JPS61278149A - Positioning device for wafer - Google Patents

Abstract

PURPOSE:To eliminate the need for pre-alignment on a stage by executing pre-alignment for a connecting wafer on a pantograph during the treatment of a preceding wafer. CONSTITUTION:A pantograph hand 3 is stretched, wafers 1 to be pre-aligned are sucked by a support member 2 for the pantograph hand 3 at a position where the edges of the wafers 1 in a wafer carrier 5 are detected by a sensor 6 for the support member 2 for the pantograph hand 3, and the pantograph 3 is shrunk. Arms 15, 16 are expanded and contracted to a position where signals from the sensor 6 detect the edges of the wafers 1 at said positions, and the positions of the edges of the wafers are memorized to a memory storage for a controller. The pantograph hand 3 is turned only by a fixed quantity, and the positions of the edges of the wafers are detected and memorized in the same manner. The position of the centers of the wafers and the direction of orientational flats thereof are computed from the informations of the memories, the pantograph hand 3 is rotated and expanded and contracted so that the wafers are positioned at a desired position, and a lifting base 13 is elevated, and the wafers 1 are received from a fixing chuck 7, and delivered to the next stage.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for keeping the wafer in a predetermined position when placing a disk-shaped semiconductor wafer (hereinafter referred to as "wafer") on a measuring device, an inspection device, an exposure device, etc. The present invention relates to a wafer positioning device for arranging wafers in the following directions.

[Prior Art] Conventionally, in semiconductor manufacturing equipment, a wafer taken out from one wafer cassette is mounted on a wafer chuck, etc.
After playing 1!11 in various places, I stored it in another cassette. However, in recent years, in order to reduce the space and make the apparatus more compact, it has been considered to return the processed wafers to their original wafer cassettes. One of these uses a pantograph-type robot hand.

By the way, the center position of the wafer stored in the wafer cassette and the orientation of the orientation flat are not constant, and even in this pantograph type one-piece hand (hereinafter referred to as the "pantograph hand"), the wafer inside the cassette is not fixed. Since no mechanism is provided to correct positional variations, the center position of the wafer on the pantograph hand and the direction of the orientation flat remain irregular.

For this reason, centering of the wafer and detection and alignment of the orientational flats 1 to 2 must be performed at the stage that receives the wafer from the pantograph hand and carries out the next process. For this reason, the orientation flat detection mechanism and positioning t! A mechanism must be established. However, this requires time for orientation on the stage each time a wafer is transferred to the stage, resulting in a problem that the throughput of the semiconductor manufacturing apparatus is reduced.

[Problems to be Solved by the Invention and Means for Solving 1] An object of the present invention is to eliminate the need for accurately orienting a wafer on a stage each time it is moved from one stage to another, thereby improving semiconductor manufacturing equipment. The purpose of this is to increase throughput, and while the wafer is being processed on the stage, the wafer taken out from the cassette for next processing is oriented on the pantograph hand, and the correctly oriented wafer is transferred to the pantograph. This is achieved by a device that uses the waiting time of the pantograph hand to position the wafer by moving it from the wafer to the stage.

That is, the wafer positioning device of the present invention includes: a pantograph hand having a support member provided with a sensor; a telescoping/rotating mechanism that extends/contracts and rotates the pantograph hand; a wafer being received from the support member in the telescoping position of the pantograph hand; a fixed chuck that holds the pantograph hand and the fixed chuck by moving the pantograph hand and the fixed chuck relatively vertically so that the supporting member and the fixed chuck are at the same height or higher than the supporting member; a lifting mechanism for moving the chuck to a lower or higher position; and a lifting mechanism connected to the sensor and the telescopic rotation mechanism, and the fixed chuck t/
controlling the expansion and contraction rotation of the pantograph hand so that the sensor follows the edge of the wafer in response to a signal from the sensor that detects the edge of the wafer held by the vine;
A control device is provided which determines the positional deviation of the wafer from the signal from the sensor and controls the expansion/contraction rotation of the pantograph hand so as to correct the positional deviation. In particular, this control device includes a storage device that stores the coordinates of the edge of the wafer detected by the sensor each time the pantograph hand rotates by a certain angle, and calculates the center position of the wafer and the direction of the orientation flat from these coordinates. and means to do so.

[Embodiment] FIG. 1 is a perspective view showing a mechanism of a wafer positioning vR position according to the present invention. In FIG. 1, 1 is a wafer, 2 is a support member, 3 is a pantograph hand, 5 is a sea urchin flake, and 6
1 is a sensor provided on the support member, 7 is a wafer fixing chuck, 8 is a rod of the wafer fixing chuck, 9 is a suction device, 1
0 is a base plate, 11 is a rotary table, 12 is a telescopic rotating machine, 13 is a lifting table, 14 is a gear, 15 is a first arm, and 16 is a second arm.

As shown in the figure, the support member 2, gear 14, first arm 15
, the second arm 16 constitutes the pantograph hand 3. The support member 2 is provided with a sensor 16. The telescoping and rotating mechanism 12 extends and contracts the pantograph hand 3 and rotates it. Wafer fixing chip 17 is pantograph 3
The pantograph is arranged so as to fit into the U-shaped groove of the support member 2 when the pantograph is retracted. In this embodiment, the lifting mechanism 17 raises and lowers the pantograph hand 3 in the vertical direction. The rod 8 supporting the wafer fixing chuck 7 is supported by the lifting table 13 or the rotary metal 11 in the normal position, but when the RIL'F table 13 is lifted up, the rod 8 is pushed up by the suction device 9. ,
The fixed chuck 7 is positioned above the pantograph hand.

