JP2884522B2 - Wafer transfer device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wafer transfer apparatus, and more particularly to an apparatus for taking out semiconductor wafers housed in a wafer carrier one by one and transferring them to another place. It is suitable for use.

<Prior Art> As is well known, when a semiconductor device is manufactured, a semiconductor wafer (hereinafter, simply referred to as a wafer) is placed in a wafer carrier and transported between manufacturing apparatuses or between manufacturing lines. . Then, when 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 place to perform the next processing.

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

As is apparent from FIG. 4, the transfer arm 1 is formed in a substantially cross shape, and a support portion 2 which comes into contact with and supports a wafer (not shown) is provided at the tip of each arm piece 1a. ing. In addition, a vacuum opening 3 is provided at the center position of the transfer arm 1, and a vacuum device (not shown) operates so that air is sucked from the vacuum opening 3. Therefore, when the transfer device 1 is inserted into the wafer carrier and the vacuum device operates with the vacuum opening 3 facing the wafer, the wafer is attracted to the vacuum opening 3. Thus, the wafer is transferred to the transfer arm 1.
When the wafer is sucked up, the transfer arm 1 is pulled out of the wafer carrier, and the wafer sucked there is moved to a predetermined position.

When the transfer of the first wafer is completed, the carrier elevator 4 on which the wafer carrier 5 is placed is moved by the wafer 6 as shown by an arrow in the perspective view for explaining the transfer state in FIG. Move up or down by a distance corresponding to the stored pitch. As a result, the transfer arm 1 moves just below the second wafer 6 and the suction by the vacuum device becomes possible, so that the second wafer 6 is sucked on the transfer arm 1 by vacuum. It is pulled out from the wafer carrier 5 and transferred to a predetermined position. By repeating such an operation, the wafer 6 stored in the wafer carrier 5 is moved to a predetermined position.

<Problem to be Solved by the Invention> However, in the case of the above-described conventional apparatus, the carrier elevator 4 is moved up and down at a predetermined fixed pitch, so that the wafer 6 is transferred to the transfer arm 1. May not always be able to be adsorbed by vacuum. That is, for example, when the wafer carrier 5 is distorted, the wafers 6 stored in the wafer carrier 5 are not placed in parallel with the carrier elevator 4. In this case, of course, the wafer 6 and the transfer arm 1 are not opposed to each other in parallel at a predetermined interval, so that the vacuum 6 is sucked onto the transfer arm 1 by the vacuum suction. The inconvenience of not being able to do it occurs. As a result, conventionally, when the wafer carrier 5 is distorted, the wafer 6 cannot be pulled out of the wafer carrier 5 by the transfer arm 1 and moved to a predetermined position.

The present invention has been made in view of the above-described problems, and even if the wafer contained therein is not placed in parallel with the upper surface of the carrier elevator because the wafer carrier is distorted, the wafer and the transfer arm can be used. Can be made to face in parallel at a predetermined interval.

<Means for Solving the Problems> A wafer transfer apparatus according to the present invention is a wafer transfer apparatus for taking out wafers stored in a wafer carrier one by one and transferring the wafers to another place. A transfer arm that enters the wafer carrier, a parallel detection sensor attached to at least three places on the transfer arm to detect a parallel state between the wafer and the transfer arm, and the wafer carrier. A parallel adjustment mechanism is provided at three points in the transfer apparatus body on which the wafer carrier is mounted to support three points from below, and adjusts the height at which the wafer carrier is supported at each point. I have.

<Operation> When the transfer arm approaches each wafer stored in the wafer carrier, a parallel adjustment mechanism is operated based on the output of a sensor provided on the transfer arm, and the wafer and the transfer arm are operated. And are opposed in parallel at a predetermined interval. Accordingly, even when the wafer carrier is not placed in parallel on the carrier elevator due to distortion of the wafer carrier, the vacuum opening provided in the transfer arm and the wafer are set in advance. It is possible to face each other at a predetermined relative position.

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

As is clear from FIG. 1, the wafer transfer apparatus of the embodiment has first to third sensors 8a, 8b, 8c on three support portions 2 provided on the transfer arm 1, respectively. It is arranged. These sensors 8a to 8c are provided 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. As the parallelism sensors 8a to 8c used for such a purpose, for example, reflective single-sided optical sensors using infrared rays as detection light can be used.

On the other hand, as shown in FIG. 2, the support pins 10 protrude immediately inside guides 9 provided at three places 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 a first to a third as shown in FIG. 3 for explaining the inside of the carrier elevator 4. The fine adjustment motors 11a, 11b, 11c are moved in the vertical direction in the figure by the operation of the motors.

