JPH01303735A - Wafer transfer device - Google Patents

Abstract

PURPOSE:To prevent any erroneous operations of a wafer transfer device from occurring by a method wherein an approach sensor is provided on a specified stoppage position of wafers while a delay circuit is set up to detect the wafers. CONSTITUTION:The title wafer carrier is composed of a device holding substrate wafers 2 and another device detecting the shifting position of each substrate wafer 2. An approach sensor 5 is provided on a position detecting part and the delay time is set up for detection of the substrate wafers 2 before and after the shifting to perform the multiple times of positional detections. That is, the approach sensor 5 is actuated to detect the shifting of an objective substrate to specified position while a delay circuit is actuated to detect the stoppage of the substrate wafer 2 on the specified position after the shifting. Through these procedures, the positional shifting and the stoppage position of substrate wafer 2 can be confirmed so that any erroneous operations in opening.closing, etc., of a vacuum valve interlocking with detection signals may be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wafer transport device in semiconductor manufacturing equipment, and more particularly to a malfunction-free wafer transport device suitable for accurate movement and position detection of a substrate wafer.

[Conventional technology]

Conventional equipment uses light (for example, infrared light) to detect the stoppage or passage of a substrate wafer once for each wafer, and in conjunction with the signal from this detection system, opens and closes the equipment vacuum valve, operates the substrate wafer, and performs sequential operations. It was a transport operation that involved moving. Here, detection of the substrate wafer has been performed by converting the state in which light from the light emitting system is blocked by the substrate and does not reach the light receiving system into an electrical signal.

[Problem to be solved by the invention]

In the above conventional technology, in order to detect the stopping or passing of a substrate wafer by light, a colorless transparent substrate such as a non-magnetic garnet (G d 3G
a50zz) There is no consideration given to the detection of single crystal films, etc., and even if the wafer is moved in the substrate wafer transport system, operations such as opening and closing the vacuum valve or sequentially feeding the wafer in conjunction with the detection signal cannot be performed. The problem was that there was no.

Furthermore, when transporting a wafer by detecting only the passing of a wafer from one predetermined position to another using light, even if a passing signal can be detected, the wafer may move to a predetermined position.
There is uncertainty as to whether or not the wafer is actually stopped at that position, and for example, opening and closing of a vacuum valve that is linked only to the detection signal that has passed through the wafer may result in failure, such as destruction of the wafer.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the prior art described above and provide a wafer transfer device that does not malfunction.

[Means to solve the problem]

The above purpose is to install a proximity sensor using high frequency corresponding to the material characteristics of the objective substrate at each predetermined stop position of the wafer, and to install a delay circuit for wafer detection to perform position detection operations multiple times. As a result, a wafer transfer device without malfunction can be achieved.

[Operation] The proximity sensor operates to detect that the objective substrate has moved to a predetermined position. and.

The delay circuit operates to detect when the substrate wafer has stopped at a predetermined position after being moved. This confirms the movement to the substrate wafer and the stop position.
This eliminates malfunctions in the opening and closing of vacuum valves linked to detection signals, and completely eliminates failures such as substrate damage during sequential wafer feeding operations.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows the configuration and operating principle of a wafer transfer device in which a wafer is moved by the self-load of a substrate wafer.

The substrate wafer 2 is mounted on the cassette holder 1.

As the vertical feed drive system 3 moves up one step at a time, the sheets slide down from the holder one by one and are moved to the carry-in chamber 4. Here, the moving wafer is detected by the proximity sensor 5. In this detection system, the presence of the wafer on the plate of the insertion valve 7 and the presence of the wafer at a predetermined stop position are confirmed by electrical signals using a proximity sensor.

After confirming that the wafer is in place on the plate of the insertion valve, close the inlet valve 6 and evacuate the loading chamber to a vacuum level of approximately ~1-0-'' Torr. After completing this evacuation, the insertion The valve 7 is opened and the wafer is slid onto the substrate holding platen 8.

Here, the wafer 2' that has moved to the platen is detected by a proximity sensor 5' installed on the platen. The detection system here is wafer detection on the insertion valve plate (
(detecting arrival and stopping). After confirming that the wafer is at a predetermined position on the platen, the insertion valve 7 is closed, the inlet valve 6 is opened, the drive system is raised one step, and the next wafer is placed on standby in the loading chamber.

