A multifunction wafer inspection apparatus

Abstract

The application discloses a kind of multifunctional wafer detection equipment, the equipment includes edge detection module, robot, two sets of parallelly arranged macroscopic detection unit and microscopic detection component.Robot is arranged in the side of edge detection module to transfer wafer.Each set of macroscopic detection unit includes transfer mechanism, rotating wafer transfer mechanism, external clamping mechanism, internal clamping mechanism and photographing module.Transfer mechanism is used to receive wafer from robot;Rotating wafer transfer mechanism covers the working range of transfer mechanism, external clamping mechanism and internal clamping mechanism and microscopic detection component, is responsible for efficient wafer transfer between them;Adjacent external clamping mechanism and internal clamping mechanism can be wafer handover;Photographing module then shoots wafer fixed by internal clamping mechanism.The application realizes efficient integration and continuous performance of wafer edge detection, macroscopic detection and microscopic detection by optimizing layout and automatic flow, significantly improves detection efficiency and automation level.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor manufacturing and detection, and relates to a wafer surface and edge defect detection technology, in particular to a multifunctional wafer detection equipment, which aims to realize efficient and high-precision automatic detection of wafer quality by integrating edge detection, macroscopic detection and microscopic detection functions, so as to ensure high yield of semiconductor products. BACKGROUND

[0002] In the field of semiconductor manufacturing, as the carrier of integrated circuits, the surface quality of wafers directly determines the performance and yield of the final chip. Therefore, it is crucial to conduct strict non-destructive testing on wafers during the production process. Macroscopic detection and edge detection are two indispensable key processes. Macroscopic detection mainly aims to quickly scan scratches, contamination, particles, pattern defects and the like on the surface of the wafer; while edge detection focuses on identifying microscopic defects such as edge collapse, cracks, etching residues and the like on the edge of the wafer.

[0003] At present, the detection scheme commonly used in the industry is to complete the functions of macroscopic detection and edge detection by independent special-purpose equipment. This kind of split equipment layout has obvious technical shortcomings: first, the macroscopic detection equipment with single function usually adopts a fixed-angle light source, and its imaging system is mainly optimized for flat surfaces, which cannot effectively cover the edge area with complex three-dimensional geometric characteristics, resulting in a high rate of missed detection of edge defects. On the contrary, although the special-purpose edge detection equipment can perform fine imaging on the edge, it cannot simultaneously complete the macroscopic defect screening of the wafer surface. This functional fragmentation makes a wafer have to go through multiple loading and unloading and transfer between different equipment to complete all the detection, which seriously affects the overall detection efficiency.

[0004] In addition, the split detection also brings a series of problems such as large equipment footprint, high initial investment cost, increased maintenance complexity, and increased risk of wafer surface contamination or mechanical damage due to multiple handling. With the continuous shrinking of semiconductor technology nodes, the requirements for wafer quality are becoming increasingly demanding, and the market urgently needs a solution that can integrate multiple detection functions and achieve efficient, high-precision and highly automated detection to overcome the inefficiency and functional limitations of existing technologies. Therefore, it is of great practical significance and application value to develop a multifunctional wafer detection equipment. SUMMARY

[0005] The present application aims to provide a multifunctional wafer detection equipment to solve the technical problems of large footprint, low transfer efficiency between different detection stations, low automation level and limited overall detection efficiency caused by the single function of the wafer detection equipment and the independent arrangement of each detection module in the prior art.

[0006] To solve the above problems, the application provides a multifunctional wafer detection device, comprising:

[0007] An edge detection module is arranged for edge detection of the wafer, and the edge detection module comprises an imaging mechanism, which comprises a camera and a plurality of optical prisms arranged on the imaging light path of the camera, and the optical paths of different detection areas of the wafer edge are guided into the same camera for imaging at the same time through the plurality of optical prisms.

[0008] A robot is arranged on the side of the edge detection module and is used for transferring the wafer.

[0009] Two sets of macroscopic detection units are arranged in parallel, and each set of macroscopic detection unit comprises a transfer mechanism, a rotating wafer transfer mechanism, an external clamping mechanism, an internal clamping mechanism and a photographing module.

[0010] A microscopic detection assembly is arranged on the side of the macroscopic detection unit and is used for microscopic detection of the wafer.

[0011] The transfer mechanism is located in the working range of the robot and is used for receiving the wafer transferred from the edge detection module by the robot; the working range of the rotating wafer transfer mechanism covers the transfer mechanism, the external clamping mechanism, the internal clamping mechanism and the microscopic detection assembly, and the rotating wafer transfer mechanism is used for transferring the wafer between them; the external clamping mechanism and the internal clamping mechanism are arranged adjacently, and the external clamping mechanism can deliver the wafer to the internal clamping mechanism; and the imaging area of the photographing module is aligned with the surface of the wafer clamped by the internal clamping mechanism.

[0012] Compared with the prior art, the multifunctional wafer detection device provided by the application has the following remarkable and beneficial technical effects:

[0013] (1) The edge detection, macroscopic detection and microscopic detection functions are integrated in one device, and two sets of parallel macroscopic detection units are adopted, so that the detection efficiency is significantly improved. The wafer is automatically transferred between the transfer mechanism, the internal and external clamping mechanisms and the microscopic detection assembly in the unit through the rotating wafer transfer mechanism, the whole process detection is completed, the detection period is shortened, the wafer damage risk is reduced, and the equipment throughput is improved.

[0014] (2) In the macroscopic unit, the external and internal clamping mechanisms are adjacent and can stably deliver the wafer, the internal clamping mechanism adopts a center support mode to provide an unobstructed complete field of view for the photographing module. The rotating transfer mechanism ensures accurate and stable transmission of the wafer, and the microscopic detection assembly realizes submicron rechecking relying on a high-rigidity platform. The modules are precisely matched to construct a high-stability detection system.

