JPH02218146A - Wafer transfer apparatus - Google Patents

Abstract

PURPOSE:To obtain a compact apparatus at a low cost by performing the detection of the orientation flat of a wafer, the sucking and removal of the wafer for aligning the orientation flat and the rotation of the wafer with a transfer robot. CONSTITUTION:The following parts are provided: a transfer means 11 having at least the function for moving a wafer 1 on a straight horizontal line and for rotating the wafer 1; a sensor 12E which detects an orientation flat 1A of the wafer 1 based on the rotation of the wafer 1; and control circuit which controls the driving of the transfer means 11 based on the detected signal from the sensor 12E. When the transfer means 11 rotates the wafer 1, the orientation flat 1A of the wafer 1 is detected with the sensor 12E. The transfer means 11 rotates the wafer 1 based on the detected signal from the sensor so as to align the orientation flat 1A to the specified direction. Thus, the apparatus can be made compact, and the cost can be lowered.

Description

[Detailed Description of the Invention] [Summary] An object of the present invention is to provide a small and inexpensive device regarding a wafer transfer device having a function of adjusting the orientation flat of a wafer during wafer transfer. The transport means has a function of moving and rotating the wafer, a sensor that detects the orientation flat of the wafer by rotation of the wafer, and a control circuit that controls driving of the transport means based on a detection signal from the sensor. The wafer is rotated so that the sensor detects the orientation flat, and the conveying means rotates the wafer to align the orientation flat in a predetermined direction based on a detection signal from the sensor.

[Industrial application field]

The present invention provides orientation flat alignment for aligning the orientation of wafer orientation flats (hereinafter referred to as orientation flats) of wafer transport equipment W in a semiconductor device manufacturing process, etc.
Regarding those with QIJ ability.

Wafers are usually provided with an orientation flat to indicate the crystal orientation, and in many wafer processing processes, it is necessary to orient the wafer using this orientation flat as a reference. When it comes to automation,
The conveyance device has an orientation flat alignment function.
It is often done.

On the other hand, as the patterns of semiconductor devices have become increasingly finer in recent years, the presence of dust during the manufacturing process has become more and more likely to have a significant impact on product yields.As a result, the specifications of clean rooms have become more sophisticated, resulting in lower construction costs and lower costs. Operating costs are also rising. Therefore, it is desired that the installation area of devices installed in a clean room be as small as possible.

[Conventional technology]

1 (') A conventional wafer transfer device with an orientation flat alignment function is shown in FIG. The process is carried out as follows.'
is attracted and moved to the centering unit 12, where it is positioned, and then stored in the carrier stage gin 13. Further, the transfer robot 11 takes out the wafer from the carrier station 13, moves it to the orientation flat alignment unit 14, aligns the orientation flat of the wafer here, and then transfers the wafer to the transfer stage again.
Move up to 15.

(Problems to be Solved by the Invention) As described above, in the conventional wafer transfer device with the ability to perform orientation flat alignment, an independent orientation flat alignment unit is provided, resulting in a large-sized device. Since a dedicated wafer suction/detachment mechanism and wafer rotation mechanism were required, there was a drawback that the cost was high.

An object of the present invention is to provide a wafer transfer device with an orientation flat alignment function that is smaller and cheaper than the conventional one. comprising at least a transport means having a function of moving and rotating the wafer, a sensor that detects the orientation flat of the wafer by rotation of the wafer, and a control circuit that controls driving of the one-bit feeding means based on a detection signal of the sensor, A transport device in which the sensor detects the orientation flat of the wafer as the transport means rotates the wafer, and the transport means rotates the wafer to align the orientation flat in a predetermined direction based on the sensor detection signal. This is achieved by doing this.

[Effect]

In the present invention, since the transfer robot performs wafer suction/detachment and wafer rotation for orientation flat detection and orientation flat alignment, the orientation flat detection function, which was conventionally provided in the orientation flat alignment unit, is transferred to the transfer robot side (centering unit). No need for orientation flat alignment unit. Therefore, the device is smaller and cheaper than before.

〔Example〕

An embodiment of a wafer transfer device with an orientation flat alignment function based on the present invention will be described with reference to FIGS. 1 to 6.

Fig. 1 is a schematic perspective view showing the overall configuration of a wafer transfer device with an orientation flat alignment function (1) based on the present invention. Wafer transport in this device is performed as follows.The wafer 1 is carried in and placed on the carry-in stage 10, and the transfer robot 11 adsorbs it and stores it in the carrier station l3. In the first process, the wafer is taken out from the carrier station 13, moved to the centering unit 12, and positioned there.Then, the center of the wafer 1 is aligned with the rotation center of the transfer robot 11, and the wafer 1 is rotated to align the orientation flat. Then, the wafer l is moved to the unloading stage 15.

