Wafer polishing system

Abstract

The application relates to the technical field of semiconductor processing, and discloses a wafer polishing system, which comprises a bearing mechanism, a plurality of polishing operation mechanisms and a driving mechanism. The bearing mechanism is used for bearing a wafer to be polished and driving the wafer to rotate. Each polishing operation mechanism is used for performing different types of polishing operations on a notch of the wafer to be polished. The driving mechanism is connected with the polishing operation mechanisms and is used for driving different polishing operation mechanisms to switch between standby stations and processing stations, and controlling the polishing operation mechanisms located in the processing stations to abut against the wafer. A posture adjusting mechanism is connected with the bearing mechanism and is used for driving the bearing mechanism to adjust the contact position of the wafer and the polishing operation mechanisms. The application aims to improve polishing efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, specifically to a wafer polishing system. Background Technology

[0002] In the field of 3D IC fabrication, wafer edge morphology control is one of the key processes to ensure chip manufacturing yield. To reduce the risk of microcracks or edge chipping during subsequent processing, ultra-precision grinding of the wafer edges is usually required to remove wafer edge defects; this is known as wafer edge trimming.

[0003] Traditionally, a high-speed rotating diamond grinding wheel is used to grind the wafer edge in a circular motion, creating a concave step to trim the edge. However, with advancements in 3D IC technology, the precision of traditional methods is insufficient for advanced process requirements. A new process utilizes a high-speed rotating grinding belt to polish the wafer edge, achieving significantly higher precision.

[0004] The wafer edge features a notch structure for precise positioning and stress relief. When processing this notch using a polishing belt, a device needs to be developed to improve process flow efficiency, facilitating high-efficiency operation of the entire machine. Summary of the Invention

[0005] The purpose of this invention is to improve polishing efficiency, and a wafer polishing system is proposed.

[0006] Embodiments of the present invention provide a wafer polishing system, comprising: A support mechanism is used to support the wafer to be polished and drive the wafer to rotate. Multiple polishing mechanisms, each of which is used to perform different types of polishing operations on the notches to be polished on the wafer; A driving mechanism is connected to the polishing operation mechanism. The driving mechanism is used to drive different polishing operation mechanisms to switch between a standby station and a processing station, and to control the polishing operation mechanism located at the processing station to abut against the wafer. An orientation adjustment mechanism, connected to the support mechanism, is used to drive the support mechanism to adjust the contact position between the wafer and the polishing mechanism.

[0007] In one embodiment, the polishing mechanism includes a support base and a polishing belt wound around the support base, wherein the surface roughness of the polishing belt of at least one of the polishing mechanisms for polishing the wafer is different from the surface roughness of the polishing belt of other polishing mechanisms for polishing the wafer.

[0008] In one embodiment, the polishing mechanism further includes a composite motion component connected to the support base for driving at least a portion of the polishing belt to vibrate and / or oscillate.

[0009] In one embodiment, the composite motion component includes: frame; A drive unit is mounted on the frame and has a first output terminal and a second output terminal, which are coaxially arranged. A swing arm is connected to the first output terminal; A vibration transmission mechanism is connected to the second output terminal; The transmission plate is connected to the vibration transmission mechanism and the support base respectively, and the transmission plate is slidably connected to the swing arm.

[0010] In one embodiment, the drive mechanism includes: Workbench; A first driving unit is disposed at the worktable, and the first driving unit has two driving ends; Two mounting frames are respectively connected to the two drive ends of the first drive unit; The second drive unit is disposed at the mounting frame, and the drive end of the second drive unit is connected to the frame.

[0011] In one embodiment, the supporting mechanism includes: Cantilever plate; A rotary joint is provided at the cantilever plate; A suction cup assembly is rotatably mounted on the rotary joint; The self-rotating drive component is mounted on the cantilever plate and connected to the suction cup component.

[0012] In one embodiment, the posture adjustment mechanism includes: tabletop; A ball spline is provided through the platform, and it has a rotating part and a lifting part. The lifting part of the ball spline is connected to the cantilever plate. A lifting drive unit is connected to the platform and to the lifting unit of the ball spline; A rotary drive unit is connected to the platform and to the rotating part of the ball spline.

