JPH0794573A - Wafer changer - Google Patents

Abstract

PURPOSE:To obtain a quick wafer changer by employing a triple transfer arm comprising three arms extending in three directions from the center of rotation and a wafer chuck provided at the tip of each arm. CONSTITUTION:The wafer changer employs a triple transfer arm comprising three arms extending in three directions at an interval of 120 deg. from the center of rotation and a wafer chuck provided at the tip of each arm. Three wafer chucks 32 are then rotary shifted to the wafer W feeding position, the wafer W changing position on a wafer disc 21, and the wafer W discharging position, sequentially. Furthermore, a wafer W is grasped by one wafer chuck 32 at the wafer feeding position and at the same time another wafer W on the wafer disc 21 is grasped by another wafer chuck at the wafer changing position. The wafer disc 21 is then rotated by 120 deg. and the wafer W grasped by one wafer chuck 32 is fed to the wafer disc 21 at the wafer changing position while simultaneously another wafer W grasped by another wafer chuck 32 is discharged at charging position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer exchange apparatus.

[0002]

2. Description of the Related Art For example, in the manufacture of a VLSI device, various impurity atoms (phosphorus, boron, arsenic, antimony, etc.) are added to a single crystal silicon wafer to give a pn junction or an impurity concentration gradient, or to a local region. The ion implantation method is generally widely used to form a highly concentrated region. This ion implantation method is characterized in that ions can be implanted at a low temperature (for example, room temperature), and the number of implanted ions can be accurately grasped by monitoring the ion current.

In an example of an ion implantation apparatus used in this ion implantation method, a wafer disk is arranged in a vacuum chamber, and, for example, 1 is arranged along the circumference of the wafer disk.
Ion implantation is carried out one by one while holding three wafers and rotating the wafer disk stepwise. Then, a wafer exchanging device is used for supplying a wafer before ion implantation to the wafer disk and for discharging a wafer after ion implantation from the wafer disk.

FIG. 9 shows an example of a conventional wafer exchange apparatus. In this example, a cassette index is built in the load lock chamber 91, and a wafer cassette is directly loaded into the load lock chamber 91 to index the wafer cassette. A plurality of wafers are vertically stored in the wafer cassette. In the load lock chamber 91, the wafers are pushed up one by one from the wafer cassette by the vertical transfer fork, and the side of the pushed-up wafer is held by the wafer gripper 93 at the tip of the transfer arm 92. The wafer held by rotating the transfer arm 92 by 90 degrees is supplied to a predetermined position of the wafer disk 94. Then, when the ion implantation of the wafer is completed, the ion-implanted wafer on the wafer disk 94 is gripped by the wafer gripper 93 of the transfer arm 92, and the transfer arm 92 is reversely rotated by 90 degrees to return the vertical transfer fork to the original position. Then, the wafer after the ion implantation is discharged to the wafer cassette. Such an operation is sequentially repeated to perform ion implantation processing on a plurality of wafers.

FIG. 10 shows another example of a conventional wafer exchange apparatus. In this example, the wafer transfer robot takes out the wafers one by one from the wafer cassette, transfers them to the vacuum cassette, transfers a plurality of wafers to the vacuum cassette, and then evacuates the vacuum cassette to bring it down to the robot chamber chamber in the front. Wafer grippers 96A and 96B at both ends incorporated into the robot chamber.
Wafer gripper 96A of the transfer arm 95 having
After gripping the wafer by, the transfer arm 95 is rotated 180 degrees to supply the wafer to the wafer disk 97 in the disk chamber. Next, when the ion implantation of the wafer is completed, after the ion-implanted wafer on the wafer disk 97 is held by the wafer gripper 96A of the transfer arm 95, the transfer arm 95 is rotated 180 degrees and the ions are transferred to the vacuum cassette at the original position. The wafer after implantation is returned, and the wafer before ion implantation is supplied to the wafer disk 97 by the other wafer gripper 96B. When the ion implantation of a plurality of wafers is completed by sequentially repeating such an operation, the vacuum cassette separates from the robot chamber and returns to the original horizontal position. The vacuum cassette is returned to the atmosphere, and the wafer after ion implantation is transferred to the original cassette by the wafer transfer robot.

[0006]

In the wafer exchanging apparatus shown in FIG. 9, the wafer is exchanged by the transfer arm 92. The transfer arm 92 rotates one wafer gripper 93 by 90 degrees to exchange the wafer. Therefore, when the wafer is supplied to the wafer disk 94 by the transfer arm 92, the wafer cannot be ejected from the wafer disk 94, and when the wafer is ejected from the wafer disk 94, the wafer cannot be ejected to the wafer disk 94. Therefore, there is a problem that it takes a long time to supply and discharge the wafer.

