JPH0444246A - Semiconductor wafer carrying device - Google Patents

Abstract

PURPOSE:To eliminate the need for retract operation function for avoiding interference with a carrying arm and enable structure and control system of carrying and placement to be simplified by providing a wafer carrying arm for installing two or two pairs or more reflection mirrors for leading light which is radiated from an optic sensor for detecting wafer or from the emission side in a side surface direction of the wafer. CONSTITUTION:An elevator 1 is gradually lowered while detecting output of optic sensor light-receiving elements 17 and 18. While the output of the optic sensor light-receiving elements 17 and 18 stays at 'H' level, it is judged that no wafers exist and the elevator 1 descends. When a wafer 6 within a cassette 2 reaches a height of light paths 12 and 13, light of optic sensor light-emitting elements 7 and 8 is screened by the wafer 6, thus enabling the output to be at 'L' level. This signal allows the elevator 1 to stop at a proper position and allows a carrying arm 14 to be inserted into the cassette 2. Then, while suctioning air from vacuum holes 15 and 16, the elevator 1 is lowered, the wafer 6 is subjected to vacuum deposition onto the carrying arm 14, and at the same time the wafer 6 is lifted up, thus allowing the wafer 6 to be taken out of the cassette 2 in chucked state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor wafer transport device, and in particular an elevator mechanism capable of vertically moving a wafer cassette, and an elevator mechanism for detecting wafers in the cassette. The present invention relates to a semiconductor wafer transfer device that includes a wafer detection mechanism using an optical sensor and a transfer arm mechanism that can take out a wafer in a cassette to the outside of the cassette.

[Conventional technology]

Conventionally, this type of semiconductor wafer transfer device has an elevator mechanism, a wafer detection mechanism that has a pair of light sensors on the light emitting side and a light receiving side, and a transfer arm mechanism that are configured independently, and the wafer in the cassette is When detecting, the optical sensor or reflective mirror of the wafer detection mechanism first
After moving to the detection position and detecting the wafer, it is evacuated to the original position, and then the transfer arm is inserted into the cassette and the wafer is taken out of the cassette.

FIG. 6 is a perspective view of a conventional semiconductor wafer transport device.

In the figure, the elevator 37 has a mechanism that moves up and down in the Z-axis direction.

The cassette 38 is placed on the elevator 37, and the wafers 40 are stored in the slot grooves 39 of the cassette 38. The optical sensor light emitting element 41, the reflecting mirror 42, and the optical sensor light receiving element 43 are each attached to a sensor fixing base 45, and the sensor fixing base 45 has a mechanism that is moved up and down by an air cylinder 44 for up and down. Also,
The light emitted from the light sensor light emitting element 41 is reflected by a reflecting mirror 42 and guided to the light sensor light receiving element 43, respectively. The transfer arm 46 has a mechanism that moves back and forth in the Y-axis direction, and a vacuum hole 47 for vacuum suctioning the wafer is provided at the tip.

Next, the operation of wafer transport will be explained. Each mechanism section operates in sequence based on signals from the control section. Figure 7 (
a) and (b) are left side views of Fig. 1 and Fig. 6; As shown in FIG. 7(a), in the operation before wafer detection, the sensor fixing table is first raised by the air cylinder 44 in the direction of the arrow (■). At this time, the light emitted from the photosensor light emitting element 41 is
The light passes through the sensor optical path 48 and is incident on the photosensor light receiving element 43 by the reflecting mirror 42 (because there is no wafer on the sensor optical path 48). Next, the elevator 37 with the cassette 38 on it descends in the direction of the arrow ■, but the wafer 40 stored in the lowest stage of the cassette 38 is placed in the sensor optical path 4.
The lowering operation is stopped at the point (position) where the light passing through 8 is blocked (wafer detection operation).

After the wafer detection operation, the sensor fixing table 45 is lowered in the direction of the arrow ■ by the air cylinder 44, as shown in FIG. 7(b). After this, the transport arm 46 moves in the direction of the arrow ■ to the bottom of the sea urchin-40 indicated by diagonal lines.
- Move -40 in the direction of arrow ■ after vacuum suction.

As described above, the wafers 40 stored in the cassette 38 are taken out of the cassette 38.

[Problems to be Solved by the Invention] The above-mentioned conventional UNINO-transport device requires three mechanical units that operate: an elevator mechanism, a UNINO-detection mechanism, and a transfer arm mechanism, so the structure of the device is complicated. It becomes complicated,
There are disadvantages in that control and position adjustment of these devices becomes difficult, and the cost of the device increases.

