Wafer chuck apparatus with variable diameter

Abstract

The application discloses a wafer chuck device with variable diameter, and belongs to the technical field of semiconductor manufacturing equipment. The device comprises a rack, a chuck adjusting mechanism and an edge detection mechanism. The chuck adjusting mechanism is arranged on the rack, and the core of the device is that the chuck adjusting mechanism comprises a rotating motor, a rotating disc driven horizontally by the rotating motor, a height adjusting mechanism and a chuck assembly. The rotating motor is fixed to the bottom or center of the rack, and the output shaft of the rotating motor is connected to the center of the rotating disc to transmit the rotating motion. The height adjusting mechanism is arranged on the rotating disc and comprises a linear motor, a push rod and a limiting mechanism composed of a guide column and a guide cylinder. The linear motor is connected to the chuck assembly through the push rod, and the guide column is slidably arranged in the guide cylinder to constrain the chuck to move vertically. The chuck assembly adopts a concentric nesting layout and comprises chuck one, chuck two and chuck three with diameters increasing in sequence. The application realizes the quick and stable adaptation of a single device to wafers of various sizes through the multi-stage chuck structure capable of independent lifting.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing and inspection equipment technology, and is mainly applied to edge detection, surface inspection, or other front-end processing steps in semiconductor wafer manufacturing. It relates to wafer support and positioning technology, specifically a variable-diameter wafer chuck device. This device aims to provide a fast, stable, and high-precision adaptive support and fixing platform for wafers of different sizes, thereby effectively improving equipment utilization, processing efficiency, and product quality in semiconductor production lines. Background Technology

[0002] In the semiconductor wafer manufacturing process, the wafer chuck, as a core component for carrying and fixing the wafer, directly determines the quality and efficiency of subsequent inspection or processing steps. With the continuous development of semiconductor technology, production lines need to handle wafers of various sizes, from 6 inches and 8 inches to 12 inches, which places higher demands on the versatility and flexibility of manufacturing equipment.

[0003] However, existing wafer chuck devices have significant limitations. Most widely used chucks are designed with a fixed diameter, meaning their structure can only perfectly fit a single, specific wafer size. In actual production, if it's necessary to switch to wafers of different sizes for processes such as edge detection, the entire chuck device must be shut down and frequently replaced. This process is not only cumbersome and time-consuming, leading to reduced equipment utilization and decreased production efficiency, but it also requires specialized technicians, increasing labor costs. More seriously, frequent mechanical disassembly and assembly can cause wear and tear on the equipment's positioning interface, increasing maintenance costs, and the replacement process can easily introduce particulate contaminants, posing a threat to the cleanroom environment.

[0004] Furthermore, fixed-diameter chucks perform poorly when dealing with size compatibility issues. If a small-diameter chuck is used to support a large wafer, the wafer edges will bend and hang unsupported due to a lack of effective support. This deformation is fatal in processes with extremely high flatness requirements, such as edge inspection. It causes imaging distortion, preventing the inspection system from acquiring accurate wafer edge images, severely impacting the accuracy of defect identification, and ultimately reducing product yield. Therefore, developing a variable-diameter chuck device that can quickly and stably adapt to various wafer sizes has become an urgent need to improve the flexibility and precision of semiconductor manufacturing. Summary of the Invention

[0005] The purpose of this invention is to provide a variable diameter wafer chuck device to solve a series of problems in the prior art, such as frequent replacements, low production efficiency, high cost, and easy bending and deformation of wafers due to improper wafer support during the inspection process, which affects the inspection accuracy.

[0006] To address the aforementioned problems, the present invention provides a variable diameter wafer chuck device, characterized in that it includes a chuck adjustment mechanism, a frame, and an edge detection mechanism;

[0007] The suction cup adjustment mechanism is mounted on the frame. The suction cup adjustment mechanism includes a rotary motor as a power source, a rotating disk driven by the rotary motor to rotate horizontally, a height adjustment mechanism for vertical height adjustment, and a suction cup assembly for directly supporting the wafer. The rotary motor is fixedly mounted at the bottom or center of the frame, and its output axis extends upward and is fixedly connected to the center of the rotating disk, so as to accurately transmit the rotational motion to the rotating disk.

