting bracket 56. The second Z-axis motor 61 is located on the top of the Z-axis motor frame 62 and is coaxially connected to the Z-axis lead screw 63 inside the Z-axis motor frame 62. The nut of the Z-axis lead screw 63 is connected to the module housing 57.

[0072] The upper code reading and edge finding unit 54 and the lower code reading and edge finding unit 55 are arranged in an alternating pattern. The distance sensor 60 is used to determine the distance between the image acquisition module and the surface of the wafer 14. Then, the Z-axis position of the image acquisition module is finely adjusted by the Z-axis correction module to ensure that the image acquisition module can clearly read the code and identify the edge of the wafer 14.

[0073] Please continue to refer to Figure 1-6The thickness measurement assembly 08 includes an upper measurement unit 64 and a lower measurement unit 65 symmetrically arranged on the upper and lower sides of the second station. Both the upper measurement unit 64 and the lower measurement unit 65 include a measurement head 66 and a controller 67, with the controller 67 electrically connected to the measurement head 66. It also includes an upper mounting plate 68 and a lower mounting base 69. The upper measurement unit 64 is fixed above the mounting frame 04 by the upper mounting plate 68, and the lower measurement unit 65 is fixed to the inner bottom surface of the mounting frame 04 by the lower mounting base 69.

[0074] When wafer 14 is in the second station, the upper measurement unit 64 and the lower measurement unit 65 measure the distance from the two measurement heads 66 to the surface of wafer 14. The controller 67 analyzes and reports the relevant data, and calculates the thickness of wafer 14 by combining the distance between the two measurement heads 66.

[0075] Figure 8 A schematic diagram of the calibration of a thickness measurement component according to a specific embodiment of this application is shown, such as... Figure 8 As shown, it also includes a calibration block composed of a first calibration block 70, a second calibration block 71, and a third calibration block 72. The measurement values ​​of the upper measurement unit 64 for step height correction of the first calibration block 70 and the second calibration block 71 are within a reasonable range, and the measurement values ​​of the lower measurement unit 65 for step height correction of the third calibration block 72 and the second calibration block 71 are within a reasonable range.

[0076] Figure 9 A schematic diagram of the shock-absorbing component structure according to a specific embodiment of the application is shown. Figure 10 A schematic diagram of the shock absorber and height detector in cooperation according to a specific embodiment of this application is shown, as follows: Figure 1-10 As shown, the shock absorption assembly 02 includes several shock absorbers 73 and height detectors 74. Each shock absorber 73 includes a mounting base 75 and a movable connecting end 76 respectively connected to the top surface of the base 01 and the bottom surface of the mounting frame 04. The number of height detectors 74 corresponds one-to-one with the number of shock absorbers 73. Each height detector 74 includes a mounting plate 77 and a slit sheet metal 78 respectively connected to the mounting base 75 and the movable connecting end 76. The mounting plate 77 is provided with a first sensor 79 and a second sensor 80. The first sensor 79 forms a detection gap with the second sensor 80. The slit sheet metal 78 transmits vertically downward through the detection gap, and a detection slit 81 is opened on the slit sheet metal 78, which is set with the sensing area corresponding to the first sensor 79 and the second sensor 80.

[0077] The device body 03 is damped by the shock absorber 73 to reduce the impact of external vibrations on the device body 03 and ensure the stability of the wafer 14 inspection operation. At the same time, a height detector 74 is set up. The sensing areas of the first sensor 79 and the second sensor 80 will interact with each other. When the detection slit 81 corresponds exactly to the sensing area of ​​the first sensor 79 and the second sensor 80, the two can interact normally. When the height of the device body 03 changes, the slit sheet metal 78 will be displaced vertically with the movable connection end 76, causing the position of the detection slit 81 to change. At this time, the interaction between the first sensor 79 and the second sensor 80 is interrupted, and the corresponding signal is output. The control program of the device stops to prevent wafer 14 from being broken during handover due to abnormal height of the device body 03.

[0078] According to a second aspect of this application, a wafer inspection method is proposed, implemented using any of the above-mentioned apparatus. Figure 11 A flowchart of a detection method according to an embodiment of this application is shown, such as Figure 11 As shown, the method includes:

[0079] S1: The lifting drive mechanism rises along the Z-axis and picks up the wafer. The lifting drive mechanism carries the wafer down to the preset edge-finding and code-reading height at the first station.

