Wafer measurement driving mechanism with center positioning module

Abstract

The invention relates to a wafer measurement driving mechanism with a center positioning module, which is characterized in that the center positioning module is arranged on the wafer measurement driving mechanism and is coaxial with a rotary table module, and at least three clamping jaws on the center positioning module abut against the edge of a wafer under the driving of a clamping jaw driving assembly; the wafer abutting part is always located on the circumference with the same radius with the circle center on the rotating shaft of the rotary table module in the moving process, so that the center of the wafer is located on the rotating shaft of the rotary table module, and the center position of the wafer transferred by the mechanical arm is corrected.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer measurement, and particularly relates to a wafer measurement driving mechanism with a center positioning module. Background Art

[0002] One of the current wafer surface measurement technologies is to use a laser to scan a high-speed rotating wafer, and a light receiving device is used to collect the reflected light (specular reflection or diffuse reflection) on the wafer surface. Defect detection or dimension measurement is performed based on the collected reflected light. Usually, a transfer system such as a robotic arm is used to transfer the wafer from the wafer cassette to the pre-alignment station, where wafer center positioning and rotation phase positioning are performed. Among them, the rotation phase positioning is performed by detecting the orientation marks on the wafer edge, such as a notch or a flat edge. After completing the wafer center positioning and rotation phase positioning, the robotic arm transfers the wafer to the wafer measurement driving mechanism located at the measurement station, and the wafer measurement driving mechanism drives the wafer to complete the measurement work.

[0003] However, limited by the accuracy of the pre-aligner and the robotic arm itself, there is still a certain error between the center of the wafer and the center of the turntable of the measurement driving mechanism, which affects the coordinate positioning of wafer defects or critical dimensions. Therefore, how to improve the wafer center positioning accuracy is a technical problem that needs to be solved by the wafer measurement driving mechanism in this field. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a wafer measurement driving mechanism with a center positioning module, and by setting a center positioning module on the wafer measurement driving mechanism, the wafer center positioning accuracy is improved.

[0005] In order to achieve the above object, the wafer measurement driving mechanism with a center positioning module of the present invention includes a translation driving module, a vertical displacement driving module, a turntable module, and a center positioning module. Among them, the vertical displacement driving module and the center positioning module are installed on the translation driving module, and the center positioning module is located above the vertical displacement driving module, or the vertical displacement driving module is installed on the translation driving module, the center positioning module is installed on the fixed part of the vertical displacement driving module, and is located above the moving part of the vertical displacement driving module; the turntable module is installed on the vertical displacement driving module, and the turntable module moves up and down under the drive of the vertical displacement driving module to load and unload the wafer from the center positioning module. The center positioning module and the turntable module move horizontally as a whole under the drive of the translation driving module, and the central axis of the center positioning module is coaxial with the rotation axis of the turntable module. The center positioning module corrects the center position of the wafer transferred by the robotic arm, so that the center of the wafer is located on the rotation axis of the turntable module, thereby improving the positioning accuracy of the wafer center.

[0006] The central positioning module includes at least three jaws, and the at least three jaws respectively abut against the edge of the wafer to position the wafer. The at least three jaws move in a plane parallel to the surface of the wafer under the drive of the jaw drive assembly. Among them, the wafer abutting parts of the at least three jaws that abut against the edge of the wafer are always located on a circumference with the same radius and the center of the circle on the rotation axis of the turntable module, so that the at least three jaws can clamp wafers of different sizes and ensure that the center of the wafer is located on the rotation axis of the turntable module.

[0007] The technical effects of the present invention are as follows: In the present invention, a central positioning module is provided on the wafer measurement drive mechanism. The central positioning module corrects the central position of the wafer transferred by the robotic arm. At least three jaws on the central positioning module abut against the edge of the wafer under the drive of the jaw drive assembly. The wafer abutting parts are always located on a circumference with the same radius and the center of the circle on the rotation axis of the turntable module, so that the center of the wafer is located on the rotation axis of the turntable module to improve the positioning accuracy of the wafer center. Description of the Drawings

[0008] Figure 1 is the overall structure diagram of the wafer measurement drive mechanism with a central positioning module.

[0009] Figure 2 is the internal structure diagram of the central positioning module.

[0010] Figure 3 is the structure diagram of the jaw.

[0011] Figure 4 is the mating structure diagram of the rotating ring and the guide rail.

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

[0013] Figure 6 is the installation structure diagram of the backup drive motor. Detailed Description of the Preferred Embodiments

[0014] The following further describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustration and explanation of the present invention, and are not intended to limit the present invention.