[0015] (3) The parallel architecture and modular design of the device bring excellent production flexibility and maintainability. Double-unit parallel operation optimizes the device beat. Modular layout facilitates maintenance and upgrading. The intelligent control system can automatically schedule wafer flow, realizing intelligentization of the whole process. The present application integrates high efficiency, high precision and high flexibility, and can meet the requirements of rapid screening of large-scale production lines and fine analysis in the research and development stage. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 A planar layout diagram of each component of the multifunctional wafer detection device of the embodiment of the present application;

[0018] Figure 2 A structural diagram of the multifunctional wafer detection device of the embodiment of the present application;

[0019] Figure 3 A three-dimensional layout diagram of each component of the multifunctional wafer detection device of the embodiment of the present application;

[0020] Figure 4 An enlarged view of A of the multifunctional wafer detection device of the embodiment of the present application;

[0021] Figure 5 A structural diagram of an edge detection module of the multifunctional wafer detection device of the embodiment of the present application;

[0022] Figure 6 A structural diagram of a photographing module of the multifunctional wafer detection device of the embodiment of the present application;

[0023] Figure 7 A structural diagram of a microscopic detection module of the multifunctional wafer detection device of the embodiment of the present application;

[0024] Figure 8 A structural diagram of a transfer mechanism of the multifunctional wafer detection device of the embodiment of the present application;

[0025] Figure 9 A structural diagram of a rotating and transferring wafer mechanism of the multifunctional wafer detection device of the embodiment of the present application;

[0026] Figure 10 A structural diagram of an internal clamping mechanism of the multifunctional wafer detection device of the embodiment of the present application;

[0027] Figure 11Figure 2 is a schematic view of the internal clamping mechanism of the multifunctional wafer detection device of the present application;

[0028] Figure 12 Figure 3 is a schematic view of the external clamping mechanism of the multifunctional wafer detection device of the present application.

[0029] Figure 1 is a schematic view of the multifunctional wafer detection device of the present application. Figure 2 is a schematic view of the internal clamping mechanism of the multifunctional wafer detection device of the present application. Figure 3 is a schematic view of the external clamping mechanism of the multifunctional wafer detection device of the present application. Figure 4 is a schematic view of the rotating and transferring wafer mechanism of the multifunctional wafer detection device of the present application. Figure 5 is a schematic view of the edge detection module of the multifunctional wafer detection device of the present application. Figure 6 is a schematic view of the microscopic detection module of the multifunctional wafer detection device of the present application. Figure 7 is a schematic view of the transferring mechanism of the multifunctional wafer detection device of the present application. Figure 8 is a schematic view of the robot of the multifunctional wafer detection device of the present application. DETAILED DESCRIPTION

[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without one or more of these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the present application.

[0031] In order to thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description in order to explain the technical solutions of the present application. The preferred embodiments of the present application are described in detail as follows, however, the present application can have other embodiments in addition to these detailed descriptions.

[0032] As Figures 1 to 4The present application shown provides a multifunctional wafer detection equipment, which integrates edge detection, macroscopic detection and microscopic detection functions in one, realizes the high automation of wafer detection process and the significant improvement of detection efficiency through optimized layout and efficient transmission mechanism. The whole equipment adopts modular design, and each functional module is relatively independent and works cooperatively, facilitating maintenance and upgrading.

[0033] Reference Figure 1 The multifunctional wafer detection equipment mainly includes an edge detection module 5, a robot 8, two sets of parallel macroscopic detection units and a microscopic detection assembly 6.

[0034] The working process of the equipment starts from the edge detection module 5. The wafer to be detected is placed at the designated position of the edge detection module 5 by upstream equipment or manually. The edge detection module 5 first performs image acquisition and defect analysis on the edge area of the wafer to check whether there are edge defects such as edge collapse, cracks and contamination. After completing the edge detection, the robot 8 takes out the wafer from the edge detection module 5. The robot 8 is a multi-joint robot with multiple degrees of freedom, and its arm span and working range can cover the transfer mechanism 7 of the edge detection module 5 and the two sets of macroscopic detection units.

[0035] The edge detection module 5, as the first detection process of the multifunctional wafer detection equipment, is responsible for rapid and accurate inspection of the edge state of the wafer. Its detection objects include the front chamfer, back chamfer, edge front, edge back and outermost circumference of the wafer edge. In order to realize efficient and compact edge detection, the module integrates a precise mechanical positioning mechanism and an optical imaging system. As shown in Figure 5 The edge detection module 5 mainly includes a centering mechanism 5.1, a code reading mechanism 5.2 and an optical assembly.

[0036] The centering mechanism 5.1 is a wafer bearing and precise positioning platform of the edge detection module, and its core function is to receive the wafer and center it and adjust its angle, providing a stable and uniform position reference for subsequent edge detection.

[0037] The core of the centering mechanism 5.1 is a solid centering platform. On the platform, a precise two-dimensional motion module system is provided for centering adjustment of the wafer in the horizontal plane. The system includes an X-axis module motor, an X-axis guide rail, a Y-axis module motor and a Y-axis guide rail. The X-axis guide rail is fixedly installed on the centering platform, and its extension direction defines the X-axis. The X-axis sliding plate is slidably arranged on the X-axis guide rail by a sliding block and is driven by the X-axis module motor, so as to accurately slide along the X-axis guide rail.

[0038] The Y-axis guide rail is fixedly installed on the X-axis sliding plate, and the extending direction thereof is perpendicular to the X-axis, and is defined as the Y-axis. The Y-axis sliding plate is slidably arranged on the Y-axis guide rail through a sliding block, and is driven by a Y-axis module motor, so that the Y-axis sliding plate can be accurately slid along the Y-axis guide rail. The "cross slide" structure is a common form of a precision positioning platform. The chuck for carrying the wafer is finally installed on the Y-axis sliding plate. Therefore, through the combination of the X-axis and Y-axis movements, the chuck can be accurately moved to any position in the horizontal plane.

[0039] The working flow of the centering mechanism 5.1 is as follows: the wafer is initially placed on the chuck of the centering mechanism 5.1, and the vacuum is turned on to adsorb and fix the wafer, but at this time, the center of the wafer usually deviates from the theoretical rotation center of the chuck. In order to accurately find the center, a side edge camera 5.11 is arranged on one side of the centering mechanism 5.1. The field of view of the side edge camera 5.11 is aligned with the edge region of the wafer. The chuck is slowly rotated by the rotation motor five. The rotation motor five is preferably a torque motor that can provide smooth and low- jitter rotary motion. During the rotation of the wafer, the side edge camera 5.11 continuously takes multiple images. An image processing algorithm accurately calculates the deviation of the current center position of the wafer relative to the rotation center of the chuck, i.e., the offset in the X direction and the Y direction, by analyzing the position changes of the wafer edge in these images. After calculating the deviation, the control system drives the X-axis module motor and the Y-axis module motor, and moves the chuck and the wafer in the XY plane through the movement of the X-axis sliding plate and the Y-axis sliding plate, to accurately compensate for the deviation, so that the geometric center of the wafer coincides with the rotation center of the chuck, and high-precision centering is achieved.

