JP2004349321A - Wafer holding device and turntable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer holding device which is lightweight and simple in structure, and also to provide a turntable which has small rotational inertia and is accurately positioned at a rotational position. <P>SOLUTION: The turntable is composed of a stationary pedestal, a rotary pad which is mounted on the stationary pedestal and driven to rotate, a plurality of holding pawls 8 which are arranged on the rotary pad in a circumferential direction and energized toward the center of the circumference, a plurality of cams 13 which are fixed on the stationary pedestal and driven to rotate coaxially with the rotary pad, and a cam follower 12 which is fixed to the holding pawl 8 and engaged with the cam 13. The rotary pad and the cams 13 are driven to rotate synchronously by different motors fixed on the stationary pedestal 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wafer holding device and a turntable used for a wafer alignment device.
[0002]
[Prior art]
An aligner or an alignment device is known for aligning the center position and orientation of a circular wafer with a regular position and orientation. This aligner fixes the wafer to a turntable, rotates the wafer, detects the outer periphery of the wafer with a sensor, obtains the amount of deviation of the center position of the wafer, and obtains an orientation flat or an orientation flat provided on the outer periphery of the wafer. It is a device that detects a notch to obtain a shift amount of the orientation of the wafer, and aligns the center position and the orientation of the wafer with a regular position based on the shift amount (for example, Patent Documents 1 and 2). ).
Generally, an electrostatic chuck or a vacuum chuck has been used as a holding device for fixing a wafer on a turntable. However, since the electrostatic chuck and the vacuum chuck are held by suction on the back surface of the wafer, it is inconvenient to handle with a fork. This is because inserting the fork into the lower surface of the wafer interferes with the electrostatic chuck or the vacuum chuck. Therefore, recently, a mechanical chuck that grips the outer periphery of a wafer with a gripping claw has been used for a gripping device.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-26912 [Patent Document 2]
JP-A-2002-76097
[Problems to be solved by the invention]
However, when a mechanical chuck and its driving source (for example, a motor) are mounted on a turntable, there is a problem that accurate positioning becomes difficult because the rotational inertia increases. In addition, when the wiring of the driving source is routed on the turntable, there is a problem that the rotation of the turntable is restricted.
Therefore, an object of the present invention is to provide a gripping device having a lightweight and simple structure. It is another object of the present invention to provide a turntable having a small rotational inertia and capable of accurate rotational positioning.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a plurality of gripping claws arranged in a circumferential direction and urged toward a center direction of the circumference, and the circular shape being arranged concentrically with the gripping claw. The wafer gripping device comprises a plurality of cams which are driven to rotate around the center of the circumference and a cam follower which is fixed to the gripping claws and engages with the cams, and the gripping claws are opened and closed by the rotation of the cams. Things. Also, a fixed base, a rotary base attached to the fixed base and driven to rotate, and a plurality of gripping claws arranged in a circumferential direction of the rotary base and urged toward a center of the circumference. A turntable comprising: a plurality of cams attached to the fixed base and driven to rotate coaxially with the rotary base; and cam followers fixed to the gripping claws and engaged with the cams. The gripping claws are opened and closed by the rotation of. Further, the rotary table and the cam are driven by separate motors fixed to the fixed table, and are configured to rotate synchronously.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a turntable showing an embodiment of the present invention, and FIG. 2 is a side sectional view of the same turntable. 3 and 4 are explanatory views showing the open state and the closed state of the gripping claws of the turntable.
In the figure, 1 is a turntable, and 2 is a fixed base of the turntable 1. On the fixed base 2, a rotary base 3 and a cam arm 4 are attached so as to be rotatable around a rotary shaft 5. The turntable 3 and the cam arm 4 are respectively driven to rotate by a first motor 6 and a second motor 7 fixed to the fixed stand 2.
[0007]
The turntable 3 is composed of three arms extending radially from the rotation shaft 5, and has a gripping claw 8 at its tip. The gripping claw 8 is supported by the arm of the turntable 3 via a linear motion guide 9 so as to be slidable in the radial direction. The spring 10 closes the gripping claw 8 in the direction toward the rotating shaft 5, that is, the wafer 11 is closed. It is urged in the direction of nipping by the three gripping claws 8. Reference numeral 12 denotes a cam follower fixed to the gripper 8.
[0008]
The cam arm 4 is composed of three arms extending radially from the rotation shaft, and has a wedge-shaped cam 13 at its tip. The cam 13 engages with the cam follower 12 of the gripping claw 8 to open and close the gripping claw 8. When the cam arm 4 rotates clockwise with respect to the turntable 3, the wedge-shaped cam 13 retreats with respect to the cam follower 12 (FIG. 3 shows this state). The wafer 11 is moved in the direction of the rotation shaft 5 by force, and holds the wafer 11. Conversely, when the cam arm 4 rotates counterclockwise with respect to the turntable 3, the wedge-shaped cam 13 advances with respect to the cam follower 12, and lifts the cam follower 12. Therefore, the gripping claws 8 move away from the rotating shaft 5 against the force of the spring 10, so that the gripping of the wafer 11 by the gripping claws 8 is released (see FIG. 4).
[0009]
The first motor 6 and the second motor 7 are synchronously controlled by a control device (not shown). By controlling the rotation of the second motor 7 to advance or delay the rotation of the first motor 6, the cam arm 4 rotates clockwise or counterclockwise relative to the turntable 3. Then, the gripping claws 8 open and close. When the first motor 6 and the second motor 7 are rotated at a constant speed, the turntable 3 and the cam arm 4 rotate while maintaining the relative positional relationship. The turntable can be rotated indefinitely while maintaining the position.
【The invention's effect】
As described above, according to the present invention, since the gripping claws are opened and closed by the cam mechanism, there is an effect that a lightweight and simple structure of the wafer gripping device, more specifically, an inexpensive wafer gripping device is realized.
Further, in the turntable of the present invention, since the motor for driving the gripping device is arranged on the fixed portion, there is an effect that the rotational inertia of the rotating portion is small and accurate positioning can be performed.
[Brief description of the drawings]
FIG. 1 is a plan view of a turntable showing an embodiment of the present invention.
FIG. 2 is a side sectional view of a turntable showing an embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a state in which a gripping claw is closed.
FIG. 4 is an explanatory diagram showing a state in which a gripping claw is opened.
[Explanation of symbols]
1 turntable, 2 fixed base, 3 rotary base, 4 cam arms, 5 rotary axes,
6 first motor, 7 second motor, 8 gripping claw, 9 linear guide,
10 spring, 11 wafer, 12 cam follower, 13 cam

Claims (3)

A plurality of gripping claws arranged in the circumferential direction and urged toward the center of the circumference, and a plurality of cams arranged concentrically with the gripping claw and driven to rotate around the center of the circumference. And a cam follower fixed to the gripping claw and engaged with the cam, wherein the gripping claw is opened and closed by rotation of the cam. In a turntable that grips and rotationally drives a wafer, a fixed table, a rotary table that is attached to the fixed table and is driven to rotate, and is disposed in a circumferential direction of the rotary table, and is disposed in a center direction of the circumference. A plurality of gripping claws urged toward, a plurality of cams attached to the fixed base and driven to rotate coaxially with the rotary base, and a cam follower fixed to the gripping nail and engaged with the cam. A turntable, wherein the gripper is opened and closed by rotation of the cam. 3. The turntable according to claim 2, wherein the rotary table and the cam are driven by different motors fixed to the fixed table, and rotate synchronously. 4.

Images