JPH0482691A - Arm type conveying device - Google Patents

Abstract

PURPOSE:To easily recognize the deformation of a cantilever-like conveying arm that is prone to deformation with a few contact by providing a sensor for optically detecting the distance from a reference plane parallel to a conveying plane to the conveying arm. CONSTITUTION:The distance from a reference plane parallel to a conveying plane to a conveying arm 10 is optically detected by a sensor 50. When the detected distance is within an allowable value, it is verified that an object to be conveyed (for example, wafer) can be conveyed parallelly on a regular conveying plane L. On the other hand, when the detected distance exceeds the allowable value, it is easily understood that it can cause conveying troubles, and thus the conveying troubles can be prevented. Further, since the distance from the reference plane to the conveying arm is optically detected by the sensor 50, the deformation of the conveying arm can be detected in non-contact manner.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an arm-type transport device.

(Prior Art) For example, in a semiconductor manufacturing process, when transporting a semiconductor wafer as an object to be processed, a multi-articulated arm or the like is used, one end connected to a drive unit is driven horizontally or rotationally, and the free end is A semiconductor wafer supported on a wafer is transported horizontally.

As this type of transfer arm, Japanese Patent Application Laid-Open No. 54-10976
82-IE11807. fll-278149,62-
150735, 62-21644, 60-120520
, 60-183736, 62-21849, 62-16
1H8, 61-99345゜1-99344.6l-9
09Ll, 61-90887, 61-87351
, 61-71! It is disclosed in No. 188B2-41129 and the like and is publicly known.

(Problem to be Solved by the Invention) This type of transport arm has a cantilever shape that supports the transported object on its free end side, so it can be easily transported by contacting the transport arm during maintenance, for example. There was a risk that the arm would become deformed.

If the transported object is transported using a transport arm that has been deformed in this way, the handling condition of the transported object may deteriorate, and the receiving surface of the transported object may be misaligned when it is transferred.
This caused transportation problems. In particular, when carrying wafers into and out of a wafer cassette, problems such as the wafers colliding with the cassette have occurred because the wafers housed in the cassette have a narrow arrangement pitch.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an arm-type transfer device that allows easy monitoring of deformation of a transfer arm.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an arm-type transport device that supports and transports a transported object on the free end side of a cantilevered transport arm. The present invention is characterized in that a sensor is provided for optically detecting the distance from the plane to the transport arm.

(Function) In the present invention, the distance from the reference plane parallel to the conveyance plane to the conveyance arm is optically detected. If the detected distance is within a tolerance value, the distance from the reference plane parallel to the conveyance plane is detected. It is confirmed that objects to be transported can be transported in parallel. On the other hand, if the permissible value is exceeded, it can be easily understood that it will cause transportation troubles, and transportation troubles can be prevented from occurring. Moreover, since the distance is detected optically, it can be detected without contact.

(Example) Hereinafter, an example in which the present invention is applied to a part of a sender of a plasma etching apparatus will be specifically described with reference to the drawings. Since the plasma etching apparatus is well known, a detailed explanation thereof will be omitted, but in this embodiment, it has a load lock chamber that can be evacuated and communicates with a process chamber for etching through a gate. The wafer before processing is carried into the process chamber via the load-lock chamber, and the wafer after processing is carried out to the receiver section via the load-lock chamber.

A portion of the sender is installed in the atmosphere, and is roughly divided into a transfer arm 10. Cassette stage 30. It is composed of a pre-alignment stage 40 and an arm deformation detection sensor 50. In this part of the sender, from a cassette (not shown) placed and fixed on the cassette stage 30,
A semiconductor wafer 1 is taken out by the transfer arm 10, and this wafer 1 is transferred to the pre-alignment stage 4.
After the wafer 1 is installed on the wafer 0 and pre-aligned, the wafer 1 is carried into the chamber by a transfer arm (not shown) on the load lock chamber side.

The transfer arm 10 is bent into an L-shape as shown in FIG.
4 is fixed on the drive side, and has a vacuum suction part 12 on its free end side. As a horizontal drive system for this transfer arm 10,
Two guide shafts 20.20 are installed horizontally on the base 16, and a movable blower 18 is provided which is movably guided in the horizontal direction by these two guide shafts 20.20.