Further, in the wafer exchanging apparatus of FIG. 10, the wafer is exchanged by the transfer arm 95. The transfer arm 95 has wafer grippers 96A and 96B at both ends, and these wafer grippers 96A and 96B are provided.
Since the wafer is exchanged by rotating the wafer by 180 degrees, when the wafer is supplied from one wafer gripper 96A of the transfer arm 95 to the wafer disk 97, the other wafer gripper 96B can eject the wafer. 9 is more efficient than the wafer exchanging device of FIG. 9, however, in the other wafer gripper 96B, since the wafer supply line and the wafer discharge line are common, the wafer gripper 96B must be discharged after the wafer is discharged. Therefore, there is a problem in that it takes a long time to supply and discharge the wafer.

An object of the present invention is to provide a wafer exchanging device capable of swiftly exchanging wafers.

[0009]

According to the present invention, there is provided a wafer exchanging device for supplying a wafer to a wafer disk by a transfer arm and discharging the wafer from the wafer disk, wherein the transfer arm has an angle of 120 degrees from a rotation center. In 3
A triple arm having three arms extending in a direction and a wafer chuck provided at a tip of each arm, wherein the triple arm connects the three wafer chucks to a wafer supply position and a wafer disk position on a wafer disk, respectively. The wafer is held in one wafer chuck at the wafer supply position and at the same time the wafer on the wafer disk is held by another wafer chuck at the wafer exchange position. Then, the three wafer chucks are rotated by 120 degrees so that the wafers of the one wafer chuck are supplied to the wafer disk at the wafer exchange position and at the same time the wafers of the other wafer chuck are discharged at the wafer discharge position. Is characterized by.

[0010]

In the wafer supply position, the supply wafer is gripped by the one wafer chuck of the triple arm, and at the same time, the discharge wafer is gripped by the other wafer chuck of the triple arm at the wafer exchange position. Then, when the three wafer chucks of the triple arm are rotated by 120 degrees,
The wafer chuck in the wafer supply position is moved to the wafer exchange position, the wafer chuck in the wafer exchange position is moved to the wafer discharge position, and the wafer chuck in the wafer discharge position is moved to the wafer supply position. . Then, the wafer of the one wafer chuck is supplied to the wafer disk at the wafer exchange position, and at the same time, the wafer of the other wafer chuck is discharged at the wafer discharge position. Therefore, the wafer supply line and the wafer discharge line are separately provided, and the wafer can be supplied and discharged in parallel, and the time required for this can be shortened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case in which an embodiment of the present invention is applied to, for example, a wafer exchange apparatus in an ion implantation apparatus will be described below. FIG. 1 is a schematic plan view of an example of the ion implantation apparatus, and FIG. 2 is a right side view. 1 is an ion source, 2 is a vacuum chamber, 3 is a triple arm, 4 is a horizontal moving hand, 5
A and 5B are load lock chambers, 6A and 6B are atmospheric transfer robots, 71 is a dummy cassette, 72 is a buffer cassette, 73 is an alignment mechanism for aligning an orientation flat (orientation flat), and 8 is a wafer cassette.

A wafer disk 21 is arranged in a vertical position in the vacuum chamber 2, and for example, 13 wafers can be held in a vertical position at even intervals along the circumference thereof. For example, when all the 13 wafers are clamped to the wafer disk 21, the wafer disk 21 is moved to the processing position, and then is rotated stepwise by the rotation mechanism 22 to move each wafer in order to the ion implantation position. Ion implantation processing is sequentially performed. When the ion implantation process for all the wafers on the wafer disk 21 is completed, the ejection of the ion-implanted wafer and the supply of a new wafer are performed in parallel as described later.

In front of the wafer disk 21, a triple arm 3 which constitutes a transfer arm of the wafer exchanging apparatus of the present invention is arranged. The triple arm 3 is provided with three arms 31 extending in three directions at an angle of 120 degrees from the center of rotation. A wafer chuck 32 is provided at the tip of each arm 31. The three wafer chucks 32 are sequentially moved to the wafer supply position, the wafer replacement position on the wafer disk 21, and the wafer discharge position by rotating the triple arm 3 stepwise by 120 degrees. You can do it. Further, as shown in FIG. 3, each wafer chuck 32 is provided with chuck pins 33 at four positions,
Each wafer chuck 32 is moved by the chuck pin drive mechanism 34.
The chuck pin 33 can be moved together to the clamp position and the unclamp position shown in FIG. Further, the triple arm 3 can be moved toward and away from the rotary arm in a direction (indicated by an arrow) perpendicular to the rotation direction.

The triple arm 3 holds the wafer on one wafer chuck 32 at the wafer supply position and at the same time holds the wafer on another wafer chuck 32 at the wafer exchange position. Next, the three wafer chucks 32 are rotated by 120 degrees, and the one wafer chuck 32 is rotated.
Of wafers at the wafer exchange position
At the same time, the wafer on the other wafer chuck 32 is discharged at the wafer discharge position.