[0080] S2: The lifting drive mechanism drives the wafer to rotate around the first θ axis, and the upper code reading and edge finding unit and the lower code reading and edge finding unit capture images of the wafer's edges;

[0081] S3: Fit the calculation of the actual center of the wafer, determine the deviation of the wafer center, the lifting drive mechanism corrects the wafer in the X and / or θ directions, the lifting drive mechanism descends and transfers the wafer to the carrier suction cup group of the displacement rotation component, and the Y-axis motion mechanism of the displacement rotation component corrects the wafer in the Y-axis direction.

[0082] S4: Correction complete. The lifting drive mechanism drives the wafer to rise and rotates around the first θ axis to the code reading position. The upper code reading edge finding unit and the lower code reading edge finding unit capture and identify the code information on the wafer surface.

[0083] S5: After code reading is completed, the lifting drive mechanism descends along the Z-axis and transfers the wafer to the carrier chuck assembly. The Y-axis motion mechanism carries the wafer to the second station. The rotary mechanism drives the wafer to rotate around the second θ-axis. The upper and lower measurement units measure the thickness of the wafer at different positions.

[0084] S6: Measurement completed. The Y-axis motion mechanism carries the wafer to the first station. The lifting drive mechanism rises to adsorb the wafer and moves to the discharge height above the first station to complete the discharge.

[0085] Specifically, the first Z-axis motor and / or the first θ-axis motor drive the lead screw spline shaft to rise and / or rotate around the first θ-axis. The receiving tray synchronously rises along the Z-axis to the position of the robotic arm to pick up the wafer. Afterward, the receiving tray descends to the edge-finding height above the first workstation. The first θ-axis motor drives the wafer to rotate and find the edge. At this time, a flying image is triggered. A position comparison signal is output through a motion control card (connected to the first θ-axis motor and a host computer, such as a computer) to achieve in-motion image capture, thereby capturing a full circle of the wafer edge. Then, image positioning processing begins, identifying the edge of the circumference in each image through changes in grayscale values, and obtaining feature point pixels. Position; further fit and calculate the wafer center, combining the pixel position of each photo and the actual servo axis shooting position to obtain the actual center; then determine whether the center deviation is within the target range, that is, compare the actual center calculated by fitting with the target position of the theoretical center. If it exceeds the range, the wafer position is adjusted by lifting drive mechanism, Y-axis motion mechanism, X-axis correction mechanism, etc., and the above edge finding operation is re-executed. If it does not exceed the range, the pixel position of Notch or screen edge feature point and the actual position of servo axis are obtained by image feature matching to complete the edge finding.

[0086] The next step involves the first theta motor rotating the wafer to the code reading position, the camera taking pictures of the upper and lower surfaces of the wafer, recognizing the characters using the OCR algorithm, and outputting the OCR recognition result.

[0087] Furthermore, the thickness measurement components need to be calibrated before starting the thickness measurement work. Figure 12 A schematic diagram of the calibration principle according to a specific embodiment of this application is shown, such as... Figure 11-12 As shown, the calibration principle is as follows: Obtain the measurement values ​​L5 and L2 from the upper measuring head to the first and second standard blocks respectively, and obtain the measurement values ​​L4 and L3 from the lower measuring head to the third and second standard blocks respectively. Then, determine whether there is a deviation in the measurement values ​​using a formula:

[0088] (L2-L5)-h1≤0.5um

[0089] (L3-L4)-h3≤0.5um

[0090] Where h1 is the reference height of the first block and h3 is the reference height of the third block.

[0091] If the deviation exceeds 0.5µm, the probe needs to be checked; if it does not exceed the limit, the probe is normal.

[0092] At this point, the reference distance L1 between the upper measuring head and the lower measuring head is:

[0093] L1 = L2 + h2 + L3

[0094] Where h2 is the reference height of the second block.

[0095] Further measurements of the wafer thickness were performed. The measurement value from the upper measuring head to the upper surface of the wafer was L6, and the measurement value from the lower measuring head to the lower surface of the wafer was L7. The calculation process for the wafer thickness T is as follows:

[0096] T = L1 - L6 - L7

[0097] This completes the three processes of wafer edge finding, code reading, and thickness measurement.