[0008] The height adjustment mechanism is located on the upper surface of the rotating disk. It includes a linear motor as a linear drive source, a push rod that transmits the power of the linear motor to the suction cup, and a limiting mechanism that ensures the stability of the lifting process. The base of the linear motor is fixed on the rotating disk, and its output end is connected to the lower end of the push rod. The upper end of the push rod is connected to the lower surface of the suction cup assembly.

[0009] The limiting mechanism consists of a guide post and a matching guide cylinder. The upper end of the guide post is fixedly connected to the lower side of the suction cup, while the guide cylinder is vertically fixed on the rotating disk. The lower end of the guide post can be slidably inserted into the inner cavity of the guide cylinder to form a sliding pair, thereby constraining the suction cup to move only in the vertical direction.

[0010] The suction cups include suction cup one, suction cup two, and suction cup three. The diameter of suction cup one is smaller than the diameter of suction cup two, and the diameter of suction cup two is smaller than the diameter of suction cup three. Suction cup one, suction cup two, and suction cup three are arranged in a concentric nested or stepped layout, with suction cup one located inside suction cup two and suction cup two located inside suction cup three.

[0011] Compared with the prior art, the variable diameter wafer chuck device provided by the present invention has the following significant and beneficial technical effects:

[0012] (1) The variable diameter wafer chuck device of the present invention can quickly and accurately adapt to wafers of different sizes through its unique chuck adjustment mechanism. It adopts a multi-level chuck with a concentric nested or stepped layout, combined with a height adjustment and limiting mechanism composed of a linear motor, push rod and guide post and guide cylinder, to ensure that the wafer is stably clamped at the preset detection height during edge detection, effectively avoiding wafer bending and deformation caused by improper clamping or frequent tooling changes.

[0013] (2) This device enables rapid adaptation of a single device to wafers of various sizes, changing the traditional operation mode where fixed-diameter chucks need to be frequently changed according to wafer size. By independently controlling the lifting and lowering of each chuck, operators can switch between testing tasks for wafers of different specifications without interrupting the production line. This highly automated adaptation process shortens tooling preparation and changeover time, reduces equipment downtime, and enables the production line to flexibly respond to the production needs of multi-variety, small-batch production.

[0014] (3) This invention directly reduces labor costs and equipment wear by reducing the need for frequent replacement of the suction cup device. Traditional replacement operations require professional technicians and are prone to wear and tear on the connecting parts of the equipment, increasing maintenance costs. This device not only saves labor and spare parts costs, but more importantly, it reduces particulate contaminants and mechanical positioning errors that may be introduced during replacement operations, thereby reducing the potential risks to wafer processing accuracy from the source. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a structural diagram of the variable diameter wafer chuck device according to an embodiment of the present invention;

[0017] Figure 2 This is a partial enlarged view of the variable diameter wafer chuck device according to an embodiment of the present invention;

[0018] Figure 3 This is a front view of the variable diameter wafer chuck device according to an embodiment of the present invention;

[0019] Figure 4 This is a side view of the variable diameter wafer chuck device according to an embodiment of the present invention;

[0020] Figure 5 This is a top view of the variable diameter wafer chuck device in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 1-Frame; 1.1-Support frame; 1.2-Shock-absorbing pad; 1.3-Platform; 2-Rotary motor; 3-Rotating disk; 4-Height adjustment mechanism; 4.1-Linear motor; 4.2-Push rod; 4.3 Suction cup one; 4.4 Suction cup two; 4.5 Suction cup three; 4.6-Guide post; 4.7 Guide cylinder; 5-Light source; 6-Image acquisition assembly; 6.1-Upper prism; 6.2-Lower prism; 6.3 Camera; 7-Horizontal linear motor; 8-Motor support plate. Detailed Implementation

[0022] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0023] To fully understand this invention, detailed steps and structures will be presented in the following description to illustrate the technical solution of this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0024] like Figures 1 to 5 In one embodiment of the variable diameter wafer chuck device of the present invention, the variable diameter wafer chuck device includes a frame 1, a chuck adjustment mechanism, and an edge detection mechanism. The frame 1 serves as the load-bearing foundation and skeleton of the entire device, employing a layered design. The bottom is a support frame 1.1, constructed from high-strength structural profiles. Above the support frame 1.1, a platform 1.3 is mounted via shock-absorbing pads 1.2. The shock-absorbing pads 1.2 are made of high-damping materials such as high-performance rubber or polyurethane, and their function is to isolate and attenuate vibration transmission. The platform 1.3 is a precision-machined marble or metal platform with good flatness and rigidity, providing a reference for the installation of the chuck adjustment mechanism and the edge detection mechanism.