FIG. 2 is a sectional view showing the structure of the transfer robot 11.

As shown in the figure, the transfer robot 11 mainly includes a robot body 20, a first arm 21 that is supported by the robot body 20 and rotates, and a second arm 22 that is supported by the first arm 21 and rotates. and a 37th arm 23 which is supported by this second arm and rotates. Third arm 23
A suction port 24 for suctioning the wafer l is provided at the tip. Although not shown in the figure, the suction port 24 is connected to a vacuum source via each arm and shaft.

25 and 26 are step motors, and the motor 25 is the first
By rotating the arm 21, the motor 26 rotates a pulley 27 supported by the first arm 21. The pulley 27 drives a pulley 29 fixed to the second arm 22 by a belt 28. Further, the pulley 31, which is coaxial with the Boo I729 and fixed to the first arm 21, drives the Boo +733, which is fixed to the third arm 23, by means of a belt 32. The diameter of the pulleys 29.31 is the same and is 1/2 of the diameter of the pulleys 27.33.

When the pulley 27 is rotated here, the second arm 22 rotates because the pulley 29 is fixed to the second arm 22. When the first arm 21 is rotated while the pulley 27 is stopped, the belt 28 rotates relative to the pulley 27, the arm 22 rotates, and the belt 32 similarly rotates, causing the pulley 33 to rotate. do. As a result, the third arm 23 performs a linear movement in the direction of moving away from and approaching the rotating shaft 35 of the pulley 27. Furthermore, when the boo IJ 27 and the first arm 21 are synchronously rotated in the same direction, they all rotate as one and perform a turning motion.

FIG. 3 is a block diagram of the control circuit of the transport port box 11. The CPU 50 connects the terminal 51 to the interface circuit 5.
Motor drive circuit 52 .
53 and an elevation drive circuit 54, respectively. Motor drive circuits 52 and 53 generate drive signals for motors 25 and 26, respectively, and output them from terminals 55 and 56. Further, the lift drive circuit 54 generates a lift drive signal and outputs it from the terminal 57. However, since the transfer robot 11 in this embodiment does not have a lifting function, the wafer stage 4 described later is used instead.
0 (Figure 5).

Figure 4 shows the operation of the robot) 11. The process of the arm contracting from the fully extended state is shown in (A) to (E).
(F) shows the state in which the arm has been rotated 90'' from the state in E).

Next, orientation flat alignment using the apparatus of the present invention will be explained with reference to FIG. In the figure, (A) is a side view, and (B) is a plan view. In the figure, 12 is a centering unit, which is fixed to the robot body 20, 12A, 12B, 1
It has five sets of sensors: 2C, 12D, and 12E. These are all transmission type optical sensors consisting of a phototransistor and a light emitting diode. 1 out of 5 sensors
The four lights 2A to 12D are for wafer positioning, and are turned ON when the wafer 1 is inserted between them and the light is blocked.12
E is for aligning the orientation flat, and becomes "OFF" when the wafer 1 is inserted between them to block light.

Wafer positioning is to correct misalignment during wafer loading, and originally the center of wafer 1 is moved to transfer robot 11.
However, in this embodiment, in order to avoid interference between various parts of the device, the device is centered at a temporary center Q, and then moved from Q to P. The sensors 12A to 12D are arranged at central angles larger than the orientation flat 1A on a circumference centered on Q and whose radius is equal to the radius of the wafer 1. Positioning is performed when two sensors detect the wafer 1 at the same time. A patent has already been applied for this positioning device (Japanese Patent Application No. 62-2627).
No. 36), detailed explanation will be omitted.

For orientation flat joining 11 (!) The sensor 12E is located at a position UX where the distance from the rotation center P of the robot 111 is smaller than the radius of the wafer 1, but larger than the radius of the circle inscribed in the orientation flat I of the evaporator 1. 40 is a wafer stage, which is also used for the wafer positioning described above, and is used to hold the wafer 1.
[7] You can place it up and down. Although this wafer stage 40 is not shown, it is attached to the robot main body 20.
It is driven by a stepped motor.

If you align the orientation flat, it will be done as follows. FIG. 6 shows flowchart 1 of orientation flat alignment (t), which will be explained with reference to the same figure.The transfer robot 11 moves the wafer 1, which has undergone the wafer positioning described above (step 60), from above the wafer stage 40 to the wafer stage 40. - Shrink the arms 21 to 23 and move the robot body 2.
042, move the center of wafer 1 to arm 21=23
(step 61), and at this time the arms 21-23 are at the origin position (the state shown in FIG. 5(E)).

Next, when the arms 21 to 23 are turned (step 62), the wafer 1 is rotated. If the sensor 12E detects the orientation flat 1A by transmitting light through the orientation flat 1A portion of the wafer 1 during rotation (step 63), the process proceeds to step 64.
If the orientation flat 1A is not detected, the rotation continues c-t until one rotation is reached, and then the process proceeds to step 74.

