Wafer center positioning mechanism

Abstract

The utility model relates to a wafer center positioning mechanism, at least three clamping jaws on the wafer center positioning mechanism are abutted against the edge of a wafer under the driving of a clamping jaw driving assembly, and the abutting parts of the wafer are always located on a circumference with a fixed circle center position and the same radius in the moving process, so that the center of the wafer is located at a preset position. And the center position of the wafer transferred by the mechanical arm is corrected.

Description

Technical Field

[0001] This utility model relates to the field of wafer measurement technology, specifically to a wafer center positioning mechanism. Background Technology

[0002] One current wafer surface measurement technology involves using laser scanning to scan a high-speed rotating wafer. A light-collecting device gathers reflected light (spectral or diffuse reflection) from the wafer surface, and defect detection or dimensional measurement is performed based on the collected reflected light. Typically, a robotic arm or other transport system transfers the wafer from the wafer cassette to a pre-alignment station. At the pre-alignment station, wafer centering and rotational phase positioning are performed. Rotational phase positioning is achieved by detecting directional markings on the wafer edges, such as notches or flat edges. After wafer centering and rotational phase positioning are completed, the robotic arm transfers the wafer to a wafer measurement drive mechanism located at the measurement station. The wafer measurement drive mechanism then drives the wafer to complete the measurement process.

[0003] However, due to limitations in the precision of the pre-aligner and the robotic arm itself, a certain error still exists between the wafer center and the turntable center of the measurement drive mechanism, affecting the coordinate positioning of wafer defects or critical dimensions. Therefore, improving the wafer center positioning accuracy is a technical problem that needs to be solved in this field. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model proposes a wafer center positioning mechanism, which positions the wafer center by setting the contact portion of the claws that abut against the edge of the wafer on a circumference of the same radius.

[0005] To achieve the above objectives, the wafer center positioning mechanism of this utility model includes at least three jaws, a support base plate, and a jaw driving assembly. The jaw driving assembly is mounted on the support base plate, and the at least three jaws are mounted on the jaw driving assembly. The at least three jaws move in a plane parallel to the wafer surface under the drive of the jaw driving assembly, and the at least three jaws respectively abut against the edge of the wafer to position the wafer. The wafer abutment portions of the at least three jaws that abut against the wafer edge are always located on a circumference of the same radius with a fixed center position, so that the at least three jaws can clamp wafers of different sizes and ensure that the wafer center is located in a predetermined position.

[0006] The technical effects of this utility model are as follows:

[0007] The wafer center positioning mechanism of this invention drives at least three jaws through a jaw drive assembly. The wafer contact portion of the at least three jaws abuts against the edge of the wafer and is always located on a circle of the same radius with the center fixed during movement. This allows for the clamping of wafers of different sizes and ensures that the wafer center is located in a predetermined position, thereby achieving wafer center positioning. Attached Figure Description

[0008] Figure 1 This is a structural diagram of the wafer center positioning mechanism.

[0009] Figure 2 This is a diagram of the internal structure of the wafer center positioning mechanism.

[0010] Figure 3 This is a structural diagram of the chuck.

[0011] Figure 4 This is a diagram showing the fit between the rotating ring and the guide rail.

[0012] Figure 5 This is another structural diagram of the mating of the rotating ring and the guide rail.

[0013] Figure 6 This is a diagram showing the installation structure of the backup drive motor. Detailed Implementation

[0014] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0015] Example 1

[0016] See Figure 1-4 A wafer center positioning mechanism includes a support base plate 4-1, three jaws 4-2, and a jaw drive assembly 4-3. The support base plate 4-1 has a turntable channel 4-11 for a turntable to pass through, and the three jaws 4-2 are arranged circumferentially around the turntable channel 4-11. Figure 3 (omitted) Figure 2 The 4-2 jaws (including the housing of the 4-2 jaws) comprise a wafer support portion 4-21 and a wafer abutment portion 4-22. The bottom surface of the wafer is supported on the wafer support portion 4-21, and the wafer abutment portion 4-22 abuts against the edge of the wafer. The wafer abutment portion 4-22 is located on a circumference of the same radius with a fixed center position. Driven by the jaw drive assembly 4-3, the three jaws 4-22 abut against the edge of the wafer, thus positioning the wafer center.

[0017] For wafers of different sizes, although the jaw drive assembly 4-3 can drive the jaw 4-2 to move to the appropriate position for clamping, in order to avoid the jaw 4-2 moving too far and taking too long, such as when switching between 6-inch, 8-inch and 12-inch wafers, it is preferable to provide multiple sets of wafer support parts 4-21 and wafer abutment parts 4-22 on each jaw 4-2. The multiple sets of wafer support parts 4-21 and wafer abutment parts 4-22 on the same jaw are located on concentric circles of different radii and are stepped in the vertical direction to avoid interference.

[0018] There are several ways in which the jaw drive assembly 4-3 drives the jaw 4-2. Preferably, the jaw drive assembly 4-3 drives the jaw 4-2 towards the center of the circle fixed at the aforementioned position. The jaw drive assembly 4-3 is mounted on the support base plate 4-1 and includes a rotating ring 4-31, a drive motor 4-32, and a guide rail 4-33. The line connecting the center of the rotating ring 4-31 and the center of the circle fixed at the aforementioned position is perpendicular to the wafer surface. The drive motor 4-32 meshes with the rotating ring 4-31 through gears, and the drive motor 4-32 drives the rotating ring 4-31 to rotate. A bearing 4-38 is provided between the rotating ring 4-31 and the support base plate 4-1. The inner ring of the bearing 4-38 is fixed to the support base plate 4-1, and the outer ring of the bearing 4-38 is fixed to the rotating ring 4-31. The jaw 4-2 is mounted on the guide rail 4-33. The rotating ring 4-31 pulls the guide rail 4-33 to move radially along the rotating ring 4-31. The guide rail 4-33 drives the jaw 4-2 to abut against the edge of the wafer, thus completing the center positioning of the wafer.

