Wafer positioning and clamping concentricity clamping device and method

Abstract

This invention relates to the field of wafer fabrication technology, specifically to a concentric clamping device and method for wafer positioning and clamping, comprising at least three clamping units; each clamping unit includes a drive module, a transmission module, and a sensing module; the drive module includes a cylinder and an independent air path for driving the cylinder; the transmission module includes a multi-link mechanism connected to the cylinder piston rod, the movable end of which is provided with a clamping post for contacting the wafer edge; the sensing module includes a position sensor and a thin-film pressure sensor. This invention achieves precise synchronous control of the movement trajectory of multiple clamping posts by configuring each clamping unit with an independent solenoid valve and air path, and introducing closed-loop feedback from the position sensor; and by setting thin-film pressure sensors at the force points of the clamping posts, combined with the adaptive force control module of the control system, it achieves the technical effect of keeping the clamping force consistently within a preset safety range.

Description

Technical Field

[0001] This invention relates to the field of wafer fabrication technology, specifically to a concentric clamping device and method for wafer positioning and clamping. Background Technology

[0002] Before processes such as marking and inspection, wafers need to be precisely centered on the wafer stage. Currently, robotic arms are commonly used to remove wafers from the cassette and place them on the positioning stage. However, due to inherent repeatability errors in the robotic arms, the initial placement of the wafer deviates from the theoretical center. Therefore, the positioning stage needs subsequent rotational precision positioning to align the center. This process often requires multiple iterations and is time-consuming, becoming a bottleneck restricting production efficiency.

[0003] Patent application CN202511113580.X discloses a wafer positioning device. This device includes a positioning platform and a driving mechanism. The positioning platform includes a receiving platform for placing the wafer and at least three positioning mechanisms evenly arranged around the receiving platform. Each positioning mechanism includes a clamping component for abutting the positioned wafer. The driving mechanism drives the clamping components to move towards the center of the receiving platform. The driving mechanism includes a first driving module, a transmission control module, and a second driving module. The transmission control module is connected to both the first and second driving modules, transmitting power generated by the first driving module to the second driving module to drive its movement. The second driving module then drives all clamping components to move and abut the positioned wafer. When the clamping components abut the positioned wafer, the transmission control module disconnects the power transmission between the first and second driving modules. This solution enables wafer positioning and protects the wafer.

[0004] Existing technology uses a first drive module to simultaneously drive multiple peripheral clamping components via a transmission control module to achieve synchronous clamping and positioning of the wafer. While this solution can achieve coarse positioning, it still has significant shortcomings: First, it uses a single mechanical transmission mechanism to drive all clamping components. Although an overload protection mechanism is designed, it cannot inherently achieve independent and precise motion control of each clamping arm, making it difficult to compensate for minor errors in the mechanical transmission chain. This may lead to asynchronous clamping, generating torque on the wafer, or even causing new positional deviations. Second, the clamping force of this device depends on the inherent characteristics of the mechanical structure and cannot be adaptively adjusted according to the wafer's thickness, warpage, or other actual conditions. This poses a risk of insufficient clamping force leading to positioning failure or excessive clamping force leading to wafer breakage.

[0005] Therefore, there is an urgent need in this field for a coarse positioning device that can achieve high-precision synchronous motion and adaptive force control, so as to improve the positioning speed while ensuring the safety and reliability of the positioning process. Summary of the Invention

[0006] In order to overcome the defects in the prior art, the present invention aims to provide a concentricity clamping device and method for wafer positioning and clamping, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, on the one hand, the present invention provides a concentricity clamping device for wafer positioning and clamping, which is installed on a wafer stage and includes a gas flow sleeve, a gas distribution ring, and at least three sets of clamping units surrounding the gas distribution ring; the clamping unit includes a drive module, a transmission module, and a sensing module.

[0008] The drive module includes a cylinder and an independent air circuit for driving the cylinder, and an independently controlled solenoid valve is provided on this independent air circuit.