In addition, in the wafer detection mechanism, there is only one pair of optical sensors that detect the wafer inside the cassette, so if the unicorn is accidentally inserted diagonally into the slot in the cassette, this error will be detected as an alarm. Unable to do so, it continues to operate normally. Therefore, there is a drawback that the wafer may be damaged when the transfer arm is inserted into the cassette.

[Means to solve the problem]

In the semiconductor wafer transfer device of the present invention, the wafer is equipped with a light sensor for detection (the light emitting side sensor, the light receiving side sensor, or both) or a reflecting mirror for guiding the light emitted from the light emitting side to the light receiving side sensor. It has two or more pairs of wafer transfer arms installed in the lateral direction.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an example of the present invention, and FIG. 2 is a left side view thereof.

In the figure, the elevator 1 has a mechanism that moves up and down in the Z-axis direction under the control of a control unit 100. Cassette 2
is placed on top of elevator l. Furthermore, wafers 4, 5, and 6 are housed in the slot groove 3 of the cassette 2.

The optical sensor light emitting element 7 and the light emitting element 8 are attached to the sensor fixing base 9 in line with the X direction, and the respective sleeves)
10. Light is emitted in the optical path 12 and optical path 13 directions through the sleeve) 11. The transport arm 14 has a mechanism that moves back and forth in the X direction, and has two vacuum holes 15 and 16. optical sensor light receiving element 17,
The light receiving elements 18 are mounted on the transport arm 14 in line in the X direction. The light receiving element 17 is a pair of optical sensors that receive the light emitted from the light emitting element 7 through the optical path 12.
The light receiving element 18 receives the light emitted from the light emitting element 8 through the optical path 13, and constitutes a pair of optical sensors different from the former.

In the above configuration, the optical sensor light receiving element 17°18
The elevator l is gradually lowered while the control unit detects the output of the elevator l. The pressure of the optical sensor light receiving elements 17 and 18 is “H”
During the level (light is being received from the photosensor light emitting elements 7 and 8), it is determined that there is no wafer and the elevator 1 descends. The wafer 6 in the cassette 2 is placed in the optical path 12.13.
When the height reaches , the light from the light sensor light emitting elements 7 and 8 is blocked by the wafer 6, and the outputs of the light sensor light receiving elements 17 and 18 become L'' level (not receiving light).

This signal causes the elevator l to stop descending at an appropriate position, and the transport arm 14 is inserted into the cassette 2.

Next, while sucking air from the vacuum holes 15 and 16, the elevator 1 is lowered, and the wafer 6 is vacuum-adsorbed onto the transfer arm 14. At the same time, the wafer 6 is lifted from the slot groove 3, and the chucked state is placed outside the cassette 2. The wafer 6 is taken and pressed.

This embodiment has the advantage that the structure of the apparatus is simple and the cost of the apparatus can be measured because there is no mechanism for moving the wafer detection section up and down. In addition, when detecting a wafer, for example, if the wafer C23 is accidentally inserted diagonally into the cassette 19 as shown in FIG. 4
As shown in FIG. A, a difference of Δt occurs between the detection times of the optical sensor light receiving element 17 and the optical sensor light receiving element 18. For this reason, an alarm detection section 200 consisting of EX-NOR and RS flip-flops as shown in FIG. 4B is connected to the light sensor light receiving element 17.
, 18 on the output side, it is possible to notify the operator of the equipment via the control unit 100 of errors such as those shown in FIG. Another advantage is that the locking operation can be stopped.

[Example 2] FIG. 5 is a plan view of Embodiment 2 of the present invention.

The elevator 25 is a mechanism that moves in a direction perpendicular to the paper surface. The cassette 26 is placed on the elevator 25, and a wafer 27 is stored inside the cassette 26. The optical sensor light emitting elements 28 and 29 are connected to the cassette 26.
They are arranged side by side in the X direction at the rear of the paper, and are at the same height in the direction perpendicular to the plane of the paper. Further, the transport arm 32 is located in front of the cassette 26 and has a mechanism that moves back and forth in the X direction to transport the wafer 27 to the outside of the cassette 26. Reflection mirrors 33 and 34 are mounted on the upper part of the transport arm 32 at an angle of 45 degrees with respect to the optical paths 30 and 31, and reflect the specific light from the optical sensor light emitting elements 28 and 29 to 90'', respectively. It plays the role of guiding the light to the light receiving elements 35 and 36.The light sensor light receiving elements 35 and 36 are
They are fixed in line in the X-axis direction at the position of point P.