The fixed portion 14 of the transport arm 10 is fixed to this movable block 18. The movable block 18
At two locations below and separated by a distance on the base 16,
Pulleys 22, 22 are rotatably supported. A belt 24 is stretched around each of the pulleys 22, 22, and one part of the belt 24 is attached to the movable block 18.
is fixed. Therefore, by rotationally driving one of the pulleys 22, the belt 24 is moved in its horizontal direction, and as a result, the transport arm 10 can be moved horizontally in the direction of the arrow X in FIG. 1 via the movable block 18. .

The cassette stage 30 holds and fixes a cassette (not shown) containing a plurality of semiconductor wafers 1, and is movable in the vertical direction by driving a vertical movement drive section 32 provided below. A cassette (not shown) supports wafers 1 arranged in a horizontal state at predetermined intervals in the height direction, and when taking out any wafer 1 from the cassette, it is moved by the vertical movement drive unit 32. What is necessary is to move the cassette in the vertical direction and set it at a position where the vacuum suction section 12 of the transfer arm 10 can be inserted below the wafer 1 to be taken out.

The pre-alignment stage 40 has a suction rotating section 42 in its center that can vacuum suction the wafer 1 and drive it rotationally. This suction rotation unit 42 is movable in the vertical direction to support the wafer 1. For example, three lift turbines 44 are provided around the suction rotating section 42 . This lift turbine 44 is movable in the vertical direction independently of the suction rotation section 42 . As shown in FIG. 5, a non-metallic noise prevention pin 46 made of, for example, Teflon (registered trademark) is fixed to the tip of the lift turbine 44 that comes into contact with the back surface of the wafer 1. A sensor arm 48 is provided adjacent to the suction rotating section 42, and this sensor arm 48
It is movable in the direction of the arrow X axis in the figure. Then, the wafer 1 is mounted and fixed on the suction rotating section 42, and the wafer 1 is
While rotating and driving the wafer 1, pre-alignment of the wafer 1 is possible by a sensor (not shown) provided on the sensor arm 48.

As a characteristic feature of the apparatus of this embodiment, an arm deformation detection sensor 50 is provided near the pre-alignment stage 40 and below the vacuum suction section 12 of the transfer arm 10.

As shown in FIG. 4(A), this arm deformation detection sensor 50 has two
First place. It has a second sensor 52.54.

This first. The second sensors 52 and 54 are both formed by small spot limited reflection type photoelectric switches. This photoelectric switch has a diameter of 0.8 m + w from an infrared light emitting diode.
It emits infrared rays, and only when it is reflected within the detection range at a distance of about 10+sm from the emission surface, the switch is turned OFF and turned ON outside the detection range.

The arm detection sensor of this device is composed of two of these photoelectric switches, each having a different distance from the transport arm 10, and their detection ranges partially overlapping.

As shown in FIG. 4(C), the detection range of the first sensor far from the transfer arm is 31ain-3sax,'
Detection of the second sensor near the RI feed arm 8 [S21 is surrounded by
It is n-32Illax. As shown in FIG. 4(B), when the permissible range in the height direction of the vacuum suction part 12 of the transfer arm 10 is set to the upper limit position L + +lower limit position 2, respectively, 5sax of the first sensor is Then, set 82w1n of the second sensor to L2. a first sensor beam;
ONL, 2nd when reflected outside the rotation between ~511in.
The sensor turns on when it is reflected outside the range between L2 and S2■aX, so this first sensor. If either one of the second sensors is ONu, it is when the reflection is outside the range of L1 to L2, that is, when the arm is deformed. 1st
．． The output of the second sensor is input to the sender's CPU (not shown), and if either one is turned on, the device is configured to stop operating. Regarding the operation of the first and second sensors 52, 54, the logic of the switches may be reversed so that when either one is turned off, the operation of the device is stopped.