[0013] In one embodiment, the lifting part of the ball spline is provided with an air passage, and a connecting pipe is connected between the rotary joint and the air passage of the lifting part of the ball spline.

[0014] In one embodiment, the polishing mechanism further includes a polishing belt take-up section and a polishing belt release section, with the two ends of the polishing belt respectively connected to the polishing belt take-up section and the polishing belt release section.

[0015] In one embodiment, a notch detection mechanism is further included, which is used to detect the location of the notch on the wafer.

[0016] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: This invention integrates multiple polishing mechanisms capable of performing different types of polishing operations on wafer notches into a single system platform. Through a drive mechanism connected to the polishing mechanism, different mechanisms can be automatically and rapidly switched between standby and processing positions, and the contact state between the polishing mechanism at the processing position and the wafer can be precisely controlled. This achieves seamless automatic connection of multiple polishing processes. A support mechanism stably supports the wafer to be polished and drives its rotation. An adjustment mechanism connected to the support mechanism drives the overall movement of the support mechanism to adjust the contact position between the wafer and the polishing mechanism. This ensures the uniformity and geometric accuracy of polishing on all curved surfaces and edges of the wafer notch, and allows for rapid and precise adaptation of the processing position when switching between different polishing mechanisms. This improves the overall continuous processing capability and automation level of the equipment, effectively meeting the high-efficiency and high-precision process requirements of semiconductor wafer mass production for notch polishing. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the connection structure between the drive mechanism and the frame of the present invention; Figure 2 This is a schematic diagram of the overall connection structure of the present invention; Figure 3 This is a schematic diagram of the connection structure between the drive mechanism and the frame from another perspective. Figure 4 This is a schematic diagram of the connection structure of the polishing mechanism of the present invention; Figure 5 This is a schematic diagram of the connection structure between the bearing mechanism and the attitude adjustment mechanism of the present invention.

[0018] In the diagram: 1. Bearing mechanism; 11. Cantilever plate; 12. Rotary joint; 13. Suction cup assembly; 14. Rotation drive assembly; 2. Polishing mechanism; 21. Support base; 22. Polishing belt; 23. Composite motion assembly; 231. Frame; 232. Drive unit; 233. Swinging arm; 234. Vibration transmission mechanism; 235. Transmission plate; 24. Polishing belt take-up unit; 25. Polishing belt unloading unit; 3. Drive mechanism; 31. Worktable; 32. First drive unit; 33. Mounting frame; 34. Second drive unit; 4. Attitude adjustment mechanism; 41. Table; 42. Ball spline; 43. Lifting drive unit; 44. Rotation drive unit; 5. Connecting pipeline; 6. Notch detection mechanism. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This application provides a wafer polishing system, including: Support mechanism 1 is used to support the wafer to be polished and drive the wafer to rotate. Multiple polishing units 2, each polishing unit 2 is used to perform different types of polishing operations on the notches to be polished on the wafer; The drive mechanism 3 is connected to the polishing operation mechanism 2. The drive mechanism 3 is used to drive different polishing operation mechanisms 2 to switch between the standby station and the processing station, and to control the polishing operation mechanism 2 located in the processing station to hold the wafer. The orientation adjustment mechanism 4 is connected to the support mechanism 1 and is used to drive the support mechanism 1 to adjust the contact position between the wafer and the polishing operation mechanism 2.

[0021] The support mechanism 1 uses vacuum adsorption and fixation, along with rotation drive, to ensure the wafer remains in a stable rotational state as it searches for the notch to be polished. Multiple polishing mechanisms 2 can be configured with polishing belts of different roughness or abrasives of different materials according to the polishing process requirements. This allows for the sequential completion of multiple processes, such as rough polishing and fine polishing, within the same polishing cycle, avoiding the reduced production efficiency caused by downtime for tool changes in traditional processes. The drive mechanism 3 enables the multiple polishing mechanisms 2 to quickly switch between standby and processing stations along a preset trajectory. The processing station is where the wafer notch directly contacts the polishing belt 22 for polishing; all other positions are standby stations. The attitude adjustment mechanism 4 enables the support mechanism 1 to achieve multi-dimensional attitude adjustment in both axial and rotational directions, precisely positioning the wafer notch relative to the polishing mechanism 2. This adapts to the polishing requirements of notches with different geometric shapes, improving the completeness of the polishing coverage.