[0025] The suction cup adjustment mechanism integrates rotary drive, vertical lifting, and multi-size suction cup adaptation functions. Its ingenious design ensures reliable operation. The rotational motion is powered by a rotary motor 2. This rotary motor 2 preferably uses a high-precision servo motor or stepper motor to ensure precise control of the rotation angle and smooth speed characteristics. The output shaft of the rotary motor 2 extends vertically upwards and is fixedly connected to the center of the rotating disk 3 via a coupling or directly. This ensures that the rotational motion generated by the rotary motor 2 can be transmitted to the rotating disk 3 above. The rotating disk 3 is made of aluminum alloy or carbon fiber composite material, ensuring sufficient rigidity while minimizing weight to reduce rotational inertia and improve response speed.

[0026] The height adjustment mechanism 4 is the core unit for achieving vertical positioning of the suction cup. It is set on the upper surface of the rotating disk 3. Each independently adjustable suction cup corresponds to one or more sets of height adjustment mechanisms 4.

[0027] As the direct power source for height adjustment, linear motor 4.1 is the preferred solution, offering advantages such as compact structure, fast response speed, high positioning accuracy, and zero mechanical backlash. The base of linear motor 4.1 is fixed to the mounting position of the rotating disk. The linear thrust generated by linear motor 4.1 is transmitted through push rod 4.2. The lower end of push rod 4.2 is connected to the output end of linear motor 4.1, and the upper end is connected to the lower surface of the corresponding suction cup.

[0028] To ensure the suction cup remains stable during vertical lifting and lowering, preventing horizontal deviation or torsion, this invention employs a limiting mechanism consisting of a guide post 4.6 and a guide cylinder 4.7. The upper end of the guide post 4.6 is fixedly connected to the lower side of the suction cup, while the guide cylinder 4.7 is fixed to the rotating disk 3. The lower end of the guide post 4.6 is slidably inserted into the inner cavity of the guide cylinder 4.7 with a small fitting clearance, together forming a high-precision sliding pair. The core function of this sliding pair is to constrain the connected suction cup, ensuring that it moves only in the vertical direction under the drive of the linear motor 4.1. This effectively resists any potential lateral forces or torques, guaranteeing the smoothness and repeatability of the lifting process.

[0029] The suction cups are the core components that directly support and secure the wafers. This invention employs a multi-level adjustable design, specifically including suction cup 4.3, suction cup 4.4, and suction cup 4.5. The diameters of these three suction cups are related as follows: the diameter of suction cup 4.3 is smaller than that of suction cup 4.4, and the diameter of suction cup 4.4 is smaller than that of suction cup 4.5, respectively used to support wafers of different sizes, such as 6-inch, 8-inch, and 12-inch wafers. They are arranged concentrically or in a stepped layout, with the smallest diameter suction cup 4.3 located inside suction cup 4.4, and suction cup 4.4 located inside suction cup 4.5. This layout makes the device compact and requires no additional planar space.

[0030] According to different embodiments, there are two main forms of connection between the suction cup and the rotating disk 3:

[0031] Example 1: Suction cup 4.3 can be directly and fixedly connected to the rotating disk 3 via at least one support column, meaning suction cup 4.3 is always maintained at a fixed high detection height, which is not adjustable. Suction cups 4.4 and 4.5, used to carry larger wafers, are connected to the rotating disk 3 via their respective independent height adjustment mechanisms 4. In non-working states or when detecting wafers of other sizes, they can control their corresponding linear motors 4.1 to lower to a lower position to avoid interference. When it is necessary to detect wafers of the corresponding size, their height adjustment mechanisms 4 independently raise and lower them to a detection height level with suction cup 4.3.

[0032] Example 2: Suction cup 1 (4.3), suction cup 2 (4.4), and suction cup 3 (4.5) are each connected to the rotating disk 3 via their own independent height adjustment mechanisms (4). This design provides maximum flexibility, allowing the height of each suction cup to be adjusted independently. For example, the height of different suction cups can be finely adjusted according to process requirements, or all suction cups can be lowered to their lowest position during maintenance and cleaning.

