JP2510282B2 - Wafer transfer device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wafer transfer apparatus which is used by incorporating it into a semiconductor manufacturing apparatus for performing processing such as plasma CVD and etching on a semiconductor wafer.

[Conventional technology]

A wafer transfer device that receives, transfers, and transfers wafers one by one between a wafer cassette placed in a vacuum preparation chamber and a wafer stage installed in a chamber of a process reaction chamber adjacent to the vacuum preparation chamber has been widely used. Various devices have already been put to practical use. Further, as an example thereof, a hand drive mechanism as a robot having a strip plate-shaped wafer holder for receiving and holding a wafer in a horizontal posture as a hand is provided in a vacuum preparation chamber, and the wafer holder is operated by operating the hand drive mechanism. And the process reaction chamber are moved forward, backward, up and down, and horizontally swiveled to receive, transfer, and deliver wafers, as disclosed, for example, in Japanese Patent Laid-Open Nos. 63-23332 and 63-152244. is there.

[Problems to be Solved by the Invention]

By the way, in order to operate the wafer transfer, transfer, and transfer of wafers accurately and at high speed by the above-described wafer transfer apparatus, the following points are important in terms of function.

(1) When receiving and delivering a wafer, the wafer is properly positioned and received and held at a designated center position on the wafer holder.

(2) When the wafer holder is moved by the operation of the hand drive mechanism, the receiving position of the wafer should not be inadvertently displaced due to the inertial force caused by its start and stop.

In this regard, in the conventional apparatus, as to the item (1), a wafer holding concave groove or stopper having the groove inner diameter matched with the outer diameter of the wafer is provided on the upper surface of the wafer holder, and the item (2) is described. To cope with this, a wafer non-slip pad made of a material having a large frictional resistance is provided on the upper surface of the wafer holder.

However, since the wafers housed side by side in the wafer cassette are not constrained in the removal direction from the cassette, the wafers pop out to some extent due to a slight disturbance of the posture when the cassette is loaded into the vacuum preparation chamber and set. And, in many cases, they are not always housed in the proper position. Therefore, if the wafer holder is inserted into the cassette in this state and the wafer is picked up and received from below, the wafer is not correctly placed at the designated center position on the wafer holder and is taken out in an unstable posture. For this reason, the wafer may unexpectedly drop off from the wafer holder during the next transfer process, or even if it does not drop off luckily, it may be transferred to the correct position when the wafer is transferred to the other stage in the next step. Transport troubles and delivery mistakes occur that you cannot do. It should be noted that the hand drive device is automatically controlled based on the position data of the wafer holder, which is a hand, as in a normal robot.

Further, even if the wafer holder is provided with a non-slip pad, if the transfer speed is increased, the wafer may be inadvertently moved on the wafer holder due to the inertial force that acts at the time of starting and stopping the forward / backward movement and horizontal turning. . In addition, if the wafer mounting position deviates from the normal position, there is a problem that the wafer cannot be delivered to the correct position with respect to the stage on the other side as described above. Therefore, the wafer must be transported at a low speed, and as a result, the wafer cannot be transferred. Transport throughput is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a wafer transfer apparatus which improves the positioning accuracy of a wafer and can transfer a wafer at high speed without fear of transfer trouble by improving the conventional apparatus. The purpose is to

[Means for solving the problem]

In order to solve the above-mentioned problems, the wafer transfer apparatus of the present invention has a wafer holder attached to a hand drive mechanism having a degree of freedom of forward / backward, upward / downward, and horizontal rotation, in which the inner diameter of the groove is substantially equal to the outer diameter of the wafer. Matching concave groove for wafer delivery,
And concave grooves for receiving the wafer, which are slightly larger than the outer diameter of the wafer, are formed by arranging them in a stepwise manner and arranged side by side with the hand drive mechanism, and the wafer received on the wafer holder is transferred within the operating area thereof. A centering mechanism for centering the center of the receiving groove is provided, and the receiving position of the wafer with respect to the wafer holder is corrected by the centering operation of the centering mechanism during the transfer process after receiving the wafer so that the wafer is held in the receiving groove. It is composed.

[Action]

With the above configuration, the hand drive mechanism and the centering mechanism are arranged in the vacuum preparation chamber which is isolated from the process reaction chamber via the vacuum sluice valve. In addition, the centering mechanism is
This is a combination of a stage divided into two segments having an arc-shaped peripheral wall corresponding to the outer diameter of the wafer, and a drive unit that opens and closes each segment left and right with respect to the center of the stage. Are installed side by side in the operating area. Then, during standby, each segment of the stage is opened to the left and right and is in the retracted position. At the time of the centering operation, each segment is pulled from the standby position toward the center, and the wafer mounted on the stage is held between the peripheral walls of the segment. Thus, the wafer is centrally positioned at the center of the handling mechanism.