[0040] Near the centering mechanism 5.1, a code reading mechanism 5.2 is arranged. The code reading mechanism 5.2 is preferably an OCR optical character recognition code reader. When the wafer is rotated to a specific angle on the centering mechanism 5.1, such as the identification code facing the code reader, the OCR code reader triggers the photographing, reads and identifies the serial number of the wafer edge, realizes the binding of the wafer identity and the detection data, and ensures the quality traceability.

[0041] After centering and centering are completed, the core edge optical detection link is entered. The edge detection module 5 of the present application has significant innovation in optical design. It adopts a unique optical path design, realizes the imaging detection of multiple edge surfaces of the wafer only by using a single camera, greatly simplifies the system structure, and reduces the cost.

[0042] The optical assembly includes a lateral motion module 5.3, an adapter plate 5.4, and an imaging mechanism. The lateral motion module 5.3 is a high-precision linear module, and its motion direction is parallel to the radial direction of the wafer. The adapter plate 5.4 is fixed on the slider of the lateral motion module 5.3, and the entire imaging mechanism is installed on the adapter plate 5.4. Therefore, the lateral motion module 5.3 can drive the imaging mechanism as a whole to approach or move away from the edge of the wafer, so as to adapt to the detection requirements of wafers of different sizes and accurately adjust the imaging object distance.

[0043] The imaging mechanism is the key to realize single-camera detection, and the core is to use a prism to perform complex light path folding and synthesis. The imaging mechanism mainly includes an upper prism 5.5, a lower prism 5.6, a light source 2 5.7, a 90-degree turning prism 5.8, a camera 2 5.9, and a camera fine adjustment mechanism 5.10.

[0044] The light path principle and working process are as follows: The edge region of the wafer to be detected usually includes five surfaces: the top front chamfer, the front edge vertical surface, the outermost circumferential surface, the back edge vertical surface, and the bottom back chamfer. Traditional edge detection equipment usually needs to be configured with 3-5 cameras to image these surfaces respectively. The present application creatively uses the upper prism 5.5 and the lower prism 5.6 as front-end light path collectors. They are precisely arranged above and below the edge of the wafer. The light source 2 5.7 provides uniform illumination for the edge of the wafer. The light from the upper edge surface of the wafer is captured and refracted by the upper prism 5.5; at the same time, the light from the lower edge surface of the wafer is captured and refracted by the lower prism 5.6. The upper prism 5.5 and the lower prism 5.6 cleverly refract and guide the light paths captured respectively, which are originally in different positions in space, to the same imaging plane. The light paths captured by the upper prism 5.5 and the lower prism 5.6 from the combination of the partial circumferential surface of the wafer are sent into the 90-degree turning prism 5.8. The 90-degree turning prism 5.8 is used to accurately turn the horizontally propagating light path by 90 degrees, becoming a vertically propagating light path. After the light path is turned, the light information of all the edge surfaces is integrated and guided to the only camera 2 5.9. The front of the camera 2 5.9 is equipped with a suitable lens to ensure that a composite image containing the information of multiple edge surfaces of the wafer can be formed on the camera sensor. The camera fine adjustment mechanism 5.10 is used to finely adjust the camera 2 5.9 in six dimensions during installation, to ensure that the light path is collimated, in focus, and the field of view is correct. The single composite image collected is transmitted to the image processing system. Through advanced image segmentation and recognition algorithms, the system can automatically separate and analyze the features of different edge regions from this image, so as to detect defects such as edge collapse, cracks, and contamination.

[0045] The single camera multi-prism optical design replaces multiple camera systems through a sophisticated optical layout, significantly reducing hardware costs and system complexity, avoiding multi-camera calibration and synchronization problems, and improving system reliability and detection efficiency. When the wafer is rotated by the alignment mechanism 5.1, the fixed imaging mechanism can perform omnidirectional scanning of the entire outer circumference of the wafer.

[0046] After completing edge detection, the robot 8 removes the wafer from the alignment mechanism 5.1 and sends it to the next detection unit. In summary, the edge detection module 5 efficiently and compactly completes the automated detection of wafer edge quality through high-precision alignment centering mechanism, reliable code reading and recognition, and innovative single camera multi-prism optical imaging system, demonstrating the significant advantages of the invention in integration and cost reduction.

[0047] The robot 8 transfers the wafer to the transfer mechanism 7 of one of the macroscopic detection units. The transfer mechanism 7 serves as a temporary buffer and transfer station for receiving and stabilizing the wafer. Subsequently, the rotating wafer transfer mechanism 3 in the macroscopic detection unit begins to work. The rotating wafer transfer mechanism 3 picks up the wafer from the transfer mechanism 7 and transfers it to the external clamping mechanism 1 and the internal clamping mechanism 2 according to the preset detection program.

[0048] The wafer is first placed on the external clamping mechanism 1. The external clamping mechanism 1 mainly performs preliminary positioning and fixation of the wafer's peripheral area. In some embodiments, the external clamping mechanism 1 can also rotate the wafer by a certain angle to facilitate multi-angle preliminary observation. Subsequently, the external clamping mechanism 1 smoothly transfers the wafer to the adjacent internal clamping mechanism 2. The internal clamping mechanism 2 clamps the wafer in a more precise manner, typically supporting the wafer near the center to avoid blocking the chip area to be detected.

[0049] When the wafer is stably clamped by the internal clamping mechanism 2, the photographing module 4 of the macroscopic detection unit begins to work. The imaging area of the photographing module 4 is accurately aligned with the surface of the wafer clamped by the internal clamping mechanism 2. The photographing module 4 can flexibly adjust the position and angle of the camera 4.3 and the light source 4.4 under the drive of the mechanical hand 4.1, and can perform scanning photography on the entire upper surface of the wafer to obtain high-resolution macroscopic images for detecting scratches, stains, particles, pattern defects, and other macroscopic defects.