In step 64, counting of motor pulses is started, and when sensor 12F turns OFF' (step 65),
The rotation of arm 2l-=-23 and the counting of motor pulses are stopped (step 6G). Next, it is determined whether or not the counted number of motor pulses is as specified (Step 67). If it is as specified, the process proceeds to Step 68, and if it has not reached the specified number, the process proceeds to Step 74.

In step 68, the arms 21 to 23 are rotated in the opposite direction by a number of pulses corresponding to 1/2 of the specified number of motor pulses. As a result, the center of the orientation flat 1A is aligned with the direction of the sensor 12E.・If the wafer stage 40
(Step 69) and release the wafer suction (Step 70), and place the wafer 1 on the wafer stage 40.
2, the arms 21 to 23 are rotated to the original position (step 71). The arms 21 to 23 suck the wafer 1 again (step 72), and the wafer stage 40 is moved down (step 73), which completes the alignment of the orientation flat (-1)
Transport to (Fig. 1) will begin.

In the case where the sensor 12E does not detect the off-lift 91A in step 63, and in the case where it is determined in step 67 that the number of motor pulses counted has not reached the specified value even if detected, the process proceeds to step 74. Become. The reason why these cases occur is that the direction of the orientation flat 1A is uncertain when the wafer 1 is placed on the carry-in stage 10 (Fig. 1), so the arms 21 to 23 move toward the orientation flat I at the time of starting alignment of the orientation flat. The positional relationship between the two arms is also unstable, and the orientation flat 1A and the arm 2l-=-23 may overlap, and in that case, the orientation flat detection by the sensor 12E is hindered. Since the orientation flat length of wafers with the same diameter is constant, if there is no such interference, the sensor 12E
The time during which the orientation flat is detected from 1 to 1 is constant. Therefore, if the measured number of motor pulses is less than the specified number or none at all, it means that there is interference.

In this case, arms 21 to 23 are attached while holding wafer 1.
The wafer 1 is rotated once to the origin position (Step 74), and then the wafer stage 40 is moved up (Step 75) and the wafer suction is released (Step 76), and the wafer 1 is placed on the wafer stage 40. After, arm 21
After rotating the wafer 23 approximately 908 times in either the forward or reverse direction (step 77), the wafer 1 is sucked again in step 78.
79), then return to step 62. Since the central angle formed by the orientation flat is approximately 45=50°, there will be no interference the second time.

〔Effect of the invention〕

As explained above, the wafer transfer device with an orientation flat alignment function according to the present invention utilizes the wafer rotation function that the transfer robot has to transfer the wafer to detect and align the orientation flat, so the wafer transfer device has an independent orientation flat alignment unit. This eliminates the need for equipment, making it possible to reduce the size and cost of the device.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the overall configuration of a wafer transfer device based on the present invention, FIG. 2 is a schematic sectional view showing the structure of a transfer robot, FIG. 3 is a block diagram of the control circuit of the transfer robot, and FIG. FIG. 5 is a diagram for explaining the orientation flat alignment by the device of the present invention, (A) is a side view, (B) is a plan view, and FIG. 6 (Part 1) is a diagram for explaining the operation of the transfer robot. ), (2) are block diagrams of orientation flat alignment using the apparatus of the present invention. FIG. 7 is a schematic perspective view showing the overall configuration of a conventional device;
1: Wafer, 1A: 10: 11: 12: 12E: 13: 14: l 5: 20: 21-23 24: 40: 50: 52: 53: 54: 60-79 Orientation flat loading stage, transfer robot, centering Unit, sensor, carrier station, orientation flat alignment unit, unloading stage, robot body, arm, suction port, wafer stage, CPU. Motor drive circuit, motor drive circuit, lifting drive circuit, Nistep. Sayaka Tobi - 〇ni - 1) qA 舅 y ζ begging piece, 1 to be treated every evening, 2 to be 1 Zuken 1 nshi Ehama 4 story block 7 Illustration 30 skin 4 za robot, 7 Tokudo 412 ear I March T37 te δ's drowning 4 page 44 also watch ζ;
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Claims (1)

[Claims] A transport means (11) having a function of at least horizontal translation and rotation of the wafer (1), and detecting an orientation flat (1A) of the wafer (1) by rotation of the wafer (1). Sensor (12E
) and the conveying means (11) according to the detection signal of the sensor (12E).
), the conveying means (11) rotates the wafer (1) so that the orientation flat (1) of the wafer (1) is controlled.
A) is detected by the sensor (12E), and the transport means (11) is detected by the detection signal of the sensor (12E).
1. A wafer transfer device, characterized in that the device (1) rotates the wafer (1) to align the orientation flat (1A) in a predetermined direction.