Next, the transfer operation when the wafers are taken out from the cassette one by one and delivered to the wafer stage in the process reaction chamber will be described. When taking a wafer out of the cassette in the vacuum preparation chamber, first, the wafer holder is inserted into the cassette by the forward operation of the hand drive mechanism, and the wafer is picked up and received by the wafer holder by the subsequent raising operation. In this case, even if the wafer accommodation position in the cassette is slightly deviated from the regular position, the deviation of the accommodation position is covered and the wafer is reliably placed and held in the wafer receiving concave groove portion having a large groove inner diameter. It

Next, after pulling the wafer holder out of the cassette, the wafer holder is moved to the centering mechanism by the subsequent turning operation, and the center of the wafer transfer groove formed in the wafer holder is aligned with the center position of the handling mechanism. To move the wafer once to the stage side of the centering mechanism. When the stage segment is closed by pulling it from the standby position toward the center, the stage segment holds the wafer from the left and right in this process, and the center of the wafer is centered so as to coincide with the center of the centering mechanism. Therefore, when the wafer holder is lifted at this position and the stage of the centering mechanism is opened to receive the wafer from the centering mechanism, the wafer is inevitably correctly accommodated and held in the wafer delivery concave groove.

After the centering operation is completed, the wafer holder is carried into the process reaction chamber through the vacuum sluice valve by the operation of the hand drive mechanism in the next step, and the wafer is transferred to the wafer stage arranged in the chamber by the subsequent descending operation of the wafer holder. It Moreover, during this transfer process, the wafer is held in the wafer transfer concave groove set to have substantially the same size as the outer diameter of the wafer and is restrained and held. Therefore, the receiving position of the wafer may be inadvertently shifted or dropped during the transfer. There is no risk of transport troubles, and when transferring the wafer to the wafer stage in the process reaction chamber, the wafer can be reliably transferred with high positioning accuracy.

When the wafers are collected in the process reaction chamber and returned to the cassette after the wafers are processed, the operations are performed in the reverse order of the above-described transfer operation so that the wafers can be transferred into the cassette without fear of transfer trouble. Can be properly housed in.

〔Example〕

1 and 2 are block diagrams of the entire wafer transfer apparatus according to the embodiment of the present invention, FIGS. 3 (a) and 3 (b) are structural views of a wafer holder, and FIGS. 4 (a) to 4 (d) are wafers. It is a figure showing the dimensional relationship between each component.

First, in FIGS. 1 and 2, 1 is a vacuum preparation chamber, 2
Is a process reaction chamber, 3 is a vacuum gate valve for isolating the vacuum preparation chamber 1 and the process reaction chamber 2 from each other, 4 is a wafer cassette,
Reference numeral 5 is a wafer housed in the cassette 4, 6 is a wafer holder, 7 is a hand drive mechanism to which the wafer holder 6 is attached, and 8 is a centering mechanism.

Here, a cathode electrode 22 connected to the high frequency power source 21, a vertically movable wafer stage 23 also serving as an anode electrode facing the cathode electrode 22, and a wafer stage 23 penetrating inside the process reaction chamber 2. It is equipped with a plurality of wafer support pins 24 fixedly arranged. The wafer cassette 4 is a multi-tiered shelf container having an open front surface, in which a plurality of wafers 5 are vertically arranged and accommodated at predetermined intervals. The cassette 4 is loaded into the chamber through the opening / closing door 11 of the vacuum preparation chamber 1 and set at a predetermined position.

On the other hand, the wafer holder 6 is a stepped plate having a rectangular plane as shown in FIGS. 3 (a) and 3 (b), and in the front area of the stepped base 61, a concave groove portion for wafer delivery is provided on the upper surface side. 6
2. Recessed groove portions 63 for receiving a wafer are formed side by side in a stepwise manner. Here, when the outer diameter of the wafer 5 is d, the groove inner diameter A of the concave groove portion 62 described above is substantially the same as the wafer outer diameter d (A ≧
d) The groove inner diameter B of the concave groove portion 63 is set to be slightly larger than the concave groove portion 62 (B> A). The groove depths of the concave groove portions 62 and 63 are set to be approximately the same as the thickness dimension of the wafer 5, and the stepped base portion 61 is formed.
Has a thickness smaller than the arrangement pitch of the wafers 5 in the wafer cassette 4 described above. Further, the hand drive mechanism 7 is a mechanical pantograph type robot having a degree of freedom in the directions of forward, backward, up and down, and horizontal rotation, and is arranged in front of the wafer cassette 4, and the tip of the pantograph arm 71 is mentioned above. A wafer holder 6 is attached.