[0050] After completing the macroscopic inspection, the wafer transfer mechanism 3 operates again, removing the wafer from the internal clamping mechanism 2. Based on the inspection results and program settings, if the wafer requires more detailed inspection, the wafer transfer mechanism 3 will transfer the wafer to the microscopic inspection assembly 6. The microscopic inspection assembly 6 utilizes a high-magnification microscope assembly 6.7 to magnify and analyze suspected defects or randomly selected inspection points found during macroscopic inspection, in order to determine the nature and size of the defects.

[0051] Because the equipment is equipped with two sets of parallel macroscopic inspection units, the robot 8 can intelligently allocate wafers to the idle transfer mechanism 7 according to the busy / idle status of each unit, thereby realizing dual-station parallel inspection and greatly improving the throughput of the equipment. After all inspections are completed, qualified wafers are returned to the transfer mechanism 7 by the rotary wafer transfer mechanism 3, and then transferred to the unloading position or the next process by the robot 8; while unqualified wafers may be sent to a specific re-inspection position or isolation area.

[0052] The macroscopic inspection unit is one of the core components of this equipment. Each unit includes a transfer mechanism 7, a rotating wafer transfer mechanism 3, an external clamping mechanism 1, an internal clamping mechanism 2, and an imaging module 4. The two units are structurally identical and are arranged mirror- or parallel within the equipment frame.

[0053] like Figure 12 As shown, the external clamping mechanism 1 is used to receive, preliminarily position, and transfer the wafer before macroscopic inspection. Its specific structure includes a fixed support 1.5, a Z-axis moving module 1.4, an adapter plate 1.3, a rotary motor 1.2, and an arc-shaped chuck 1.1.

[0054] The fixed support 1.5 is mounted on the main base plate or frame of the equipment, providing a stable support foundation for the entire external clamping mechanism 1. The fixed support 1.5 is usually made of aluminum alloy or stainless steel and is precision machined to ensure the flatness of the mounting surface.

[0055] The Z-axis moving module 1.4 is fixedly mounted on the upper surface of the fixed support 1.5. The Z-axis moving module 1.4 preferably employs a high-precision linear motor module or ball screw module, driven by a servo motor. Internally, it includes a linear guide and a slider, enabling precise and smooth reciprocating motion along the vertical direction. The Z-axis moving module 1.4 itself has a grating ruler or magnetic encoder for real-time feedback of the slider's position information, achieving closed-loop control with a positioning accuracy down to the micrometer level.

[0056] The adapter plate 1.3 is fixedly connected to the output end of the Z-axis moving module 1.4 via a connecting block. Therefore, when the Z-axis moving module 1.4 moves, the adapter plate 1.3 will move up and down along the Z-axis. The adapter plate 1.3, as a mounting platform, is made of hard aluminum alloy through stress relief and precision milling.

[0057] Rotary motor one 1.2 is bolted to the upper surface of adapter plate one 1.3. Rotary motor one 1.2 preferably adopts a hollow shaft type servo motor or a stepper motor, with high torque and low jitter characteristics. The rotation angle of the motor is precisely controlled by the control system.

[0058] Arc-shaped chuck 1.1 is connected to the output shaft of rotary motor one 1.2 through a flange or a coupling. Arc-shaped chuck 1.1 is designed in a circular arc shape matching the edge curvature of a wafer, with good wear resistance and anti-static performance. On the contact surface of arc-shaped chuck 1.1, a plurality of fine vacuum suction grooves are opened, which are connected to an external vacuum generator through internal channels. When it is necessary to suck the wafer, the vacuum generator works to generate negative pressure in the suction grooves, thereby firmly sucking the edge area of the wafer onto arc-shaped chuck 1.1. Arc-shaped chuck 1.1 allows the majority of the surface of the wafer, especially the central effective chip area, to be completely exposed and not blocked by the clamping mechanism.

[0059] During operation, when rotary wafer transfer mechanism 3 delivers the wafer above external clamping mechanism 1, Z-axis moving module one 1.4 drives arc-shaped chuck 1.1 to rise and gently hold the back edge of the wafer. The vacuum is turned on to suck the wafer. Then, rotary motor one 1.2 can rotate the wafer by a specific angle as needed for preliminary observation from different directions or preparation for subsequent transfer. After the operation is completed, Z-axis moving module one 1.4 lowers the wafer to the appropriate height, ready for transfer to adjacent internal clamping mechanism 2.

[0060] Internal clamping mechanism 2 is arranged adjacent to external clamping mechanism 1, for receiving the wafer from external clamping mechanism 1 and performing more precise positioning and support to cooperate with photographing module 4 to complete high-quality macro imaging.

[0061] Internal clamping mechanism 2 is a key component of the device for realizing precise positioning and attitude adjustment of the wafer, with more complex structure and function compared to external clamping mechanism 1, aiming to cooperate with photographing module 4 to realize no-dead-angle and high-quality macro detection. As shown in Figure 10 and Figure 11 Internal clamping mechanism 2 mainly includes fixed support 2.1, Z-axis moving module two 2.2, adapter plate two 2.3, deflection motor 2.4, synchronous belt 2.5, gear drive motor 2.6, gear 2.7, rack 2.8, gear motor mounting plate 2.9, rotary motor two 2.10, chuck one 2.11, rotating shaft 2.12, support 2.13, connecting rod shaft 2.14, and connecting rod 2.15.

[0062] The fixed support 2.1 is installed on the main base plate of the device, and provides a stable support base for the entire internal clamping mechanism 2. The fixed support 2.1 is made of cast iron or steel with excellent rigidity to ensure no deformation during movement.

[0063] The Z-axis movement module two 2.2 is vertically fixedly installed on the fixed support 2.1. The module is preferably a high-precision and high-rigidity ball screw linear module, is driven by a servo motor, and is equipped with a high-resolution grating ruler for position feedback to realize closed-loop control. The Z-axis movement module two 2.2 is mainly responsible for driving the entire upper execution mechanism to perform accurate lifting movement in the vertical direction, and the positioning accuracy directly affects the accuracy of wafer handover and detection height.

[0064] The adapter plate two 2.3 is fixedly connected with the output slider of the Z-axis movement module two 2.2 through a connecting block. Therefore, when the Z-axis movement module two 2.2 acts, the adapter plate two 2.3 will be lifted along the Z-axis together. The adapter plate two 2.3 is a core installation platform, and a plurality of motors and transmission components need to be installed thereon, so that the flatness, rigidity and machining precision thereof are required to be high, and the adapter plate two 2.3 is made of 7075 aerospace aluminum alloy after heat treatment and precision machining.