[0022] In some embodiments of this application, the polishing mechanism 2 includes a support base 21 and a polishing belt 22 wound around the support base 21. The surface roughness of the polishing belt 22 of at least one polishing mechanism 2 used for polishing the wafer differs from the surface roughness of the polishing belt 22 of other polishing mechanisms 2 used for polishing the wafer. Figure 4 As shown, specifically, the polishing mechanism 2 uses a flexible polishing belt as the main grinding medium. The polishing belt 22 can adapt to the complex inner curved surface contour of the wafer notch through its own elastic deformation, achieving full-surface contact and uniform polishing. The support base 21 serves as the load-bearing and guiding structure for the polishing belt 22, and is internally equipped with multiple sets of guide rollers and pressure rollers to maintain constant tension and precise direction of the polishing belt 22 during operation, preventing belt deviation or slack during high-speed operation.

[0023] To address the needs of different polishing process stages, this application adopts a differentiated surface roughness configuration strategy: the polishing belt 22 with a larger surface roughness is configured in the polishing operation mechanism 2 of the rough polishing stage. Its attached abrasive grains are coarser, and the material removal rate is high. It is used to quickly remove macroscopic defects, edge chipping, and large surface damage layers at the wafer notch, laying a good foundation for subsequent fine polishing. The polishing belt 22 with a smaller surface roughness is configured in the polishing operation mechanism 2 of the fine polishing stage. Its attached abrasive grains are finer, and the material removal rate is relatively mild. It is used to further reduce the surface roughness value of the wafer notch after rough polishing, controlling the surface roughness of the notch within the precision machining standard range of Ra≤0.2μm, improving surface finish and geometric accuracy, and ensuring the alignment accuracy of subsequent photolithography processes.

[0024] In other embodiments of this application, the polishing belts 22 of the multiple polishing mechanisms 2 may also have different materials. Some polishing mechanisms 2 use non-woven abrasive belts for dry grinding with polyester or polyamide as the base material. Some polishing mechanisms 2 use chemical mechanical polishing (CMP) abrasive cloth or microfiber cloth for wet grinding. The combination of different materials can be adapted to special process requirements.

[0025] In some embodiments of this application, the polishing mechanism 2 further includes a composite motion component 23, which is connected to the support base 21 and is used to drive at least a portion of the polishing belt 22 to vibrate and / or oscillate, such as Figure 2 and Figure 4 As shown, the core function of the composite motion component 23 is to transform the linear motion of the single polishing belt into a three-dimensional composite motion. This allows the working section of the polishing belt 22 to not only make tangential contact with the wafer notch, but also to form complex cutting trajectories near the contact point through high-frequency vibration and multi-angle oscillation, thereby significantly improving the uniformity of material removal and the microscopic surface quality. In this application, the two sets of oscillation and vibration motions are spatially superimposed at the notch to form a high-frequency and uniform composite cutting trajectory. This composite motion mode has the following significant advantages compared with traditional fixed-angle unidirectional polishing: First, it can achieve full-envelope coverage of various complex curved surfaces inside the notch without dead angles; second, the diversity of cutting trajectories effectively refines the polishing texture and greatly improves the surface finish; third, it reduces the peak contact stress per unit area, reducing the risk of damage to the wafer edge.

[0026] In some embodiments of this application, the composite motion component 23 includes: Rack 231; The drive unit 232 is mounted on the frame 231 and has a first output end and a second output end, which are coaxially arranged. The swing arm 233 is connected to the first output end; Vibration transmission mechanism 234 is connected to the second output terminal; The transmission plate 235 is connected to the vibration transmission mechanism 234 and the support base 21 respectively. The transmission plate 235 is slidably connected to the swing arm 233, as shown below. Figure 2 and Figure 4As shown, the frame 231 is the structural support body of the composite motion component 23, made of high-rigidity cast iron or welded steel to withstand the combined loads during swinging and vibrating motion. In the embodiment of this application, the drive unit 232 is a transmission unit consisting of two separate servo motors and a reducer. An outer shaft is rotatably mounted on the frame 231, and an inner shaft is mounted at the center of the outer shaft. The inner shaft is rotatably connected to the inside of the outer shaft. The outer shaft and the inner shaft are driven by two servo motors, a reducer, and a synchronous belt, respectively. The outer shaft is the first output end, and the inner shaft is the second output end. The first output end is connected to the swing arm 233, driving it to swing back and forth. The second output end is connected to the vibration transmission mechanism 234, driving it to rotate continuously to generate reciprocating vibration. The two output ends are designed to be coaxial, allowing the two drive systems to be highly integrated in a compact space, significantly reducing the overall dimensions of the composite motion component 23.