[0009] The transmission module includes a multi-link mechanism connected to the cylinder piston rod, and the movable end of this linkage mechanism is provided with a clamping post for contacting the edge of the wafer;

[0010] The sensing module includes a position sensor for detecting the displacement of the cylinder piston rod and a thin-film pressure sensor for detecting the clamping force applied to the wafer by the clamping post.

[0011] The clamping device also includes a control system, whose signal input is connected to a position sensor and a thin-film pressure sensor, and whose signal output is connected to a number of solenoid valves. The control system is configured to receive feedback signals from the position sensor and the thin-film pressure sensor and independently control each solenoid valve, while the clamping columns move synchronously to a preset position and apply a preset clamping force to the wafer.

[0012] As a further improvement to this technical solution, the contact area between the clamping post and the wafer is provided with a buffer pad made of flexible material, and the thin-film pressure sensor is disposed between the buffer pad and the clamping post body.

[0013] As a further improvement to this technical solution, the multi-link mechanism includes a pull rod, an adjusting rod, and a moving rod that are hinged sequentially. The moving rod is fixedly connected to the cylinder piston rod. The top surface of the gas distribution ring is provided with a plurality of clamping rods at equal intervals in a ring shape. The pull rod is hinged to the clamping rods. The clamping post is embedded in the upper end of the adjusting rod. The extension and retraction movement of the cylinder triggers the clamping post to switch between a vertical clamping position and an inclined avoidance position.

[0014] As a further improvement to this technical solution, an air pump is connected to the bottom of the gas flow sleeve via a pipe. The side wall of the gas distribution ring is provided with several gas ports at equal intervals in a ring shape, and the inner end of the gas port penetrates the bottom surface of the gas distribution ring and is connected to the gas flow sleeve. The cylinder is connected to the gas port via an air pipe, and the solenoid valve is installed in this air pipe.

[0015] As a further improvement to this technical solution, the control system includes a synchronization control module, which is configured to: compare the feedback values ​​of each position sensor and dynamically adjust the control signals of each solenoid valve through a control algorithm to keep the displacement trajectories of all clamping columns consistent.

[0016] As a further improvement to this technical solution, the control system includes an adaptive force control module, which is configured to adjust the opening degree or on / off frequency of the solenoid valve in real time according to the feedback value of the diaphragm pressure sensor, so that the clamping force is stabilized at a preset target value.

[0017] As a further improvement to this technical solution, the preset target clamping force can be retrieved and set according to the input wafer specification information.

[0018] As a further improvement to this technical solution, a groove is provided on the top surface of the outer end of the clamping rod, and a slider is slidably connected in the groove and fixed in the groove by bolts; the slider is L-shaped, and a cylinder is installed on its vertical side wall; a slide rail is fixedly provided on the top surface of the horizontal section of the slider, and a telescopic block is slidably connected on the slide rail; the moving rod is installed on the top surface of the telescopic block.

[0019] The clamping device system is integrated with the precision positioning stage. The control system communicates with the main controller of the precision positioning stage and sends a positioning completion signal to the main controller after completing the coarse positioning of the clamping column.

[0020] As a further improvement to this technical solution, a visual positioning module is also included, which is used to detect the initial position deviation of the clamped wafer on the wafer stage. The visual positioning module is communicatively connected to the control system. The control system is further configured to: calculate the theoretical displacement required by several clamping posts based on the initial position deviation, and use this as the control target of the preset position.

[0021] On the other hand, the present invention provides a concentric clamping method for wafer positioning and clamping, comprising the following steps:

[0022] S1. The robotic arm places the wafer on top of the wafer stage, and the vision positioning module detects the initial position deviation of the wafer.

[0023] S2. The control system retrieves the corresponding preset clamping force and target displacement parameters according to the wafer specifications.

