JPH09216180A - Semiconductor wafer cassette conveyance system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct high-speed transfer operation with a conveyance device of trackless traveling system by mounting a robot arm where degree of freedom in a mobile robot mechanism, the length of an arm and so on are selected to the minimum according to the mounting height of wafer cassettes at a loader/ unloader in a group of manufacturing equipment. SOLUTION: An arm mechanism of horizontal articulated type is used. A robot base 10 is fixed on a dolly 2, on which a vertical motion mechanism 11 is installed. The first arm 12 which has rotational axis parallel to a vertical motion axis, is connected with the vertical motion mechanism 11. The second arm 13 which has a rotational axis parallel to the first arm 12, is connected with the top part of the first arm 12. The top part of the second arm 13 is provided with the third rotational axis which is parallel to the rotational axis of the second arm 13 and a hand mechanism 15 which clamps and releases a cassette 4, is fixed at the third rotational axis. For the transfer mechanism of a conveyance device constituted like this, manufacturing equipment for each process is limited so that the mechanism configuration, degree of freedom, reach, working area and so on may be millimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile robot for supplying / recovering a semiconductor wafer cassette to / from a manufacturing equipment group installed in a semiconductor pre-process.

[0002]

2. Description of the Related Art A semiconductor pre-process is a process for forming various thin film circuit patterns on a silicon wafer, and its manufacturing plant has manufacturing facilities collectively carrying out the same processing for each processing step as shown in FIG. Job shop 100, 100 '
It has a layout with many arranged. The job shop is a clean room, with a central work passage 101,
Manufacturing equipment groups 102, 102 '... Are arranged on both sides of 101'.

The semiconductor wafers 103 are stored in a cassette 4 capable of storing 25 sheets as shown in FIGS. 7 and 8, and supplied / recovered to / from each manufacturing facility. The supply / collection work of the wafer cassette manufacturing equipment in the job shop is generally called in-process transportation. Normally, in this in-process transfer, the attitude of the cassette 4 when it is supplied to the manufacturing equipment requires two attitudes A and B in which the wafer exit position 104 is changed by 90 degrees, as shown in FIGS. And

Regarding the automation of the in-process transportation, conventionally, as shown in FIG. 9, the position and orientation of the three-dimensional space can be uniquely determined so that one transportation device can be applied to all the processes. Degree Vertical Articulated Robot Arm Mechanism 11
0 uses a trackless carrier 130 in which a carrier 111 carrying 0 travels along a guide wire 112 attached on the floor of a clean room, or, as shown in FIG.
A guided vehicle 114 equipped with a simple mechanism pick-and-place unit 113 having about four degrees of freedom uses a tracked carrier device 140 that runs on a fixed rail 115 installed under the floor of a clean room.

[0005]

However, in the prior art, a trackless carrier equipped with a 6-degree-of-freedom vertical articulated robot arm has a low carrier capacity, and four or more carrier vehicles are used in a specific process. Must run 2m × 2
There was a problem that operation was difficult in the working passage of about 0 m.

The low transfer capability is caused by the slow transfer operation of the cassette by the robot arm. In other words, the robot arm needs to reach to some extent in order to cover all of the manufacturing equipment as a transfer target.
Conventionally, for example, the sum of the lengths of the upper arm and the forearm is 800 to 90.
It is set to 0 mm. Since the length of the arm is long, the acceleration and speed cannot be sufficiently increased so as not to apply the extreme vibration (allowable vibration acceleration of 0.3 G or less) to the wafer in the cassette. It was slow.
Also, because of the vertical multi-joint structure, there are two axes (upper arm axis and forearm axis) that are responsible for the gravity load when positioning in three-dimensional space, overcoming the gravity load and performing sufficient vibration control in the high speed range. It was difficult to do, and there was a drawback that the moving speed was slow.

On the other hand, in a tracked type transfer device which is said to have a higher transfer capacity than a trackless type, since the transfer vehicle travels on a fixed rail, it is difficult to reconstruct the rail even if the layout of the process is changed. In addition to not being flexible, there is a problem that if one of a plurality of transport vehicles traveling on a fixed rail fails, it is difficult to remove it and the entire transport system goes down.

It is an object of the present invention to provide a carrier system with a high carrier capacity in a trackless carrier vehicle.

[0009]

In order to achieve the above object, according to the present invention, the mechanism structure, the degree of freedom, the reach, and the operation of the transfer mechanism are adjusted according to the position and the posture of the loader of the manufacturing equipment installed in the process. A transfer system will be constructed in which a robot arm mechanism that determines the range etc. to the minimum is mounted on a trackless transfer vehicle.

