JP2003170378A - Transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer device capable of easily detecting whether or not an article such as a wafer and a liquid crystal glass is properly held on a hand without impairing the compactness of the hand in the transfer device for transferring the article by the hand while holding the article. <P>SOLUTION: In this transfer device, a first sucking hole 34 for suckingly holding the article 10 and a first air hole 40 connected to the first sucking hole through a through groove 43 are formed in the hand 31. Also a second sucking hole 44 and a second air hole 45 connected to the second sucking hole 44 through a through groove 48 are formed in the hand 31. The first air hole 40 and the second air hole 45 are connected to sucking means 41 and 46. In addition, the device comprises an air detection means 47 for detecting the suction pressure of the sucking means 46 connected to the second air hole 45. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention holds an article (particularly a flat article) in a hand by air suction and transfers it.
The present invention relates to the configuration of a transfer device.

[0002]

2. Description of the Related Art Conventionally, a flat plate-like article (single sheet), for example, a wafer or a glass for liquid crystal is suction-held on a hand, taken out from a cassette storing a wafer or the like, and transferred to an inspection device or a processing device. , Transfer devices are known. In this transfer device, the hand is provided with a suction hole for sucking and holding the article, an air hole connected to the suction means, and a through groove for connecting the air hole and the suction hole. The air is sucked by the suction means to hold the article in the hand.

[0003]

In this configuration, consider a case where a power failure occurs due to some abnormality, for example, in the power supply unit that supplies power to the transfer device while the hand is sucking the article. In this case, the driving of the suction means is also stopped and the suction holding force of the hand with respect to the article is lost. If there is a power failure while the hand is not performing transfer work, it is unlikely that the article will slip with respect to the hand even if the holding power is lost, and the suction means was driven again after the power failure. In this case, since the article is sucked and held again while maintaining the proper position with respect to the hand, the work of adjusting the article to the proper position is unnecessary. On the other hand, if the hand is in the process of being transferred, especially if a power failure occurs while accelerating or stopping while holding the item, the item on which inertial force acts may shift from the hand position. Can be considered enough. In this state, even if the power is restored and the suction means is driven again, the article will be held out of position with respect to the hand, and as it is the cause of the trouble that the article cannot be properly delivered to another device. Becomes Therefore, in this case, it is necessary to return the article to an appropriate position and hold it by the hand.

However, in the conventional transfer device, it was difficult to attach a sensor for detecting whether the article is properly held in the hand to the hand. That is, when a flat article is stored in a cassette or the like, it is customary to store a plurality of stacked articles at a short interval in order to save the storage space, and the article is inserted in such a narrow space. Inevitably, the hand for taking out the sensor was required to have a high degree of compactness, and there was no room to attach the sensor to the hand.

Therefore, it has not been possible to automatically confirm whether the article is held at the proper position in the hand or whether the article is held at the improper position due to a deviation when a power failure occurs. After all, in such a case, the operator goes to the transfer device, moves the hand to a position where it can be seen, and then confirms whether or not the article is held at the proper position on the hand. There was no choice but to do this confirmation work was extremely complicated.

The present invention has been made in view of this point, and an object of the present invention is to determine whether or not an article such as a wafer or glass for liquid crystal is properly held in the hand without impairing the compactness of the hand. An object is to provide a transfer device that can be easily detected.

[0007]

The problem to be solved by the present invention is as described above, and the means for solving this problem will be described below.

That is, in claim 1, there is provided a transfer device for transferring an article while holding it by a hand, wherein the hand has a first suction hole for sucking and holding the article.
A first air hole passing through the first suction hole and connected through the groove, and further, a second suction hole is connected to the hand by the second suction hole and connected through the groove. A second air hole,
The first air hole and the second air hole are respectively connected to the suction means, and the pressure detection means for detecting the suction pressure of the suction means connected to the second air hole is provided.

In the second aspect, the second suction hole is
Formed at a site that is not closed by the article when the article is held in an appropriate position by the hand,
A third suction hole is formed in the hand at a portion closed by the hand when the article is held at an appropriate position by the hand, and the third suction hole is connected to a suction means. The pressure detecting means for detecting the suction pressure is provided.