[0027] The swing arm 233 is a mechanical transmission component that converts the rotational motion of the first output shaft of the drive unit 232 into the swing displacement of the conduction plate 235. Its structural form is usually elbow-shaped or L-shaped, with one end rigidly connected to the first output end of the drive unit 232 and the other end extending to the vicinity of the conduction plate 235.

[0028] The vibration transmission mechanism 234 includes an eccentric wheel fixed to the second output end of the drive unit 232 and a contact block disposed on the transmission plate 235. The surface of the contact block has paired protrusions, and the eccentric wheel is located between the two protrusions and dynamically abuts against them. When the second output end of the drive unit 232 rotates continuously, the rotational motion of the eccentric wheel is converted into a reciprocating linear displacement of the transmission plate 235 along the extension direction of the polishing belt through periodic collisions and separations with the protrusions of the contact block, achieving reciprocating vibration of ±4mm to ±8mm. This eccentric cam transmission mechanism has advantages such as simple structure, precise and controllable transmission ratio, and rapid response.

[0029] The transmission plate 235 is a key mechanical transmission component connecting the bearing support 21, the swing arm 233, and the vibration transmission mechanism 234. The connection of the swing arm 233 adopts a sliding pair form, which allows the transmission plate 235 to move freely back and forth relative to the swing arm 233 in a direction perpendicular to the swing plane, thereby realizing the decoupled transmission of the two sets of motions: swing and vibration. In this embodiment, the sliding pair between the transmission plate 235 and the swing arm 233 can be a linear guide rail to ensure the accuracy and repeatability of the motion trajectory.

[0030] The vibration motion is driven by the continuous rotation of the central shaft, which drives the eccentric wheel to generate reciprocating linear motion. The amplitude range is controlled between ±4mm and ±8mm, preferably ±6mm. This amplitude range is selected based on the following physical considerations: If the amplitude is less than ±4mm, the vibration amplitude of the polishing belt is insufficient, the relative motion speed between the abrasive grains and the workpiece surface decreases, the number of cutting micro-elements per unit time decreases, resulting in a decrease in material removal efficiency and difficulty in effectively eliminating micro-scratches and roughness peaks on the wafer notch surface; if the amplitude is greater than ±8mm, frequent high-amplitude reciprocating motion will cause a sharp increase in dynamic contact force, and the periodic alternating stress borne by the conduction plate 235 will exceed the fatigue limit of the material. At the same time, excessive vibration will cause the resonance of the composite motion component 23 to intensify, and periodic separation and contact phenomena will occur between the polishing belt and the notch, leaving obvious vibration marks on the wafer surface, which may lead to edge chipping damage in severe cases. Therefore, the preferred amplitude of ±6mm ensures sufficient cutting efficiency and surface quality while minimizing the risk of damage to the equipment body and the wafer.

[0031] The oscillating motion is driven by the first driving component to reciprocate the angular displacement of the rotating shaft, causing the working section of the polishing belt 22 to oscillate back and forth around the contact point with the wafer notch within a preset angle range. The angle range is controlled between ±60° and ±80°, preferably ±74°. This angle range is set based on the typical geometry of the wafer notch: the wafer notch is usually a concave structure of an arc groove, including multiple geometric feature surfaces such as the upper arc surface, the lower arc surface, and the edge contour. If the oscillation angle is less than ±60°, the oscillation stroke of the polishing belt is insufficient, the contact time between the edge transition area and the polishing belt is too short or even completely disconnected, resulting in insufficient local material removal and uneven polishing, causing the geometric parameters such as the notch angle and radius of curvature to deviate from the design tolerance range. If the oscillation angle is greater than ±80°, the oscillating arm generates excessive inertial impact at the extreme position, which accelerates the wear rate of the rotating shaft bearing and may interfere with and collide with the non-processed area of ​​the wafer, causing secondary damage to the wafer.