[0024] S3. The control system controls each solenoid valve to operate independently, driving several cylinders to push the multi-link mechanism, so that the clamping column moves from the inclined avoidance position to the vertical clamping position, and simultaneously contacts the edge of the wafer.

[0025] S4. The position sensor provides real-time feedback on the displacement of the cylinder piston rod, and the diaphragm pressure sensor on the clamping column provides real-time feedback on the clamping force data. The control system adjusts several solenoid valves through the synchronous control module and the adaptive force control module to achieve synchronous displacement of the clamping column and stable clamping force.

[0026] S5. Once all clamping columns have reached the target position and the clamping force has stabilized, the control system sends a positioning completion signal to the precision positioning stage.

[0027] S6. After the precise positioning is completed, the control system controls the cylinder to retract, driving the clamping column to return to the tilted avoidance position.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The concentricity clamping device and method for wafer positioning and clamping achieves precise synchronous control of the movement trajectory of multiple clamping columns by configuring an independent solenoid valve and air circuit for each clamping unit and introducing closed-loop feedback from position sensors; and by setting thin-film pressure sensors at the force points of the clamping columns and combining them with the adaptive force control module of the control system, the real-time monitoring and dynamic adjustment of the wafer clamping force are achieved, thereby achieving the technical effect of keeping the clamping force stable within a preset safety range.

[0030] 2. The concentricity clamping device and method for wafer positioning and clamping cleverly combines the slider, slide rail and multi-link mechanism to achieve fine mechanical adjustment of the initial installation position of the cylinder and the final clamping point of the clamping column. This achieves the technical effect of ensuring the final positioning accuracy of the entire system through mechanical fine adjustment even after long-term use or component wear, thus improving the long-term stability and maintainability of the equipment. Attached Figure Description

[0031] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, will select various possible shapes and proportions to implement the invention according to specific circumstances.

[0032] Figure 1 This is a schematic diagram of the clamping device of the present invention in its working state;

[0033] Figure 2 This is a schematic diagram of the assembly structure of the clamping device of the present invention;

[0034] Figure 3 This is a top view of the assembled clamping unit of the present invention;

[0035] Figure 4This is a side view of the assembled clamping unit of the present invention;

[0036] The meanings of the labels in the diagram are as follows:

[0037] 100. Gas flow sleeve;

[0038] 200. Gas distribution ring; 210. Gas interface; 220. Clamping rod; 221. Slide groove; 230. Slider;

[0039] 300. Clamping unit; 310. Cylinder; 311. Telescopic block; 312. Slide rail; 320. Clamping column; 330. Adjusting rod; 340. Pulling rod; 350. Moving rod; 360. Bolt. Detailed Implementation

[0040] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art will conceive of any possible variations of the invention, all of which should be considered within the scope of the invention. The terms "installation" and "connection" should be interpreted broadly, referring to direct connection as well as indirect connection through an intermediate medium.

[0041] The terms "central axis," "vertical," "horizontal," "front," "rear," "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer" used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of the invention, "a number" means two or more, unless otherwise explicitly specified.

[0042] Please see Figures 1-4 As shown, the present invention provides a concentricity clamping device for wafer positioning and clamping, which is installed on a wafer stage and includes a gas flow sleeve 100, a gas distribution ring 200, and at least three sets of clamping units 300 surrounding the gas distribution ring 200; the clamping unit 300 includes a drive module, a transmission module, and a sensing module.

[0043] Specifically, the drive module includes a cylinder 310 and an independent air circuit for driving the cylinder 310, and an independently controlled solenoid valve is provided on this independent air circuit.

[0044] A gas pump is connected to the bottom of the gas flow sleeve 100 via a pipe. The side wall of the gas distribution ring 200 is provided with several gas ports 210 at equal intervals in a ring shape. The inner end of the gas port 210 penetrates the bottom surface of the gas distribution ring 200 and is connected to the gas flow sleeve 100. The cylinder 310 is connected to the gas port 210 via a gas pipe. The solenoid valve is installed in this gas pipe.

