JPH0529435A - Transferring apparatus - Google Patents

Abstract

PURPOSE:To surely perform a sealing operation by reducing a torque loss, to make a motor small-sized, to make an apparatus small-sized and to make the life of a seal long. CONSTITUTION:The title apparatus is provided with the following: one pair of first arms which a turn around two of first support shafts 20, 20 which are arranged to be separated on a base stand which can turn horizontally; one pair of second arms which turn around second support shafts which are installed in end parts of the pair of first arms; and the support part, of an object to be transferred, on which two of third support shafts which support end parts of the pair of second arms so as to turn freely have been formed. One pair of parallel cranks which turn the second support shafts by working in conjunction with the first support shafts 20, 20 are arranged and installed between the two of the second support shafts. A magnetic fluid seal 96 is installed in the upper position than upper-part bearing part 84, 86, 90 for five shafts, i.e., the shaft of the base stand, shafts 44, 44 of the two of the second support shafts 20 and shafts 46, 46 of two of the pair of parallel cranks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier device, and more particularly to a frog leg type carrier device for horizontally moving a carrier.

[0002]

2. Description of the Related Art For example, as a device for robotically transferring a semiconductor wafer in a semiconductor device manufacturing apparatus, a frog leg type transfer device is widely used. This is a pair of first arms that rotate around two first support shafts that are spaced apart from the base, and a second support shaft that is provided at the end of each of the pair of first arms. A pair of second arms that rotate around the center of the second arm, and a support portion of the transferred body that forms two third support shafts that rotatably support the ends of the pair of second arms. Consists of This type of frog leg type transport device is disclosed in Japanese Patent Laid-Open No. 54-10976, 62-161.
67, 61-278149, 62-150735, 62-21644, 60-120520,
60-183736, 62-21649, 62-161608, 61-99345, 61
-99344, 61-90903, 61-90887, 61-87351, 61-7
1383, 62-41129, etc. Further, in such a frog leg type transfer apparatus, wafer transfer is performed under reduced pressure, in which case the drive source is placed under normal pressure, the power transmission section is hermetically sealed, and the driven section under reduced pressure is powered. Need to communicate. In this case, it is general to provide an O-ring in the rotary drive portion to enhance airtightness.

[0003]

In the above-mentioned conventional frog leg type conveying device, since the O-ring is used for the rotary driving portion, the O-ring becomes a rotational resistance and the rotational torque becomes large, and the O-ring increases. There is a problem that a large motor with a large output is required, the size of the device becomes large, and the life of the O-ring is shortened due to wear.
In particular, as a unique problem when using in a vacuum atmosphere,
If the O-ring is brought into close contact with the rotating part in order to ensure airtightness, the torque is further increased. There is also a problem that the torque cloth becomes large in proportion to the increase in the diameter of the rotating portion.

Therefore, an object of the present invention is to enable reliable sealing in a state where the torque cross is small, to downsize the motor, and further to downsize the device, and to extend the life of the seal. It is to provide a carrier.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems. As a means for solving the problems, the transport apparatus of the present invention comprises two first bases arranged on a horizontally rotatable base. Pair of first arms that rotate around the respective support shafts, and a pair of second arms that rotate about the second support shafts respectively provided at the ends of the pair of first arms.
Transporting device, which is driven under reduced pressure, having a second arm and a support portion for the transported object that forms two third support shafts for rotatably supporting the ends of the pair of second arms. At
The rotating shaft of the base, the rotating shafts of the two first supporting shafts, and 2
One or a plurality of drive sources for driving the five rotation shafts of the respective rotation shafts of the second support shaft are arranged under normal pressure, and on the pressure reduction region side of the respective upper bearing portions of the five rotation shafts. A magnetic fluid seal is provided.

[0006]

In the transporting apparatus of the present invention having the above-described structure, the rotary shaft of the base, the rotary shafts of the two first support shafts, and the rotary shafts of the two second support shafts are respectively provided. The magnetic fluid seal provided on the pressure reducing region side of the upper bearing portion makes it possible to provide a reliable airtight seal for each rotating shaft. Also,
In the case of a seal using a magnetic fluid, since there is little mechanical frictional contact, there is little torque loss, the drive source can be made smaller accordingly, the size of the device can be reduced, and since there is no wear, the life of the seal is extended.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the transfer apparatus of the present invention is applied to a semiconductor wafer transfer apparatus in a semiconductor element manufacturing apparatus will be described below with reference to FIGS.

