JP2003168723A - Wafer attitude aligning device and automatic guided vehicle mounted with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer attitude aligning device equipped with a rotating body which rotates a wafer as it holds the wafer by suction, which is capable of keeping a sucked state by shutting off a suction path even if a sucking means is stopped because it sucks up the wafer, keeping airtightness and restraining the wafer from being deformed when it sucks up the wafer. <P>SOLUTION: A wafer attitude aligning device is composed of an annular groove 44 provided to a rotating body 41, O rings 45 and 46 which are different from each other in diameter, brought into contact with the bottom of the annular groove 44, and protrude partially from the annular groove 44, a suction opening 47 opened at the bottom of the annular groove 44, suction paths 48a, 48b, and 48c which are provided inside the rotating body 41 so as to communicate with the suction opening 47, and a suction means which is connected to the suction paths 48a, 48b, and 48c. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the configuration of a wafer alignment device.

[0002]

2. Description of the Related Art An attitude aligning apparatus for rotating a wafer while sucking and holding the wafer to adjust its attitude has been conventionally known.
For example, one mounted on an unmanned transfer vehicle that transfers wafers is known. The general structure of the mounting table in this attitude adjusting device is as shown in FIGS. 7 (a) and 7 (b).
The mounting table 60 is arranged with its axis vertical and rotatable about the axis, and a mounting surface 60a is formed on the upper surface of the circular mounting table, and a suction hole 62 is opened at the center position of the mounting surface 60a. It is what is done. The mounting surface 60a is provided with a large number of concentric suction grooves 64 centered on the opening of the suction hole 62 at appropriate intervals and a large number of suction grooves 65 radially extending from the openings. I have set up. A suction path 63 is formed inside the mounting table 60, one end thereof is connected to the suction hole 62, and the other end is connected to a suction means (not shown) such as a vacuum pump.
In this structure, as shown in FIG.
The suction means is operated in a state where the above is placed on the placement surface 60a to suck the air from the suction holes 62, whereby the placement surface 60
The wafer 10 placed on a is adsorbed and held on the mounting table 60, and the mounting table 60 is rotated so that the wafer 10 is in a predetermined posture while maintaining this state.
The attitude of the wafer 10 is adjusted.

However, in the configuration of such an attitude adjusting device, air is constantly leaked from the suction hole 62 to the suction path 63 side through the gap between the mounting table and the wafer when the wafer 10 is sucked as shown in FIG. 7C. Therefore, in order to maintain the adsorption state, the suction means such as the vacuum pump must be continuously driven. This is not only desirable from the viewpoint of saving power consumption, but the exhaust of the vacuum pump often causes dust to be taken up.
This is inconvenient for an environment such as a clean room, which does not like dust.

In order to solve such a problem, the following structure has been developed and is known. This configuration is shown in FIG.
As shown in (a) and (b), a shallow circular recess 51 (in place of the suction grooves 64 and 65) is formed on the upper surface of the mounting table 41, and a suction port 52 is opened on the bottom surface of the recess 51. While connecting the suction port 52 to the suction path 48 ',
The O-ring 46 is arranged around the suction port 52. The suction path 48 'is provided with a valve (not shown) that can open and close the suction path 48'. In this configuration, when the wafer 10 is placed on the upper surface (mounting surface 41a) of the mounting table 41, the upper end of the O-ring 46 is in contact with the lower surface of the wafer 10, and the wafer 10 and the bottom surface of the recess 51 become. Since the space surrounded by the O-ring 46 is hermetically sealed against the atmosphere, the space can be brought into a low-pressure state close to vacuum by suctioning with the vacuum pump or the like from this state. You can

Due to this hermeticity, the vacuum pump is driven for a predetermined time to bring the space into a low pressure state and then the valve is closed, so that the low pressure state is maintained even after the vacuum pump is stopped (that is, adsorption to the wafer). It is possible to hold the state). Therefore, it is not necessary to constantly drive the vacuum pump, so that electric power can be saved, and exhaust by driving the vacuum pump is also suppressed, so that the dust is prevented from being wound up.

[0006]

However, in this structure, since the internal space of the O-ring 46 is at a low pressure close to vacuum, the wide area at the center of the lower surface of the wafer 10 (area surrounded by the O-ring). Is strongly pulled downward, and the wafer 10 is deformed as shown in FIG. 6C.

