JP2002252268A - Holding device for conveying substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding device for conveying a substrate, which does not generate powder dust and can correct the central position of the substrate, having a small and thin positioning detector which hardly generates powder dust. SOLUTION: The holding device 1 for conveying a substrate, which holds the substrate W to convey it, comprises a plurality of holding claws 2, 4. At least one of these claws 2, 4 is a movable claw which pushes the substrate W to the other claw side, and the movable claw has a positioning detector 3 which can detect the moving position of the movable claw itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding device for transferring and holding a thin substrate such as a semiconductor wafer or a liquid crystal glass substrate.

[0002]

2. Description of the Related Art Conventionally, there are a device for holding a substrate under vacuum and a device for holding the periphery of a substrate (edge gripping) as a conventional device for holding a substrate. Since vacuum suction cannot be used, edge gripping has been an effective means.
As an edge gripping method, an apparatus for holding an edge of a substrate with a plurality of gripping claws has already been proposed (for example, Japanese Patent Application Laid-Open No. 7-201947).

[0003]

However, in this case, since one of the gripping claws is movable and the other is fixed, if there is a tolerance in the outer diameter of the substrate, the gripping center shifts, and as a result, the positioning accuracy of the substrate is reduced. However, there was a problem that was reduced.
For such a problem, a method of detecting the displacement of the movable claw and correcting the center of the substrate can be considered. In this case,
It is necessary to mount the detection mechanism directly on the gripping device. However, conventionally used detectors are large in shape,
When a substrate is picked up, there is a problem that the detector interferes with another substrate. Furthermore, when the movable gripper comes into contact with the edge of the substrate, there is a problem that dust is generated due to the impact at that time and the surface of the substrate is contaminated. The present invention has been made in order to solve such a problem, and it is possible to perform correction of the center of the substrate without generating dust, and to realize a small and thin position that hardly generates dust. It is an object of the present invention to provide a substrate holding device having a detector.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a substrate transport gripping device for holding and transporting a substrate, wherein a plurality of gripping claws for radially pressing and gripping the substrate are provided. And at least one of the holding claws is a movable claw that presses the substrate toward the other holding claw side;
The movable claw is provided with a position detecting device for detecting a moving state of the movable claw itself.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a state in which a substrate is gripped by a substrate transfer gripping device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a substrate holding device, and W denotes a thin substrate, such as a semiconductor wafer or a liquid crystal glass substrate, held by the substrate holding device 1. 2 is the substrate holding device 1
A movable claw provided at the base of the upper surface of the device is set to move linearly in the direction of arrow A by, for example, an air cylinder (not shown), and presses the substrate W in the radial direction. Reference numeral 3 denotes a position detector provided on the movable claw 2, which is constituted by a magnet and a magnetic field detection element (not shown), and detects a moving amount of the movable claw 2. Reference numeral 4 denotes fixed claws, for example, two fixed claws, which receive the substrate W pressed by the movable claws 2. In such a configuration, the substrate W is held by the movable claw 2 and the fixed claw 4. In this case, the center of the substrate W is located on a vertical bisector of the fixed claw 4. Fixed nail 4
Since the distance between them is constant, when the outer diameter of the substrate W changes, the moving amount of the movable claw 2 changes. By setting the amount of movement of the movable claw 2 according to the outer diameter of the substrate W in advance, the changed amount of movement can be detected by the position detector 3 to calculate the outer diameter of the substrate W. it can. This makes it possible to accurately correct the center position of the substrate W. As shown in FIG. 2, the displacement X of the movable claw 2 in the pressing direction is represented by R ₀ , the radius of the substrate to be detected, R, and the dimension between the fixed claws 4 as A, as shown in FIG. And the following (1)
It can be calculated by an equation.

[0006]

(Equation 1)