The semiconductor wafer transfer apparatus of this embodiment is arranged, for example, in a load lock chamber of a plasma etching apparatus, opens the load lock, and receives a semiconductor wafer from a sender in which a wafer carrier is arranged. Stored in the load lock chamber, closed the load lock, and made the pressure atmosphere almost the same as the process chamber.
The load lock on the process chamber side is set to an open state and then transferred to the process chamber. The inside of the process chamber and the load lock chamber is decompressed to a vacuum atmosphere. Further, this transfer device employs a frog leg type transfer arm, and as shown in FIG.
It is mainly composed of a first arm 10, a second arm 12, a top arm 14 as a support portion of the transferred body, and a crank 16.

The first arms 10 are composed of a pair, and the base ends of the pair of first arms 10 are separated from a base 18 rotatable with respect to a housing 82 fixed to a base plate 80. Two first support shafts 2 arranged
They are attached to the shafts 0 and 20 and rotate about these first support shafts 20 and 20. In addition, at the tips of the first arms 10 and 10, the second support shafts 22 and 2 are respectively provided.
Two are provided. In the load lock chamber, the upper part of the base plate 80 is in a vacuum atmosphere, and the lower part of the base plate 80 is open to the atmosphere.

The second arm 12 is the first arm 1 described above.
The pair of second arms 12 and 12 are configured to correspond to 0, and the base ends of the pair of second arms 12 and 12 are the second support shafts 22 and 22 provided at the distal ends of the pair of first arms 10 and 10, respectively. And is adapted to rotate around these second support shafts 22, 22.

The top arm 14 is provided with two third support shafts 24, 24 at the base end thereof, and the third support shafts 24, 24 are provided.
The tip ends of the pair of second arms 12, 12 are attached to 24, and the second arm 12,
The tip of 12 is rotatably supported.
Further, at the free end side of the top arm 14,
A mounting portion 26 for mounting a semiconductor wafer is provided. A plurality of small protrusions 28 for supporting the semiconductor wafer are formed on the upper surface of the mounting portion 26 to support the semiconductor wafer at points and to make the contact area with the back surface of the semiconductor wafer a small area to prevent dust and the like from adhering. I try to avoid it. Further, since the arm portion of the carrying device is in a cantilever state, a lightening portion 30 having, for example, a triangular hole shape is formed through the mounting portion 26 so as to reduce the weight. Further, the top arm 14 is rotated from the first arm 10 and the second arm 12 from one end side of the base 18 through the overlapping state of the first arm 10 and the second arm 12,
It can be moved linearly between the opposite sides of the base 18,
In this case, when the first and second arms 10 and 12 get over the overlapping state, the first and second arms 10 and 12
If the arm lengths are the same, the arm is loaded and becomes immobile, so the third support shaft 24 of the arm holder 32 provided with the third support shafts 24, 24,
Between 24, forming a slit 34 along the length direction,
The arm holder 32 is bent through the slit 34, thereby forming an escape area.

As shown in FIG. 2, the crank 16 includes two first support shafts 20 and 2 of a pair of first arms 10 and 10.
0 and the two second support shafts 22 and 22 of the pair of second arms 12 and 12, respectively, and are respectively arranged in conjunction with the first support shafts 20 and 20. 2 support shaft 2
It is designed to rotate 2, 22. Each of these cranks 16, 16 is composed of, for example, a pair of parallel crank arms 36, 38.

Next, the drive mechanism for the first support shafts 20, 20 and the cranks 16, 16 will be described with reference to FIGS. This drive mechanism transmits a drive force from one motor 40, which is a drive source, to the first support shafts 20, 20 and the cranks 16, 16 via a drive transmission portion 42. Specifically, the first support shafts 20, 2
0 is the outer shafts 44, 44 for the first support shafts, each of which has a cylindrical shape.
A pair of crank arms 36, 38 which are mounted on the shafts 16 and 16 and which constitute the cranks 16, 16 are mounted on inner shafts 46, 46 whose base ends penetrate the outer shafts 44, 44. The drive shaft 44 and the center shaft 46 are connected to the drive transmission unit 42. The outer shaft 44,
Reference numeral 44 designates upper and lower bearings 84, 84, and the center shafts 46, 4
6 is rotatably supported by upper and lower bearings 86, 86. The outer shafts 44, 44 are covered with a case 88.