[0033] All suction cups have adsorption structures on their working surfaces for securing the wafers. These can be vacuum adsorption holes covering the surface, connected to an external vacuum generator via vacuum channels; or they can be electrostatic adsorption structures that adsorb the wafers by applying a high-voltage electrostatic field. Both methods provide stable and uniform clamping force for the wafers during the inspection process, preventing wafer slippage or warping.

[0034] To ensure the accuracy of lifting, a position sensor is also installed on the rotating disk 3. This position sensor can be a photoelectric sensor or a proximity switch, used to detect whether the suction cup accurately reaches the preset detection height after rising through the height adjustment mechanism 4. The sensor signal is fed back to the control system, forming a closed-loop control, thereby ensuring the repeatability accuracy of each positioning.

[0035] The edge detection mechanism is mounted on the frame 1 via a motor support plate 8. Preferably, a height adjustment structure 10 can also be provided between the motor support plate 8 and the platform 1.3 of the frame 1. This height adjustment structure 10 can adjust the vertical detection height of the edge detection mechanism as a whole, thereby adapting to the focusing requirements of wafers of different thicknesses or different optical systems.

[0036] The motor support plate 8 is fixedly mounted on the frame 1 or connected to the frame 1 via the height adjustment structure 10. A horizontal linear motor 7 is mounted on the plate, which drives the optical components on it to move linearly in a direction parallel to the wafer plane.

[0037] The edge detection light source 5 and the image acquisition module 6 are the core optical components, mounted on the horizontal linear motor 7. The image acquisition module 6 is located to the side of the edge detection light source 5, making it easy to receive light emitted by the light source after refraction, reflection, or scattering at the wafer edge. The edge detection light source 5 provides high-intensity, uniform illumination light of a specific wavelength, illuminating the wafer edge area. The image acquisition module 6 includes an upper prism 6.1, a lower prism 6.2, and a camera 6.3. Its working principle is as follows: after light is emitted from the edge detection light source 5, it illuminates and passes through the wafer edge at a certain angle. The light carrying information such as edge morphology and defects reaches the upper prism 6.1 and the lower prism 6.2, ultimately imaging a clear edge image onto the photosensitive surface of the camera 6.3. The camera 6.3 is typically a high-resolution CCD or CMOS industrial camera. This double-prism structure can effectively fold the optical path, achieving long working distance and high magnification imaging within a limited space.

[0038] Taking Example 1 as an example, the working process of this variable diameter wafer chuck device is as follows:

[0039] Preparation phase: Equipment initialization, all moving parts return to their positions. Suction cups 2 (4.4) and 3 (4.5) are in their lowered positions, only suction cup 1 (4.3) is in its high detection plane position. The edge detection mechanism is adjusted to the appropriate height.

[0040] Small wafer (e.g., 6-inch) inspection: The operator places the 6-inch wafer on the working surface of the chuck 4.3 and initiates vacuum or electrostatic adsorption to fix it in place. The control system activates the rotary motor 2, which drives the rotating disk 3 and the wafer on it to rotate at a constant speed. Simultaneously, the lateral linear motor 7 is activated, which drives the edge detection light source 5 and the image acquisition module 6 to move laterally, performing a spiral scan on the edge of the rotating wafer. The camera 6.3 continuously acquires images and transmits them to the image processing system for analysis.

[0041] For medium-sized wafers (e.g., 8-inch): The control system instructs the linear motor 4.1 corresponding to suction cup 4.4 to move, pushing suction cup 4.4 upward via push rod 4.2. Guide post 4.6 slides within guide cylinder 4.7 to ensure smooth and vertical ascent. When position sensor 9 detects that suction cup 4.4 has reached the preset detection height (aligned with suction cup 4.3), linear motor 4.1 stops. The 8-inch wafer is placed on suction cup 4.4 and held in place. The detection process of rotation, scanning, and image acquisition is then repeated. At this point, although suction cup 4.3 is in a high position, its smaller diameter places it below the 8-inch wafer, preventing interference.

[0042] Large wafer (e.g., 12-inch) inspection: Control chuck three (4.5) to rise to the inspection height, and place the 12-inch wafer for inspection. Chuck one (4.3) and chuck two (4.4) are located below it, without interference.