[0045] Specifically, the transmission module includes a multi-link mechanism connected to the piston rod of the cylinder 310. The movable end of this linkage mechanism is provided with a clamping post 320 for contacting the edge of the wafer. The contact part between the clamping post 320 and the wafer is provided with a buffer pad made of flexible material, such as a silicone pad, to protect the wafer.

[0046] The multi-link mechanism includes a pull rod 340, an adjusting rod 330, and a moving rod 350 that are hinged in sequence. The moving rod 350 is fixedly connected to the piston rod of the cylinder 310. The top surface of the gas distribution ring 200 is provided with a number of clamping rods 220 at equal intervals in a ring shape. The pull rod 340 is hinged to the clamping rods 220. The clamping post 320 is embedded in the upper end of the adjusting rod 330. The extension and retraction movement of the cylinder 310 triggers the clamping post 320 to switch between a vertical clamping position and an inclined avoidance position.

[0047] Meanwhile, to improve clamping accuracy, a fine-tuning structure is incorporated; a groove 221 is provided on the top surface of the outer end of the clamping rod 220, and a slider 230 is slidably connected within the groove 221 and fixed within the groove 221 by bolts 360; the slider 230 is slidably moved within the groove 221 by the adjustment of the bolts 360, thereby adjusting the initial position of the cylinder 310; by changing the initial positions of the three cylinders, the clamping column 320 is adjusted to center the wafer.

[0048] Furthermore, the slider 230 is L-shaped, the cylinder 310 is installed on its vertical side wall, and the top surface of the horizontal section of the slider 230 is fixedly provided with a slide rail 312. A telescopic block 311 is slidably connected on the slide rail 312, and the moving rod 350 is installed on the top surface of the telescopic block 311, so that the moving rod 350 is supported and slides, thereby stably driving the adjusting rod 330 to follow the moving rod 350 to adjust the tilt angle.

[0049] Specifically, the sensing module includes a position sensor for detecting the displacement of the piston rod of the cylinder 310 and a thin-film pressure sensor for detecting the clamping force applied to the wafer by the clamping post 320; the thin-film pressure sensor is disposed between the buffer pad and the body of the clamping post 320. Alternatively, the thin-film pressure sensor may be disposed at the connection between the multi-link mechanism and the drive module.

[0050] It is worth noting that the clamping device also includes a control system, whose signal input terminals are connected to a position sensor and a diaphragm pressure sensor, and whose signal output terminals are connected to several solenoid valves. This control system is configured to receive feedback signals from the position sensor and the diaphragm pressure sensor, and independently control each solenoid valve. The clamping posts 320 then move synchronously to preset positions and apply a preset clamping force to the wafer. The control signals of each solenoid valve are dynamically adjusted primarily through a PID algorithm to ensure that the displacement trajectories of all clamping posts 320 remain consistent.

[0051] The control system includes a synchronization control module, which is configured to compare the feedback values ​​of each position sensor and dynamically adjust the control signals of each solenoid valve through a control algorithm to keep the displacement trajectories of all clamping columns 320 consistent.

[0052] The control system includes an adaptive force control module, which is configured to adjust the opening degree or on / off frequency of the solenoid valve in real time based on the feedback value of the diaphragm pressure sensor, so that the clamping force is stabilized at a preset target value. The preset target clamping force can be retrieved and set according to the input wafer specification information.

[0053] The control system sends opening signals to several solenoid valves, and cylinders 310 begin to extend synchronously. Position sensors provide real-time feedback on the displacement of each piston rod. The synchronization control module compares the three displacement values. If it finds that one of the clamping units 300 is lagging, it finely adjusts the opening of the solenoid valve of that unit to accelerate it until the displacements of several clamping units 300 are synchronized. When the clamping post 320 contacts the edge of the wafer, the thin-film pressure sensor provides a force signal. The adaptive force control module compares the feedback force with the preset target force and dynamically adjusts the opening of the solenoid valve through PID calculations, so that the clamping force quickly reaches and stabilizes at the target value.