In this embodiment, a cover 60 is provided that covers substantially the front surface of a portion of the sender. This cover 60 has a cutout for the vertical movement path of a cassette (not shown) placed and fixed on the cassette stage 32, and a cutout for the movement trajectory of the portion where the transfer arm 10 intersects with the cover 60. There is.

This cover 60 has a mesh-like structure on its entire surface in order to accommodate the downflow inside the clean room, so that the downflow can be taken into the sender. This cover 60 is a side panel 6 that covers the side of a part of the sender.
A cover mounting portion 6 is bent almost horizontally at the upper end of 2.
It is removably fixed at 4. The mounting surface of this cover mounting portion 64 is formed of a rubber magnet, for example, and the cover 60 is formed on a surface corresponding to this cover mounting portion 64.
It is possible to adsorb and hold metal parts.

Next, the effect will be explained.

In order to take out one wafer 1 from the cassette in this part of the sender, the cassette stage 30 is first moved in the vertical direction by its vertical movement drive unit 32, and the height position of the wafer 1 to be taken out is adjusted by the transfer arm 10. Set above the horizontal movement plane of Thereafter, one of the pulleys 22 is rotationally driven by a drive source (not shown), and the movable block 18 is horizontally moved along the guide shaft 20.20, thereby moving the transfer arm 10 fixed in one direction with the movable block 18 as shown in FIG. to the right. Then, within the cassette, the vacuum suction section 12 of the transfer arm 10 stops its horizontal movement at a position set below the wafer 1 to be taken out. When the cassette stage 30 is moved downward in this state, one wafer 1 is placed on the vacuum suction section 12, and then by turning on the vacuum, the wafer 1 is suctioned and held by the vacuum suction section 12. I can do it. The wafer 1 can be removed from the cassette by horizontally moving the transfer arm 10 to the left in FIG. The transfer arm 10 □ is stopped when the wafer 1 reaches above the suction rotating section 42 on the pre-alignment stage 40 .

In this pre-alignment stage 40, the lift turbine 44 is first driven upward and moved above the support position of the wafer 1 placed on the vacuum suction section 12 in a vacuum-off state. This wafer 1 can be supported on three lift turbines 44. Thereafter, the rotary suction section 42 is moved upward or the lift turbine 44 is moved downward, and the wafer 1 is placed on the suction rotation section 42, and the vacuum is turned on to suction and hold the wafer 1. In this state, pre-alignment of the wafer 1 becomes possible, and the sensor arm 48 moves in the X-axis direction in FIG. 2, and the pre-alignment of the wafer 1 is executed while rotating the suction rotating section 42. after that,
The sensor arm 48 is retracted, and the lift turbine 44 is raised to support the wafer 1 placed on the suction rotation section 42 on the lift turbine 44. The supporting position of the wafer 1 is set above the wafer transfer line L shown in FIG. Thereafter, a transfer arm (not shown) on the load lock chamber side moves to the sender side, moves below the wafer 1 along the wafer transfer line L, and stops. By moving the lift turbine 44 downward, the wafer 1 can be delivered to the transfer arm on the load lock chamber side. Thereafter, the wafer 1 is carried toward the process chamber by the transfer arm on the load lock chamber side.

Here, in the transport arm 10 that transports the wafer 1, only the fixed part 14 on one end side thereof is connected and fixed to the drive side, and the vacuum suction part 12 side is set as a free end part. Therefore, there is a risk that the transport arm 10 may be easily deformed by contacting the transport arm 10 during maintenance, for example. In this embodiment, such deformation of the transfer arm 10 is detected by the arm deformation detection sensor 50, and if this deformation exceeds a permissible value, the operation of the apparatus is stopped. That is, when the vacuum suction section 12 of the transfer arm 10 stops above the arm deformation detection sensor 50, the first. The second sensor 52,54 is activated. That is, a small spot of light is emitted from the infrared light emitting diode of the first sensor 52, and it is detected whether the transfer arm 10 is within the range of the allowable upper limit position 1 shown in FIG. 4(B). This first sensor 52 is
It is turned ON when the transport arm 10 is located at a position beyond the above-mentioned allowable upper eye position [L].