On the other hand, in the platen chamber 15' maintained at a high vacuum with a degree of vacuum of 10-' to 10-'' Torr, the platen is rotated to the process processing position 9, where ion implantation is performed. It is also possible to perform evaporation, sputtering, deposition, and etching.Next, once the prescribed above-mentioned process treatment is completed,
The platen is rotated to the wafer lowering position w10. When the platen rotates, the insertion valve 12 of the unloading chamber 11
The wafer 2' on the platen is moved by sliding it onto the plate of the outlet valve 13 of the unloading chamber.

Here, the wafer that has been moved to the unloading chamber is detected by a proximity sensor 5' installed on the outlet valve.

The detection system here is also the same as the method in the loading room and the platen room. After confirming that the wafer is in a predetermined position on the outlet valve plate, the insertion valve 12 is closed, and at the same time, the platen is rotated and moved to a position on the loading chamber side to receive the wafer.

In the unloading chamber, air is first introduced to lower the degree of vacuum to bring it to a state close to atmospheric pressure, and then the outlet valve 13 is opened.
The processed wafer 2' is received by the exit cassette holder 15. When receiving the wafers, the exit-side vertical feed drive system 14 is raised one step at a time, and the wafers are stored in the same order as in the entrance-side cassette holder. Such a series of transfer operations is performed by moving the next wafer after the previous wafer has been moved and the valve opening/closing operations have been completed. Therefore, during the above-described transfer operation, when the first wafer reaches the unloading chamber, the second wafer that has been waiting is moved onto the platen, and the third wafer is moved onto the platen.
wafers are waiting in the loading room. By repeating the above-described transport operation in sequence, the processing of all wafers is completed.

FIG. 2(a) is a diagram illustrating the wafer detection method in the above-mentioned transfer device, using a wafer stop confirmation state in the AA' cross section of FIG. 1 as a specific example. 2 moves to the loading room 4, the output signal 16 of the proximity sensor 5 shown in FIG.
is from the OFF state 17 to the ON state 18
become. Here, in the wafer detection signal 19, a wafer arrival signal pulse 20 is first applied to confirm the ON state, that is, the arrival of the wafer. After about 5 seconds (delay time).

A wafer stop signal pulse 21 is applied to indicate that the wafer is stopped and present at a predetermined position specified by the stop guide 25 and stopper 26 on the plate of the carry-in valve 7 through the inlet guide 23, and the wafer is turned ON, that is, the presence of the wafer. Check.

When the arrival and presence of such a series of wafers is confirmed, the inlet valve 6 in FIG. 1 is closed in response to the valve close signal 22, and vacuum evacuation is performed. After completing this evacuation, the insertion valve 7 is opened and the wafer 2' is slid onto the platen 8 through the insertion guide 24. Furthermore, when detecting a wafer on the platen, the arrival and presence of the wafer is confirmed using a detection signal pulse provided with a delay time similar to that shown in FIG.

The performance of the proximity sensor shown in the embodiments of FIGS. 1 and 2 can be selected depending on the material characteristics of the target substrate wafer, the sensing distance, etc.

The transport system and the detection system provided with the proximity sensor and delay circuit as described above have the following effects.

FIG. 3 shows an example of a wafer malfunction state to explain this effect. The figure is similar to Figure 2, A-A of the loading room.
'Represents the pattern in cross section. (,) shows the moment when the wafer reaches the plate of the insertion valve, and (b) shows the state in which the wafer bounces onto the end of the plate of the valve and is stopped by the cushion material 28 such as the stopper 26.

Here, the cushion material 28 is generally attached to the tip of the stopper in order to soften the impact when the wafer enters. First, the state (a) is confirmed by the arrival pulse signal 20. Next, the delay time τ
(55ec), when the presence of the wafer is confirmed by the stop pulse signal 21, the proximity sensor output signal 1
6 is in the OFF state, so the valve close signal 22 is not output. Therefore, if the wafer exists in such an abnormal stopping position, the valve will not close, and the wafer will not be caught and destroyed by the valve. Since the sequential feeding process of the wafer transport system is stopped, there is an effect that malfunctions can be prevented.

In addition, in the transfer and detection system of the conventional device, there is no delay circuit, so the valve closes only when the arrival of the wafer is confirmed. A destructive failure has occurred.