[0032] In some embodiments of this application, the drive mechanism 3 includes: Workbench 31; The first drive unit 32 is disposed at the worktable 31, and the first drive unit 32 has two drive ends; Two mounting frames 33 are respectively connected to the two drive ends of the first drive unit 32; The second drive unit 34 is located at the mounting frame 33, and its drive end is connected to the frame 231. The drive mechanism 3 enables rapid switching and precise positioning of multiple polishing operation mechanisms 2 between preset workstations. The first drive unit 32 adopts a configuration of a double-rod cylinder or two separate hydraulic / pneumatic cylinders, with two drive ends arranged opposite to each other and driving in opposite directions. In this application, a double-rod cylinder structure is specifically adopted, that is, a single cylinder body has a design with piston rods on two opposite end faces, and the driving forces of the two drive ends are equal and opposite in direction.

[0033] Two mounting frames 33 are rigidly connected to the two drive ends of the first drive unit 32, each supporting a polishing operation mechanism 2. Figure 1 and Figure 3 As shown, a first slide rail is provided on the mounting frame 33. The first slide rail includes a slide rail and a slider. The slider of the first slide rail is fixedly installed on the bottom surface of the first worktable. The slider is slidably connected to the slide rail, and the slide rail is fixedly installed on the mounting frame 33. By providing the first slide rail, it is ensured that the polishing mechanism 2 moves smoothly and quickly along a preset trajectory under the push of the first drive unit 32, eliminating any lateral swaying or rotation. The connection between the mounting frame 33 and the first drive unit 32 adopts a ball joint or a flexible coupling to absorb minor installation eccentricity or dynamic imbalance and prevent impact loads from damaging the cylinder.

[0034] The second drive unit 34 independently drives the polishing mechanism 2 located at the processing station, advancing it towards the wafer notch to abut the polishing belt 22 against the wafer notch. The second drive unit 34 employs an independent hydraulic or pneumatic cylinder configuration. A second slide rail is also provided on the mounting frame 33, comprising a slide rail and a slider. The slide rail of the second slide rail is fixedly installed at the bottom of the mounting frame 33, and the slider of the second slide rail is slidably connected to the slide rail. A displacement plate is also provided on the frame 231, on which the slider of the second slide rail is fixedly installed. Therefore, when the second drive unit 34 drives the displacement plate, it can indirectly drive the frame 231 and the polishing mechanism 2 on the frame 231 to move. Through the cooperation of the second slide rail, the accuracy and stability of the second drive unit 34 during driving are ensured.

[0035] In some embodiments of this application, the carrier mechanism 1 includes: Cantilever plate 11; Rotary joint 12 is located at cantilever plate 11; The suction cup assembly 13 is rotatably mounted on the rotary joint 12; The self-rotating drive assembly 14 is mounted on the cantilever plate 11 and connected to the suction cup assembly 13, such as... Figure 5As shown, the cantilever plate 11 is the main structural component of the bearing mechanism 1. One end of it is rigidly connected to the lifting part of the ball spline 42 of the attitude adjustment mechanism 4, and the other end extends cantilevered in the horizontal direction. The rotary joint 12 is a key component for achieving a sealed transition of vacuum or pneumatic pipelines between the rotating and fixed components. Its structure includes two pipeline interfaces: a rotating end and a fixed end. The rotating end of the rotary joint 12 is connected to the pipeline connecting the wafer back-side suction cup assembly 13, and can rotate with the suction cup assembly 13 without causing the pipeline to become entangled or twisted; the fixed end is connected to the connecting pipeline 5 and remains stationary. The suction cup assembly 13 is a vacuum adsorption structure that directly contacts the wafer, and it mainly includes an adsorption platform and a vacuum channel system. The bearing surface of the adsorption platform has regularly distributed adsorption holes that are connected to the vacuum system. The wafer is flatly adsorbed and fixed on the platform by negative pressure.