[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, an annular groove formed in the rotating body, and two O-rings having different diameters, which are in contact with the bottom surface of the annular groove and project a part thereof from the annular groove, A suction port opened on the bottom surface of the annular groove at a position sandwiched between the two O-rings, a suction path formed inside the rotating body and communicating with the suction port, and a suction connected to the suction path. Means and at least.

According to a second aspect of the present invention, only one suction port is provided, and the suction route includes a first route connected to the suction port and a second route formed in the center inside the rotating body. Is included at least.

According to a third aspect of the present invention, an automatic guided vehicle is provided, which is equipped with the above-mentioned wafer position adjusting device and is also provided with a single wafer transfer device for transferring the wafer.

[0011]

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 automated guided vehicle 1 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 and 20, and a vehicle body 2 is supported by traveling wheels 9 at the four front, rear, left and right corners, respectively. The traveling wheels 9 are 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 ... Are arranged on the stocker 22 at predetermined intervals. 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 body 10 of the automatic guided vehicle 1 has a wafer 10, 10 ...
A transfer device 3 for transferring the ... Is arranged, and an attitude alignment device 4 and a buffer cassette 5 are arranged in front and back so as to sandwich the transfer device 3. 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 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. The ID mark 11 is provided at a position having a certain relationship with the orientation flat 10a, and this relationship is used for the attitude alignment of the wafer 10 by the attitude alignment device 4 described later.

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 link mechanism including a transfer hand 31, a first arm 32 and a second arm 33 is assembled, and a servo (not shown). It is configured to expand and contract by a motor.

The transfer hand 31 is formed in a flat plate shape,
Adsorption holes 34.3 on each of the forked ends
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 attitude adjusting device 4 of the present invention will be described. The attitude adjusting device 4 shown in FIGS. 2 and 3 includes a casing 40, and in the casing 40,
The mounting table 41, the linear sensors 42, 42, an optical character reading device (hereinafter referred to as “OCR”) 43, and the like are housed. The casing 40 is open on the side facing the transfer device 3, and the linear sensors 42, 42 are arranged near the entrance thereof. Each linear sensor 42 includes an upper projector 42a and a lower light receiver 42b. It is composed of a pair. As shown in FIG. 3, one linear sensor 42 is arranged on each of the near side and the far side from the mounting table 41, and the linear sensor 42 on the near side is used to measure the 8-inch wafer (reference numeral 10L shown in FIG. 3). The orientation flat 10a is detected, and the orientation sensor 10a of a 12-inch wafer (reference numeral 10S in the figure) can be detected by the linear sensor 42 on the far side, so that the wafer 10 can have any size of 8 inches / 12 inches. Even if there is, it is possible to adjust the posture.

The OCR 43 is installed in the back of the casing 40, and the information of the ID mark 11 attached to the wafer 10 is read by the OCR 43 and the wafer 10 is read.
It is possible to specify.

Inside the casing 40, a mounting table 41 (rotating body), which is a main component of the present invention, is installed. The mounting table 41 has a horizontal circular mounting surface 41a formed on the upper surface thereof, and is driven and rotated by a driving force transmitted by a motor (not shown). By holding and rotating the wafer 10 on the mounting surface 41 a, the wafer 1
It is possible to adjust the posture to 0. The transfer device 3 is
The transfer hand 31 is inserted into the casing 40 in a state in which the wafer 10 is adsorbed, and the wafer 10 is mounted slightly above the mounting surface 41a of the mounting table 41 and at the center of the wafer 10. When the center of the surface 41a reaches a position where the centers of the surfaces 41a coincide with each other, the transfer hand 31 releases the suction of the wafer 10 and mounts the wafer 10 on the mounting surface 41a. In this state, by driving a vacuum pump (suction means) connected to the mounting table 41, the wafer 10 is suction-held on the mounting surface 41a, and when the mounting table 41 is rotated, the wafer 10 is also integrated. It is designed to rotate. The suction means is not limited to the vacuum pump, but may be another suction device such as a vacuum ejector.