In the present invention, the third suction hole is connected to the first air hole, and at least a part of the passage groove connecting the first suction hole and the first air hole. However, it is also used as a groove for connecting the third suction hole and the first air hole.

In the fourth aspect, the suction means and the pressure detection means are activated at least when the power supply to the transfer device is stopped and then the power supply is restarted (returned).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the appearance of an automated guided vehicle in a clean room. 2 is a side sectional view of the automatic guided vehicle, and FIG. 3 is a plan view of the same. 4A and 4B are plan views of the wafer. FIG. 4A shows a wafer having an orientation flat formed, and FIG. 4B shows a wafer having a notch.

First, the overall structure of the automatic guided vehicle 1 equipped with the transfer device of the present invention will be described. In the following description, for convenience, the arrow F direction in FIG. 1 will be described as the front.

As shown in FIG. 1, an automated guided vehicle 1 is constructed as a tracked vehicle that automatically travels on traveling rails 20 in a clean room, and a vehicle body 2 is supported by traveling wheels 9 at four front, rear, left and right corners. Then, each traveling wheel 9 is driven by the drive motor 8 (FIG. 2), and the traveling rails 20 and 20 are driven by four-wheel drive.

Processing units 21, 21 ..., Stockers 22 are arranged along the traveling rails 20, 20, and a plurality of cassettes 23, 23. It is set up. Each cassette 23 ・ 23 ・
.. is configured in a box shape, and its opening is placed toward the traveling rails 20 and 20. A shelf for holding the side edge of the wafer 10 is vertically arranged on the inner surface of the cassette 23 sandwiching the opening. A large number of stages are provided at equal intervals in the direction, and the wafers 10, 10, ... Are horizontally placed and stored in each shelf. In this embodiment, the stocker 22 is of a flat type, but instead of this, an automatic system provided with a loading / unloading port for the cassette 23, a large number of shelves, and a stacker crane for transferring the cassette 23 between the shelves and the loading / unloading port. It may be configured in a warehouse.

As shown in FIGS. 2 and 3, the wafers 10, 10, ... Are provided in the center of the body 2 of the automatic guided vehicle 1.
A single-wafer transfer device 3 for transferring the sheet is arranged, and an attitude alignment device 4 and a buffer cassette 5 are arranged in front and back so as to sandwich it. The attitude alignment device 4 is a wafer 10.
Is for aligning the direction and center position of
The buffer cassette 5 is for temporarily storing the wafers 10. The single wafer transfer device 3
Stores the wafers 10 received from the device groups 21 and 22 in a shelf in the buffer cassette 5 temporarily, or takes out the wafers 10 on the shelf in the buffer cassette 5,
The wafer is used for transfer work such as transferring the wafer 10 to the processing device 21 after adjusting the position and the attitude of the wafer 10 by the attitude aligning device 4.

The wafer 10 is formed of a silicon single crystal in a substantially disc shape. Since the crystal of silicon has orientation, means for identifying the direction are formed. For example, as shown in FIG.
0 has an orientation flat (orientation flat) 10a formed by linearly cutting out a part of the outer periphery thereof, or a notch formed by cutting out a part of the outer periphery of the wafer 10 as shown in FIG. 4B. For example, it has 10b. In any case, an ID mark 11 that encodes wafer information such as a wafer manufacturing history is stamped on the peripheral portion on the front surface or the back surface. This ID mark 1
1 is read by an appropriate mark reading device installed in the above-mentioned attitude adjusting device 4, whereby the automated guided vehicle 1 can obtain the information of the wafer.

Next, the transfer device 3 will be described.
As shown in FIGS. 2 and 3, the transfer device 3 includes transfer arms 30M and 30S, a base 38, a turntable 39, and the like. The base 38 is embedded in the center of the vehicle body 2 and can be raised and lowered by an elevator mechanism (not shown). The base 38
A turntable 39 is rotatably attached to the upper surface,
A pair of transfer arms 30M.3 are mounted on the turntable 39.
0S is attached.

