JPH10284576A - Wafer conveyer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer conveyer equipped with a wafer conveyer robot which saves space, reduces tact time and simplifies structure. SOLUTION: A robot 1 arranged in the conveyer has an arm 9 turnably arranged on a machine stand 5 and a hand arm 11 turnably arranged on the arm 9 so as to vacuum hold a wafer W. The arm 9 has a 1st arm 9A linked to a main shaft 7 and a 2nd arm 9B linked to the hand arm 11 and is constituted so as to be bent at that node. At the turning center position of 1st arm, a holding shaft 13 for temporarily holding the wafer W is arranged so as to be vertically moved and in the state of holding the wafer W on the holding shaft 13, a CCD camera 15 arranged inside the conveyer above the wafer W is arranged so as to pick up the entire image of wafer W. The entire image of wafer W picked up by the CCD camera 15 is compared with a regular position by an image processor 17, and its position shift quantity is detected. The position shift quantity of wafer W is inputted through a controller 20 to the robot 1 as a correcting command, and the hand arm 11 is moved just for that correcting amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer apparatus for transferring a wafer, and more particularly, to providing a wafer transfer robot having an alignment correction function for correcting a positional shift of a wafer.

[0002]

2. Description of the Related Art Conventionally, a wafer transfer robot (hereinafter, referred to as a robot) takes out a wafer stored in a cassette, transfers the wafer to an orientation flat aligner, and then transfers the corrected wafer to the cassette or the next position. It was placed in the transport device to transport it to the process.

[0003] Further, the robot has an arm body rotatably arranged on the machine base and having two arms and arranged to bend and extend, and a wafer rotatably arranged at the tip of the arm body. And a hand arm for adsorbing the wafer.The arm is driven by a driving device disposed inside the machine base, and each arm is transmitted by a belt or a chain so as to move the wafer linearly. It is configured.

However, since a semiconductor substrate using a wafer as a substrate is extremely reluctant to adhere to dust and dirt, processing and transport of the wafer are generally performed in a clean room.
As the number of apparatuses for processing wafers increases with the increase in orders for semiconductor substrates, the amount of dust and dirt generated from each apparatus tends to increase, and the space in the clean room is reduced. Therefore, space saving in a clean room has been required even in a transfer device for transferring a wafer. In order to solve this problem, a transfer robot equipped with a so-called alignment function for detecting and correcting a position shift of a wafer in a robot arranged in the wafer transfer apparatus has been proposed as shown in FIG. .

The transfer robot 21 has an arm 24 connected to a main shaft 23 of a machine base 22 and a hand arm 25 connected to the arm. The arm 24 has two arms and can be bent and extended. And the hand arm 25 is configured to be rotatable with respect to the arm unit 24, so that the wafer W sucked and held by the tip of the hand arm 25 is moved linearly. On the other hand, a holding shaft 26 is disposed in the main shaft 23 so as to pass therethrough, and a support surface for sucking and holding the wafer W is formed at an upper end of the holding shaft 26. The holding shaft 26 is connected to a drive source different from the drive of the arm 24 and is moved in the main shaft 23 in the vertical direction, the horizontal direction, and the front-back direction. The arm connected to the main shaft 23 is formed in a disk shape, and an orientation flat position detecting device 27 is provided on the upper surface of the arm. The wafer W sucked and moved by the hand arm 25 is moved to the holding shaft 26. When the misalignment is detected by the orientation flat position detection device 27 and corrected by the correction movement of the holding shaft 26, the wafer is conveyed to the next step by the hand arm 25. As a result, the orientation flat alignment device that is arranged separately from the conventional robot is eliminated, and it is possible to achieve space saving in the transfer device.

[0006]

However, in the conventional transfer robot 21 arranged in the above-described transfer device,
The installation of the orientation flat position detection device 27 on the arm portion 24 requires the configuration of the orientation flat position detection device 27 itself to be compact, which not only complicates the configuration and increases the manufacturing cost, but also increases the production cost. The arm connected to the main shaft must be manufactured in a special shape in order to take up the space on the upper surface. Further, when the hand arm 25 moves the wafer W onto the holding shaft 26, in order to avoid interference with the orientation flat position detecting device 27,
Extra movement of the hand arm 25 is required.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and eliminates the orientation flat alignment device which is separately provided from the conventional robot, and saves the functions in the clean room by disposing the function on the robot side. It is an object of the present invention to provide a wafer transfer apparatus having a wafer transfer robot with an alignment correction function capable of minimizing tact time without manufacturing a special arm while increasing space.