[0043] In one specific embodiment, suction cups 4.3, 4.4, and 4.5 are all made of materials with extremely low coefficients of thermal expansion, high specific stiffness, and excellent dimensional stability. Preferred materials are silicon carbide reinforced aluminum alloy or Invar, ensuring that the suction cups themselves do not undergo significant deformation when ambient temperature fluctuates, thereby maintaining the long-term accuracy of the support plane.

[0044] The three chucks are arranged in a concentric nested layout. A precise annular gap exists between the inner diameter of chuck two (4.4 mm) and the outer diameter of chuck one (4.3 mm), and between the inner diameter of chuck three (4.5 mm) and the outer diameter of chuck two (4.4 mm). This gap is controlled between 0.5 mm and 1 mm. Too small a gap can cause friction or even jamming during lifting, while too large a gap increases the risk of edge deformation when supporting large wafers due to increased overhang. During processing, ultra-high precision CNC grinding machines and coordinate boring machines are used to ensure the roundness, flatness, and concentricity of each chuck. The working surface of each chuck undergoes optical-grade grinding and polishing to achieve a mirror finish, ensuring perfect adhesion to the back of the wafer and avoiding stress or micro-deformation caused by surface unevenness.

[0045] In one specific embodiment, a large number of tiny vacuum adsorption holes, each with a diameter of 0.2 mm to 0.5 mm, are machined on the working surface of each chuck, using a multi-region concentric ring layout. For example, for an 8-inch chuck II 4.4, the adsorption holes are distributed on 2 to 3 concentric rings to ensure uniform distribution of adsorption force and prevent bending torque on the wafer due to uneven local adsorption force. Below all the adsorption holes is a network of vacuum channels inside the chuck.

[0046] The vacuum channels for suction cups 4.3 (1), 4.4 (2), and 4.5 (3) are independent and connected to external vacuum sources. Each independent vacuum line is equipped with a high-speed response electromagnetic valve and a precision vacuum regulator. The control system can intelligently open the vacuum valve of the corresponding suction cup and close the vacuum valves of other suction cups based on the suction cup currently carrying the wafer. This saves vacuum consumption and reduces the load and energy consumption of the vacuum generator. Furthermore, it prevents airflow leakage from the suction holes of non-working suction cups, which could create uncontrollable turbulence under the wafer, affecting the stability of the inspection environment and even stirring up particulate contaminants.

[0047] To prevent the rigid suction cup surface from impacting or electrostatically damaging the wafer during adsorption and release, this invention also incorporates a compliant adsorption control logic. At the start of adsorption, the solenoid valve does not open fully instantaneously; instead, the control system adjusts the vacuum regulator to allow the adsorption force to smoothly build up from a lower value to the rated value within 100-200 milliseconds. Similarly, when the wafer needs to be removed after testing, the system first closes the vacuum valve and then briefly introduces highly filtered, dry nitrogen gas into the vacuum line to neutralize the vacuum and aid in smooth wafer desorption.

[0048] In one specific implementation, electrostatic adsorption can be used. In this case, an electrode layer, isolated by a high-voltage-resistant, high-thermal-conductivity ceramic thin film, is embedded beneath the working surface of each suction cup. The electrode layer is made of alumina or aluminum nitride. The electrodes are designed as bipolar or Johannesson-Labeck type. The advantages of electrostatic adsorption are no airflow and no particle generation, uniform adsorption force, and suitability for high-temperature environments. However, its control system is more complex, requiring a high-voltage DC power supply and a safe discharge circuit. In this device, when electrostatic adsorption is used, independent high-voltage power supply modules and control circuits are configured for the three suction cups to achieve time-sharing independent control.

[0049] Taking Example 1 as an example, its height control logic is as follows:

[0050] Initial / Returning State: Both suction cups 2 (4.4) and 3 (4.5) descend to a safe low position, with their top surfaces at least several millimeters lower than the top surface of suction cup 1 (4.3). At this point, the device presents itself as a single, high-precision 6-inch suction cup.