The transfer arm 30M (30S) is a scalar arm type robot hand in which a transfer mechanism 31, a first arm 32 and a second arm 33 are assembled into a link mechanism, and a servo (not shown) is provided. It is configured to expand and contract by a motor.

The transfer hand 31 is formed in a flat plate shape,
The bifurcated tip has suction holes 34.3, respectively.
4 is provided and is configured to be sucked by a vacuum pump and to suck and hold the wafer 10, which is an article, on the transfer hand 31. This detailed configuration will be described in detail.

A mapping sensor 35 is attached to one transfer arm 30M at the end of the transfer hand 31 opposite to the suction holes 34. The mapping sensor 35 has a "V" shape in plan view with a forked end, and the photoelectric sensor 35a, 35a is provided at the tip. With this configuration, the base 38 is raised to bend and move the transfer arm 30M to bring the mapping sensor 35 close to the buffer cassette 5, and then the base 38 is lowered while the photoelectric sensors 35a and 35a are used for buffering. Cassette 5
By detecting each of the shelves, it is possible to detect whether or not the wafer 10 is placed on each of the shelves.

Next, the structure of the transfer hand 31 of the present invention will be described. FIG. 5 is a perspective view of the transfer hand, and FIG. 6 is a perspective view illustrating wafer position detection in the transfer hand.

The transfer hand 31 is formed in the shape of a rectangular flat plate, one side in the longitudinal direction (the tip side of the transfer hand 31) is U-shaped, and the tip side is symmetrically bifurcated. It is said that. Then, the wafer 10 is attracted to the upper surface of each of the branched tips to transfer the hand 31.
The suction holes 34, 34 for holding the same are formed. The pair of suction holes 34, 34 correspond to the first suction holes in the present invention.

A first air hole 40 is formed on the upper surface of the transfer hand 31 at a portion located on the opposite side in the longitudinal direction from the side where the suction hole 34 is formed. One end of an air pipe 50 is connected to the first air hole 40.
0 is passed through the inside of the first arm 32 and the second arm 33, and the other end side is a first vacuum pump 41 serving as suction means.
Are connected. A first pressure detection switch 42 is connected to the air pipe 50 so that the suction pressure of the first vacuum pump 41 can be detected. The first pressure detection switch 42 is connected to a control device (not shown) of the automatic guided vehicle 1. It is connected.

A first groove 43 is formed inside the transfer hand 31. The first passage groove 43 is formed in a U shape in a plan view, and the suction holes 34 are connected to both ends of the first passage groove 43, and the first air holes 40 are connected to the middle portion thereof. With this configuration, the first passage groove 43 allows the single first air hole 40 and the two suction holes 34 to communicate with each other.

Further, a pair of misalignment detecting holes 44, 44 are formed in the middle of the transfer hand 31 in the longitudinal direction. The misalignment detection holes 44, 44 are provided in the transfer hand 31.
It is provided at a position that does not overlap with the wafer 10 in a plan view when the wafer 10 is held at an appropriate position on the top. However, the position where the position shift detection holes 44, 44 are formed is close to the outline of the wafer 10 held at the proper position. This misalignment detection hole 44
Corresponds to the third suction hole in the present invention.

On the other hand, a second air hole 45 is provided in the transfer hand 31 at a position near the first air hole 40. One end of an air pipe 51 is connected to the second air hole 45, the air pipe 51 is passed through the inside of the first arm 32 and the second arm 33, and the other end side thereof is connected with a vacuum pump 46 as a suction means. To be done. A second pressure detection switch 47 is connected to the air pipe 51 so that the suction pressure of the vacuum pump 46 can be detected, and the second pressure detection switch 47 is connected to a control device (not shown) of the automatic guided vehicle 1. ing. The vacuum pump 46 is not always driven, and is used only when detecting the position of the wafer 10 after a power failure or the like, as will be described later.