[0008]

SUMMARY OF THE INVENTION A wafer transfer apparatus according to the present invention is configured as follows to solve the above-mentioned problems. That is, the cassette includes an arm portion rotatably disposed on the machine base and capable of bending and extending, and a hand portion rotatably disposed on the arm portion and sucking and holding a wafer. A wafer transfer robot provided with a wafer transfer robot for transferring a wafer stored in a next step, wherein a wafer holding shaft is disposed at a rotation center position of the arm portion so as to be vertically movable, and the holding shaft is Holding the wafer so that a whole image of the wafer is captured by a CCD camera arranged near the robot,
An image of the wafer detected by the D camera is output to a control device via an image processing device, and the correction unit issues a correction command from the control device so that the center position of the wafer is located at a regular position. A wafer transfer device for moving a wafer.

[0009] Preferably, the CCD camera is arranged so as to image the wafer from above the wafer.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

A wafer transfer robot 1 (hereinafter referred to as a robot 1)
1) is disposed in a wafer transfer device (hereinafter, referred to as a transfer device) M as shown in FIG.
It is arranged so that it can be conveyed. As shown in FIG. 2, the robot 1 is provided with an arm 9 that is rotatably connected to the machine 5 via a main shaft 7 at the center of the machine 5. A hand arm 11 rotatably connected to the arm unit 9 is provided at a distal end. The arm portion 9 includes a first arm 9A connected to the main shaft 7 and a second arm 9B connected to the hand arm 11, and is configured to be able to bend and extend at its node. When the first arm is rotationally driven by a driving unit (not shown) arranged in the machine base 5, the hand arm 11 sucks and holds the wafer W in the cassette 2 by bending and extending the arm unit 9, and holds the wafer W. Convey linearly.

A through hole 7a is formed in the main shaft 7 connected to the first arm 9A along the central shaft portion, and the holding shaft 13 is inserted through the through hole 7a. The holding shaft 13 is driven by a driving means (not shown) in the machine base 5 so as to be able to move in the vertical direction. A boss 13 a is formed above the holding shaft 13 so as to be wider than the holding shaft 13 so as to hold the wafer W. An intake hole for adsorbing the wafer W is formed in the upper surface of the boss 13a, and is connected to an intake device (not shown) via a pipe formed in the holding shaft 13.

Further, the robot 1 disposed in the transfer device M
The CCD camera 15 is mounted on a support stand erected near the camera. The CCD camera 15 is disposed above the holding shaft 13, captures an entire image of the wafer W held on the holding shaft 13, and an image processing device 17 is connected to the CCD camera 15. 20. Accordingly, in the entire image of the wafer W captured by the CCD camera 15, the current position of the wafer W is detected by the image processing device 17, and at the same time, the positional deviation from the normal position of the wafer W is calculated. 20. Then, the correction amount is commanded to the robot 1 in the control device 20, and the hand arm 11
Is rotated by an angle corresponding to the correction amount with respect to the center axis of the arm 9 and is corrected and moved in the horizontal direction.

This operation will be described with reference to FIGS.

FIG. 3 shows a position where the main shaft 7 is driven and the arm portion 9 (the first arm 9A and the second arm 9B) is extended so that the wafer W stored in the cassette device 2 is sucked, grasped and taken out. In this state, the upper surface of the boss 13a of the holding shaft 13 is located slightly below the upper surface of the first arm 9A, and is arranged so as not to interfere with the turning of the second arm.

Next, the spindle 7 is raised and the hand arm 11 is raised to lift the wafer W,
To the holding shaft 13 arranged at the rotation center position of the arm 9 of the robot 1. During this movement, the wafer 2
Reference numeral 9 moves linearly toward the holding shaft 13 from the position on the cassette device 31.

When the wafer W reaches the holding shaft 13 as shown in FIG. 4, the suction of the hand arm 11 to the wafer W is released, and the holding shaft 13 is driven so as to move upward. W is lifted slightly above the hand arm 11 (see FIG. 5). At this time, the boss 13a of the holding shaft 13 is inserted into the intermediate portion of the U-shaped hand arm with respect to the U-shaped hand arm 11, so that it does not interfere with the hand arm 11. Then, the wafer W is sucked and held on the upper surface of the boss 13a of the holding shaft 13 by the operation of a suction device (not shown). Then, the holding shaft 13 further rises and stops while holding the wafer W by suction.

When the wafer W reaches the above position, CC
The D camera 15 starts imaging the wafer W (see FIG. 2). Then, as shown in FIG.
5 can capture the entire image of the wafer W and detect its current position. The whole image of the wafer W is processed by the image processing device 17 as it is, converted into an electric signal, and sent to the control device 20. In the image processing apparatus 17, the current center position P of the imaged wafer W with respect to the reference center position P of the wafer W
1 are calculated, and the positional deviations Δθ and ΔX between P and P1 are calculated.