Although not shown in FIG. 1, a control device is connected to the sensor 6 and the telescopic rotation mechanism, and this control device controls the edge of the wafer 1 detected by the sensor 6 every time the pantograph hand 3 rotates by a certain angle. It includes a storage device for storing coordinates, and means for calculating the center position of the wafer and the direction of the orientation flat from these coordinates. The control I device rotates the pantograph hand 3 intermittently, and rotates the pantograph in response to a signal from the sensor 6 so that the sensor 6 detects the edge of the wafer 1 held by the fixed chuck 7 when the pantograph hand 3 is stopped. The pantograph hand 3 controls the expansion and contraction rotation of the hand 3 so that the sensor 6 follows the edge of the wafer 1, determines the positional deviation of the wafer from the detection signal from the sensor 6, and then corrects the positional deviation.
The pantograph 3 is oriented at an appropriate position with respect to the wafer 1 on the fixed desk Z by controlling the expansion and contraction rotation of the pantograph 3. At this proper position, the wafer 1 is received from the fixed chuck 7 and the support member 2
Hold wafer 1 on top.

The pre-alignment operation of the embodiment of the wafer positioning apparatus of the present invention will be described with reference to FIGS. 1 and 2.

First, extend the pantograph hand 3 and attach the wafer 1 to the support member 2 at a position where the edge of the pre-aligned wafer 1 in the wafer carrier 5 is detected by the sensor 6 of the support member 2 of the pantograph hand 3. (see broken line in Figure 1, Figure 2a), then retract the pantograph 3 (see solid line in Figure 1, Figure 2b).

The lifting table 13 is lowered by the lifting mechanism 17 and the rod 8 of the wafer fixing chuck is pressed against the suction device 9 (see FIG. 2b). The elevator table 13 is lowered as it is, the wafer 1 on the support member 2 of the pantograph hand is transferred to the fixed chuck 7, and the support member 2 of the pantograph hand is further lowered to a position where it does not come into contact with the wafer 1 (FIG. 2C). .

At that position, the arms 15, 16 are extended and retracted to a position where the signal from the sensor 6 detects the edge of the wafer 1, and the position of the wafer edge is stored in the memory of the controller (not shown). Next, after rotating the pantograph hand for a certain number of meters, the position of the edge of the wafer is similarly detected and stored. This is repeated, and the edge position around the entire wafer is memorized along with the rotation angle of the pantograph.

From this information, the center position of the wafer and the direction of the oriented flat are calculated. Based on this Kt II result, the pantograph hand is rotated and expanded/contracted so that the wafer center position J3 and the orientation flat are located at the desired locations, and then the lifting table 13 is raised and the wafer 1 is fixed (? 7I)) The receiver is removed and passed to the next stage where the wafer is inspected, measured or processed.

In this way, the wafer that has undergone pre-alignment can be supplied to the next stage by the pantograph hand.

It is desirable that the sensor 6 be capable of detecting the edge of the wafer with high precision and without contact. Anti-OA'l'! Alternatively, a transmission type optical sensor or the like can be used.

In this embodiment, the pantograph hand is rotated to detect the entire circumference of the wafer, but it is also possible to rotate the fixed chuck and memorize the angle while detecting the edge of the wafer using a sensor. The wafer is transferred once between the fixed chuck and the pantograph hand, and orientation of the orientational flat can be achieved by passing the wafer once.The key to accurate centering is as follows.
If you receive the item twice, you can pass it on.

[Effects of the Invention] According to the present invention, pre-alignment of the subsequent wafer can be carried out on the pantograph during the processing of the preceding 1 wafer, so pre-alignment 1- on the stage is no longer necessary, which eliminates the need for wafer alignment on the stage conventionally. This saves time and increases throughput.

In addition, wafers are transferred only on the back side of the wafer, which eliminates problems during transportation such as dust adhesion, wafer chips, and cracks that occur during the semiconductor manufacturing process. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the wafer positioning apparatus of the present invention. Figures 2a, 2b, and 20 are explanatory diagrams of the operation of the wafer positioning device of the present invention. Figure 2a shows a pantograph pulling out a wafer from a wafer carrier, and Figure 2b shows a pantograph hand holding a wafer up to a fixed chuck. FIG. 2C shows the state in which the pantograph hand transfers the wafer to the fixed chuck. In the figure; 1: wafer, 2: support member, 3: pantograph hand,
5: Wafer carrier, 6: Sensor, 7: Wafer fixing chuck, 8: Rod, 9: Adsorption device, 10: Substrate, 11: Rotating table, 12: Telescopic rotation mechanism, 14: Gear, 15.16:
Arm, 17: Lifting mechanism.

Claims (1)

[Claims] 1. A pantograph hand having a support member provided with a sensor; A telescoping/rotating mechanism that extends, contracts, and rotates the pantograph hand; Receives a wafer from the support member at the retracted position of the pantograph hand; Holding a wafer fixing chuck; moving the pantograph hand and the fixing chuck relatively vertically so that the supporting member and the fixing chuck are at the same height, or the fixing chuck is lower than the supporting member. a lifting mechanism for moving the wafer to a lower or higher position; and a lifting mechanism connected to the sensor and the telescoping rotation mechanism in response to a signal from the sensor detecting an edge of the wafer held in the stationary chuck. Controlling the telescopic rotation of the pantograph hand so that a sensor follows the edge of the wafer, determining misalignment of the wafer from a signal from the sensor, and controlling the telescopic rotation of the pantograph hand so as to correct the misalignment. A wafer positioning device characterized by comprising a control device for controlling the wafer. 2. The control device includes a storage device that stores the coordinates of the edge of the wafer detected by the sensor each time the pantograph hand rotates by a certain angle, and determines the center position of the wafer and the direction of the orientation flat from these coordinates. The wafer positioning apparatus according to claim 1, further comprising calculating means.