[0054] Furthermore, the clamping device system is integrated with the precision positioning stage. The control system communicates with the main controller of the precision positioning stage. After completing the coarse positioning with the clamping posts 320, the control system sends a positioning completion signal to the main controller. After positioning is completed, when all clamping posts 320 have reached the preset position and the clamping force is stable, the control system determines that the coarse positioning is complete and sends a signal to the main controller of the precision positioning stage. The precision positioning stage then begins the subsequent precise positioning operation.

[0055] It is worth noting that the clamping device also includes a vision positioning module for detecting the initial positional deviation of the clamped wafer on the wafer stage. The vision positioning module is communicatively connected to the control system. The control system is further configured to calculate the theoretical displacement required by several clamping posts 320 based on the initial positional deviation, and use this as the control target for the preset position. For example, after the robotic arm places the wafer down using a CCD camera, the vision positioning module first takes a picture of the wafer to identify the initial deviation (Δx, Δy) between its center and the center of the wafer stage. Based on this deviation, the control system calculates the theoretical displacement (L1, L2, L3) required by the three clamping posts 320 to push the wafer towards the center. Subsequently, the clamping process is controlled with these three theoretical displacements as targets, achieving more targeted and precise coarse positioning, further reducing the workload of the fine positioning stage.

[0056] The concentricity clamping method for wafer positioning and clamping of the present invention includes the following steps:

[0057] S1. The robotic arm places the wafer on top of the wafer stage, and the vision positioning module detects the initial position deviation of the wafer.

[0058] S2. The control system retrieves the corresponding preset clamping force and target displacement parameters according to the wafer specifications.

[0059] S3. The control system controls each solenoid valve to operate independently, driving several cylinders 310 to push the multi-link mechanism, so that the clamping column 320 moves from the inclined avoidance position to the vertical clamping position, and simultaneously contacts the edge of the wafer.

[0060] S4. The position sensor provides real-time feedback on the displacement of the piston rod of cylinder 310, and the diaphragm pressure sensor on clamping column 320 provides real-time feedback on clamping force data. The control system adjusts several solenoid valves through the synchronous control module and the adaptive force control module to achieve synchronous displacement of clamping column 320 and stable clamping force.

[0061] S5. When all clamping columns 320 reach the target position and the clamping force is stable, the control system sends a positioning completion signal to the precision positioning stage.

[0062] S6. After precise positioning is completed, the control system controls the cylinder 310 to retract, driving the clamping column 320 to return to the tilted avoidance position. This method, through multi-sensor feedback and independent air path control, achieves high-precision synchronization and adaptive force control in the wafer clamping process, effectively improving concentricity positioning accuracy and operational safety.

[0063] It should be noted that the fixed connections and fixing methods of the present invention are achieved using conventional fixing means such as bolt connections or welding. The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A concentricity clamping device for wafer positioning and holding, mounted on a wafer stage, characterized in that: It includes a gas flow sleeve, a gas distribution ring, and at least three sets of clamping units surrounding the gas distribution ring; the clamping unit includes a drive module, a transmission module, and a sensing module; The drive module includes a cylinder and an independent air circuit for driving the cylinder, and an independently controlled solenoid valve is provided on this independent air circuit. The transmission module includes a multi-link mechanism connected to the cylinder piston rod, and the movable end of this linkage mechanism is provided with a clamping post for contacting the edge of the wafer; The sensing module includes a position sensor for detecting the displacement of the cylinder piston rod and a thin-film pressure sensor for detecting the clamping force applied to the wafer by the clamping post. The clamping device also includes a control system, whose signal input is connected to a position sensor and a thin-film pressure sensor, and whose signal output is connected to a plurality of solenoid valves; the control system is configured to receive feedback signals from the position sensor and the thin-film pressure sensor and independently control each solenoid valve, while the plurality of clamping columns move synchronously to a preset position and apply a preset clamping force to the wafer. The control system includes a synchronization control module, which is configured to: compare the feedback values ​​of each position sensor and dynamically adjust the control signals of each solenoid valve through a control algorithm to keep the displacement trajectories of all clamping columns consistent. The control system includes an adaptive force control module, which is configured to adjust the opening degree or on / off frequency of the solenoid valve in real time according to the feedback value of the diaphragm pressure sensor, so that the clamping force is stabilized at a preset target value. The preset target value can be retrieved and set based on the input wafer specification information.