The wafer 10 is placed on the mounting surface 41a of the mounting table 41.
When the wafer 10 is sucked and held, the outer peripheral edge of the wafer 10 corresponds to the corresponding sensor 42 (a linear sensor far from the mounting table 41 when the wafer 10 is 12 inches, and from the mounting table 41 when the wafer 10 is 8 inches). It is detected by the linear sensor on the near side. Therefore, when the mounting table 41 is rotated,
The orientation flat 10a of the wafer 10 is detected by the linear sensor 42 in a certain rotation phase. The linear sensor 42 is connected to an appropriate controller together with an appropriate sensor that detects the rotation phase of the mounting table 41, and the controller is connected to the linear sensor 42.
On the basis of the rotation phase of the mounting table 41 when the orientation flat 10a is detected,
The rotation phase of the mounting table 41 necessary to position it in the readable area of the CR 43 is calculated, and the mounting table 41 is rotated by driving the motor so that the obtained rotation phase is obtained. , The ID mark 11 is the O
Adjust so that it is located in the readable area of CR43.

Next, a structure for adsorbing the wafer 10 to the mounting table 41, which is an essential part of the present invention, will be described. 5A and 5B are views showing the configuration of the mounting table, FIG. 5A is a plan view, FIG. 5B is a side sectional view, and FIG. 5C is a side sectional view showing a state where a wafer is sucked. FIG. 6 is a diagram showing a configuration of a conventional mounting table,
Similar to FIG. 5, (a) is a plan view, (b) is a side sectional view,
(C) is a side sectional view showing a state where a wafer is sucked.

As shown in FIG. 5, an annular groove 44 having an appropriate depth is formed on the mounting surface 41a on the upper surface of the mounting table 41.
The center of the formation position of the annular groove 44 is the mounting surface 41 described above.
The position coincides with the center of a. A first O-ring 45 is arranged on the inner edge of the annular groove 44, and a second O-ring 46 having a larger diameter than the first O-ring 45 is arranged on the outer edge. . Both of the O-rings 45 and 46 are arranged such that a part of the upper portion thereof protrudes above the annular groove 44.

As shown in FIG. 5A, only one suction port 47 is opened on the bottom surface of the annular groove 4 at a position sandwiched by the two O-rings 45 and 46 in plan view. This suction port 4
As shown in FIG. 5 (b), a first path 48 a bored inside the mounting table 41 is connected to 7. The first route 4
8a is constituted by a vertical hole 49 extending downward from the suction port 47 in parallel with the rotation axis of the mounting table 41, and a horizontal hole 50 formed from the lower end of the vertical hole 49 toward the rotation axis. It The reason why only one suction port 47 is provided is that the suction path connected thereto can be simplified and the mounting table 41 can be easily manufactured. Further, since the ring-shaped lecture 44 and the suction port 47 are small, the suction port 4
Even if a plurality of 7 are provided, the effect of suppressing uneven suction is not so great.
In addition, if a plurality of suction ports 47 are provided, it is necessary to receive a plurality of first paths 48a according to the number, and the space that must be evacuated increases with the number of suction ports 47, and the suction paths are evacuated. There is a problem that it takes more time.
That is, by providing only one suction port 47, the suction path can be simplified and the suction path can be evacuated in the shortest time.

The first path 48a passes through the connecting portion 48b,
It is connected to the second path 48c and further connected to a vacuum pump (not shown) as a suction means via a valve not shown. The connection portion 48b is located on the rotation axis of the mounting table 41, and the second path 48c extends downward along the rotation axis of the mounting table 41. Since the second path 48c is formed along the rotation axis of the mounting table 41, suction means such as a vacuum pump can be easily connected.

When the wafer 10 is placed on the placing surface 41a in the above configuration, the upper ends of both O-rings 45 and 46 are in contact with the lower surface of the wafer 10 as shown in FIG. 5C. A space A surrounded by the lower surface of the wafer 10, the bottom surface of the annular groove 44, and the O-rings 45 and 46.
Will be hermetically sealed to the atmosphere.
By sucking with the vacuum pump from this state, the air in the space A is exhausted by the vacuum pump through the suction path, and the space can be brought into a low-pressure state close to vacuum.

Due to the above-mentioned hermeticity, the vacuum pump is driven for a predetermined time to bring the space A into a low pressure state, and then the valve is closed to shut off the suction path (the second path 48c). Space A after stopping
The low pressure state (that is, the suction state with respect to the wafer 10) can be maintained. Therefore, it is not necessary to constantly drive the vacuum pump, which saves power and
Exhaust due to the driving of the vacuum pump is also suppressed, and winding of dust is also suppressed.