[0065] The deflection motor 2.4 is fixedly installed on one side of the adapter plate two 2.3 through a motor seat. The deflection motor 2.4 is preferably a servo motor with a brake function to ensure that the position can be locked in the non-working state. A driving synchronous wheel is installed on the output shaft of the deflection motor 2.4. A reversing shaft is rotatably connected to the top of the adapter plate two 2.3 through a bearing seat, and a driven synchronous wheel is installed on the reversing shaft. The driving synchronous wheel and the driven synchronous wheel are connected through a synchronous belt 2.5. Therefore, when the deflection motor 2.4 rotates, the reversing shaft can be driven to perform accurate deflection movement around its own axis through the transmission of the synchronous belt 2.5. The synchronous belt transmission has the advantages of stable transmission, no slip, and low noise.

[0066] One end of the reversing shaft is fixedly connected with the gear motor mounting plate 2.9 through a flange, and the other end is fixedly connected with a support 2.13. The reversing shaft is designed in a hollow structure, and a through hole is arranged in the interior. A connecting rod shaft 2.14 passes through the through hole, so that the connecting rod shaft 2.14 can not only perform deflection movement together with the reversing shaft, but also can relatively move in the axial direction in the through hole.

[0067] The connecting rod shaft 2.14 is designed as an L-shaped structure, and a rack 2.8 is arranged at one end of the L-shaped structure close to the gear motor mounting plate 2.9. A gear drive motor 2.6 is mounted on the gear motor mounting plate 2.9, and a gear 2.7 is mounted on the output shaft of the gear drive motor 2.6. The gear 2.7 is in meshing engagement with the rack 2.8. When the gear drive motor 2.6 is in operation, the gear 2.7 is rotated to drive the rack 2.8 to move along the axial direction of the connecting rod shaft 2.14.

[0068] The other end of the L-shaped structure of the connecting rod shaft 2.14 extends downward, and the lower part of the L-shaped structure is rotatably connected to one end of a connecting rod 2.15 through a hinge shaft. The other end of the connecting rod 2.15 is rotatably connected to the bottom of the rotating shaft 2.12. The middle part of the rotating shaft 2.12 is rotatably connected to the support 2.13. Therefore, the rotating shaft 2.12 can rotate freely relative to the support 2.13.

[0069] The top of the rotating shaft 2.12 is fixedly mounted with a rotary motor 2.10. The rotary motor 2.10 is preferably a hollow shaft type DC brushless servo motor, which has high rotation accuracy and low jitter characteristics. The output shaft of the rotary motor 2.10 is connected to a chuck 2.11. The chuck 2.11 is a component for directly carrying a wafer. In order to maximize the exposure of the pattern surface of the wafer during macroscopic detection, the chuck 2.11 is usually designed as a small-diameter circular vacuum chuck, or is composed of three to four small vacuum nozzles arranged in a central symmetric manner. The support point of the chuck 2.11 is strictly controlled in the absolute center area or the designated non-pattern area of the back surface of the wafer, so as to ensure that the field of view of the photographing module 4 is not blocked. A vacuum channel is led out through the hollow shaft of the rotary motor 2.10 and the hole in the rotating shaft 2.12, and is connected to a vacuum system.

[0070] Working principle and movement process of internal clamping mechanism 2: When the rotary transfer wafer mechanism 3 transports the wafer to above the internal clamping mechanism 2, the Z-axis moving module 2.2 drives the entire actuator to rise, so that the suction cup 2.11 gently contacts the center of the back side of the wafer. Vacuum is activated, adsorbing the wafer. Then the Z-axis moving module 2.2 can descend to the preset detection height. When wafer orientation or circumferential scanning is required, the rotary motor 2.10 starts, directly driving the suction cup 2.11 and the adsorbed wafer to rotate continuously 360 degrees, facilitating observation by the imaging module 4 from different angles or panoramic scanning. When it is necessary to adjust the tilt angle of the wafer relative to the horizontal plane for illumination and observation at a specific angle, the deflection motor 2.4 operates. The deflection motor 2.4 drives the tilting shaft to rotate via the synchronous belt 2.5. Since the gear motor mounting plate 2.9 and the bracket 2.13 are both fixed to the tilting shaft, the entire actuator unit, consisting of the gear drive motor 2.6, connecting shaft 2.14, connecting rod 2.15, rotating shaft 2.12, rotary motor 2.10, and suction cup 2.11, will deflect along with the tilting shaft. This deflection motion causes the wafer plane to tilt. The mechanism can also adjust the wafer's pitch angle when the wafer is tilted or horizontal. The gear drive motor 2.6 operates, driving the gear 2.7 to rotate, which, through the rack 2.8, causes the connecting shaft 2.14 to move axially. The movement of the connecting shaft 2.14 pushes or pulls the connecting rod 2.15. Since one end of connecting rod 2.15 is hinged to connecting rod shaft 2.14 and the other end is hinged to the bottom of rotating shaft 2.12, and the middle of rotating shaft 2.12 is supported by bracket 2.13, the movement of connecting rod 2.15 will force rotating shaft 2.12 to swing around its hinge point with bracket 2.13. This swinging motion will translate into a change in the pitch angle of suction cup 2.11.

[0071] In summary, the internal clamping mechanism 2 achieves highly flexible and precise attitude adjustment of the wafer at the macroscopic inspection station through a composite motion of Z-axis lifting, overall deflection, pitch adjustment, and rotation, providing a solid foundation for obtaining optimal inspection images. Its complex linkage and gear rack design ensures motion accuracy and reliability, representing a significant innovation of this invention.

[0072] The rotary wafer transfer mechanism 3 is the wafer handling hub within the macroscopic inspection unit, and its working range covers the transfer mechanism 7, the external clamping mechanism 1, the internal clamping mechanism 2, and the microscopic inspection component 6. For example... Figure 9 As shown, its specific structure includes a fixed base 3.1, a Z-axis moving module 3.2, an adapter plate 3.3, a rotary motor 3.4, a rotating rod 3.5, and a clamping suction cup 3.6.