[Second Embodiment] In this second embodiment, as shown in FIG. 3, a rotary drive unit 5 having, for example, a pinion and a rotary drive having, for example, a rack are provided on the substrate holding device 1. A linear motion conversion mechanism 6 is provided to move the movable claw 2 in the radial direction of the substrate W by driving the rotation driving unit 5 so as to press the substrate W. The position detector 3
As shown in FIG. 4, there is provided a disk-shaped magnet 7 which is magnetized in two poles in a single direction and rotates in the same manner as the rotating part of the rotation driving part 5, and has a circumferential surface of the magnet 7. The magnetic sensing surfaces of the first and second magnetic field detection elements 8 and 9 are arranged in a direction perpendicular to the magnetic field detection device to detect a magnetic signal. While the position detector in the second embodiment detects the amount of movement of the movable claw 2 itself, the position detector 3 in the third embodiment determines the rotational position of the rotating part of the rotation drive unit 5. To detect. The detection of the rotation angle of the rotating unit is performed as follows. When the magnet makes one rotation, a sine wave of one cycle is generated from the first magnetic field detecting element 8. Further, the second magnetic field detecting element 9 arranged so that the phase of the output signal is shifted by 90 degrees generates a cosine wave of one cycle. As a result, two signals having a relationship of a sine wave and a cosine wave can be obtained. When the arc tangent is obtained from these two signals,
The rotation angle of the rotation unit of the rotation drive unit 5 can be detected, and the movement amount of the movable claw can be calculated. As shown in FIG. 5, the change amount θ of the rotation angle of the rotation unit of the rotation drive unit 5 is R ₀ , the radius of the substrate to be detected is R, the radius of the detected substrate is R, and the rotation amount of the rotation unit of the rotation drive unit 5 is R. Radius r, fixed claw 4
Assuming that the dimension between them is A, it can be calculated by the following equation (2).

[0008]

(Equation 2)

For example, r is 3 mm, A is 170 mm, R
FIG. 6 is a graph showing the relationship between the amount of change in the rotation angle of the rotation unit of the rotation drive unit 5 and the error in the outer diameter of the substrate W when _{0 is set} to 150 mm. Understand. Therefore, the outer diameter of the substrate serving as a reference is measured in advance by using the position detector 3, and by comparing with the reference value, an error in the radius of the substrate W having a variation can be accurately detected. The center position of the substrate W can be corrected. As described above, in both the first embodiment and the second embodiment, the combination of the magnet and the magnetic field detecting element can be directly mounted on the gripping device by using the thin flat magnet and the small Hall element as the magnetic field detecting element. A simple detector can be configured. Further, with respect to the problem of dust generation due to impact, the movable claw 2 is used by using the signal of the position detector 3.
Detects the proximity of the substrate to the position where it collides with the substrate W, reduces the rotational drive speed just before the collision, and makes the contact slowly, so that the substrate W is gripped without significantly lowering the processing speed, and dust is generated. Can be reduced.

[0010]

As described above, according to the present invention, there is an effect that a small and thin position detector capable of correcting the center of the substrate can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a holding device for transferring a substrate according to a first embodiment of the present invention, showing a state where a substrate is held.

FIG. 2 is a diagram for explaining symbols of equation (1) in the first embodiment.

FIG. 3 is a plan view illustrating a gripping device for transporting a substrate according to a second embodiment of the present invention, showing a state where the substrate is gripped.

FIG. 4 is a plan view showing a position detector according to a second embodiment of the present invention.

FIG. 5 is a diagram for explaining symbols of Expression (2) in the second embodiment.

FIG. 6 is a graph showing a relationship between a change amount of a rotation angle of a rotation unit of a rotation drive unit 5 and an error of an outer diameter of a substrate.

[Explanation of symbols]

 Reference Signs List 1 substrate gripping device, 2 movable claw, 3 position detector, 4 fixed claw, 5 rotation drive unit, 6 rotation-linear motion conversion drive unit, 7 magnet, 8 first magnetic detection element, 9 second magnetic detection element , W substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65G 49/07 B65G 49/07 F

Claims (5)

[Claims] 1. A holding device for transferring and holding a substrate, comprising: a plurality of holding claws for pressing the substrate in a radial direction by pressing the substrate in a radial direction; A movable claw that presses the substrate on a gripping claw side of the moving claw, and the movable claw includes a position detecting device that detects a moving state of the movable claw itself. 2. The holding device for transporting a substrate according to claim 1, wherein the driving portion of the movable claw is constituted by a linear driving device. 3. The substrate transfer grip according to claim 1, wherein the drive unit of the movable claw is constituted by a rotary drive and a mechanism for converting a rotary motion by the rotary drive into a linear motion. apparatus. 4. The movable claw position detecting device according to claim 2, wherein said source signal generating section comprises a magnet and a magnetic field detecting element for generating a different output according to the rotational position of said magnet. 4. The holding device for transferring a substrate according to item 1. 5. The holding device for transporting a substrate according to claim 2, wherein the outer shape of the magnet is a disk shape and is magnetized in two poles in a single direction.