As described above, the transport and detection system of the present invention has the advantage that no wafer damage occurs.

Furthermore, since the transport/detection system with a delay circuit using a proximity sensor is also applied to wafer detection on platen 8, it has the effect of completely eliminating the possibility of wafers being destroyed due to rotational movement of the platen, etc. There is.

FIG. 4 is a schematic diagram for explaining a method of detecting movement and passage of a wafer in a conventional transfer device. Same figure (
Similar to FIG. 2, a) shows the pattern in the AA' cross section of the loading chamber. The wafer 2 mounted on the cassette holder 1 slides down into the loading chamber 4 as the vertical feed drive system rises. At this time, the output signal 29 of the infrared sensor 33 installed at the entrance of the loading room is as shown in FIG.
The FF state 30 changes to an ON state 31, and when the wafer has completely passed through, the state changes to an OFF state 32 again. here,
After waiting for the OFF state 32 when the wafer has completely passed, a valve close signal pulse 34 is applied to close the inlet valve 6. However, even if the wafer completely passes through the infrared sensor, the wafer may stop midway on the insertion valve plate due to the relationship such as the coefficient of friction between the wafer material and the insertion valve plate material, as shown in the figure. , or it may still be in the process of slipping away. Even under such conditions, the opening and closing operations of the inlet valve proceed in the conventional device, resulting in an accident in which the wafer was caught between the valves and destroyed. Wafer damage can be completely eliminated. That is, in a series of electrical transmission processes for confirming the arrival and presence of wafers, it is possible to completely prevent accidents caused by malfunctions as described above.

〔Effect of the invention〕

According to the present invention, since the stoppage or presence of the substrate carrier is detected by the proximity sensor, there is an effect that even a colorless transparent substrate that completely transmits light can be detected and transported.

Furthermore, the state of the substrate wafer after it has been moved can be confirmed by a mechanism equipped with a delay circuit to confirm its arrival and presence at the specified position. This has the effect of completely eliminating malfunctions such as wafer damage caused by opening/closing operations.

Additionally, after detecting the presence of a wafer at a specified location,
Since the opening/closing operation of the vacuum valve, process processing, and sequential feeding movement are performed, there is an effect that no malfunction occurs in wafer transport.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view of a main part of a wafer transfer device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA' in FIG. Signal timing diagram, Figure 3. FIG. 4 is a cross-sectional view of the loading chamber for explaining how the present invention prevents erroneous wafer detection, and FIG. 4 is a cross-sectional view of the loading chamber and a detection signal timing diagram for explaining wafer damage in a conventional device. 1... Substrate wafer cassette holder, 2... Substrate wafer (2', 2'), 3... Vertical feed drive system, 4
... Loading room, 5... Proximity sensor (5', 5")
, 6... Inlet valve, 7... Insertion valve, 8... Substrate holding platen, 9... Processing platen position,
DESCRIPTION OF SYMBOLS 10... Wafer lowering platen position, 11... Unloading chamber, 12... Insertion valve, 13... Outlet valve, 1
4...Vertical feed 1 drive system, 15...Outlet cassette holder, 15'...Platen chamber, 16...Proximity sensor output signal, 17...OFF state, 18...○N state, 19... Wafer detection signal, 2o... Arrival pulse signal, 21... Stop pulse signal, 22... Valve closing signal, 23... Entrance guide, 24... Insertion guide, 25... Stop guide, 26...stopper, 27
... Jumping wafer, 28 ... Cushion material, 2
9... Infrared sensor output signal, 30... OFF state, 31... ON state, 32... OFF state, 33.
...Infrared sensor, 34...Valve close signal pulse. Z1Figure 5.5', s'Ane枦7〕Sir 13
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Claims (1)

[Scope of Claims] 1. In a wafer transfer device that includes a device that holds a plurality of substrate wafers and a device that detects the movement position of the substrate wafers one by one, a proximity sensor is provided in the position detection section, and the movement A wafer transfer device characterized in that a delay time is provided for detecting the front and rear substrate wafers, and position detection is performed multiple times. 2. The wafer transfer device according to claim 1, wherein the substrate wafer is moved by the self-load of the substrate. 3. The wafer transport apparatus according to claims 1 and 2, wherein the transport process sequentially shifts to the next operation after position detection is performed a plurality of times with the delay time set forth above.