[0073] The fixed base 3.1 is the base of the entire mechanism. It is fixed to the equipment base plate by bolts and has high rigidity and stability to reduce vibration during movement.

[0074] Z-axis moving module three 3.2 is vertically mounted on fixed base 3.1. It is also a high-precision linear module, responsible for driving the whole arm structure to move up and down along the Z-axis, to realize the pick-and-place action of the wafer. Its stroke can reach the height of all target positions, such as transfer mechanism 7, external clamping mechanism 1, internal clamping mechanism 2, and chuck assembly 6.6 of microscopic inspection assembly 6.

[0075] Adapter plate three 3.3 is connected with the output end of Z-axis moving module three 3.2, and rises and falls with the module. Adapter plate three 3.3 provides a mounting surface for rotary motor three 3.4.

[0076] Rotary motor three 3.4 is fixedly mounted on adapter plate three 3.3. Rotary motor three 3.4 preferably adopts a servo motor capable of realizing 360-degree continuous rotation, with extremely high rotation accuracy.

[0077] Rotary rod 3.5 is connected with the output shaft of rotary motor three 3.4 through a shaft coupling at the middle, and is suspended at both ends. Rotary rod 3.5 has sufficient lightweight and rigidity, and is usually made of carbon fiber tube or thin-walled aluminum alloy tube, to reduce the moment of inertia and improve the motion speed and stability. The length of rotary rod 3.5 determines the working diameter of rotary wafer transfer mechanism 3.

[0078] Clamping chuck 3.6 is mounted at the end of rotary rod 3.5. Clamping chuck 3.6 is the component that directly contacts and handles the wafer, and includes a main body and multiple vacuum nozzles. These nozzles are uniformly stressed when adsorbing the wafer, and will not cause the wafer to warp or stress concentrate. The vacuum passage is led out through the hollow shaft of rotary rod 3.5 and rotary motor three 3.4, and is connected to the external vacuum system. The vacuum on-off is precisely controlled by an electromagnetic valve.

[0079] The working process of rotary wafer transfer mechanism 3 is as follows: when it is needed to pick a wafer from transfer mechanism 7, rotary motor three 3.4 and Z-axis moving module three 3.2 drive rotary rod 3.5 to rotate and descend, so that clamping chuck 3.6 moves to the position directly below transfer chuck 7.3 of transfer mechanism 7. Then, Z-axis moving module three 3.2 rises, so that clamping chuck 3.6 contacts the back of the wafer and adsorbs the wafer by opening the vacuum. Next, Z-axis moving module three 3.2 rises to lift the wafer. Rotary motor three 3.4 is actuated again to transport the wafer to the position above the target position, Z-axis moving module three 3.2 descends to release the vacuum, and the wafer is placed on the target mechanism. Through the coordinated movement of rotary motor three 3.4 and Z-axis moving module three 3.2, it can efficiently transfer the wafer between several stations.

[0080] Photographing module 4 is responsible for acquiring the macro image of the wafer surface, such as Figure 6As shown, the photographing module 4 includes a mechanical hand 4.1, an adapter plate 4.2, a camera 1 4.3 and a light source 1 4.4.

[0081] The mechanical hand 4.1 is the motion core of the photographing module 4. Preferably, the mechanical hand 4.1 is a six-axis mechanical hand. The six-axis mechanical hand has six rotary joints, simulates the motion mode of human arms, can realize positioning of any position and posture in its working space, and has extremely high flexibility. The bottom of the mechanical hand 4.1 is fixedly installed on the equipment base plate, and the arm span and working range thereof cover the entire wafer surface area clamped by the internal clamping mechanism 2. Each axis of the mechanical hand 4.1 is driven by a servo motor, and is provided with a high-resolution encoder, and the repeat positioning accuracy can reach the micron level. The control system thereof is integrated with the equipment main control system, receives the instructions of the main control system, plans the motion trajectory, and realizes rapid, smooth and accurate positioning.

[0082] The adapter plate 4.2 is installed on the flange of the sixth axis at the end of the mechanical hand 4.1. The adapter plate 4.2 is a customized mounting plate for simultaneously fixing the camera 1 4.3 and the light source 1 4.4, ensuring the relative position of the camera and the light source to be stable, and enabling the mechanical hand 4.1 to move smoothly.

[0083] The camera 1 4.3 is a key sensor for image acquisition, and preferably adopts a high-resolution and high-frame-rate industrial area CCD or CMOS camera, with a resolution reaching the level of ten million pixels, so as to ensure that the tiny defects on the wafer surface can be captured. The camera is provided with a high-quality telecentric lens, which can eliminate the magnification error caused by slight changes in the object distance, and ensure the consistency of the image. The camera is connected to an image processing computer through a high-speed data line.

[0084] The light source 1 4.4 provides illumination for shooting. Preferably, the light source 1 4.4 is a ring-shaped light source, and is arranged around the lens of the camera 1 4.3. The ring-shaped light source can provide uniform and shadowless illumination, and is particularly suitable for detecting defects such as scratches and pits of a flat surface object. The light source usually adopts a high-brightness LED, with stable color temperature and adjustable brightness. Through different lighting angles, such as high-angle, low-angle, coaxial light and the like, different types of defects can be highlighted. The power supply and control of the light source 1 4.4 are responsible by a dedicated light source controller, and are integrated into the equipment control system.

[0085] In work, the main control system controls the mechanical hand 4.1 to drive the camera 1 4.3 and the light source 1 4.4 to move to the starting position above the wafer according to the preset detection program. Then, the mechanical hand 4.1 moves according to the planned path, usually a grid-shaped path, and the camera 1 4.3 triggers shooting at each shooting point, and transmits the image to the image processing system in real time for analysis and judgment. The entire scanning process is efficient and automated.

[0086] The micro-inspection assembly 6 is used for high magnification microscopic observation of the wafer to confirm the defects found in macro-inspection or to perform fine measurement at a specific point. As shown in FIG. 6, the micro-inspection assembly 6 includes a motion platform 6.1, a slide plate 6.3, a base plate 6.5, a chuck assembly 6.6, and a microscope assembly 6.7. Figure 7

[0087] The motion platform 6.1 is the base platform of the micro-inspection assembly 6, which has good stability and shock absorption performance. The motion platform 6.1 is installed on the equipment base through a shock isolation element.