[0036] The rotation drive assembly 14 drives the suction cup assembly 13 and the wafer adsorbed on it to rotate around the axis of the suction cup assembly 13 and the axis of the wafer, thereby achieving circumferential alignment of the wafer notch. The rotation drive assembly 14 includes a stepper motor or servo motor and its matching transmission mechanism, such as synchronous belt pulley transmission, gear transmission, or direct drive motor configuration. The rotation drive assembly 14 also integrates a position feedback sensor, such as a photoelectric encoder or absolute rotary encoder, to monitor the rotation angle of the wafer in real time, providing accurate position information for notch alignment control. In other embodiments of this application, the suction cup assembly 13 can also use electromagnetic adsorption or mechanical grippers to fix the wafer, adapting to the carrying requirements of wafers made of special materials or with special shapes.

[0037] In some embodiments of this application, the posture adjustment mechanism 4 includes: Table 41; A ball spline 42 is provided through the platform 41, and it has a rotating part and a lifting part. The lifting part of the ball spline 42 is connected to the cantilever plate 11. The lifting drive unit 43 is connected to the platform 41 and is connected to the lifting part of the ball spline 42; The rotary drive unit 44 is connected to the platform 41 and to the rotating part of the ball spline 42. The ball spline 42 adopts a high-precision ball spline pair structure. The lifting drive unit 43 adopts a precision ball screw pair drive or a hydraulic cylinder drive. Figure 5 As shown, this application specifically employs a precision ball screw pair driven by a cylinder or servo motor to drive the stage 41 and the wafers on it to rise or fall. This allows the stage to receive the wafers during rise and descend after receiving them for subsequent polishing operations. The rotary drive unit 44 is driven by an independent servo motor or stepper motor and is connected to the rotary unit via a synchronous belt drive or gear drive. The rotary drive unit 44 is equipped with a rotation angle encoder or rotation sensor to provide real-time feedback of rotation angle information, providing position feedback to the control system.

[0038] In some embodiments of this application, the lifting part of the ball spline 42 is provided with an air passage, and a connecting pipe 5 is connected between the rotary joint 12 and the air passage of the lifting part of the ball spline 42, such as... Figure 5 As shown, the connecting pipe 5 can be a flexible hose, which can withstand the torsional force during the swing process. The lifting part of the ball spline 42 has an air passage inside along its axial direction. The air passage runs through the entire length of the lifting part. The rotary joint 12 is fixedly installed on the cantilever plate 11. Its rotating end is connected to the air pipe of the suction cup assembly 13, and the fixed end of the rotary joint 12 is connected to the connecting pipe 5. When adsorbing and fixing the wafer, the lifting part of the ball spline 42 can be connected to the external air source. Under the negative pressure state, the wafer is adsorbed and fixed by the suction cup assembly 13 under the air pressure transmission of the lifting part of the ball spline 42, the connecting pipe 5 and the rotary joint 12. The whole process reduces the number and complexity of the external pipes of the system and improves the overall compactness and aesthetics.

[0039] In some embodiments of this application, the polishing mechanism 2 further includes a polishing belt take-up section 24 and a polishing belt release section 25, with the two ends of the polishing belt 22 respectively connected to the polishing belt take-up section 24 and the polishing belt release section 25, such as... Figure 4 As shown, both the polishing belt take-up section 24 and the polishing belt unwinding section 25 consist of servo motors and winding rollers. The two ends of the polishing belt 22 are connected to the two winding rollers respectively. During the polishing process, the polishing belt 22, through the cooperation of its two ends with the polishing belt take-up section 24 and the polishing belt unwinding section 25, continuously winds up the used, worn-out polishing belt 22 onto the take-up reel, while unused polishing belt is continuously released to the working area by the unwinding reel. This mechanism of continuous renewal of the belt working surface ensures that each contact with the wafer notch is with a new polishing belt 22 working surface, thereby improving material removal efficiency and the consistency of polished surface quality.

[0040] In some embodiments of this application, a notch detection mechanism 6 is also included. The notch detection mechanism 6 is used to detect the location of the notch on the wafer, such as... Figure 2 and Figure 5 As shown, the notch detection mechanism 6 is used to accurately detect and position the circumferential position of the wafer notch before polishing, providing a reliable position signal for the rotation drive of the supporting mechanism 1. This ensures that the wafer notch can be accurately rotated to a predetermined position corresponding to the swing center of the polishing mechanism 2, thus laying an accurate geometric reference for subsequent multi-process gradient polishing. In this application, a visual inspection scheme using a CCD high-definition camera or a CMOS camera in conjunction with a ring light source is specifically adopted. The detection head of the notch detection mechanism 6 is fixed at a specific position on the equipment by an adjustable bracket, and the detection line of sight is parallel to the edge contour of the wafer, so that the detection field of view can completely capture the notch features of the entire wafer edge.

