JPH0691151B2 - Wafer centering positioning device for semiconductor wafer transfer equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a wafer processing apparatus that performs various process processing such as film formation and etching on a semiconductor wafer For wafer transfer equipment that transfers the
The present invention relates to a wafer centering positioning device for correctly correcting and holding a wafer at a centering position of a wafer holder mounted on a robot during wafer transfer.

[Conventional technology]

First, the structure of the above-mentioned initial wafer transfer robot and the wafer transfer operation performed between the wafer cassette and the wafer processing apparatus will be described with reference to FIGS. In the figure, 1 is a cassette in which a plurality of wafers 2 are vertically arranged and accommodated, 3 is a load lock chamber connected to a process reaction chamber such as a plasma CVD apparatus, 4 is a relay preparation chamber provided in the preceding stage of the load lock chamber 3, Gate valves 5a and 5b partition the entrance and exit passages of the relay preparation chamber 4, and a relay tray 6 is provided inside the relay preparation chamber to receive and hold wafers carried in from outside. The wafer transferred to the relay tray is carried into the reaction chamber by a wafer transfer device (not shown). Here, a robot 7 as a wafer transfer device is installed outside the relay preparation chamber 4 facing the entrance.

This robot 7 is a well-known mechanical pantograph type robot, and its configuration is a drive unit 71, an arm 72 connected to an output shaft of the drive unit and operated up and down (Z direction) and turning (θ direction), and an arm. The arm 73 is configured to be linearly moved in the left-right direction on the 72, and the wafer holder 74 attached to the tip of the arm 73. By operating the arms 72 and 73 with such a configuration, , Wafer holder 74
Can be moved on the X, Y, Z coordinate system. Further, the robot 7 is moved by numerical control according to a program command given to the operation control unit so as to give a desired movement with the center 01 of the wafer suction surface of the wafer holder 74 as a reference point. On the other hand, the wafer holder 74 has a suction hole of a vacuum suction mechanism 75 for sucking and holding the wafer 2 face up as a wafer suction tray on the surface of the tray.

With this configuration, the wafer 7 is taken out from the cassette 1 in a predetermined order by the operation of the robot 7 and the wafer holder 74
Of the wafer 2 is adsorbed and held on the upper surface of the wafer, and is transferred into the relay preparation chamber 4 through the gate valve 5b opened by following the transfer path of the arrow P, and the wafer 2 is transferred to the relay tray 6 there. The relay tray 6 has a two-part saucer structure in which a central portion thereof is cut out so as not to interfere with the wafer holder 74 on the robot 7 side, and a tapered guide portion inclined toward the inner peripheral side is provided on the peripheral edge thereof. I have it. When the wafer is transferred to the relay tray 6, the wafer holder 74 of the robot 7 is retracted to the outside of the chamber, the gate valve 5b is closed, and the relay preparation chamber 4 is evacuated. Next, the gate valve 5a between the load lock chamber 3 and the load lock chamber 3 is opened, and the wafer 2 received and held on the relay tray 6 is received by the wafer transfer device (not shown) disposed on the side of the load lock chamber. Send into the process reaction chamber that is not present. When the predetermined wafer processing is completed and the wafer is carried out of the room through the carry-out path, the next wafer 2 to be processed next is taken out from the cassette 1 by the operation of the robot 7 in the relay preparation room 4 as described above. It is sent.

[Problems to be solved by the invention]

By the way, in the wafer transfer process, when the robot 7 serving as a wafer transfer device transfers the wafer 2 to the relay tray 6, the transfer position of the wafer 2 with respect to the relay tray 6 is often deviated, and the taper guide surface of the relay tray 6 is slid. Due to instability and the like, a delivery error such as a wafer being caught in an oblique posture on the relay tray 6 may occur. The cause of the deviation of the wafer transfer position is the deviation of the accommodation position of the wafer 2 in the cassette 1 and the wafer holder of the robot 7 in addition to the tolerance of the outer diameter of the wafer.
The reason is that the wafer 2 is not held at the correct centering position with respect to the wafer holder 74 due to slippage when picking up and picking up the wafer 2 from the cassette 1 at 74, and such a centering position is displaced. Therefore, no matter how high the operation accuracy of the robot 7 is, the delivery position to the relay tray 6 is displaced. Moreover, if such a transfer error occurs, it interferes with the wafer transfer process in the subsequent stage, so the operation of the device must be stopped each time and the wafer position must be corrected by the operator. Bring about a decline.

The present invention has been made in view of the above points, and an object thereof is to perform correct centering for a wafer holder during wafer transfer before transferring a wafer taken out from a cassette by operating a wafer transfer device to a process processing apparatus. It is an object of the present invention to provide a wafer handling positioning device for a wafer transfer device that is corrected and held at a position.