[0088] An X-axis slide rail 6.2 is arranged on the motion platform 6.1. The X-axis slide rail 6.2 is a precision linear guide rail pair, and the length thereof determines the movement range of the wafer in the X direction. The slide plate 6.3 is slidably installed on the X-axis slide rail 6.2 through a sliding block. The movement of the X-axis is realized by a ball screw or a linear motor driven by a servo motor, and the positioning accuracy can reach a sub-micron level.

[0089] A Y-axis slide rail 6.4 is arranged on the slide plate 6.3. The Y-axis slide rail 6.4 is perpendicular to the X-axis slide rail 6.2 in the horizontal plane. The base plate 6.5 is slidably arranged on the Y-axis slide rail 6.4 through a sliding block. The movement of the Y-axis is also controlled by a precision servo drive system.

[0090] Through the combination of the movements of the X-axis and the Y-axis, the base plate 6.5 can make two-dimensional precise movement in the horizontal plane on the motion platform 6.1. The chuck assembly 6.6 is arranged on the base plate 6.5. Therefore, the wafer carried on the chuck assembly 6.6 can make precise movement in the XY plane relative to the fixed microscope assembly 6.7, so as to move any point on the wafer to the position directly below the objective lens of the microscope.

[0091] The chuck assembly 6.6 is used for carrying and fixing the wafer to be detected. In a preferred embodiment, the chuck assembly 6.6 includes a linear motor, a rotating motor, a rotating disc, and a micro-inspection chuck. The linear motor is used to drive the micro-inspection chuck to make fine lifting movement in the vertical direction, for adjusting the focusing plane of the wafer. The rotating motor is used to drive the micro-inspection chuck to rotate, so as to adjust the direction of the wafer, facilitating the observation of the microstructure in a specific direction. The micro-inspection chuck itself is also a vacuum chuck, which firmly fixes the wafer through negative pressure, preventing displacement during high-speed movement or focusing.

[0092] The microscope assembly 6.7 is the core of the micro-inspection. It is arranged on the motion platform 6.1 through a support structure and located above the chuck assembly 6.6. The microscope assembly 6.7 includes an objective lens rotating disc, an illumination system, a CCD or CMOS camera, and related optical components. An automatic focusing system is configured to quickly find the best focusing plane.

[0093] ​In a preferred embodiment, the support structure comprises a connecting plate 6.8 and a support plate 6.9. One end of the support plate 6.9 is fixed firmly to the edge of the motion platform 6.1, and the other end is cantilevered towards the center of the platform, forming a cantilever beam structure. The microscope assembly 6.7 is mounted on the cantilevered end of the support plate 6.9 through the connecting plate 6.8, so that there is enough space below the microscope to accommodate the wafer stage moving in XY without interference. The support plate 6.9 has high rigidity, which can reduce the impact of vibration on high magnification imaging.

[0094] During microscopic inspection, the rotating wafer transfer mechanism 3 places the wafer on the chuck assembly 6.6 of the microscopic inspection assembly 6. After vacuum suction and fixation, the equipment control system drives the X-axis and Y-axis motion systems to accurately move the target point under the microscope objective according to the defect coordinates provided by macroscopic inspection or randomly generated sampling point coordinates. Then, the autofocus system works to find a clear image, and the camera takes high-magnification microphotographs for subsequent analysis.

[0095] As shown in Figure 8 The transfer mechanism 7 includes a base 7.2, a transfer support shaft 7.1, a transfer plate 7.4, and a transfer chuck 7.3. The lower end of the transfer support shaft 7.1 is fixed to the base 7.2, serving as support and lifting. The transfer plate 7.4 is fixed to the top of the transfer support shaft 7.1. The transfer chuck 7.3 is installed on the transfer plate 7.4, which is a simple vacuum chuck used to temporarily carry and fix the wafer transferred by the robot 8, waiting for the rotating wafer transfer mechanism 3 to take the wafer. Its height position ensures smooth interface with the robot 8 and the rotating wafer transfer mechanism 3.

[0096] The robot 8 is a key handling equipment connecting the edge detection station and the two sets of macroscopic inspection units. A SCARA robot or a six-axis articulated robot suitable for clean environments is used. The robot end is equipped with an end effector suitable for wafers, usually a gripper with a vacuum chuck or edge clamping mechanism. The motion trajectory and beat of the robot are optimized to maximize the production efficiency of the equipment.

[0097] The normal operation of the equipment cannot be achieved without advanced control systems and image processing software. The entire equipment is controlled by a master PLC or industrial PC. The master system is responsible for coordinating the motion timing and logic interlocking of the robot 8, the rotating wafer transfer mechanism 3, the Z-axis modules, the rotating motor, the mechanical hand 4.1, the motion platform 6.1, and all other moving parts, ensuring safe and orderly operation of the equipment.

[0098] The image processing software runs on a dedicated industrial computer. It is responsible for controlling the camera 4.3 and microscope camera for image acquisition, and real-time processing and analysis of the acquired images. The software algorithm includes image preprocessing, defect detection algorithm, defect classification and size measurement. Finally, a detection report containing defect position, type, size, etc. information is generated, and the results can be mapped to the wafer map.

[0099] The human-computer interaction interface allows the operator to perform formula management, start / stop detection, view real-time status and historical data, and review defect images, etc.

[0100] The present application realizes the full-process automation of wafer detection by integrating edge detection, macroscopic detection and microscopic detection in one device. The design of two sets of parallel macroscopic detection units ingeniously utilizes the cooperation of the robot 8 and the rotating wafer transfer mechanism 3 to realize pipeline parallel operation, significantly improving the detection efficiency. The compact layout of each functional module reduces the movement distance and time of the wafer during transmission. The modular design also facilitates maintenance and upgrading of specific functions.

[0101] The working process of the device is clear in logic: edge detection is performed first to remove wafers with serious edge defects; then efficient parallel macroscopic detection is performed to quickly scan the entire surface; finally, targeted microscopic detection is performed to confirm suspicious points. This "fast first, slow later" and "from surface to point" detection strategy maximizes the detection efficiency while ensuring the detection quality.

[0102] In summary, the multifunctional wafer detection device provided by the present application has the advantages of high integration, high automation, high detection efficiency, reasonable layout, etc., and is very suitable for the strict requirements of modern semiconductor manufacturing enterprises on wafer quality control.