[0051] 8-inch wafer inspection process: The robotic arm transports the 8-inch wafer to the top of the device. The control system issues a command to drive the linear motor 4.1 corresponding to suction cup 4.4. The linear motor 4.1, via push rod 4.2, smoothly pushes suction cup 4.4 upward at a controlled speed. The sliding pair formed by guide post 4.6 and guide cylinder 4.7 ensures no wobbling during the ascent. The position sensor 9 mounted on the rotating disk 3 monitors the height of suction cup 4.4 in real time. When it detects that the top surface of suction cup 4.4 is coplanar with the top surface of the fixed suction cup 4.3, the linear motor 4.1 stops. The robotic arm places the 8-inch wafer on the coplanar suction cups 4.3 and 4.4. Although the wafer is mainly supported by suction cup 4.4, suction cup 4.3 provides auxiliary support in the central area, further enhancing the overall rigidity. The control system only opens the vacuum valve leading to suction cup 4.4; if necessary, the vacuum valve of suction cup 4.3 can also be opened simultaneously to adsorb the annular area on it, thus adsorbing and fixing the wafer.

[0052] 12-inch wafer inspection process: Similar to the 8-inch wafer inspection process described above, control suction cup three (4.5) to rise to a height coplanar with suction cup one (4.3) and suction cup two (4.4). At this point, the three suction cups together form a complete 12-inch support plane.

[0053] In one specific implementation, the edge detection light source 5 is a complex light source module integrating a high-brightness, multi-wavelength LED array, a focusing lens group, and a diffuser plate. The LED array can select different wavelengths to enhance the contrast of defects in different materials, such as blue 470nm, green 530nm, and red 630nm. The light emitted by the light source passes through the lens group and forms a collimated beam or a beam of tilted light at a specific angle, which illuminates the edge of the wafer.

[0054] The imaging module 6 is a telecentric imaging lens group, with a lower prism 6.2 and an upper prism 6.1 arranged in front and behind it for optical path deflection. The core advantage of the telecentric lens lies in its low distortion and constant magnification within the depth of field. Even if there are slight fluctuations in the detection height at the edge of the wafer, the size of the image on the camera sensor will not change, which is crucial for accurate dimensional measurement and defect localization.

[0055] The lower prism 6.2 and upper prism 6.1 are made of high-refractive-index optical glass, such as BK7 or H-ZF52, and coated with an anti-reflection film to reduce light energy loss on each reflecting surface. The two prisms are fixed in a lens mount made of a low-thermal-expansion material such as Invar alloy to ensure the stability of the optical axis under temperature variations. The lens mount is mounted on the substrate of the image acquisition module 6 via a fine-tuning mechanism, allowing technicians to make micron-level fine adjustments to the prism's orientation in six degrees of freedom to precisely calibrate the optical path and ensure that the light rays converge unbiasedly to the center of the camera sensor target surface. This fine-tuning mechanism can be a set wire driven by a micrometer head.

[0056] The camera 6.3 employs a high-resolution, high-frame-rate global shutter CMOS camera. High resolution ensures the ability to resolve edge defects at the micrometer or even submicrometer level; high frame rate guarantees that the image will not exhibit motion blur during high-speed wafer rotation and lateral scanning; global shutter mode exposes all pixels of the sensor simultaneously, avoiding distortion that may occur with rolling shutter, which is crucial for capturing fast-moving edge contours.

[0057] In a preferred embodiment, to achieve 360-degree detection of the entire wafer edge without blind spots, the movement of the lateral linear motor 7 and the wafer rotation driven by the rotary motor 2 are synchronized. The control system plans the helical scanning trajectory based on a high-performance PLC or motion control card.

[0058] There is a mathematical relationship between the moving speed V of the horizontal linear motor 7 and the rotational speed ω of the rotary motor 2:

[0059] V = ω × R × (Pitch / 360°), where R is the radius of the detection point from the wafer center, and Pitch is the set scanning pitch. The control system uses electronic gears or interpolation algorithms to ensure that the movement of these two axes is executed according to this relationship, thereby ensuring that the acquired images can be seamlessly stitched into a complete edge image.

[0060] The entire edge detection mechanism can be mounted on the rack 1 via the height adjustment structure 10. When switching between wafers of different thicknesses, or when focal length compensation is required due to mechanical wear, the control system can instruct the lifting platform to move the entire edge detection mechanism vertically by a small amount, ensuring that the optical system is always on the optimal imaging focal plane. Preferably, a laser displacement sensor can be integrated or an image sharpness evaluation function can be used to achieve autofocus, giving the system adaptive focusing capability.

[0061] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, nor is it limited to variable diameter wafer chuck devices. Devices and structures not described in detail herein should be understood as being implemented in a manner common to the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, still fall within the protection scope of the present invention.