According to the above means, the wafer cassette is transferred by the transfer vehicle equipped with the robot arm mechanism having the minimum degree of freedom and the minimum arm length according to the manufacturing apparatus installed in the process. The wafer cassette transfer path is simplified and shortened, the cassette transfer time is shortened, and the transfer capacity is increased. Further, since a trackless carrier is used, there is flexibility in changing the traveling path.

As described above, by using the transfer device according to the present invention, it is possible to realize an in-process transfer system that has a transfer capability and is easy to use. Therefore, automation of in-process transfer is facilitated.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS.

The target manufacturing equipment is limited for each process (job shop), and the transfer mechanism of the transfer device used therein is designed to minimize the mechanical structure, the degree of freedom, the reach, the operating range, and the like. As shown in FIGS. 1 and 2, the arm mechanism 1 is installed in the central portion of the carriage 2 and a maximum of four wafer cassette mounts 3 are mounted around the arm mechanism. As shown in FIG. 2, the wafer cassette 4 is tilted about 45 degrees with respect to the upper surface of the carriage.

As shown in FIG. 2, the arm mechanism 1 is of a horizontal articulated type. The robot base 10 is fixed to the upper surface of the carriage 2, and the vertical movement mechanism 11 is installed on the robot base 10. Although not shown, the drive motor of the vertical movement mechanism 11 is built in the robot base 10 together with the vertical movement mechanism. First arm 1 having a rotation axis parallel to the vertical movement axis
Reference numeral 2 is rotatably connected to the vertical movement mechanism portion, and the drive motor of the first arm is incorporated in the robot base 10 although not shown.

Although the vertical drive mechanism is not shown,
A linear motion mechanism using a ball screw or the like may be used, or a parallel link mechanism may be used, and a horizontal / vertical combined articulated robot arm mechanism may be used in which the vertical mechanism is configured without using the linear motion mechanism.

A second arm 13 having a rotation axis parallel to the first arm is rotatably connected to the tip of the first arm 12. The drive motor 14 of the second arm 13 is fixed on the first arm 12. A third rotation shaft parallel to the second arm rotation shaft is provided at the tip of the second arm 13, and a hand mechanism 15 for gripping and releasing the wafer cassette 4 is fixed to the third rotation shaft. The third rotary shaft drive motor 16 is installed at the rear end of the second arm 13. Hand machine part 1
5 is a parallel opening / closing mechanism for gripping and releasing the cassette 4,
And a posture changing mechanism 17 for rotating the grasped cassette about its central axis.

Details of the hand mechanism 15 will be described with reference to FIG. The power of the motor 21 provided on the hand base 20 is transmitted via the pinion 22 of the motor shaft to the hand base 2
It is transmitted to racks 24 and 24 'fixed to straight guides 23 and 23' provided at 0. The racks 24 and 24 'are connected to the hand arms 25 and 25', respectively.

Lever 26, 26 'are rotatably supported on the hand arms 25, 25', respectively, and rotary shafts 27, 27 'of the levers 26, 26' have a spline structure. It is fitted with 28 '. A spur gear 29 is fixed to the spline bearings 28 and 28 ', and is supported by the hand base 20 by radial bearings 30 and 30'. And the motor 31
Power of the spur gear 29 by the pinion 32 at the motor shaft end.
It is transmitted to.

The levers 26, 26 'are link rods 33, 3
The levers 34, 34 'are rotatably supported by the tip portions of the hand arms 25, 25' via 3 '. Claws 35 and 35 'for holding the cassette 4 are attached to the levers 34 and 34', and the levers 34 and 3 '
The rotation axis of 4'is substantially aligned with the center of the cassette 4. This rotation axis is the attitude conversion axis of the cassette.

With the combination of the arm mechanism and the hand mechanism described above, the wafer cassette is gripped, the other drive shafts are not operated, and the attitude of the cassette is changed by operating only one attitude conversion shaft of the cassette. be able to.

Here, the transfer operation range of the above-mentioned arm mechanism will be examined. FIG. 4 and FIG. 5 are examinations of the length of the arm with respect to the manufacturing equipment considered to require the widest operating range for the arm mechanism.

In FIG. 4, the manufacturing equipment 50 is of a type capable of mounting four cassettes (4, 4 ', 4 ", 4"'), the interval is L, the installation dimension of the cassette is D,
The width of the carriage 2 is W, the gap between the carriage 2 and the manufacturing apparatus 50 is C,
If the lengths of the arms of the arm mechanism 1 are set to a and the second arm, respectively, as shown in FIG. Should be established.

