JPH09148401A - Wafer transfer apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer apparatus which suppresses vibration of a finger holding a wafer. SOLUTION: A finger 10 holding a wafer 1 has a double-layer structure consisting of a main thin plate 11 and an auxiliary plate 12 stacked on the main thin plate 11. These plates are combined by using concave and convex portions 11a and 12a provided at a boundary portion. This causes friction between the main thin plate 11 and the auxiliary plate 12 when the finger vibrates, which converts vibration energy into thermal energy caused by friction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer device used in a semiconductor manufacturing process for transferring a wafer between devices.

[0002]

2. Description of the Related Art A semiconductor device manufacturing apparatus is provided with a wafer transfer device called a carrier for taking out a wafer from a wafer storage container and vice versa.

The carrier has a plurality of storage shelves formed at a narrow pitch in the vertical direction, and the wafers are held on the respective shelves. Therefore, in the conventional wafer transfer apparatus, the wafer is taken out from between the narrow storage shelves by using thin plate fingers.

[0004]

By the way, the above-mentioned fingers are generally used by being attached to a multi-axis positioning device. However, since they are thin plates as described above, they are very likely to vibrate. There is.

That is, each axis of the multi-axis positioning device is composed of a prime mover such as a servomotor and a stepping motor, a transmission mechanism such as a ball screw, a gear and a belt, and a guide mechanism such as a linear motion bearing. Sometimes some vibration is generated. Further, the generated vibration becomes larger as the movement is faster, and further includes various frequency components from low frequency to high frequency.

On the other hand, the thin plate finger is shown in FIG.
As shown in (a) to (c), it has various vibration modes and their corresponding natural frequencies. When the vibration generated from each of the above axes is transmitted to the finger, the finger may resonate with it. In this case, even if the vibration at the vibration source is not so large, the finger will be expanded beyond the allowable value.

When the deflection of the fingers becomes large,
There is a possibility that the position of the wafer held by the finger may be displaced during transportation or may fall off. Moreover, the problem becomes more serious as the transfer operation is accelerated.

In order to avoid such a situation, it is conceivable to eliminate the vibration source first, but it is very costly to realize a multi-axis positioning device with little vibration. Further, it is impossible to eliminate the occurrence of vibration while maintaining a certain operating speed.

It is also conceivable to make the natural frequency of the finger sufficiently smaller or larger than the frequency of the vibration source to avoid resonance. However, if the finger is further thinned in order to reduce the natural frequency, the rigidity of the finger becomes too low and the finger may bend when the wafer is placed or during acceleration / deceleration.

Further, in order to increase the natural frequency, it is necessary to increase the thickness of the fingers, but as described above, the pitch of the carrier racks is narrow, which is also a limitation. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wafer transfer device capable of effectively suppressing vibration generated in a finger that supports a wafer.

[0011]

A first means of the present invention is a wafer transfer apparatus for holding a wafer on a finger and transferring the wafer, wherein the finger is composed of a plurality of laminated plates. The wafer transfer device is characterized in that, when vibrated, the vibrations of the fingers are attenuated by causing a displacement between the plurality of plates.

The second means is that in the wafer transfer apparatus of the first means, each plate of the fingers is formed with irregularities, and the respective plates are laminated by combining these irregularities. A characteristic wafer transfer device.

According to this structure, when the fingers vibrate, the fingers generate a displacement between the laminated plates, thereby converting the vibration energy into heat energy generated by friction or the like. This makes it possible to suppress the vibration.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a carrier 2 for accommodating a wafer 1 and a wafer transfer device 3 for taking out the wafer 1 from the carrier 2.

The carrier 2 is the wafer transfer device 3 described above.
It is composed of a box-shaped main body 4 opened to the side, and a storage rack 5 provided on the inner wall of the main body 4 in the vertical direction at a predetermined pitch.
Each of the storage shelves 5 is composed of a projecting piece 6 projecting from the inner wall surface of the carrier 2 by a predetermined dimension so that the peripheral edge of the wafer 1 can be held.