Next, the wafer calibration operation in the configuration of the second embodiment described above will be explained.

First, after the transfer arm 32 moves to point P, the elevator 25 descends and the wafer 27 blocks the light on the optical path 30° 31 (light from the optical sensor light receiving element 35, 361 and the optical sensor light emitting element 28, 29). stops in a state where no light is incident). The wafer transport operation is the same as in the first embodiment.

In this embodiment, since the reflecting mirror is installed on the transport arm, there is an advantage that the shape of the transport arm can be made smaller and simpler. Furthermore, since the optical sensor is not installed on the transport arm, there is an advantage that the shape, size, etc. of the optical sensor can be easily selected.

〔Effect of the invention〕

As explained above, the present invention provides an optical sensor for detection (a light-emitting side sensor, a light-receiving side sensor, or both) or a reflecting mirror for guiding light emitted from the light-emitting side to a light-receiving side sensor. By installing the wafer on the wafer transfer arm, after the wafer detection mechanism detects the wafer, the evacuation function to avoid interference with the transfer arm becomes unnecessary, and the storage structure, control system, position adjustment, etc. This has the effect that it can be simplified and the cost of the device can be reduced.

In addition, since there are two or more optical sensors for wafer detection toward the side of the wafer, if the wafer is accidentally inserted diagonally into the slot in the cassette, each wafer detection sensor Due to the timing shift of the wafer detection signal, it becomes possible to detect this as an alarm.

Therefore, it is possible to stop the operation of the apparatus before the transfer arm is inserted into the cassette, and to notify the outside (equipment operator, etc.) of a wafer insertion error without damaging the wafer.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of one embodiment of the present invention, FIG. 2 is a left side view of FIG. 1, FIG. 3 is a front view of the cassette when a wafer is incorrectly inserted into the cassette, and FIG. 4A is a timing chart when the wafer inside the cassette of FIG. 3 is detected by the apparatus of the present invention, FIG. 4B is a block diagram showing an example of an alarm calibration circuit in that case, and FIG. FIG. 6 is a plan view of one embodiment, and FIG. 7 is a perspective view of a conventional semiconductor wafer transfer device, and FIGS.
) is a left side view of FIG. 6, (a) is a diagram of the operation before detection, and (b) is a diagram of the operation after wafer detection. l...Elevator, 2...Cassette, 3
...Slot groove, 4,5.6...Wafer 7...Photo sensor light emitting element, 8...
- Optical sensor light receiving element, 9...Sensor fixing base, 10.
11... Slab) b, 12... Light path,
13... Optical path, 14... Transfer arm,
15.16... Vacuum hole, 17.18.
... light sensor light receiving element, 19 ... cassette),
20...slot) L 21, 22, 23.2
4...River/Wafer, 25...Elevator, 26
...Cassette, 27...Wafer, 28.
29... Optical sensor light emitting element, 30.31... Mark/light path, 32... Mark/transport arm, 33.34...
Reflection mirror 35.36...Photo sensor light receiving element,
Elevator for 37..., cassette for 38..., 39...
...Slot groove, 5o...Group, wafer 41...
... Optical sensor light emitting element, 42 ... Reflection mirror 4
3... Optical sensor light receiving element, 44... Air cylinder, 45... Sensor fixing base, 46...
River/transport arm, 47...vacuum hole 48/old...sensor light path. Agent Patent Attorney Susumu Uchihara 1 Zuhoen Aie Fe 8-he 1 no Ri 17-1d Aku 4Δ times Hoki Otsu■

Claims (2)

[Claims] (1) An elevator mechanism unit that moves a cassette containing semiconductor wafers up and down; a wafer detection mechanism unit that has an optical sensor that can detect the presence or absence of wafers housed in the cassette one by one; In a wafer transport device having a transport arm mechanism capable of taking out the wafer, a wafer detection optical sensor (a light emitting side sensor or a light receiving side sensor or a sensor on both the light emitting side and a light receiving side) or a sensor emitted from the light emitting side is provided. 1. A semiconductor wafer transfer device, characterized in that two or more pairs of reflecting mirrors for guiding light to a light-receiving sensor are installed on the wafer transfer arm toward a side surface of the wafer. (2) when the optical path from the light emitting side sensor to the light receiving side sensor is blocked by the wafer in the cassette;
The semiconductor wafer transport apparatus according to claim 1, wherein the elevator mechanism stops and the transport arm mechanism takes out the wafer.