[Means for solving problems]

In order to achieve the above object, according to the present invention, a suction type wafer holder mounted on the upper surface side of the tip of a robot arm is provided, and a wafer taken out from a cassette by the operation of the robot arm is transferred to a wafer processing apparatus. A semiconductor wafer transfer device, which is a wafer centering positioning device for correcting and holding a wafer at a centering position with respect to a wafer holder during wafer transfer, and a guide base arranged on a movement trajectory of the wafer holder, A plurality of centering pins, which are point-distributed relative to the center of the guide base, project upward from the base surface, stand upright, and are movably guided in the radial direction of the guide base, and the centering pins are simultaneously formed. It consists of a drive unit that moves the same amount in the radial direction, and moves the wafer holder to the center position of the guide base during wafer transfer. In this state, once the wafer suction is released, the centering pin is pulled to the peripheral edge of the wafer to correct and move the wafer to the centering position on the wafer holder, and at this position the wafer is again sucked and held on the wafer holder. At the same time, the drive unit is composed of a cam plate concentrically arranged at the center of a guide base having a scroll groove that fits with the base of each centering pin, and a drive motor for rotating the cam plate. .

[Action]

With the above configuration, for example, four centering pins are guided and supported in the radial guide grooves which are dispersed and opened on the base on the guide base, and the drive unit is fitted to the base of each centering pin. It is composed of a cam plate concentrically arranged in the center of a guide base having a matching scroll groove, and a drive motor for rotating the cam plate.

Here, the wafer holder is transferred to the centering positioning device during the transfer of the wafer taken out from the cassette to the wafer processing device, and the wafer holder is stopped by aligning the center of the wafer holder with the center position of the guide base. Once remove the adsorption of. On the other hand, on the side of the guide base, the centering pin is retracted to the outer periphery of the base, and when the cam plate is rotated by the drive motor, the multiple centering pins simultaneously move like the scroll chuck of a machine tool. The centering pin is moved by the same amount along the guide groove of the guide base, and in this process, the centering pin sandwiches the outer peripheral edge of the wafer and is drawn to the center position of the guide base. As a result, the wafer mounted freely on the wafer holder moves to the centering position of the wafer holder by the above-mentioned pulling operation by the centering pin, and the deviation of the centering position caused during the process of taking out from the cassette becomes the correct position. Will be fixed. Therefore, by re-sucking the wafer to the wafer holder at this correction position and then restarting the wafer transfer by the robot operation, the wafer can be transferred to the relay tray of the processing apparatus side correctly without any mistake. Moreover, by the pulling operation of the centering pin, it is possible to flexibly deal with the change of the wafer size, the variation of the outer diameter tolerance of the wafer and the like with the same device.

〔Example〕

1 to 4 show an embodiment of the present invention,
FIGS. 1 and 2 are a general view of the apparatus, FIGS. 3 and 4 are a plan view and a side sectional view showing the detailed structure of the wafer centering positioning device, and FIGS. Corresponding identical members are designated by the same reference numerals.

That is, according to the present invention, a wafer centering positioning device indicated by the reference numeral 8 is mounted and arranged on the robot body via the support 9 on the side of the robot 7 along the movement trajectory of the wafer holder 74 attached to the robot arm. . The centering positioning device 8 includes a guide base 10, four centering pins 11 that are distributedly arranged so as to project to the upper surface side of the base 10 and are supported by guides in the radial direction, and the same amount of each centering pin 11 at the same time. And a drive unit 12 which is moved only in the radial direction.

The detailed structure of the centering positioning device 8 will now be described in the third section.
Explaining with reference to FIG. 4 and FIG. 4, first, the guide base 10 has centering pins on its upper surface at intervals of 90 degrees around the center 02.
Four guide grooves 13 that extend in the radial direction, into which 11 are fitted, are open, and one guide groove 13 is provided for each centering pin 11
Is supported by a guide. The drive unit 12 is composed of a combination of a cam plate 14 concentrically arranged on the lower surface side of the guide base 10 with its center aligned, and a drive motor 15 for rotating the cam plate 14, and the cam plate 14 Has a centering pin 11
Four scroll grooves 16 are formed to fit with the base of the. The mechanism of such a drive unit is the same mechanism as a scroll chuck equipped in a machine tool or the like, and by rotating the cam plate 14 by the drive motor 15, four centering pins 11 are simultaneously moved according to the rotation direction. Guide groove by amount 13
Will move forward and backward in the direction of arrow Q.
Further, the cam plate 14 is mounted on the drive shaft 17 of the drive motor 15 such as a radial bearing 18, a thrust slip plate 19, and a pressing bias spring 20.
Are connected via a spring-biased joint. By using this joint, the cam plate 14 will slip with respect to the motor drive shaft 17 when a load of a predetermined torque or more is applied to the cam plate 14 during motor driving.

Next, the centering and positioning operation of the wafer having the above configuration will be described. One wafer 2 is taken out from the cassette through the wafer holder 74 by the operation of the robot 7, and transferred to the wafer centering positioning device 9 before being transferred to the process processing device in the course of the transfer process by the rotating operation of the robot arm. After the centering correction operation described later is performed, the centering correction operation is performed, and the sheet is transferred to the process processing apparatus side and transferred to the relay tray 6.