[0041] The specific working principle of the inspection process is as follows: First, after the wafer is adsorbed onto the suction cup assembly 13, the self-rotating drive assembly 14 drives the wafer to rotate at a constant low speed, so that the wafer edge contour passes through the field of view of the CCD camera in sequence; Second, the CCD camera identifies the wafer edge contour, and when a notch feature signal is detected, the control system records the wafer rotation angle value at that moment; Third, based on the recorded angle information and the preset polishing station angle parameters, the additional rotation angle increment required is calculated, and the self-rotating drive assembly 14 is driven to continue rotating the wafer to the target position, so that the wafer notch is aligned with the polishing belt 22 for subsequent polishing operations.

[0042] The wafer polishing process includes the following steps: Step 1, Wafer Clamping and Alignment: The lifting drive unit 43 of the attitude adjustment mechanism 4 is activated, driving the ball spline 42 to move upward, which in turn raises the cantilever plate 11 and the suction cup assembly 13 to the clamping height. The operator or automated handling mechanism places the wafer to be processed on the bearing surface of the suction cup assembly 13. Then, the external vacuum negative pressure source is activated. The negative pressure is transmitted to the suction cup assembly 13 through the air passage of the ball spline 42 lifting unit, the connecting pipe 5, the rotary joint 12, and the conduction pipe, forming a negative pressure area between the suction cup assembly 13 and the wafer, which flatly adsorbs and fixes the wafer on the suction cup assembly 13.

[0043] Step 2, Notch Alignment: Activate the self-rotating drive component 14, which drives the suction cup component 13 and the wafer to rotate. The notch detection mechanism 6 scans the wafer edge contour in real time. When a notch feature signal is detected, the control system immediately records the rotation angle, calculates the required additional rotation amount, and continues to drive the wafer to rotate until the notch center and the swing center are completely aligned at the target position.

[0044] Step 3, Lowering and Positioning and Contact Establishment: After the Notch port is aligned, the lifting drive unit 43 of the posture adjustment mechanism 4 drives the ball spline 42 to move downward, causing the cantilever plate 11 and the suction cup assembly 13 to descend to the processing height where the polishing belt is located.

[0045] Step 4, Execution of Gradient Polishing Process: This application is equipped with two polishing operation mechanisms 2: coarse polishing and fine polishing. First, the first drive unit 32 of the drive mechanism 3 is activated, and the polishing operation mechanism 2 equipped with a coarse-grained polishing belt is moved by the drive of the double-outlet cylinder. Then, the second drive unit 34 is activated to drive the polishing operation mechanism 2 to the processing station. At the same time, the composite motion component 23 in the polishing operation mechanism 2 is activated. The first output end of the drive unit 232 drives the swing arm 233 to reciprocate around the rotation axis, so that the polishing section reciprocates periodically around the contact rotation point with the wafer notch within an angle range of ±74°. The second output end of the drive unit 232 simultaneously drives the central rotating shaft to rotate, and the rotational motion is converted into a reciprocating linear displacement of the conduction plate 235 along at least a portion of the length of the polishing belt 22 with an amplitude of ±6mm through the eccentric wheel mechanism. The oscillating and vibrating motions superimpose in space, forming a high-frequency and uniform composite cutting trajectory at the notch opening. The polishing section achieves full-envelope, uniform coverage of the upper and lower arc surfaces and concave arc surfaces of the notch without any blind spots. Simultaneously, the polishing belt take-up section 24 and the polishing belt release section 25 work together to continuously refresh the working surface, ensuring that each contact is with a new polishing belt 22. When the rough polishing process reaches the preset time or material removal amount, the control system stops the operation of the first drive unit 32 and the composite motion assembly 23.

[0046] Step 5, Fine Polishing Process and Station Switching: After the rough polishing process is completed, the first drive unit 32 and the second drive unit 34 of the drive mechanism 3 are activated to remove the rough polishing head from the processing station and simultaneously move the fine polishing head into the processing station. The polishing belt in the fine polishing stage uses fine-grained abrasives, and the material removal rate is relatively mild, further reducing the surface roughness of the wafer notch. The final surface roughness is precisely controlled within a high-precision range of Ra≤0.2μm to ensure the positioning accuracy of subsequent photolithography processes.