[0098] This method achieves a high degree of automation in three steps: wafer code reading, edge finding, and thickness measurement. From receiving the wafer from the receiving tray to the first θ motor driving the wafer to rotate and find its edge, if the wafer's center deviation is too large, the wafer's position needs to be finely adjusted and corrected to complete the edge finding operation. At this point, the wafer is rotated to the code reading position, and the code information on the wafer surface is further captured and identified by OCR. After code reading is completed, the wafer is automatically controlled to the second station, where the second θ motor drives the wafer to rotate around the second θ axis. The upper and lower measurement units measure the thickness at different positions on the wafer, thus completing all three steps. This method has high detection accuracy and can effectively avoid the phenomenon of defective wafers being mixed with good wafers due to low detection accuracy during unloading.

[0099] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A wafer inspection device comprising a base, a shock absorbing assembly and a device body stacked in sequence, characterized in that, The device body comprises a mounting frame, and a jacking assembly, a displacement rotation assembly, a code reading and edge searching assembly, and a thickness measuring assembly arranged on the mounting frame; The displacement rotation assembly comprises a Y-axis movement mechanism and a rotating mechanism slidingly arranged thereon, the Y-axis movement mechanism is provided with a first work station and a second work station at intervals, and the rotating mechanism switches between the first work station and the second work station along the Y-axis movement mechanism; the jacking assembly comprises a jacking driving mechanism and a receiving disc arranged at the first work station, the jacking driving mechanism drives the receiving disc to ascend and descend along a Z-axis and rotate around a first θ-axis; the rotating mechanism has a bearing port in the center for the receiving disc to pass through, and the bearing port has a bearing suction disc group for bearing a wafer; the rotating mechanism is configured to drive the wafer to rotate around a second θ-axis. The code reading and edge searching assembly and the thickness measuring assembly are respectively arranged on the upper side and the lower side of the first work station and the second work station.

2. The wafer inspection apparatus according to claim 1, wherein The jacking driving mechanism comprises a screw spline shaft, a jacking base plate, a first Z-axis motor and a first θ motor fixed on the jacking base plate, the receiving disc is connected to the top end of the screw spline shaft, and the top surface of the receiving disc is further provided with a receiving suction disc group; the screw spline shaft vertically passes through the jacking base plate, and the nut of the screw spline shaft is fixed on a connecting frame above the jacking base plate; the screw spline shaft passes through a spline connection first pulley and a second pulley below the jacking base plate and above the connecting frame respectively, and the output ends of the first Z-axis motor and the first θ motor are in transmission connection with the first pulley and the second pulley through a first belt and a second belt.

3. The wafer inspection apparatus according to claim 2, wherein Further comprising an X-axis correction mechanism and an X-axis base plate, the X-axis correction mechanism comprises a pair of X-axis sliding rails arranged on the X-axis base plate in the X-axis direction, and the X-axis sliding blocks of the X-axis sliding rails are connected to the bottom surface of the jacking base plate; the jacking base plate is further provided with an X motor frame, the top of the X motor frame has an extension plate extending outward, and the first θ motor is fixed below the extension plate; one end of the X motor frame is provided with an X-axis motor, the output end of the X-axis motor is coaxially connected to an X-axis screw in the X direction, and the nut side of the X-axis screw is connected to the top surface of the X-axis base plate.

4. The wafer inspection apparatus according to claim 1, wherein The code reading and edge searching assembly comprises an upper code reading and edge searching unit and a lower code reading and edge searching unit staggered arranged on the upper side and the lower side of the first work station, the upper code reading and edge searching unit and the lower code reading and edge searching unit each comprise a code reading mounting frame and a Z-axis correction module fixed thereon, the Z-axis correction module is slidingly provided with an image acquisition module, one side of the image acquisition module is provided with a distance measuring sensor, and the Z-axis correction module is configured to drive the image acquisition module to ascend and descend along a Z-axis.

5. The wafer inspection apparatus according to claim 1, wherein The rotating mechanism comprises a bearing plate, a second θ motor and a rotating unit, the second θ motor is arranged at a corner of the lower surface of the bearing plate through a machine base, and the output end of the second θ motor is connected to a θ pulley upward; the rotating unit comprises a toothed steel ring and a shaft ring, the middle part of the bearing plate is provided with an opening for embedding the shaft ring, the inner ring of the shaft ring is sleeved on the upper part of the toothed steel ring, and the inner ring of the toothed steel ring constitutes the bearing port; the outer tooth surface of the toothed steel ring is drivingly connected to the θ pulley through a θ synchronous belt below the bearing plate.