A horizontal moving hand 4 is provided in front of the triple arm 3. This horizontal moving hand 4 has 2
One gripping part 41 and 42 are provided, and one gripping part 41
Receives the wafer from the load lock chamber 5B for supply, supplies the wafer to the wafer chuck 32 of the triple arm 3, receives the wafer from the wafer chuck 32 of the triple arm 3 by the other holding portion 42, and loads the wafer for discharge. Discharge to the lock chamber 5A.

As shown in FIG. 5, the load lock chambers 5A and 5B can be rotated 90 degrees from a horizontal posture to a vertical posture, and the gate valves 51A and 51B provided in the vacuum chamber 2 are provided in the vertical posture. As a result, the wafers are supplied to and discharged from the horizontally moving hand 4. The horizontal posture and the vertical posture mean the posture of the held wafer. The load lock chamber 5B for supply is shown in FIGS.
For example, as shown in FIG.
2, the whole wafer guide 52 is sequentially pushed forward, and the wafers W are held one by one by the horizontal moving hand 4.

Next, the operation of the above apparatus will be described.
The wafers W are taken out one by one from the wafer cassette 8 arranged on the atmosphere side by the atmosphere transfer robot 6B and transferred to the alignment mechanism 73. After the orientation mechanism 73 aligns the orientation of the orientation flat, the atmosphere transfer robot 6A temporarily stores the wafer W in the buffer cassette 72. Next, a predetermined number of sheets, for example, 2 from the buffer cassette 72 to the load lock chamber 5B in the horizontal posture by the atmosphere transfer robot 6A.
Convey 5 sheets. The load lock chambers 5A and 5B are the rotation shaft 5
1 and the revolving shaft 52 are integrated into a vertical posture to be integrated with the gate valve. After evacuating the load lock chambers 5A and 5B to a predetermined pressure, the gate valve is opened.

When performing the first ion implantation process, since the wafer is not yet supplied onto the wafer disk 21, the wafer is not discharged but only the wafer is supplied. Further, after the final ion implantation process, the wafer is not supplied but only ejected. However, the wafer supply or discharge operation in this case is also performed by the same operation as the case where the supply and discharge are performed in parallel, which will be described later, and thus the description thereof will be omitted.

The operation of the wafer ion implantation process during the first time and the middle time except the last time will be described below.
The cassette of the load lock chamber 5B for wafer supply strokes to the front vacuum chamber 2, and as shown schematically in FIG.
In the clamped state in which one wafer is clamped, the triple arm 3 moves forward to the position of the wafer chuck 32A at the wafer supply position. At the same time, the other holding portion 42 of the horizontal moving hand 4 moves forward to the wafer chuck 32B at the wafer discharge position of the triple arm 3 in a clamped state in which the wafer is not held, that is, in an empty clamped state.

Next, the wafer chucks 32A, 32B, 32
C is one grip portion 41 and the other grip portion 4 at the same time.
2. The wafer chuck 21 moves closer to the wafer disk 21 and the wafer chucks 32A, 32B and 32C are simultaneously clamped.
That is, one wafer chuck 32A clamps the wafer W held by one holding portion 41, and the other wafer chuck 32C clamps the ion-implanted wafer W held by the wafer disk 21, and The wafer chuck 32B clamps the wafer in the empty state at the other holding portion 42. Next, the one grip portion 41 and the other grip portion 42 of the horizontal moving hand 4 and the wafer disk 21 are unclamped at the same time, and the wafer W is transferred from one grip portion 41 to the one wafer chuck 32A. The wafer W after ion implantation is transferred from the other to the other wafer chuck 32C.

Next, after the wafer chucks 32A, 32B and 32C of the triple arm 3 are moved backward, the triple arm 3 is rotated by 120 degrees and the wafer chuck 32 is again rotated.
A, 32B, and 32C move closer to the wafer disk 21, one holding portion 41, and the other holding portion 42, respectively. Then, the wafer disk 21, the one grip portion 41,
The other grip 42 is simultaneously clamped. That is,
Wafer disk 21 is wafer W with wafer chuck 32A
And the other holding portion 42 holds the wafer W of the wafer chuck 32C, and the one holding portion 41 clamps the wafer W in an empty state. Next, the wafer chucks 32A, 3
2B and 32C are unclamped simultaneously, the wafer W is transferred from the wafer chuck 32A to the wafer disk 21, and the wafer W is transferred from the wafer chuck 32C to the other holding section 42.