A second groove 48 is formed inside the transfer hand 31. The second passage groove 48 is formed in a U shape in a plan view, and is arranged in parallel to and inside the first passage groove 43. The position deviation detection holes 44, 44 are connected to both ends of the second passage groove 48, and the second air hole 45 is connected to a middle portion thereof. With this configuration, the second passage groove 48 connects the single second air hole 45 and the two positional deviation detection holes 44, 44 to each other.

Further, a pair of position deviation confirming holes 49, 49 are formed in the middle of the transfer hand 31 in the longitudinal direction. The positional deviation confirmation holes 49, 49 are provided in the transfer hand 31.
The wafer 10 is provided at a position overlapping with the wafer 10 in plan view when the wafer 10 is held at an appropriate position. However, the position where the position shift confirmation holes 49 are formed is close to the outline of the wafer 10 held at the proper position. This misalignment confirmation hole 49/49
Corresponds to the second suction hole in the present invention.

The position deviation confirmation holes 49, 49 are communicated with the middle portion of the first passage groove 43, and the first air hole 4
It is connected to 0. In other words, the suction holes 34
It means that a part of the first passage groove 43 that connects the first air hole 40 with the first air hole 40 is also used as a passage groove that connects the positional deviation confirmation hole 49 and the first air hole 40.

The operation of the above configuration will be described with reference to FIG. The position A of the wafer 10 shown by the solid line in FIG. 6 is the proper holding position of the wafer 10 on the transfer hand 31. Normally, the wafer 10 is placed at this position, the first vacuum pump 41 is driven to generate a vacuum, and the vacuum is sucked and held by the suction holes 34. In this state, the transfer operation by the transfer device 3 is performed. . When the wafer 10 is held by the transfer hand 31 at the proper position A, the position deviation confirmation holes 49 of the transfer hand 31 are closed by the wafer 10 as shown in FIG. Deviation detection hole 4
4.44 is not closed.

In this configuration, let us consider a case where a power failure occurs in the power supply section for supplying power to the transfer device 3, for example, while the wafer 10 is being sucked by the transfer hand 31, and a power failure occurs. In this case, the power supply to the first vacuum pump 41 is also cut off, and the wafer 10 of the transfer hand 31 is cut off.
The adsorption and holding power for will be lost. Here, if a power failure occurs when the transfer hand 31 is not performing a transfer operation, the wafer 10 is displaced from the proper position A with respect to the transfer hand 31 even if the holding force is lost. When the first vacuum pump 41 is driven again after recovering from the power failure, the wafer 10 is sucked and held again while maintaining the proper position with respect to the transfer hand 31. When recovering from a power failure, the work of adjusting the wafer 10 to an appropriate position is unnecessary. On the other hand, when the transfer hand 31 is just in the middle of the transfer operation, and especially when a power failure occurs while accelerating or stopping while holding the wafer 10, the wafer 10 on which the inertial force acts is transferred. It is quite possible that the hand 31 is out of position. In this state, even after the power is restored and the first vacuum pump 41 is driven again, the wafer 10 is moved to the position (for example, the position B or the position C) deviated from the proper position as shown by the chain line. If the wafer 10 is held as it is, it may cause a trouble that the wafer 10 cannot be properly delivered to another device. Therefore, in this case, it is necessary to return the wafer 10 to an appropriate position and hold it by the transfer hand 31.

In the present embodiment, whether or not the position of the wafer 10 is at the proper position A is detected as follows. Power is supplied after recovery from a power failure. Then,
The controller of the transfer device 3 that has detected the power failure detects the re-supply of electric power, first drives the two vacuum pumps 41 and 46, and checks the pressure detected by the two pressure detection switches 42 and 47.

If the position of the wafer 10 is at the proper position A,
The positional deviation confirmation hole 49 is closed by the wafer 10 (as a matter of course, the suction hole 34 is closed), and the first pressure detection switch 42 becomes a vacuum pressure. On the other hand, since the position shift detection hole 44 is opened, the second pressure detection switch 42 detects the atmospheric pressure.