6. The wafer inspection apparatus according to claim 5, wherein Further comprising at least one tensioning unit, the tensioning unit comprises a fixed plate, a rotating shaft vertically arranged on the bottom surface of the fixed plate, and a tensioning wheel rotationally connected to the rotating shaft, the top surface of the fixed plate is connected to the bottom surface of the bearing plate, the tensioning wheel is located at the same horizontal height as the θ pulley, and the θ pulley abuts against the back surface of the θ synchronous belt, and the bottom surface of the toothed steel ring is further provided with at least one eccentricity-preventing baffle.

7. The wafer inspection apparatus of claim 1, wherein The Y-axis motion mechanism comprises a pair of Y-axis sliding rails arranged on the two inner sides of the mounting frame along the Y-axis direction, at least two Y-axis sliding blocks are arranged on the Y-axis sliding rails, and the top surface of the Y-axis sliding block is connected to the bottom surface of the rotating mechanism; a Y motor frame is arranged below the Y-axis sliding rail on one side, one end of the Y motor frame is provided with a Y-axis motor, the output end of the Y-axis motor is coaxially connected to a Y-axis screw in the Y direction, the other end of the Y-axis screw is rotationally arranged on the Y motor frame, and the nut of the Y-axis screw is connected to the bottom of a Y-axis sliding block.

8. The wafer inspection apparatus of claim 1, wherein The thickness measuring assembly comprises upper and lower measuring units symmetrically arranged on the upper and lower sides of the second station; the upper and lower measuring units each comprise a measuring head and a controller, and the controller is electrically connected to the measuring head; the assembly further comprises an upper mounting plate and a lower mounting seat, the upper measuring unit is fixed above the mounting frame through the upper mounting plate, and the lower measuring unit is fixed to the inner bottom surface of the mounting frame through the lower mounting seat.

9. The wafer inspection apparatus of claim 1, wherein The damping assembly comprises a plurality of dampers and a height detector, the damper comprises a mounting seat and a movable connection end respectively connected to the top surface of the base and the bottom surface of the mounting frame; the height detector comprises a mounting plate and a slit metal plate respectively connected to the mounting seat and the movable connection end, the mounting plate is provided with a first sensor and a second sensor, the first sensor faces the second sensor and forms a detection gap, the slit metal plate vertically downwardly penetrates into the detection gap, and a detection slit corresponding to the sensing area of the first sensor and the second sensor is formed in the slit metal plate.

10. A wafer inspection method, characterized by, The device is implemented by using any one of claims 1-9, comprising: S1: the jacking drive mechanism ascends along the Z-axis and takes the wafer, and the jacking drive mechanism carrying the wafer descends to a preset edge-finding and code-reading height on the first station; S2: the jacking drive mechanism drives the wafer to rotate around the first θ axis, and the upper and lower code-reading and edge-finding units shoot the edge image of the wafer; S3: fitting the actual center of the wafer, judging the deviation of the center of the wafer, the lifting drive mechanism correcting the wafer in X and / or θ direction, the lifting drive mechanism descending, and transferring the wafer to the bearing chuck group of the displacement rotation assembly, the Y-axis movement mechanism of the displacement rotation assembly correcting the wafer in Y-axis direction; S4: after the correction is completed, the lifting drive mechanism drives the wafer to rise and rotate around the first θ axis to the code reading position, and the upper code reading and edge finding unit and the lower code reading and edge finding unit shoot and identify the code information on the surface of the wafer; S5: after the code reading is completed, the lifting drive mechanism descends along the Z axis and transfers the wafer to the bearing chuck group, the Y-axis movement mechanism carries the wafer to the second station, the slewing mechanism drives the wafer to rotate around the second θ axis, and the upper measurement unit and the lower measurement unit measure the thickness of the wafer at different positions; S6: after the measurement is completed, the Y-axis movement mechanism carries the wafer to the first station, the lifting drive mechanism rises to adsorb the wafer, and moves to the discharge height above the first station, and the discharge is completed.

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