[0103] The preferred embodiments of the present application have been described above. It should be understood that the present application is not limited to the above specific embodiments, nor is it limited to the multifunctional wafer detection device. The devices and structures not fully described should be understood as being implemented in the ordinary way in the art; any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application using the disclosed technical content without departing from the scope of the technical solutions of the present application, or modify them as equivalent embodiments of equivalent changes, which does not affect the essential content of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments in accordance with the technical essence of the present application, without departing from the technical solutions of the present application, all still belong to the scope of protection of the technical solutions of the present application.

Claims

1. A multifunctional wafer inspection device, characterized in that, include: Edge detection module, used for edge detection of wafers; A robot, positioned to the side of the edge detection module, is used to transfer wafers; Two macroscopic inspection units are provided, each of which includes a transfer mechanism, a rotating wafer transfer mechanism, an external clamping mechanism, an internal clamping mechanism, and an imaging module; the two macroscopic inspection units are set up in parallel. The micro-inspection component is located to the side of the macro-inspection unit and is used to perform micro-inspection on the wafer; The transfer mechanism is located within the robot's working range and is used to receive wafers transferred from the edge detection module by the robot. The working range of the rotating wafer transfer mechanism covers the transfer mechanism, external clamping mechanism, internal clamping mechanism, and micro-inspection component, and is used to transfer wafers between them. The external clamping mechanism and the internal clamping mechanism are arranged adjacent to each other, and the external clamping mechanism can transfer wafers to the internal clamping mechanism. The image-capturing area of ​​the imaging module is aligned with the surface of the wafer held by the internal clamping mechanism. The rotary transfer wafer mechanism includes a fixed base, a Z-axis moving module three, an adapter plate three, a rotary motor three, a rotating rod, and a clamping chuck; the Z-axis moving module three is mounted on the fixed base; the adapter plate three is connected to the output end of the Z-axis moving module three so as to be driven by the Z-axis moving module three to move in the vertical direction; the rotary motor three is mounted on the adapter plate three, and its output shaft is connected to the rotating rod. The internal clamping mechanism includes: The fixed bracket is rigidly mounted on the main base plate of the equipment. Z-axis moving module two is vertically fixed on a fixed bracket; Adapter plate two is fixedly connected to the output end of Z-axis moving module two; The deflection motor is fixed on the second adapter plate, and its output shaft drives the tilting shaft to rotate via a synchronous belt; The gear motor mounting plate and bracket are fixedly connected to both ends of the tilting shaft, respectively. A gear-driven motor is mounted on a gear motor mounting plate, and the gear on its output shaft meshes with a rack. The connecting rod shaft is L-shaped, with a rack at one end, which passes through the hollow through hole of the flip shaft and is driven by gears to move axially. A rotating shaft, the middle of which is rotatably connected to the end of the bracket; The connecting rod has its two ends hinged to the other end of the connecting rod shaft and the bottom of the rotating shaft, respectively. Rotary motor two is fixedly mounted on the top of the rotating shaft; and Suction cup one is connected to the output shaft of rotary motor two and is used to adsorb wafers; Among them, the Z-axis moving module 2 drives the suction cup 1 to perform Z-axis lifting and lowering motion, the deflection motor drives the suction cup 1 to perform deflection motion, the gear drive motor drives the rotating shaft to swing through gears, racks, connecting rods and connecting rods, thereby causing the suction cup 1 to perform pitching motion, and the rotary motor 2 drives the suction cup 1 to perform rotational motion.

2. The multifunctional wafer inspection equipment according to claim 1, characterized in that: The transfer mechanism includes a base, a transfer support shaft, an adapter plate, and a transfer suction cup; The lower end of the transfer support shaft is fixed to the base; The adapter plate is fixed to the top of the transfer support shaft; The transfer chuck is mounted on adapter plate six and is used to temporarily support and fix the wafer.

3. The multifunctional wafer inspection equipment according to claim 1, characterized in that: The external clamping mechanism includes a fixed support, a Z-axis moving module, an adapter plate, a rotary motor, and an arc-shaped suction cup; The Z-axis moving module is fixedly installed on the fixed support; The adapter plate is connected to the output end of the Z-axis moving module to move vertically by being driven by the Z-axis moving module. A rotary motor is mounted on an adapter plate. An arc-shaped chuck is connected to the output shaft of the rotary motor so that it can be driven to rotate by the rotary motor. The arc-shaped chuck is used to support the wafer.

4. The multifunctional wafer inspection equipment according to claim 1, characterized in that: The camera module includes a robotic arm, four adapter boards, one camera, and one light source; The bottom of the robotic arm is fixedly mounted, and its operating end is connected to the adapter plate. Camera 1 and light source 1 are both mounted on adapter plate 4. The robotic arm is used to drive adapter plate 4 and the camera 1 and light source 1 mounted on it to move.

5. The multifunctional wafer inspection equipment according to claim 4, characterized in that: The robotic arm is a six-axis robotic arm.

6. The multifunctional wafer inspection equipment according to claim 4, characterized in that: The first light source is a ring light source, which is set around the first camera.

7. The multifunctional wafer inspection equipment according to claim 1, characterized in that: The microscopic inspection module includes a motion platform, an X-axis slide rail, a slide plate, a Y-axis slide rail, a base plate, a suction cup assembly, a microscope assembly, and a support structure; The motion platform is equipped with an X-axis slide rail, and the skateboard is slidably mounted on the X-axis slide rail; The skateboard is equipped with a Y-axis slide rail, and the base plate is slidably mounted on the Y-axis slide rail; The suction cup assembly is mounted on the base plate and is used to support and fix the wafer to be inspected; The microscope assembly is mounted on the motion platform via a support structure and is located above the suction cup assembly.

8. The multifunctional wafer inspection equipment according to claim 7, characterized in that: The suction cup assembly includes a linear motor, a rotary motor, a rotating disk, and a microscopic inspection suction cup; A linear motor is used to drive the microscopic inspection suction cup to move vertically; The rotating motor is used to drive the microscopic inspection suction cup to rotate.

9. The multifunctional wafer inspection equipment according to claim 7, characterized in that: The support structure includes a connecting plate and a support plate. One end of the support plate is fixed to the motion platform via the connecting plate, and the other end is suspended. The microscope assembly is installed on the suspended end of the support plate.

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