In this embodiment, the operation of the first fine adjustment motor 11a is controlled by the detection output of the first sensor 8a, and the operation of the second fine adjustment motor 11b is controlled by the output of the second sensor 8b. . In addition, the operation of the third fine adjustment motor 11c is controlled by the detection output of the third sensor 8c to finely adjust the parallel state of the wafer 6 stored in the wafer carrier 5.

Next, the operation of the thus configured wafer transfer apparatus of the embodiment will be described.

When the wafer carrier 5 in which the wafers 6 are stored is placed on the carrier elevator 4, the coarse adjustment motor 12 operates, and moves the carrier elevator 4 downward, for example. This downward movement is caused by any one of the sensors 8a to 8c provided on the transfer arm 1 inserted into the wafer carrier 5.
The process is performed until the wafer 6 approaches a predetermined distance.

When a certain sensor, that is, a certain supporting portion 2 and the wafer 6 approach each other to a predetermined distance, an approach 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 by the control of the controller.

When the operation of the coarse adjustment motor 12 is stopped, next, of the fine adjustment motors 11a, 11b, and 11c, the fine adjustment motor corresponding to the sensor that has not yet approached the wafer 6 to a predetermined position. Operate. That is, for example, it is assumed that the first sensor 8a is close to the wafer 6 to a predetermined distance, and the second and third sensors 8b and 8c are not yet close to the wafer 6 to a predetermined distance. . In this case, the second fine adjustment motor 11b and the third fine adjustment motor 11c corresponding to the second and third sensors 8b and 8c operate, and these motors 8b and 8c
Lower the support pin 10 corresponding to 8c. This allows
The support state of the wafer carrier 5 changes, and the second and third
Sensors 8b, 8c and the wafer 6 approach each other. Then, when these intervals approach a predetermined distance, an approach detection output is derived from each of the sensors 8b and 8c, and the corresponding fine adjustment motors 11b and 11c stop operating.

By performing the fine adjustment in this manner, when the three points on the transfer arm 1 are at a predetermined distance from the wafer 6, the wafer 6 and the transfer arm 1 are spaced apart from each other by a predetermined distance to be parallel. opposite. Next, the vacuum device is operated to start suction from the vacuum opening 3, and the wafer 6 is sucked onto the transfer arm 1. In this case, since the transfer arm 1 is opposed to the wafer 6 in parallel at a predetermined interval, the wafer 6 can be easily and reliably attracted to the transfer arm 1. Therefore, according to the wafer transfer apparatus of the embodiment, even when the wafer 6 is not placed in parallel on the carrier elevator 4 because the wafer carrier 5 is distorted, for example, the wafer 6 and the transfer arm 1 are kept in a predetermined position. At a distance of. Therefore, even if the wafer carrier 5 accommodating the wafer 6 to be transferred is distorted, stable vacuum suction can be performed, and the inconvenience due to the distortion of the wafer carrier 5 can be reliably prevented.

<Effect of the Invention> As described above, the present invention provides the approach detection sensors at three places on the transfer arm, and when the transfer arm approaches each wafer stored in the wafer carrier, The parallel adjustment mechanism is operated based on the output so that the wafer and the transfer arm are opposed to each other in parallel at a predetermined interval, so that the wafer contained in the wafer carrier is distorted due to distortion of the wafer carrier or the like. Even if the wafer is not placed in parallel on 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 set in advance. In addition, the wafer transfer operation can be stabilized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a transfer arm showing one embodiment of the present invention, FIG. 2 is a perspective view of a carrier elevator, FIG. 3 is an internal explanatory view of the carrier elevator, and FIG. FIG. 5 is a perspective view showing a configuration of a main part of a conventional wafer transfer apparatus. DESCRIPTION OF SYMBOLS 1 ... Transfer arm, 2 ... Support part, 3 ... Vacuum opening, 4 ...
Carrier elevator, 5… wafer carrier, 6… wafer, 8a
... 8c ... parallelism detection sensor, 10 ... support pins, 11a-11c ... fine adjustment motor.

Claims (1)

(57) [Claims] 1. A wafer transfer device for taking out wafers housed in a wafer carrier one by one and transferring the wafers to another place, a transfer arm which enters the wafer carrier to take out the wafers, At least three parallel detection sensors mounted on the transfer arm for detecting a parallel state between the wafer and the transfer arm, and the wafer carrier for supporting the wafer carrier from below are mounted. And a parallelism adjusting mechanism provided at three points in the main body of the transfer device for adjusting the height at which the wafer carrier is supported at each point.