Further, the centering mechanism 8 has a stage divided into two segments 81 and 82 each having an arc-shaped peripheral wall corresponding to the outer diameter of the wafer 5, and each segment 81 and 82 in the left-right direction with respect to the center of the stage. This is a combination of a screw mechanism 83 that opens and closes and a drive unit that is composed of a drive motor 84, and is arranged side by side on the side of the hand drive mechanism 7 described above and arranged side by side within its operating region. In FIG. 1, the centering mechanism 8 is drawn side by side behind the hand drive mechanism 7,
The actual arrangement is located on the side of the hand drive mechanism 7 as shown in FIG. In the centering mechanism 8, the segments 81 and 82 of the stage are opened to the left and right and are in the retracted position in the standby state.
When 81 and 82 are closed so as to be pulled from the standby position to the center, the wafer mounted on the stage is held between the peripheral walls of the segments and centered at the center of the handling mechanism 8.

Next, the dimensional relationship between the wafer 5 and the respective components of the wafer holder 6, the stage segments 81 and 82 of the centering mechanism, and the wafer stage 23 in the process reaction chamber described above in FIG. 4 is shown. In the figure, the outer diameter of the wafer 5 is d, the groove inner diameter of the receiving concave groove portion 62 in the wafer holder 6 is A, the groove inner diameter of the receiving concave groove portion 63 is B, and the stage with the segments 81 and 82 of the centering mechanism opened Is defined as C and the inner diameter of the concave groove of the stage 23 in the process reaction chamber is D, the dimensions of each component are defined as d ≦ A <D <B <C.

The transfer operation of the wafer transfer device having the above configuration is performed as follows. First, the transfer operation for taking out the wafer 5 from the cassette 4 and delivering it to the wafer stage 23 of the process reaction chamber 2 will be described. With respect to the wafer 5 accommodated in the cassette 4, the wafer holder 6 is moved forward by the hand drive mechanism 7. Are inserted into the lower surface of the wafer 5. In this case,
When the accommodation position of the wafer 5 is slightly projected from the cassette 4, the wafer 5 hits the front end surface of the stepped base portion 61 of the wafer holder 6 and is pushed back into the cassette. Then, the wafer holder 6 is positioned at the wafer receiving position and then lifted to pick up the wafer 5 and receive it in the receiving groove portion 63 of the wafer holder 6. In this case, since the groove inner diameter B of the receiving concave groove portion 63 is larger than the wafer outer diameter d, the wafer 5 can be reliably transferred to the wafer holder 6 without any trouble even if the accommodation position of the wafer 5 is slightly deviated.

Next, the wafer holder 6 is retracted to completely remove it from the cassette 4, and then horizontally swiveled to perform the wafer holder 6 operation.
Is moved to the centering mechanism 8 and the center of the centering mechanism 8 is aligned with the center of the wafer delivery concave groove portion 62 designated by the wafer holder 6. As a result, the stage is lowered between the two divided stage segments 81 and 82. Then, the wafer 5 is once delivered to the stage side of the centering mechanism 8. In this case, as described in FIG. 4, the dimension C>
Because of the relationship B, the wafer 5 is reliably transferred from the wafer holder 6 to the stage side of the centering mechanism 8. Then, when the stage segments 81 and 82 of the centering mechanism 8 are closed so as to be drawn to the center, the wafer 5 is placed at the center of the centering mechanism, that is, the concave groove portion of the wafer holder 6.
Centering is done to match the center of 62.
Therefore, next, when the wafer holder 6 is lifted and the stage segments 81 and 82 of the centering mechanism 8 are opened, the wafer 5 is transferred from the centering mechanism 8 to the wafer holder 6, and at the same time, the wafer 5 has a concave groove portion for handing over the wafer. It will be accepted to fit into 62 surely.

As a result, even if the receiving position of the wafer 5 taken out of the cassette 4 is out of the concave groove portion 62 of the wafer holder 6, the receiving position is corrected by the subsequent centering operation, and the wafer 5 is moved to the center position designated in advance with respect to the wafer holder 6. It will be positioned correctly.