That is, when the wafer 2 taken out from the cassette 1 is transferred to the wafer centering positioning device 8 while being sucked and held on the upper surface of the wafer holder 74 by the robot operation,
Here, the wafer holder 74 is aligned and stopped so that the center 01 of the wafer suction surface coincides with the center 02 of the guide base 10, and the suction of the wafer 2 is once released at this position. Next, the cam plate 14 is rotated by the drive motor 15 so that the four centering pins 11 which are in the standby position on the outer peripheral side of the guide base 10 are simultaneously sandwiched by the same amount along the guide groove 13 from the outer periphery. And move it toward the center 02. As a result, the deviation of the centering position between the wafer 2 and the wafer holder 74 in the process of taking out the wafer 2 from the cassette 1 is corrected and moved in the process of pulling the centering pin 11, so that the wafer 2 moves to the center 01 on the wafer holder 74. The centering position will be correct.

When the correction operation of the centering position is performed in this manner, the wafer 2 is again sucked and held by the wafer holder 74,
From here, the robot 7 is restarted to transfer the wafer holder 74 to a designated transfer position for the relay tray 6 on the process processing apparatus side, where the suction of the wafer holder is released and the wafer 2 is transferred to the relay tray 6. . Moreover, in this transfer / conveyance process, the deviation of the centering position that occurs when the wafer 2 is first taken out from the cassette 1 is corrected by the above-mentioned centering operation, so that the wafer 2 is delivered to the relay tray 6 without any transfer error. It can be delivered to the centering position with high accuracy.

In addition, by setting the moving range of the centering pin 11 in advance to be sufficiently large in the above structure, it is possible to flexibly deal with wafers of various sizes having different diameters. Further, if an excessive force is applied to the wafer 2 via the centering pin 11 in the process of pulling the centering pin, the wafer may be damaged. However, as described above, the driving of the cam plate 14 and the drive motor 15 is performed. The wafer 2 is connected to the shaft via a spring-biased joint, and the cam plate slips when the load exceeds a predetermined value.
It is possible to skillfully release an excessive force applied to the wafer when sandwiched by.

〔The invention's effect〕

As described above, according to the present invention, as a result of adopting the above configuration, the displacement of the position of the wafer with respect to the wafer holder caused during the process of taking out the wafer from the cassette by the robot operation is provided on the way of the wafer transfer path. The centering positioning device can correct the centering position and transfer it to the next process. This allows the wafers to be transferred to the wafer processing unit side without any transfer errors to the relay tray with high accuracy and smoothness. Can be handed over to. Moreover, since the centering position is corrected by pulling the centering pin, it is possible to flexibly deal with the change of the wafer size and the variation of the outer diameter tolerance of the wafer.

[Brief description of drawings]

1 and 2 are plan layout views showing the overall construction of an embodiment of the present invention, and side views thereof, and FIGS. 3 and 4 are plan views showing the detailed structure of the wafer centering positioning device in FIG. 1, respectively. , And a side sectional view, and FIGS. 5 and 6 are wafer transfer system diagrams between a conventional cassette and a process processing apparatus. In each figure, 1: cassette, 2: wafer, 3: wafer processing equipment load lock chamber, 4: relay preparation chamber, 6: relay tray, 7: robot as a wafer transfer device, 74: wafer holder, 75: Wafer suction mechanism, 8: Wafer centering positioning device, 10: Guide base, 11: Centering pin, 12: Drive part, 13: Guide groove, 1
4: Cam plate, 15: Drive motor, 16: Scroll groove, 01: Center of wafer holder, 02: Center of guide base.

Claims (3)

[Claims] 1. A wafer transfer to a semiconductor wafer transfer device, which is equipped with a suction type wafer holder attached to the upper surface side of the tip of a robot arm and transfers wafers taken out from a cassette to the wafer processing apparatus by the operation of the robot arm. A wafer centering positioning device that corrects and holds a wafer at a centering position with respect to a wafer holder on the way of a wafer, and a guide base arranged on a movement trajectory of the wafer holder and a point with respect to a center of the guide base. Drive to move a plurality of centering pins at the same time in the radial direction at the same time by a plurality of centering pins that are distributed to the object, project upward from the base surface, stand up, and are guided and supported to be movable in the radial direction of the guide base. The wafer holder is moved to the center position of the guide base during the wafer transfer, and the suction of the wafer is In the released state, the centering pin is pulled to the peripheral edge of the wafer to correct and move the wafer to the centering position on the wafer holder, and at this position the wafer is again sucked and held by the wafer holder, and the drive unit causes each centering pin to move. A cam plate concentrically arranged at the center of the guide base having a scroll groove that fits with the base of
A wafer centering positioning device for semiconductor wafer transfer equipment comprising a drive motor for rotating the cam plate. 2. The wafer centering positioning device according to claim 1, wherein the guide base has four centering pins guided and supported in radial guide grooves distributed and opened on the base. A wafer centering positioning device for semiconductor wafer transfer equipment. 3. The wafer centering positioning device according to claim 1, wherein the cam plate slips when a load of a predetermined torque or more is applied to the drive motor shaft via a spring-biased joint. A wafer centering positioning device for semiconductor wafer transfer equipment, characterized in that it is coupled.