[0015] Embodiment 1

[0016] See Figure 1-4, A wafer measurement driving mechanism with a central positioning module, comprising a translation driving module 1, a vertical displacement driving module 2, a turntable module 3, and a central positioning module 4. The vertical displacement driving module 2 is installed on the translation driving module 1, and the turntable module 3 is installed on the vertical displacement driving module 2. During wafer measurement, the wafer is fixed on the turntable 3-1 of the turntable module 3. The translation driving module 1 realizes the translation movement of the wafer, the vertical displacement driving module 2 realizes the up and down displacement of the wafer, and the turntable module 3 realizes the rotation movement of the wafer. Using the driving devices commonly used in the field of wafer measurement to realize the translation, up and down displacement, and rotation of the wafer is not the innovation point of the present invention, and the specific structure will not be elaborated here.

[0017] The central positioning module 4 is installed on the fixed part 2-1 of the vertical displacement driving module 2, located above the moving part 2-2 of the vertical displacement driving module 2, and the central axis of the central positioning module 4 is coaxial with the rotation axis of the turntable module 3. The central positioning module 4 and the vertical displacement driving module 2 move as a whole under the drive of the translation driving module 1, and the turntable module 3 moves up and down under the drive of the vertical displacement driving module 2 to load and unload the wafer from the central positioning module 4. The robotic arm transfers the wafer to the central positioning module 4. After the central positioning module 4 completes the central positioning of the wafer, the turntable module 3 moves upward under the drive of the vertical displacement driving module 2 to load the wafer from the central positioning module 4, and completes the wafer measurement process in cooperation with the translation driving module 1. Then, the turntable module 3 moves downward under the drive of the vertical displacement driving module 2 to unload the wafer on the central positioning module 4, and the robotic arm transfers the wafer away from the central positioning module 4.

[0018] As Figure 2 (omitting Figure 1 the housing of the central positioning module 4 in Figure 3 (omitting Figure 2 the housing of the claw 4-2 in

[0019] For wafers of different sizes, although the chuck driving assembly 4-3 can drive the chuck 4-2 to move to a suitable position for clamping, in order to avoid the chuck 4-2 moving too far and taking a long time, for example, when switching between 6-inch, 8-inch, and 12-inch wafers, preferably, multiple sets of wafer support portions 4-21 and wafer abutting portions 4-22 are provided on each chuck 4-2. The multiple sets of wafer support portions 4-21 and wafer abutting portions 4-22 on the same chuck are respectively located on circumferences with different radii centered on the rotation axis of the turntable module 3 and are stepped in the vertical direction to avoid interference.

[0020] There are various ways for the chuck driving assembly 4-3 to drive the chuck 4-2. Preferably, the chuck driving assembly 4-3 drives the chuck 4-2 along the radial direction of the turntable 3-1. The chuck driving assembly 4-3 is installed on the support base plate 4-1 and includes a rotating ring 4-31, a driving motor 4-32, and a guide rail 4-33. Among them, the rotating ring 4-31 is coaxial with the rotation axis of the turntable 3-1, the driving motor 4-32 is engaged with the rotating ring 4-31 through gears, and the driving 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 on the support base plate 4-1, and the outer ring of the bearing 4-38 is fixed on the rotating ring 4-31. The chuck 4-2 is installed on the guide rail 4-33, and the rotating ring 4-31 guides the guide rail 4-33 to move along the radial direction of the rotating ring 4-31. The guide rail 4-33 drives the chuck 4-2 to abut against the edge of the wafer to complete the centering of the wafer.

[0021] Preferably, the fixed part of the guide rail 4-33 is installed on the support base plate 4-1, a guide groove 4-34 is provided on the moving part of the guide rail 4-33, the guide groove 4-34 is inclined relative to the radial direction of the rotating ring 4-31, and a guide post 4-35 is provided on the rotating ring 4-31. 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 guides the guide rail 4-33 to move along the radial direction of the rotating ring 4-31.

[0022] In order to reduce the processing cost of the gear pair between the driving motor 4-32 and the rotating ring 4-31 and not require 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 clearance of the gear pair through the tension spring 4-36.