[0019] Preferably, the fixed portion of the guide rail 4-33 is mounted on the supporting base plate 4-1, and the moving portion of the guide rail 4-33 has a guide groove 4-34. The guide groove 4-34 is radially inclined relative to the rotating ring 4-31. A guide post 4-35 is provided on the rotating ring 4-31, and the guide post 4-35 is embedded in the guide groove 4-34. Through the cooperation of the guide post 4-35 and the guide groove 4-34, the rotating ring 4-31 pulls the guide rail 4-33 to move radially along the rotating ring 4-31.

[0020] In order to reduce the processing cost of the gear pair between the drive motor 4-32 and the rotating ring 4-31, it is not necessary to use a gear pair with high meshing accuracy. Preferably, a tension spring 4-36 is provided between the rotating ring 4-31 and the support base plate 4-1 to eliminate the meshing gap of the gear pair.

[0021] Example 2

[0022] For wafers of different sizes, the rotation angle of the drive motor 4-32 driving the rotating ring 4-31 is preset. To avoid excessive compression of wafers with dimensional deviations, preferably, such as Figure 5At least one pair of guide posts 4-35 and guide slots 4-34 have an adjustment space S along the moving path of the guide post 4-35, as shown in the figure. An adjustment space S is left between the upper right side of the guide post 4-35 and the radially inner side of the groove wall of the guide slot 4-34. Correspondingly, a compression spring 4-37 is provided between the moving part of the guide rail 4-33 and the supporting base plate 4-1. The compression spring 4-37 drives the radially outer side of the groove wall of the guide slot 4-34 to abut against the guide post 4-35. If there is no deviation in the wafer size, the radial displacement of the three jaws 4-2 is the same. Otherwise, the wafer will resist the pressure of the compression spring 4-37, preventing the jaws 4-2, which have an adjustment space S between the guide post 4-35 and the guide slot 4-34, from continuing to move. Even worse, under the push of other jaws, this jaw may be pushed in the opposite direction to prevent the wafer from being crushed.

[0023] Example 3

[0024] To prevent insufficient power or damage to a single drive motor 4-32 from affecting normal processes, preferably, such as Figure 6 The chuck drive assembly 4-3 also includes a backup drive motor 4-38, which is mounted on the support base plate 4-1. The output shaft of the backup drive motor 4-38 is connected to a gearbox 4-39 to provide greater power. The output end of the gearbox 4-39 meshes with the rotating ring 4-31 via gears.

[0025] The basic principles, main features, and advantages of this utility model in the explored field have been described in detail above, and some usage examples have been detailed. Finally, it should be noted that the examples given above are only for illustrative purposes and are not intended to limit this utility model. Although we have described this utility model in detail with reference to the examples, those skilled in the art can still modify the described examples and solutions, or replace related technical parts. Therefore, any modifications or equivalent substitutions made within the spirit and principles of this utility model are within the protection scope of the claims of this utility model patent.

Claims

1. A wafer center positioning mechanism, characterized by: The device includes at least three jaws, a support base plate, and a jaw drive assembly. A turntable channel for a turntable to pass through is provided on the support base plate, and the at least three jaws are arranged circumferentially around the turntable channel. The jaw drive assembly is mounted on the support base plate, and the at least three jaws are mounted on the jaw drive assembly. The jaw drive assembly drives the at least three jaws to move in a plane parallel to the wafer surface. The at least three jaws include a wafer support portion and a wafer abutment portion, and the wafer abutment portion remains on a circle of the same radius with a fixed center position throughout the movement.

2. A wafer center positioning mechanism as set forth in claim 1, further characterized by: The chuck drive assembly includes a rotating ring, a drive motor, and a guide rail. The line connecting the center of the rotating ring and the fixed center is perpendicular to the wafer surface. The drive motor meshes with the rotating ring via gears. A bearing is provided between the rotating ring and the support base plate. The fixed part of the guide rail is mounted on the support base plate, and the chuck is mounted on the moving part of the guide rail. The rotating ring pulls the moving part of the guide rail to move radially along the rotating ring.

3. A wafer center positioning mechanism as claimed in claim 2, characterized in that: A guide groove is provided on the moving part of the guide rail, and the guide groove is radially inclined relative to the rotating ring. A guide post is provided on the rotating ring, and the guide post is embedded in the guide groove.

4. A wafer center positioning mechanism as claimed in claim 3, wherein: At least one pair of guide posts and guide grooves have adjustment space on the moving path of the guide posts. A compression spring is provided between the moving part of the guide rail and the supporting base plate. The compression spring drives the radially outer groove wall of the guide groove to abut against the guide post.

5. A wafer center positioning mechanism as claimed in claim 1, wherein: Multiple wafer support parts and wafer abutment parts are provided on each jaw. The multiple wafer support parts and wafer abutment parts on the same jaw are located on concentric circles of different radii and are arranged in a stepped manner in the vertical direction.

6. A wafer center positioning mechanism as claimed in claim 2, wherein: A tension spring is provided between the rotating ring and the supporting base plate.

7. A wafer center positioning mechanism as described in claim 2 wherein: The chuck drive assembly also includes a backup drive motor, which is mounted on the support base plate. The output shaft of the backup drive motor is connected to a gearbox, and the output end of the gearbox meshes with the rotating ring via gears.

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