At the same time, the second sensor 54 operates, and this second sensor 54 similarly detects that the transport arm 10 is at the lower allowable limit rx.
It is detected whether or not it is within the range of t L 2.

This second sensor 54 turns ON when the transport arm 10 is at a position below the allowable lower limit position 2. Therefore, this first. If at least one of the sensors is ONL, the CPU inputting the outputs of the second sensors 52 and 54 can determine that the deformation of the transfer arm 10 exceeds its permissible value. In such a case, the CPU will stop the operation of the entire sender. Such deformation detection of the transport arm 10 may be performed, for example, only at the start of operation after maintenance is completed, or every time the transport arm 10 is stopped above the arm deformation detection sensor 50 by a part of this sender. May be detected.

In this manner, in this embodiment, the degree of deformation of the transport arm 10 can be monitored by the arm deformation detection sensor 50 before it is carried into the cassette. Therefore, by stopping the operation of the apparatus when the degree of deformation exceeds an allowable value, various troubles due to deformation of the transfer arm 10, such as transportation troubles such as collision with the wafer 1, can be prevented. I can do it.

Further, in this embodiment, a noise prevention pin 46 made of non-metallic Teflon or the like is provided at the tip of the lift turbine 44. A part of this sender is set in the atmosphere, and the lift turbine 44
When the pin 44 was constructed of only metal bottles, an abnormal noise was generated every time the pin 44 came into contact with the back surface of the wafer 1. By configuring the distal end side with the noise prevention pin 46 as in this embodiment, generation of unpleasant noise can be reliably reduced.

Furthermore, in this embodiment, the cover 60 that covers almost the entire upper limit side of the sender can be easily attached and detached by contacting or non-contacting the cover mounting portion 64 formed of a rubber magnet on the upper end side of the side panel 62. can.

Conventionally, this type of cover was fixed to the sender device with screws, but the screws had to be attached and removed every time it was maintained, which was not only troublesome, but also caused the generation of dust. This was also a factor in lowering the processing yield. In this embodiment, the cover 60
Since the attachment and detachment can be achieved using magnets, the attachment and detachment work is extremely simple and the generation of dust can be further reduced.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible within the scope of the invention.

The arm deformation detection sensor 50 for detecting the deformation of the transport arm 10 is not limited to the means of the above embodiments, but may be used to optically measure the distance of the transport arm 10 from a reference plane parallel to the transport surface of the transport arm 10. Any sensor that can detect the flatness may be used, and in order to check the flatness, this type of sensor may be arranged at three locations. Furthermore, the present invention is not necessarily applied to a part of a sender, a part of a receiver, etc. that are set under normal pressure, but can be similarly applied to a device that transports a transported object under negative pressure.

[Effects of the Invention] As explained above, according to the present invention, the deformation of a cantilevered transport arm that is easily deformed by slight contact can be detected optically by the distance from the reference plane parallel to the transport surface. This allows for easy recognition, and has the effect of preventing transport troubles caused by deformation of the transport arm.

[Brief explanation of drawings]

FIG. 1 is a schematic front sectional view showing an embodiment in which the present invention is applied to a part of a sender of a plasma processing apparatus, and FIG.
FIG. 3 is a right side view of the device shown in FIG. FIG. 5 is an enlarged view of the upper end portion of the lift turbine. 10...Transport arm, 12...Vacuum suction part, 44
...Lift turbine, 46...Noise prevention pin, 50.
...Arm detection sensor 52...First sensor 54...Second sensor 60...Cover...
- Allowable upper limit position, L2... Allowable lower limit position.

Claims (2)

[Claims] (1) In an arm-type transfer device that supports and transfers an object on the free end side of a cantilevered transfer arm, a sensor is installed to optically detect the distance from a reference plane parallel to the transfer surface to the transfer arm. An arm-type transfer device characterized by the following: (2) In claim (1), the first sensor is activated when the distance to the transport arm exceeds the permissible upper limit, and the second sensor is activated when the distance to the transport arm is below the permissible lower limit. An arm-type transfer device that includes the above sensor.