[0023] Embodiment 2 For wafers of different sizes, the angle by which the driving motor 4-32 drives the rotating ring 4-31 to rotate is preset. In order to avoid wafers with dimensional deviations from being over-pressed, such as Figure 5, preferably, there is an adjustment space S between at least one pair of guide posts 4-35 and the guide groove 4-34 on the moving path of the guide post 4-35. As shown in the figure, there is an adjustment space S between the upper right side of the guide post 4-35 and the radially inner groove wall of the guide groove 4-34. Correspondingly, a compression spring 4-37 is provided between the moving part of the guide rail 4-33 and the support base plate 4-1. The compression spring 4-37 drives the radially outer groove wall of the guide groove 4-34 to abut against the guide post 4-35. If there is no deviation in the wafer size, then the radial displacement amounts of the three jaws 4-2 are the same. Otherwise, the wafer will resist the pressure of the compression spring 4-37 to prevent the jaw 4-2 with the adjustment space S between the guide post 4-35 and the guide groove 4-34 from moving further. Moreover, under the push of other jaws, this jaw will be pushed in the reverse direction to avoid crushing the wafer.

[0024] Embodiment III To prevent the insufficient power or damage of a single driving motor 4-32 from affecting the normal process, such as Figure 6 , preferably, the jaw driving assembly 4-3 further includes a standby driving motor 4-38. The standby driving motor 4-38 is installed on the support base plate 4-1. The output shaft of the standby driving motor 4-38 is connected with a transmission 4-39 to provide greater power. The output end of the transmission 4-39 is meshed with the rotating ring 4-31 through gears.

[0025] The basic principles, main features and its advantages in the field of exploration of the present invention have been described in detail above, and some usage examples have been elaborated. Finally, it should be noted that: the above examples are only used to explain this patent and not to limit the present invention. Although we have described the present invention in detail with reference to the examples, those skilled in the art can still modify the described examples and solutions, or replace relevant technical parts. Therefore, any modifications and equivalent replacements made within the spirit and principle of the present invention are within the protection scope of the claims of this invention patent.

Claims

1. A wafer measurement drive mechanism with a center positioning module, comprising a translation drive module, a vertical displacement drive module, a turntable module and a center positioning module; the vertical displacement drive module and the center positioning module are installed on the translation drive module, and the center positioning module is located on the upper part of the vertical displacement drive module, or the vertical displacement drive module is installed on the translation drive module, and the center positioning module is installed on the fixed part of the vertical displacement drive module and is located on the upper part of the moving part of the vertical displacement drive module; the turntable module is installed on the moving part of the vertical displacement drive module, and the central axis of the center positioning module is coaxial with the rotation axis of the turntable module; The center positioning module includes at least three claws, a supporting base plate and a claw driving assembly, wherein the supporting base plate is mounted on the translation driving module or on the fixed part of the vertical displacement driving module; a turntable channel for the turntable module to pass through is provided on the supporting base plate, and the at least three claws are arranged circumferentially around the turntable channel; the claw driving assembly is mounted on the supporting base plate, and the at least three claws are mounted on the claw driving assembly, and the claw driving assembly drives the at least three claws to move in a plane parallel to the wafer surface; the at least three claws include a wafer supporting part and a wafer abutting part, and the wafer abutting part is always located on a circle with the same radius whose center is on the rotation axis of the turntable module during the movement.

2. The wafer measurement drive mechanism with a center positioning module as claimed in claim 1, characterized in that: The claw driving assembly includes a rotating ring, a driving motor and a guide rail. The rotating ring is coaxial with the rotating axis of the turntable, and the driving motor is meshed with the rotating ring through gears. A bearing is provided between the rotating ring and the supporting base plate. The fixed part of the guide rail is mounted on the supporting base plate, and the claw 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. The wafer measurement drive mechanism with a center positioning module as claimed in claim 2, characterized in that: A guide groove is arranged on the moving part of the guide rail, and the guide groove is arranged to be inclined relative to the radial direction of the rotating ring. A guide column is arranged on the rotating ring, and the guide column is embedded in the guide groove.

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

5. The wafer measurement drive mechanism with a center positioning module as claimed in claim 1, characterized in that: Multiple sets of wafer supporting parts and wafer abutting parts are respectively arranged on each clamping claw. The multiple sets of wafer supporting parts and wafer abutting parts on the same clamping claw are respectively located on circles of different radii with the center on the rotating axis of the turntable module, and are arranged in a stepped manner in the vertical direction.

6. The wafer measurement drive mechanism with a center positioning module as claimed in claim 2, characterized in that: A tension spring is arranged between the rotating ring and the supporting bottom plate.

7. The wafer measurement drive mechanism with a center positioning module as claimed in claim 2, characterized in that: The claw driving assembly also includes a backup driving motor, which is mounted on the supporting base plate. The output shaft of the backup driving motor is connected to a transmission, and the output end of the transmission is meshed with the rotating ring through a gear.

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