JPH0462951A - Wafer transfer apparatus - Google Patents

Abstract

PURPOSE:To suck a wafer on a conveyance arm even when a wafer carrier is distorted and to stabilize a transfer operation by a method wherein a parallelism adjustment mechanism is actuated on the basis of an output of a sensor and the wafer and the conveyance arm are faced in parallel at a prescribed interval. CONSTITUTION:A first sensor to a third sensor 8a, 8b, 8c are arranged and installed respectively in three support parts 2 installed at a conveyance arm 1. The sensors 8a to 8c are arranged and installed in order to detect an interval between the individual support parts 2 and a wafer 6 when the conveyance arm 1 is brought close to the wafer 6 housed inside a wafer carrier 5. Consequently, the conveyance arm 1 and the wafer 6 can be faced in parallel at a prescribed interval. For example, a reflectiontype photosensor using infrared rays as detection light can be used as the parallelism sensors 8a to 8c which are used for such a purpose.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a wafer transfer device, and particularly to a device that takes out semiconductor wafers stored in a wafer carrier one by one and transfers them to another location. It is suitable for use.

<Prior art> As is well known, when manufacturing semiconductor devices, semiconductor wafers (hereinafter simply referred to as wafers) are placed in wafer carriers and transported between manufacturing equipment or manufacturing lines. . After the wafer carrier is transported to a predetermined position, the wafers are taken out one by one from the wafer carrier and transferred to another location for the next process.

FIG. 4 is a perspective view showing the configuration of a transfer arm in a conventional wafer transfer device.

As is clear from FIG. 4, this transfer arm 1 is formed in a substantially cross shape, and a support portion 2 that comes into contact with and supports a wafer (not shown) is provided at the tip of each arm piece 1a. ing. Further, a vacuum opening 3 is provided at the center of the transfer arm 1, and a vacuum device (not shown) is operated to suck air from the vacuum opening 3. Therefore, when the transfer arm 1 is inserted into the wafer carrier and the vacuum apparatus is operated with the vacuum opening 3 facing the wafer, the wafer is attracted to the vacuum opening 3. After the wafer is attracted onto the transfer arm 1 in this manner, the transfer arm 1 is pulled out from the wafer carrier and the wafer adsorbed thereon is transferred to a predetermined position.

Then, when the -th wafer transfer is completed, the fifth wafer is transferred.
The carrier elevator 4 on which the wafer carrier 5 is placed is moved up or down by a distance corresponding to the pitch at which the wafers 6 are stored, as shown by arrows in the perspective view for explaining the transfer state in the figure. . As a result, the transfer arm 1 moves directly below the two-piece wafer 6 and can be sucked by the vacuum device, so the two-piece wafer 6 is vacuum-adsorbed onto the transfer arm 1. The wafer is pulled out from the wafer carrier 5 and transferred to a predetermined position.

By repeating such operations, the wafer 6 housed in the wafer carrier 5 is transferred to a predetermined position.

<Problem to be Solved by the Invention> However, in the case of the conventional apparatus described above, the carrier elevator 4 is moved up and down at a preset constant pitch, so the wafer 6 is moved up and down by the transfer arm 1.
vacuum adsorption may not always be possible.

That is, for example, if the wafer carrier 5 is distorted, each wafer 6 stored in the wafer carrier 5
is no longer placed parallel to the carrier elevator 4. Therefore, in this case, as a matter of course, the wafer 6 and the transfer arm 1 no longer face each other parallel to each other at a predetermined interval, so the vacuum suction causes the evaporator 6 to
There arises an inconvenience that it becomes impossible to adsorb the material onto the transport arm 1. As a result, conventionally, if the wafer carrier 5 is distorted, the wafer 6 could not be pulled out from the wafer carrier 5 by the transfer arm l and transferred to a predetermined position.

In view of the above-mentioned problems, the present invention has been made in view of the above problems, and even if the wafer stored inside the wafer carrier is not placed parallel to the upper surface of the carrier elevator because the wafer carrier is distorted, the wafer and the transfer arm are The object of the present invention is to make it possible to oppose each other in parallel with a predetermined interval.

<Means for Solving the Problems> The wafer transfer device of the present invention takes out wafers stored in a wafer carrier one by one and transfers them to another location. In order to detect a parallel state between the wafer and the transfer arm, the transfer arm enters the wafer carrier, and parallelism detection sensors are attached to at least three locations on the transfer arm, and the wafer carrier is connected to the transfer arm. The wafer carrier is provided at three locations within the transfer apparatus main body on which the wafer carrier is placed for three-point support from below, and includes parallel adjustment mechanisms for adjusting the height of supporting the wafer carrier at each point. There is.

<Operation> When the transfer arm approaches each wafer stored in the wafer carrier, the parallel adjustment mechanism is operated based on the output of the sensor provided on the transfer arm, and the wafer and the transfer arm are brought closer together. and facing each other in parallel at a predetermined interval. As a result, even if the wafer is not placed parallel to the carrier elevator due to distortion of the wafer carrier, etc., the vacuum opening provided in the transfer arm and the wafer can be aligned in advance. It becomes possible to make them face each other at a predetermined relative position.

<Embodiment> FIG. 1 is a perspective view of a transfer arm 1 showing an embodiment of the wafer transfer apparatus of the present invention, and FIG. 2 is a perspective view of a carrier elevator 4.

As is clear from FIG.
First to third sensors 8a, 8b, and 8c are respectively disposed in each of these.