The position shift of the wafer W calculated by the image processing device 17 is output as a correction command to the robot 1 by the control device 20, and the correction amount △ θ is changed by the hand arm 11 in the robot 1 according to the correction command. , And moves in the horizontal direction by the correction amount ΔX.

When the holding shaft 13 is lowered to a position where the wafer W comes into contact with the upper surface of the hand arm 11, the suction of the holding shaft 13 is released, and instead, the suction portion of the hand arm 11 is actuated to hold the wafer W by suction. I do. Thereafter, the holding shaft 13 is lowered to the original position. When the holding shaft 13 reaches the lowermost position, the hand arm 13 returns to the original position by the amount of the displacement correction amount (Δθ, ΔX). Then, the wafer W is transferred and stored in the next process cassette 3.

Therefore, the first arm 9A of the robot 1
An alignment function can be provided without a special shape. In addition, the movement of the hand arm 11 during wafer transfer is minimized, and the tact time can be reduced.

Incidentally, as described above, the holding shaft 13 is
Even if the holding shaft 13 can be moved up and down at the center of rotation of the first arm 9A, any structure may be used without being configured to pass through the through hole 7a. For example, the first arm 9A
Up and down driving means may be provided inside.

Further, even if the CCD camera 15 is not located above the wafer W held by the holding shaft 13, the CCD camera 15 is arranged in the robot 1 and picks up an image of a part of the peripheral edge of the wafer W from below the wafer W. It may be installed as follows. In this case, if the holding shaft 13 is configured to rotate around the axis with respect to the center, the entire circumferential edge of the wafer W can be imaged, and the displacement can be detected.

Further, as in the conventional case, the holding shaft 13 is driven separately from the driving of the arm portion 9 by the through-hole 7a of the main shaft 7.
It is also possible to move in the horizontal direction in this case,
Since the position shift of the wafer W is corrected by the horizontal movement of the holding shaft 13, the correction of the hand arm 11 is not required.

[0025]

According to the present invention, the wafer transfer device is provided with an arm portion rotatably disposed on the machine base and capable of bending and extending,
A hand unit rotatably arranged on the arm unit and holding a wafer by suction, and comprising a wafer transfer robot for transferring a wafer stored in a cassette to a next process, A holding shaft is provided at the rotation center position of the arm portion so as to be vertically movable, and the holding shaft is configured to hold the wafer such that a whole image of the wafer is captured by a CCD camera arranged near the robot. It is configured to hold. An image of the wafer detected by the CCD camera is output to a control device via an image processing device, and the correction command from the control device is used to arrange the center position of the wafer at a regular position. Since the hand unit is moved, it is not necessary to separately provide a conventional orientation flat positioning device, and space can be saved. Further, since the first arm does not need to be formed in a special shape, the cost can be reduced, and the hand arm is corrected and moved, so that a complicated structure for driving the holding shaft as in the related art is not required.

Further, the position of the wafer is shifted from above by the CCD.
Since images are taken by the camera, there are no extra parts or devices on the first arm other than the holding shaft for holding the wafer. Therefore, there is no obstacle when the hand is transferred to the holding shaft, so that the movement of the hand arm can be minimized, and the tact time can be reduced.

[Brief description of the drawings]

FIG. 1 is a simplified plan view illustrating a transport device according to one embodiment of the present invention.

FIG. 2 is a schematic front view showing an alignment state of the robot in FIG. 1;

FIG. 3 is a view showing a wafer transfer process of the robot in FIG. 1;

FIG. 4

FIG. 5

FIG. 6 is a diagram showing a position shift state of a wafer.

FIG. 7 is a schematic view showing a conventional transfer robot.

[Explanation of symbols]

 M: transfer device 1 ... robot 2 ... cassette 3 ... next process cassette 5 ... machine base 9A ... first arm (arm) 9B ... second arm (arm) 11 ... hand arm 13 ... holding shaft 15 ... CCD camera 17 ... Image processing device 20 ... Control device W ... Wafer

Claims (2)

[Claims] 1. An arm portion rotatably arranged and rotatable with respect to a machine base, and a hand portion rotatably arranged on the arm portion and sucking and holding a wafer. A wafer transfer robot provided with a wafer transfer robot for transferring wafers stored in a cassette to a next step, wherein a holding shaft is provided at a rotation center position of the arm portion so as to be vertically movable; Is a CCD arranged near the robot
Holding the wafer so that the whole image of the wafer is captured by a camera, outputting an image of the wafer detected by the CCD camera to a control device via an image processing device, and executing a correction command from the control device Wherein the hand unit is moved so that the center position of the wafer is positioned at a regular position. 2. The wafer transfer device according to claim 1, wherein the CCD camera is arranged to image the wafer from above the wafer.