On the other hand, when the position of the wafer 10 is at the position B which is displaced forward, both the displacement confirmation hole 49 and the displacement detection hole 44 are opened, so that the two pressure detection switches 42 and 47 are both large. The atmospheric pressure will be detected.

On the other hand, when the position of the wafer 10 is at the position C which is displaced backward, the position deviation confirmation hole 49 and the position deviation detection hole 44 are closed, so that the two pressure detection switches 42.
All 47 detect the vacuum pressure.

Therefore, after returning from the power failure, the control device checks the pressures respectively detected by the two pressure detection switches 42 and 47, the first pressure detection switch 42 detects the vacuum pressure, and the second pressure detection switch 47. By detecting the atmospheric pressure, it is determined that the wafer 10 is not displaced from the proper position A. On the other hand, the above two pressure detection switches 4
If the combination of the detected values of 2.47 is other than those described above, it is determined that the position shift of the wafer 10 has occurred.

The control device of the transfer device 3 is capable of exchanging signals with the controller of the automated guided vehicle system, so that a signal such as whether or not the positional deviation of the wafer 10 has occurred can be transmitted to the controller. It has become.
The controller is configured so that the operator can be notified by a notification means such as a lamp or a buzzer that the position shift of the wafer 10 has occurred in the automated guided vehicle 1. Therefore, when the power is restored from the power failure as described above, the operator does not have to visually inspect whether or not the wafer 10 is held at the proper position each time. Only when the operator is notified by the controller that the positional deviation of the wafer 10 has occurred, it is sufficient for the operator to go to the location of the automatic guided vehicle 1 and adjust the position of the wafer 10. Therefore, the transfer operation of the transfer device 3 can be restarted earlier than when the operator visually inspects each time a power failure occurs. As a result, the automated guided vehicle system can be operated more efficiently.

Although the first air hole 40 and the second air hole 45 are connected by separate vacuum pumps in this embodiment, they may be connected by a common vacuum pump. For example, from the vacuum pump 41 through the valve to the second air hole 4
5 may be connected, and the valve may be opened when confirming the positional deviation of the wafer 10 due to a power failure or the like.
Further, in this embodiment, the vacuum pump 41.
Although 46 is used, it is not limited to a vacuum pump,
For example, other suction means such as a vacuum ejector may be used. Further, in this embodiment, the confirmation of the positional deviation of the wafer 10 is
Although it is a special case such as a power failure, it may be checked every time the wafer 10 is placed, or may be checked all the time.

Note that, in reality, the other device (the processing device 21) to which the wafer 10 is transferred by the transfer hand 31.
Etc. allow a slight error in the delivery position of the wafer 10, so the opening positions of the position deviation detection hole 44 and the position deviation confirmation hole 49 are adjusted in consideration of the allowable range. As a result, even if the wafer 10 is not strictly located at the proper position A, as long as it is located within a certain range (a range corresponding to the allowable range) centered on the proper position 10, the control device Judges that there is no positional deviation and does not notify the operator of the necessity of adjusting the position of the wafer 10.

[0041]

Since the present invention is constructed as described above,
The following effects are achieved.

That is, as described in claim 1, there is provided a transfer device for transferring an article while holding it by a hand, wherein the hand has a first suction hole for sucking and holding the article.
A first air hole passing through the first suction hole and connected through the groove, and further, a second suction hole is connected to the hand by the second suction hole and connected through the groove. A second air hole,
Is formed, the first air hole and the second air hole are respectively connected to the suction means, and the pressure detection means for detecting the suction pressure of the suction means connected to the second air hole is provided, so that the article is Whether or not it is in the proper position on the hand can be determined by detecting the suction pressure of the second suction hole by the pressure detection means without visually observing it, so that the operator is not frequently forced to perform visual confirmation work. . Further, since the air pressure for adsorbing the article is used to determine whether or not the article is in the proper position on the hand, the compactness of the hand can be reduced as compared with the configuration in which a special sensor is provided on the hand. It is good.