[0023]

[Equation 1]

L = 300 mm, D = 200 mm, W = 600
mm, C = 100 mm, and b = 250 to 300 mm, the arm length a should be about 600 mm. Therefore, compared to the conventional arm length of 800 to 900 mm, 2
It can be shortened by 100 to 300 mm.

As described above, by using the arm mechanism according to the present invention, the length of the arm is 200 to 30.
It can be shortened by about 0 mm. Also, the mechanism structure of the arm is a horizontal joint type, the attitude conversion axis of the cassette is arranged in the hand mechanism section, and it is almost aligned with the center axis of the cassette, so that the transfer operation of the wafer cassette can be simplified, Control becomes simple.

Further, since the degree of freedom of the arm mechanism is reduced and the structure is made into a horizontal joint type, the axis for supporting the gravity load is only one axis of the upper and lower coaxial axes, and the vibration control of the cassette becomes relatively easy, and the movement of the arm is moved. It is possible to speed up the mounting operation and reduce the price of the transfer device main body.

Further, the wafer cassette has a difference in posture of 90 degrees as shown in FIGS. 7 and 8 depending on the manufacturing equipment. However, as shown in FIG. 2, if the inclination of the cassette on the cassette stand of the carriage is 45 degrees, which is the middle of 90 degrees,
In either of the postures, the minimum movement amount is 45 degrees, which also makes it possible to speed up the transfer operation of the arm.

[0028]

According to the present invention, since the transfer operation in the trackless traveling type transfer device can be speeded up, it is possible to realize a transfer system having a high flexibility of the line configuration at the production site and a high transfer capacity. Easy to use, high speed
A highly efficient transfer system can be provided. Further, since the degree of freedom of the arm is also reduced, the price can be reduced, and it can be easily introduced as an automation means, and the automation in the process can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a carrying device according to the present invention.

FIG. 2 is a side view showing an embodiment of a carrying device according to the present invention.

FIG. 3 is an explanatory diagram of an embodiment of a hand mechanism according to the present invention.

FIG. 4 is an explanatory diagram regarding an arm length of the robot arm mechanism according to the present invention.

FIG. 5 is an explanatory diagram regarding an arm length of the robot arm mechanism according to the present invention.

FIG. 6 is a perspective view showing an example of a layout of a semiconductor factory.

FIG. 7 is an explanatory diagram of a posture for supplying the semiconductor wafer cassette to a manufacturing facility.

FIG. 8 is an explanatory diagram of a posture for supplying the semiconductor wafer cassette to a manufacturing facility.

FIG. 9 is an explanatory diagram of a trackless carrier which is a carrier of the related art.

FIG. 10 is an explanatory diagram of a tracked carrier which is a carrier of the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Arm mechanism, 2 ... Cart, 3 ... Cassette stand, 4 ... Wafer cassette, 10 ... Robot base, 11 ... Vertical mechanism, 12 ... 1st arm, 13 ... 2nd arm, 15 ... Hand mechanism, 17 ... Posture conversion Mechanism, 50 ... Manufacturing equipment, 130
... Trackless carrier, 140 ... Tracked carrier.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshiaki Kobayashi, Yoshiaki Kobayashi 5-20-1, Josuihoncho, Kodaira-shi, Tokyo Inside the Semiconductor Division, Hitachi, Ltd. (72) Michiyuki Shimizu 5 Sanmizuhoncho, Kodaira-shi, Tokyo No. 20-1 Stock Company Hitachi Ltd. Semiconductor Division

Claims (6)

[Claims] 1. A mobile robot for supplying / recovering wafer cassettes to / from a manufacturing equipment group installed in a process, depending on the installation height, depth, and attitude of the wafer cassette in a loader / unloader of the manufacturing equipment group. A semiconductor wafer cassette transfer system in which a robot arm, which has the minimum degree of mechanical freedom, arm length, and operating range of a lever, is mounted on a trackless transfer vehicle. 2. The robot arm mechanism is installed at the center of a carriage, and a wafer cassette mounting table is provided around the robot arm mechanism.
The transport system described in. 3. The transfer system according to claim 1, wherein the wafer cassette is mounted at an angle of 45 degrees. 4. The transfer system according to claim 1, wherein a 4-DOF horizontal joint robot is used. 5. The transfer system according to claim 1, wherein a 4-DOF compound articulated robot is used. 6. An automation method for automating the inside of a process by using the transfer system according to claim 1, claim 2, or claim 3.