Claims

1. A wafer chuck device with a variable diameter, characterized in that, Includes a suction cup adjustment mechanism, a frame, and an edge detection mechanism; The suction cup adjustment mechanism is mounted on the frame. The suction cup adjustment mechanism includes a rotary motor as a power source, a rotating disk driven by the rotary motor to rotate horizontally, a height adjustment mechanism for vertical height adjustment, and a suction cup assembly for directly supporting the wafer. The rotary motor is fixedly mounted at the bottom or center of the frame, and its output axis extends upward and is fixedly connected to the center of the rotating disk, so as to accurately transmit the rotational motion to the rotating disk. The height adjustment mechanism is located on the upper surface of the rotating disk. It includes a linear motor as a linear drive source, a push rod that transmits the power of the linear motor to the suction cup, and a limiting mechanism that ensures the stability of the lifting process. The base of the linear motor is fixed on the rotating disk, and its output end is connected to the lower end of the push rod. The upper end of the push rod is connected to the lower surface of the suction cup assembly. The limiting mechanism consists of a guide post and a matching guide cylinder. The upper end of the guide post is fixedly connected to the lower side of the suction cup, while the guide cylinder is vertically fixed on the rotating disk. The lower end of the guide post can be slidably inserted into the inner cavity of the guide cylinder to form a sliding pair, thereby constraining the suction cup to move only in the vertical direction. The suction cups include suction cup one, suction cup two, and suction cup three. The diameter of suction cup one is smaller than the diameter of suction cup two, and the diameter of suction cup two is smaller than the diameter of suction cup three. Suction cup one, suction cup two, and suction cup three are arranged in a concentric nested or stepped layout, with suction cup one located inside suction cup two and suction cup two located inside suction cup three.

2. The variable diameter wafer chuck device according to claim 1, characterized in that: Suction cup one is directly and fixedly connected to the rotating disk via at least one support column, and is always maintained at a fixed high detection height; while suction cup two and suction cup three are connected to the rotating disk through their respective independent height adjustment mechanisms, and can be independently raised or lowered to the detection height or lowered to a low position through their corresponding height adjustment mechanisms.

3. The variable diameter wafer chuck device according to claim 1, characterized in that: Suction cup one, suction cup two, and suction cup three are each connected to the rotating disk through their own independent height adjustment mechanisms, so that the height of each suction cup can be adjusted independently.

4. The variable diameter wafer chuck device according to claim 3, characterized in that: The edge detection mechanism is mounted on the frame via a motor support plate and a height adjustment structure located between the motor support plate and the frame. This height adjustment structure can adjust the vertical detection height of the edge detection mechanism as a whole.

5. The variable diameter wafer chuck device according to claim 1 or 2, characterized in that: The edge detection mechanism includes an edge detection light source for providing illumination, an image acquisition module for acquiring images of the wafer edge, a lateral linear motor for moving the edge detection light source and the image acquisition module laterally to scan the wafer edge, and a motor support plate for supporting the lateral linear motor.

6. The variable diameter wafer chuck device according to claim 5, characterized in that: The motor support plate is fixedly mounted on the frame. The horizontal linear motor is mounted on the motor support plate. The edge detection light source and the image acquisition module are mounted side by side on the sliding part of the horizontal linear motor. The image acquisition module is located on the side of the edge detection light source to receive edge illumination light.

7. The variable diameter wafer chuck device according to claim 5, characterized in that: The image acquisition module includes an upper prism, a lower prism, and a camera. After the light is emitted by the edge detection light source, it passes through the edge of the wafer and is focused and deflected by the upper and lower prisms, and finally the image is formed on the camera.

8. The variable diameter wafer chuck device according to claim 2 or 3, characterized in that: A position sensor is installed on the rotating disk to detect whether the suction cup accurately reaches the preset detection height after rising through the height adjustment mechanism.

9. The variable diameter wafer chuck device according to claim 1, characterized in that: Vacuum adsorption holes or electrostatic adsorption structures are provided on the working surfaces of suction cup one, suction cup two and suction cup three to fix the wafer during the inspection process.

10. The variable diameter wafer chuck device according to claim 1, characterized in that: The frame includes a support frame, a shock-absorbing pad, and a platform, with the shock-absorbing pad installed between the support frame and the platform.

Images