2. The concentricity clamping device for wafer positioning and clamping according to claim 1, characterized in that, The contact area between the clamping post and the wafer is provided with a buffer pad made of flexible material, and the thin-film pressure sensor is disposed between the buffer pad and the clamping post body.

3. The concentricity clamping device for wafer positioning and clamping according to claim 2, characterized in that, The multi-link mechanism includes a pull rod, an adjusting rod, and a moving rod that are hinged in sequence. The moving rod is fixedly connected to the cylinder piston rod. The top surface of the gas distribution ring is provided with a number of clamping rods at equal intervals in a ring shape. The pull rod is hinged to the clamping rods. The clamping post is embedded in the upper end of the adjusting rod. The extension and retraction movement of the cylinder triggers the clamping post to switch between a vertical clamping position and an inclined avoidance position.

4. The concentricity clamping device for wafer positioning and clamping according to claim 3, characterized in that, A gas pump is connected to the bottom of the gas flow sleeve via a pipe. The side wall of the gas distribution ring has several gas ports that are evenly spaced in a ring shape. The inner end of each gas port penetrates the bottom surface of the gas distribution ring and is connected to the gas flow sleeve. The cylinder is connected to the gas port via a gas pipe, and a solenoid valve is installed in this gas pipe.

5. The concentricity clamping device for wafer positioning and clamping according to claim 4, characterized in that, The outer end of the clamping rod has a groove, and a slider is slidably connected in the groove and fixed in the groove by bolts. The slider is L-shaped, and a cylinder is installed on its vertical side wall. A slide rail is fixedly installed on the top surface of the horizontal section of the slider, and a telescopic block is slidably connected on the slide rail. The moving rod is installed on the top surface of the telescopic block.

6. The concentricity clamping device for wafer positioning and clamping according to claim 5, characterized in that, It also includes a vision positioning module for detecting the initial position deviation of the clamped wafer on the wafer stage. The vision positioning module is communicatively connected to the control system. The control system is further configured to calculate the theoretical displacement required by several clamping posts based on the initial position deviation, and use this as the control target of the preset position.

7. A concentricity clamping method for wafer positioning and clamping, using the concentricity clamping device for wafer positioning and clamping as described in claim 6, characterized in that: Includes the following steps: S1. The robotic arm places the wafer on top of the wafer stage, and the vision positioning module detects the initial position deviation of the wafer. S2. The control system retrieves the corresponding preset clamping force and target displacement parameters according to the wafer specifications. S3. The control system controls each solenoid valve to operate independently, driving several cylinders to push the multi-link mechanism, so that the clamping column moves from the inclined avoidance position to the vertical clamping position, and simultaneously contacts the edge of the wafer. S4. The position sensor provides real-time feedback on the displacement of the cylinder piston rod, and the diaphragm pressure sensor on the clamping column provides real-time feedback on the clamping force data. The control system adjusts several solenoid valves through the synchronous control module and the adaptive force control module to achieve synchronous displacement of the clamping column and stable clamping force. S5. Once all clamping columns have reached the target position and the clamping force has stabilized, the control system sends a positioning completion signal to the precision positioning stage. S6. After the precise positioning is completed, the control system controls the cylinder to retract, driving the clamping column to return to the tilted avoidance position.

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