Next, the wafer holder 6 is carried into the process reaction chamber 2 through the vacuum sluice valve 3 by the forward operation of the hand drive mechanism 7, and after the wafer 5 is transferred onto the wafer support pins 24 provided in the chamber by the subsequent descending operation. Moved to the outside of the room.
On the other hand, when the vacuum sluice valve 3 is closed and the wafer stage 23 is lifted after the wafer holder is retreated from the room, the wafer 5
Are transferred from the support pins 24 to the stage 23. In this case, the inner diameter D of the concave groove of the stage 24 is in the relation of D> A with respect to the inner diameter A of the concave groove portion 62 of the wafer holder 6, so that the wafer 5 placed on the support pins 24 can be transferred to the stage without a delivery error. It is surely transferred to 23.

In this state, next, while maintaining the process reaction chamber 2 at a vacuum pressure of about 1 Torr, a reaction gas is introduced from a gas supply system (not shown) between the cathode electrode 22 and the stage 23 also serving as the anode electrode. A high frequency voltage is applied from the high frequency power source 21 to generate plasma, and the wafer 5 is subjected to plasma CVD or plasma etching processing. After the processing is completed, the stage 23 is moved down to transfer the wafer 5 onto the support pins 24 again, and on the other hand, the vacuum sluice valve 3 is opened and the wafer holder 6 waiting outside is carried into the room.
Is picked up from the support pin 24. In this case,
Since the groove inner diameter B of the wafer receiving concave groove portion 63 on the wafer holder side has a relationship of B> D with respect to the groove inner diameter D of the stage 23,
The wafer 5 is reliably transferred to the wafer holder 6.

Subsequently, the wafer holder 6 is moved to the centering mechanism 8 on the way of the transfer path for returning the wafer 5 to the cassette 4 and the centering operation similar to the above is performed, and then the wafer holder 6 is inserted into the cassette 4 to transfer the wafer 5 to the cassette. It is accommodated, and the series of transport operations is completed. Thereafter, the same operation as described above is repeated to perform the process processing on all the wafers contained in the cassette.

The centering mechanism can be implemented by a mechanism other than the illustrated example.

〔The invention's effect〕

Since the wafer transfer apparatus of the present invention is configured as described above, it has the following effects.

(1) When the wafer is received from the wafer cassette or the wafer stage in the process reaction chamber, even if the receiving position of the wafer is slightly deviated from the designated receiving groove on the wafer holder, the wafer does not fall off and the inner diameter of the groove does not drop. The receiving position of the wafer is corrected by the centering operation performed by the centering mechanism so that the wafer is correctly accommodated in the wafer receiving concave groove portion, and the wafer is restrained and held in the concave groove portion. As a result, a high positioning accuracy can be ensured when the wafer is transferred from the wafer holder to the partner's stage, and the wafer can be reliably transferred to the partner's side without any transfer trouble or delivery error.

(2) As long as the wafer is accommodated in the transfer groove of the wafer holder, the receiving position of the wafer does not inadvertently shift even if the inertial force caused by the start and stop is exerted in the subsequent transfer movement process. Therefore, the throughput of wafer transfer can be significantly improved as compared with the conventional apparatus.

[Brief description of drawings]

1 and 2 are a side view, a plan view, and FIGS. 3 (a) and 3 (b) showing the configuration of a wafer transfer apparatus according to an embodiment of the present invention.
FIG. 4A is a plan view of the wafer holder, FIG. 4B is a side sectional view, and FIG. In the figure, 1: vacuum preparation chamber, 2: process reaction chamber, 23: wafer stage, 4: wafer cassette, 5: wafer, 6: wafer holder, 6
2: Wafer receiving concave groove portion, 63: Wafer receiving concave groove portion, 7: Hand drive mechanism, 8: Centering mechanism, d: Wafer outer diameter, A,
B: Groove inner diameter of the groove.

Claims (1)

(57) [Claims] 1. A wafer is received and transferred between a wafer cassette and a wafer stage provided in a process reaction chamber.
A wafer transfer device for delivering and receiving
For a wafer holder mounted on a hand drive mechanism that has a degree of freedom of horizontal swiveling, a concave groove portion for wafer delivery, whose groove inner diameter is almost the same as the outer diameter of the wafer, and a wafer holder that is slightly larger than the outer diameter of the wafer A centering mechanism for arranging the concave grooves for use in a stepwise manner and arranging them side by side with the hand driving mechanism to center the wafer received on the wafer holder with respect to the concave groove for wafer delivery in the operating region. A wafer transfer device, wherein the wafer transfer device is arranged so that the wafer receiving position with respect to the wafer holder is corrected by the centering operation of the centering mechanism and held in the wafer transfer recessed groove portion during the transfer process after the wafer is received. .