As described in claim 2, the second suction hole is
Formed at a site that is not closed by the article when the article is held in an appropriate position by the hand,
A third suction hole is formed in the hand at a portion closed by the hand when the article is held at an appropriate position by the hand, and the third suction hole is connected to a suction means. Since the pressure detection means for detecting the suction pressure is provided, the second suction hole is opened when the article deviates from the proper position to one side, and the third suction hole is closed when the article deviates to the other side. By detecting this by the pressure detecting means, even if the article is displaced in any direction, the displacement can be accurately detected.

According to a third aspect of the present invention, the third suction hole is connected to the first air hole, and at least one of the passage grooves connecting the first suction hole and the first air hole is connected. Since the portion is also used as a through groove that connects the third suction hole and the first air hole, the structure of the through groove can be simplified and the manufacturing cost can be reduced.

As described in claim 4, since the suction means and the pressure detection means are activated at least when the power supply to the transfer device is stopped and then the power supply is restarted (returned), the suction means is provided. After the held article is no longer held due to a power failure, when power is restarted and the article is again held by the suction means, a positional deviation easily occurs, but this positional deviation can be detected by the detection means. . For this reason, when the power supply is restored after a power failure, the detecting device detects the positional deviation of the article, thereby eliminating the need for the operator's visual confirmation work, which was conventionally necessary, and restarting the transfer work of the transfer device earlier. Can be made.

[Brief description of drawings]

FIG. 1 is a perspective view showing an automated guided vehicle in a clean room.

FIG. 2 is a side sectional view of an automated guided vehicle.

FIG. 3 is a plan view of the same.

FIG. 4 is a plan view of a wafer. (A) shows a wafer having a configuration in which an orientation flat is formed, and (b) shows a wafer having a notch.

FIG. 5 is a perspective view of a transfer hand.

FIG. 6 is a perspective view for explaining the detection of the position of the wafer in the transfer hand.

[Explanation of symbols]

3 Transfer device 10 Wafer (article) 31 Transfer Hand 34 Adsorption hole (first suction hole) 40 First air hole 41 First vacuum pump (suction means) 42 First pressure detection switch (pressure detection means) 43 street ditch 44 Position deviation detection hole (second suction hole) 45 Second air hole 46 Second vacuum pump (suction means) 47 Second pressure detection switch (pressure detection means) 48 street ditch 49 Misalignment confirmation hole (3rd suction hole)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroki Fujita             Murata Machine, 136 Takeda Mukoyo-cho, Fushimi-ku, Kyoto             Machine Co., Ltd. Headquarters factory F-term (reference) 3C007 AS05 AS24 BS15 CS08 DS01                       ES17 FS01 FU04 KS05 KV15                       KX08 NS13                 5F031 CA02 CA05 FA01 FA02 FA07                       FA11 GA08 GA36 JA10 JA17                       JA22 JA27 JA47 JA51 PA02                       PA08

Claims (4)

[Claims] 1. A transfer device for transferring an article while holding it by a hand, wherein the hand has a first suction hole for sucking and holding the article, and a groove passing through the first suction hole. A first air hole connected via the second suction hole and a second air hole connected to the second suction hole via a groove are formed in the hand. The first air hole and the second air hole are respectively connected to the suction means, and pressure detection means for detecting the suction pressure of the suction means connected to the second air hole is provided. Mounting device. 2. The second suction hole is formed in a portion that is not closed by the hand when the article is held in the proper position by the hand, and the hand is held in the proper position by the hand. In the case where the hand is closed by the article, a third suction hole is formed in the hand, the third suction hole is connected to suction means, and pressure detection means for detecting suction pressure of the suction means is provided. The transfer device according to claim 1, wherein: 3. The third suction hole is connected to the first air hole, and at least a part of the passage groove connecting the first suction hole and the first air hole is the first groove. The transfer device according to claim 2, which is also used as a groove for connecting the three suction holes and the first air hole. 4. The suction means and the pressure detection means operate at least when power supply to the transfer device is stopped and then power supply is restarted (restored). The transfer device according to claim 3.