The drive transmission section 42 is used for the output shaft 4 of the motor 40.
8 and the gear 50 attached to the crankshaft 8 and the center shaft 46 of each crank 16 side.
Gears 52 and 54 attached to the first support shafts 20 and 20
Side gears 56 and 58 attached to the outer shaft 44, and intermediate gears 60 and 62 are integrally formed on the upper surface side of one gear 54 of the center shaft 46 and the lower surface side of one gear 56 of the outer shaft 44, respectively. Installed. Then, the gear 5 of the center shaft 46
2, 54 and the gears 56, 58 of the outer shaft 44 are meshed with each other, and the gear 50 of the output shaft 48, the intermediate gear 60 of the center shaft 46 and the intermediate gear 62 of the outer shaft 44 are meshed with each other. ing.

Therefore, when the single motor 40 is rotationally driven, for example, in the clockwise direction, on the first support shafts 20 and 20, as shown in FIG. The intermediate gear 62 of the left outer shaft 44, the left outer shaft 44
Gear 56 and the gear 58 of the right outer shaft 44, the left outer shaft 44 rotates counterclockwise and the right outer shaft 44 rotates clockwise to open the first arms 10 and 10. It has become. Further, on the side of the cranks 16 and 16, FIG.
As shown in FIG. 3, the gears 50 of the output shaft 48, the intermediate gear 60 of the right middle shaft 46, the gear 54 of the right middle shaft 46 and the gear 52 of the left middle shaft 46 are sequentially transmitted to the left middle shaft 46.
Is rotated clockwise, the right middle shaft 46 is rotated counterclockwise, and the second support shafts 22 and 22 are respectively rotated inward through the pair of parallel crank arms 36 and 38, and the second arm 12 and Each of the 12 rotates inward.

The gear 52 of the center shaft 46 and the gear 56 of the outer shaft 44 are formed by superposing two gears, and a force between the two gears is larger than the rotational torque applied to the gears 52 and 56. A spring 64 for pulling these gears is interposed to eliminate backlash of the gears.
It should be noted that this spring is preferably provided in the final gear in which gear backlash accumulates.

Further, a ring-shaped gear 66 is attached to the rotary shaft 18a of the base 18 on which the first arms 10 and 10 are attached, and a gear 68 meshing with the gear 66 is rotated on the base. The direction of the top arm 14 can be changed by integrally mounting it on the output shaft 72 of the motor 70 and rotating the base 18 horizontally by rotating the motor 70. The base 18 is rotatably supported by bearings 90 provided above and below the housing 82.

The two outer shafts 44, 44 and 2
5 of the two center shafts 46, 46 and the rotating shaft 18a of the base 18
A magnetic fluid seal 92 is provided on each of the two shafts. Each magnetic fluid seal 92 is composed of a magnet 94 attached to each shaft, and a magnetic fluid 96 attracted to the magnet 94 to seal between each shaft and the outer shaft 44, the case 88, and the housing 82. ing. Further, each magnetic fluid seal 92 is disposed above the bearings 84, 86, 90 of the upper portion that locks the outer shaft 44, the center shaft 46, and the base rotation shaft 18, on the pressure reducing side, and is in a vacuum state. It is designed to seal.

Next, the operation of this embodiment will be described.

First, the transfer device provided in the load lock chamber extends toward the sender side, the transfer arm extends, and the motor 40 is rotated while the semiconductor wafer is mounted on the mounting portion 26 of the top arm 14. When driven, the outer shafts 44, 44 are mutually rotated outward via the gear 50 of the output shaft 48 of the motor 40, the intermediate gear 62, and the gears 56, 58, so that the first arms 10, 10 move to the first arm. Support shaft 20, 20
The tip side is rotated outward around the center.

Then, as the first arms 10 and 10 rotate, the gear 50 of the output shaft 48 of the motor 40 and the intermediate gear 6 are rotated.
0, the center shaft 46 rotates inwardly through the gears 54, 52, and the pair of parallel crank arms 36, 38 connected to the center shaft 46 rotate the second support shafts 22, 22 inwardly. , The distal ends of the second arms 12, 12 are rotated inwardly relative to each other. Then, the top arm 14 supported by the tip end of the second arm via the third support shafts 24, 24 recedes in the linear direction. In this case, the crank 16
Since it has a mechanical connection structure, it does not generate dust due to friction or the like, can be transported in a dust-free state, and has no influence on the semiconductor wafer. Further, a reliable operating state can be obtained without transmission loss of driving force. Further, since this drive is realized by the motor 60 that is a single drive source, energy saving is achieved, and the power transmission from the motor 60 that is a single drive source to the four driven parts is performed. Since this is achieved by the outer shaft 4 and the center shaft 46 which are coaxially provided on the first support shafts 20, 20, the device can be made compact.