These sensors 8a to 8c are arranged to detect the distance between each support portion 2 and the wafer 6 when the transfer arm 1 approaches the wafer 6 stored in the wafer carrier 5. This allows the transfer arm 1 and the wafer 6 to face each other in parallel at a predetermined interval. Parallelism sensors 8a to 8c used for such purposes
For example, a reflective optical sensor that uses infrared rays as detection light can be used.

On the other hand, as shown in FIG. 2, support pins 10 are made to protrude just inside guides 9 provided at three locations on the upper surface 4a of the carrier elevator 4.

These support pins 10 are provided to support the carrier elevator 4, and each support pin 10 has first to third support pins 10, as shown in FIG. Fine adjustment motors lla, llb,
It is arranged to move in the vertical direction in the figure by the operation of llc.

In this embodiment, the detection output of the first sensor 8a controls the operation of the first fine adjustment motor lla, and the output of the second sensor 8b controls the operation of the second fine adjustment motor lla.
b. Further, the operation of a third fine adjustment motor llc is controlled by the detection output of the third sensor 8c, and the parallel state of the wafer 6 housed in the wafer carrier 5 is finely adjusted.

Next, the operation of the wafer transfer apparatus of the embodiment configured as described above will be explained.

When the wafer carrier 5 containing the wafers 6 is placed on the carrier elevator 4, the coarse adjustment motor 12 is operated to move the carrier elevator 4 downward, for example. This downward movement is caused by the transfer arm 1 inserted into the wafer carrier 5.
This is continued until any one of the sensors 8a to 8c provided above approaches the wafer 6 by a predetermined distance.

The sensor consists of a support part 2 and a wafer 6.
When the two approaches to a predetermined distance, a proximity detection output is derived from the sensor. When this approach detection output is given to a controller (not shown), the operation of the coarse adjustment motor 12 is stopped under the control of the controller.

When the operation of the coarse adjustment motor 12 is stopped, next, among the fine adjustment motors lla, llb, and llc, if the wafer 6 is
The fine adjustment motor corresponding to the sensor that is not close to the predetermined position is operated.

That is, for example, assume that the first sensor 8a has approached the wafer 6 to a predetermined distance, and the second and third sensors 8b and 8c have not yet approached the wafer 6 to a predetermined distance. . In this case, the second fine adjustment motor llb and the third fine adjustment motor llc corresponding to the second and third sensors 8b and 8c operate, and these motors 8b.

Lower the support pin 1o corresponding to 8c. As a result, the supporting state of the wafer carrier 5 changes, and the second and third sensors 8b, 8c and the wafer 6 approach each other. When these distances approach a predetermined distance, each sensor 8b, 8c outputs an approach detection output, and the corresponding fine adjustment motor 11b, llc stops operating.

By making fine adjustments in this way, when the three points on the transfer arm 1 reach a predetermined distance from the wafer 6,
The wafer 6 and the transfer arm 1 face each other in parallel with a preset distance apart. Next, the vacuum device is operated to start suction from the vacuum opening 3, and the wafer 6 is attracted onto the transfer arm 1. In this case, since the transfer arm l is opposed to the wafer 6 in parallel at a predetermined interval,
The wafer 6 can be easily and reliably attracted onto the transfer arm 1. Therefore, according to the wafer transfer apparatus of the embodiment, even if the wafer 6 is not placed parallel to the carrier elevator 4 because the wafer carrier 5 is distorted, the wafer 6 and the transfer arm 1 can be moved to a predetermined position. They can be placed parallel to each other at a distance of . For this reason, the wafer carrier 5 in which the wafer 6 to be transferred is stored
Even if the wafer carrier 5 is distorted, stable vacuum suction can be performed, and problems caused by distortion of the wafer carrier 5 can be reliably prevented.

<Effects of the Invention> As described above, the present invention provides proximity detection sensors at three locations on the transfer arm, and when the transfer arm approaches each wafer stored in the wafer carrier, the sensors The parallel adjustment mechanism is operated based on the output, and the wafer and the transfer arm are made to face each other in parallel at a predetermined interval. Even when the wafer is not placed parallel to the carrier elevator, the relative position between the vacuum opening provided in the transfer arm and the wafer can be set to a predetermined relative position. .

Therefore, even if the wafer carrier is distorted, the wafer stored therein can be reliably attracted onto the transfer arm, and the wafer transfer operation can be stabilized.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a transfer arm showing an embodiment of the device of the present invention, FIG. 2 is a perspective view of a carrier elevator, FIG. FIG. 5 is a perspective view of the transfer arm shown in FIG. 1...Transportation arm, 2...Support part. 3...Vacuum opening. 4...Carrier elevator. 5...Wafer carrier. 6...Wafer. 8a to 8c...Parallelism detection sensor 10...Support bin. 11a-llc...Fine adjustment motors. Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Scope of Claims] A wafer transfer device that takes out wafers stored in a wafer carrier one by one and transfers them to another location, comprising: a transfer arm that enters the wafer carrier to take out the wafers; In order to detect the parallel state between the wafer and the transfer arm, parallelism detection sensors are attached to at least three locations on the transfer arm, and the wafer carrier is attached to support the wafer carrier at three points from below. A wafer transfer device comprising: parallelism adjustment mechanisms provided at three locations in a transfer device main body on which the wafer carrier is placed, and adjusting the height of supporting the wafer carrier at each point.