Next, the wafer chucks 32A, 32B,
32C moves backward, and at this time, the wafer disk 21 is rotated stepwise by one wafer. On the other hand, the horizontally moving hand 4 retracts in the opposite direction and returns to the original position, the one gripping part 41 and the other gripping part 42 are unclamped at the same time, and the cassette of the load lock chamber 5B for supply and the cassette for discharge are discharged. The cassette in the load lock chamber 5A makes a stroke, and the wafer W on the other grip portion 42 is stored in the load lock chamber 5A for ejection. Then, a new wafer W in the supply load lock chamber 5B is clamped by the one grip portion 41, and the same operation as above is repeated.

When the ejection of, for example, 13 wafers after the ion implantation on the wafer disk 21 and the supply of new, for example, 13 wafers onto the wafer disk 21 are thus completed, the gate valves 51A and 51B are closed. Vent gas is flowed through the load lock chambers 5A and 5B to return to atmospheric pressure. Then, the load lock chambers 5A and 5B return from the vertical posture to the original horizontal posture.

Then, for example, 1 on the wafer disk 21.
Ion implantation is sequentially performed on the three wafers, and while the ion implantation is being carried out, the cassette from the load lock chamber 5A for ejection to the atmosphere transfer robot 6 is released.
The wafer is transferred to the original wafer cassette 8 by B, and the atmosphere transfer robot 6 is transferred from the buffer cassette 72.
By A, a new wafer is transferred to the cassette in the load lock chamber 5B for supply. The time required for the ion implantation process is, for example, about 140 seconds.

According to the above embodiments, the triple arm 3
The three wafer chucks 32 are sequentially moved to the wafer supply position, the wafer exchange position, and the wafer ejection position by rotating 120 degrees, so that the wafer supply, the wafer exchange, and the wafer ejection are continuously and shortly performed. Can be done in time. Further, by moving the supply gripping portion 41 and the discharge gripping portion 42 of the horizontal moving hand 4 back and forth, the wafer W is supplied from one of the load lock chambers 5B to the wafer chuck 32 of the triple arm 3. However, since the wafer W after the ion implantation can be discharged from the other wafer chuck 32 to the other load lock chamber 5A, the supply and the discharge of the wafer can be performed as compared with the conventional wafer exchanging apparatus of FIGS. 9 and 10. It can be done efficiently in a short time. Moreover, during the ion implantation process of the wafer, the operation of supplying a new wafer to the supply load lock chamber 5B and the operation of ejecting the ion-implanted wafer from the ejection load lock chamber 5A are performed in parallel. , Wafer ion implantation process can be performed quickly with a short waiting time,
Throughput can be improved.

[0026]

According to the present invention, 12 triple arms are provided.
By rotating the wafer chuck by 0 degree, the three wafer chucks are sequentially moved to the wafer supply position, the wafer exchange position, and the wafer discharge position to perform the wafer supply, the exchange, and the discharge, thereby reducing the time required for these. be able to.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an example of an ion implantation apparatus configured using a wafer exchange apparatus according to an embodiment of the present invention.

FIG. 2 is a right side view of the ion implanter of FIG.

FIG. 3 is a front view of a triple arm.

FIG. 4 is an explanatory diagram of a triple-arm wafer chuck of FIG.

FIG. 5 is an explanatory diagram of 90 ° rotational movement of the load lock chamber.

FIG. 6 is an explanatory diagram showing the inside of a load lock chamber for supply.

FIG. 7 is a left side view of the load lock chamber of FIG.

FIG. 8 is an explanatory view of the operation of the embodiment of the present invention.

FIG. 9 is a schematic explanatory view showing an example of a wafer exchanging apparatus applied to a conventional ion implantation apparatus.

FIG. 10 is a schematic explanatory view showing another example of a wafer exchange apparatus applied to a conventional ion implantation apparatus.

[Explanation of symbols]

 2 vacuum chamber 21 wafer disk 3 triple arm 31 arm 32 wafer chuck 4 horizontal moving hand 41 one gripping part 42 the other gripping part 5A load lock chamber for discharging 5B load lock chamber for supplying

Claims (1)

[Claims] 1. A wafer exchange apparatus for supplying a wafer to a wafer disk by a transfer arm and ejecting the wafer from the wafer disk, wherein the transfer arm comprises three arms extending in three directions at an angle of 120 degrees from a rotation center. And a wafer chuck provided at the tip of each arm, wherein the triple arm comprises the three wafer chucks,
The wafer supply position, the wafer exchange position on the wafer disc, and the wafer ejection position are rotated in order, respectively. At the same time, the wafer is gripped by one wafer chuck at the wafer supply position and at the same time the wafer disc is moved at the wafer exchange position. The upper wafer is gripped by another wafer chuck, then the three wafer chucks are rotated by 120 degrees, and the wafer of the one wafer chuck is supplied to the wafer disk at the wafer exchange position, and at the same time, the wafer of the other wafer chuck is fixed. A wafer exchanging device, wherein the wafer is discharged at a wafer discharging position.