A circular concave portion 51 is formed on the mounting surface 41a, an O-ring 46 is arranged on the outer edge of the circular concave portion 51, and a suction port 52 is opened on the bottom surface of the concave portion 51 to connect a suction path 48 '. A conventional configuration for sucking air from the suction path 48 'is shown in FIGS. 6 (a) and 6 (b). With this configuration, since the central position of the wafer 10 is sucked in the wide circular area B (FIG. 6C), there is a problem that the wafer 10 is largely deformed as shown in FIG. 6C. However, in the present invention, since the region for sucking the wafer 10 (the space A shown in FIG. 5C) is annular, such deformation of the wafer 10 can be effectively avoided.

However, in the configuration of FIG.
A small circular recess is further formed at a portion inside the annular groove 44 of a (that is, an inner region surrounded by the first O-ring 45), and a third O-ring is arranged on the peripheral edge of the recess. A configuration in which the suction path is connected to the bottom of the recess is also possible.

[0033]

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

That is, as described in claim 1, an annular groove formed in the rotating body, and two O-rings having different diameters that come into contact with the bottom surface of the annular groove and project a part thereof from the annular groove. , A suction port opened on the bottom surface of the annular groove at a position sandwiched between the two O-rings, a suction path formed inside the rotating body and communicating with the suction port, and connected to the suction path Since at least the suction means is included, the groove connected to the suction path has an annular shape, and the area for sucking the wafer has an annular shape. Therefore, a strong suction force close to vacuum acts. However, the deformation of the wafer is effectively avoided.

According to a second aspect of the present invention, only one suction port is provided, and the suction route includes a first route connected to the suction port and a second route formed in the center inside the rotating body. Since it is configured to include at least and, the suction path can be simplified. Further, as compared with the case where a plurality of suction ports are provided, the number of the first paths connected is smaller, so that the space to be evacuated is smaller and the suction path can be evacuated in a shorter time. Moreover, since the second path is formed along the rotation axis of the mounting table, a suction means such as a vacuum pump can be easily connected.

According to a third aspect of the present invention, the wafer position adjusting device is mounted and the single wafer transfer device for transferring the wafer is provided to form an automatic guided vehicle. Since an excellent posture alignment device and a single-wafer transfer device for wafer transfer are provided, it is possible to provide an automated guided vehicle having excellent functions as a whole.

[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.

5A and 5B are views showing a configuration of a mounting table, FIG. 5A is a plan view, FIG. 5B is a side sectional view, and FIG. 5C is a side sectional view showing a state where a wafer is sucked.

6A and 6B are views showing a configuration of a conventional mounting table, like FIG. 5, FIG. 6A is a plan view, FIG. 6B is a side sectional view, and FIG. 6C is a side sectional view showing a state where a wafer is sucked. Is.

7A and 7B are views showing a configuration of a conventional mounting table, FIG. 7A is a plan view, FIG. 7B is a side sectional view, and FIG. 7C is a side sectional view showing a state where a wafer is sucked.

[Explanation of symbols]

1 Automated guided vehicle 4 Positioning device 41 Mounting table (rotating body) 44 annular groove 45 First O-ring 46 Second O-ring 47 Suction port 48a First route 48b connection 48c Second route

Claims (3)

[Claims] 1. An apparatus for aligning a wafer, comprising a rotating body that rotates while sucking and holding a wafer, comprising: an annular groove formed in the rotating body; and a bottom surface of the annular groove that is in contact with the annular groove. Two O-rings having different diameters, a part of which protrudes from the annular groove, a suction port opened at the bottom of the annular groove at a position sandwiched by the two O-rings, and formed inside the rotating body. A wafer attitude aligning device including at least a suction path communicating with the suction port and a suction unit connected to the suction path. 2. The suction port is provided only one, and the suction route includes at least a first route connected to the suction port and a second route formed in the center inside the rotating body. The wafer orientation alignment apparatus according to claim 1, which is configured by: 3. An automated guided vehicle, comprising the wafer alignment device according to claim 1 or 2 and a single wafer transfer device for transferring the wafer.