Further, when the rotational driving of the motor 40 is continued, the first arms 10 and 10 and the second arms 12 and 1 are
2 and 2 are overlapped with each other, and further overcoming the overlapped state, the vehicle retreats on a straight line. When overcoming this overlapping state, the slit 34 formed in the arm holder 32 of the top arm 14 bends the arm holder 34 to absorb the load when the arms overlap, so that a smooth operation state can be obtained.

Next, when the motor 70 is rotated with the top arm 14 retracted most as described above, the gear 68 provided on the output shaft 70 of the motor 70 and the base 1 are rotated.
The base 18 horizontally rotates through the gear 66 which the crocodile 8 also receives, and changes the direction of the transfer arm. Therefore, when the motor 40 is rotated to the inlet position of the process chamber and the motor 40 is rotated in the opposite direction to that at the position, the first arm 10, 10 and the second arm 12, 12 extend and the top arm 14 moves. The semiconductor wafer is transferred to enter the chamber.

Further, during the operation of the above-described transfer device, the load lock chamber is kept in the base plate 8
Since the upper part has a vacuum atmosphere and the lower part has an air atmosphere, a vacuum seal is required in the middle of the drive transmission part. In this embodiment, the outer shafts 44, 44, the middle shafts 46, 46,
Since the five shafts of the rotating shaft 18a of the base 18 are sealed by the magnetic fluid seal 92, a reliable vacuum seal can be realized. Moreover, the magnetic fluid seal 92
Since the magnetic fluid 96 only comes into contact with the stationary side, torque cross of the rotational driving force is not caused, and a good operating state can be obtained. In particular, a rotary shaft 18a that drives the base 18 to rotate.
However, since the magnetic fluid seal 92 does not increase the mechanical contact resistance in proportion to the diameter of the conventional O-ring seal, the diameter of the seal does not increase in spite of the increase in the diameter of the seal shaft. The life can be extended. According to the experiment, the motor 70 that drives the rotating shaft 18a can be replaced with a motor having a torque 1/10 that of the conventional motor.
As described above, since the outer shaft 44 and the center shaft 46 are provided coaxially with the first support shafts 20 and 20 to transmit the rotation of the four shafts, the magnetic fluid seal is structurally assembled. It has the advantage of being easy.

In the above embodiment, the case where the transfer apparatus of the present invention is installed in the load lock chamber for receiving the semiconductor wafer from the sender and transferring it to the process chamber has been described, but the present invention is not limited to the above example. It is also possible to provide a transfer device other than a semiconductor wafer such as a printed circuit board or LCD substrate, or a load lock chamber.

[0026]

As described above, the carrying device of the present invention has five rotary shafts of the rotary shaft of the base, the rotary shafts of the two first support shafts, and the rotary shafts of the pair of parallel cranks. The magnetic fluid seals provided on the pressure reducing region side of each of the upper bearings have the effect of achieving a reliable vacuum seal even when the diameter of the rotating shaft to be sealed increases.
Further, in the case of a seal made of a magnetic fluid, the torque loss is small, the drive source can be made smaller accordingly, the apparatus can be downsized, and there is no wear, so that the life of the seal is extended.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of FIG.

FIG. 3 is an enlarged sectional view of a drive mechanism portion of FIG.

FIG. 4 is an explanatory diagram showing a relationship between an inner drive shaft and its gear.

FIG. 5 is an explanatory diagram showing a relationship between an outer drive shaft and its gear.

FIG. 6 is a cross-sectional view showing a state of a magnetic fluid seal of a rotary drive part.

[Explanation of symbols]

10 First Arm 12 Second Arm 14 Top Arm 16 Crank 18 Base 18a Rotating Shaft 20 First Support Shaft 22 Second Support Shaft 24 Third Support Shaft 36, 38 Crank Arm 44 Outer Shaft 46 Middle Shaft 84 , 86, 90 Bearing 92 Magnetic fluid seal 94 Magnet 96 Magnetic fluid
TE032801

Claims (1)

Claim: What is claimed is: 1. A pair of first arms that respectively rotate around two first support shafts that are spaced apart from each other on a horizontally rotatable base, and a pair of the first arms. A pair of second shafts that rotate around second shafts that are respectively provided at the ends.
Transporting device, which is driven under reduced pressure, having a second arm and a support portion for the transported object that forms two third support shafts for rotatably supporting the ends of the pair of second arms. In the above, the rotating shaft of the base, the rotating shafts of the two first supporting shafts, and
Drives five rotary shafts of each rotary shaft of two second support shafts 1
Alternatively, a plurality of drive sources are arranged under normal pressure, and a magnetic fluid seal is provided on the pressure reduction area side of the upper bearing portions of the five rotary shafts.