[0047] Step 6, Polishing Completion and Unloading: After all gradient processes are completed, the lifting drive unit 43 of the attitude adjustment mechanism 4 drives the suction cup assembly 13 to rise to the unloading height, shuts off the vacuum negative pressure source to release the negative pressure, and the robot or personnel remove the processed wafer from the suction cup and transfer it to the subsequent process.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wafer polishing system, characterized in that, include: The support mechanism (1) is used to support the wafer to be polished and drive the wafer to rotate. Multiple polishing mechanisms (2), each of the polishing mechanisms (2) is used to perform different types of polishing operations on the notches to be polished on the wafer; The driving mechanism (3) is connected to the polishing operation mechanism (2). The driving mechanism (3) is used to drive different polishing operation mechanisms (2) to switch between the standby station and the processing station, and to control the polishing operation mechanism (2) located at the processing station to abut against the wafer notch to be polished. The orientation adjustment mechanism (4) is connected to the support mechanism (1) and is used to drive the support mechanism (1) to adjust the contact position between the wafer and the polishing operation mechanism (2).

2. The wafer polishing system according to claim 1, characterized in that, The polishing operation mechanism (2) includes a support base (21) and a polishing belt (22) wound around the support base (21). The surface roughness of the polishing belt (22) of at least one of the polishing operation mechanisms (2) used for polishing the wafer is different from the surface roughness of the polishing belt (22) used for polishing the wafer of other polishing operation mechanisms (2).

3. The wafer polishing system according to claim 2, characterized in that, The polishing mechanism (2) further includes a composite motion component (23), which is connected to the support base (21) and is used to drive at least a portion of the polishing belt (22) to vibrate and / or oscillate.

4. The wafer polishing system according to claim 3, characterized in that, The composite motion component (23) includes: Rack (231); A drive unit (232) is disposed on the frame (231) and has a first output end and a second output end, wherein the first output end and the second output end are coaxially arranged. The swing arm (233) is connected to the first output end; The vibration transmission mechanism (234) is connected to the second output terminal; The transmission plate (235) is connected to the vibration transmission mechanism (234) and the support base (21) respectively, and the transmission plate (235) is slidably connected to the swing arm (233).

5. The wafer polishing system according to claim 4, characterized in that, The drive mechanism (3) includes: Workbench (31); A first drive unit (32) is disposed at the worktable (31), and the first drive unit (32) has two drive ends; Two mounting frames (33) are respectively connected to the two driving ends of the first driving unit (32); The second drive unit (34) is disposed at the mounting frame (33), and the drive end of the second drive unit is connected to the frame (231).

6. The wafer polishing system according to claim 1, characterized in that, The supporting mechanism (1) includes: Cantilever plate (11); A rotary joint (12) is provided at the cantilever plate (11); The suction cup assembly (13) is rotatably mounted on the rotary joint (12); The self-rotating drive assembly (14) is disposed on the cantilever plate (11) and connected to the suction cup assembly (13).

7. The wafer polishing system according to claim 6, characterized in that, The posture adjustment mechanism (4) includes: Tabletop(41); A ball spline (42) is provided through the platform (41), and has a rotating part and a lifting part. The lifting part of the ball spline (42) is connected to the cantilever plate (11). The lifting drive unit (43) is connected to the platform (41) and connected to the lifting part of the ball spline (42); A rotary drive unit (44) is connected to the platform (41) and connected to the rotating part of the ball spline (42).

8. The wafer polishing system according to claim 7, characterized in that, The lifting part of the ball spline (42) is provided with an air passage, and a connecting pipe (5) is connected between the rotary joint (12) and the air passage of the lifting part of the ball spline (42).

9. The wafer polishing system according to claim 2, characterized in that, The polishing operation mechanism (2) further includes a polishing belt take-up section (24) and a polishing belt release section (25), with the two ends of the polishing belt (22) connected to the polishing belt take-up section (24) and the polishing belt release section (25) respectively.

10. The wafer polishing system according to claim 1, characterized in that, It also includes a notch detection mechanism (6), which is used to detect the location of the notch on the wafer.

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