On the other hand, the wafer transfer device 3 has a base 7
And a multi-axis positioning mechanism 8 provided on the base 7,
The multi-axis positioning mechanism 8 includes a moving body 9 that is driven to move back and forth in the direction of the carrier 2, and a wafer holding finger 10 fixed to the moving body 9.

The multi-axis positioning mechanism 8 drives the finger 10 in the vertical, horizontal and rotational directions. Each axis of the mechanism 8 has a prime mover such as a servo motor or a stepping motor, a ball screw, a gear, It is composed of a transmission mechanism such as a belt and a guide mechanism such as a linear motion bearing.

As shown in FIG. 2, the finger 10 is composed of a main thin plate 11 fixed to the movable body 9 and an auxiliary thin plate 12 laminated on the upper side of the main thin plate 11.
FIG. 3 is a vertical cross-sectional view of the finger 10 seen in the direction of arrow A in FIG.

The main thin plate 11 and the auxiliary thin plate 12 are respectively formed with irregularities 11a and 12a which are alternately provided in the width direction of the finger 10, and both are respectively irregularities 11a and 1a.
2a is laminated by engaging with each other.

The main thin plate 11 and the auxiliary thin plate 12 are
They are not bonded to each other, but are only bonded by the resinous sealing material 13 provided at both ends in the width direction. In addition, the upper surface of the auxiliary thin plate 12 is formed flat,
It serves as a holding surface for the wafer 1.

Next, the operation of this device will be described.
This apparatus is used, for example, to take the wafer 1 out of the carrier 2, align the orientation flat (1a shown in FIGS. 1 and 2), and then store the wafer 1 in the carrier 2 again.

In this case, the wafer transfer device 3 operates the multi-axis positioning mechanism 8 so that the tips of the fingers 10 face the open side of the carrier 2. Then, by moving the moving body 9 in the direction of the carrier 2,
The fingers 10 are inserted into the lower side of a predetermined storage rack 5 (wafer 1) (state of FIG. 1).

In this state, the finger 10 is slightly raised to hold the wafer 1 on the upper surface of the auxiliary thin plate 12 of the finger 10. Then, by moving the moving body 9 backward, the wafer 1 is taken out from the carrier 2.

Next, the multi-axis positioning mechanism 8 makes the fingers 10 face an orientation flat aligning device (not shown) and transfers the wafer 1 to this device. When the orientation flat alignment is performed, the wafer 1 is again held by the finger 10 described above.
To be stored in each shelf 5 of the carrier 2.

When performing the above-described operation, the fingers 10 are driven in the vertical, horizontal and rotational directions by the multi-axis positioning mechanism 8 to perform the operation of receiving and delivering the wafer 1. Positioning mechanism 8
A considerable vibration is transmitted from the side.

This vibration is first transmitted to the main thin plate 11 through the moving body 9. However, the auxiliary thin plate 12 is laminated on the main thin plate 11, and the auxiliary thin plate 12 is not fixed to the main thin plate 11. Therefore, when the main thin plate 11 warps while trying to vibrate, the boundary portion between the main thin plate 11 and the auxiliary thin plate 12 (irregularities 11a, 12).
In a), relative displacement occurs between the two and "rubbing" (friction) occurs. Further, along with this, the sealing material 13 is distorted.

When friction and strain occur in this way, the temperature at this boundary rises, and this rise in temperature absorbs vibration energy. This effectively damps the vibration of the finger 10. Therefore, the vibration generated in the finger 10 is suppressed before reaching the resonance range.

With this structure, the effects described below can be obtained. That is, according to the above configuration, the finger 10 has a two-layer structure composed of the main thin plate 11 and the auxiliary thin plate 12, and friction or the like is generated between the both, so that the finger 10 has a vibration damping characteristic. did. This has the effect of effectively suppressing the vibration generated in the finger 10 with a simple configuration.

Further, both of them have irregularities 11a and 12a.
Since they are combined by engaging with each other, the contact area becomes larger than that in the case where flat surfaces are brought into contact with each other. Therefore, the amount of energy generated by friction can be increased correspondingly, so that the damping characteristic can be increased.

Further, the main thin plate 11 and the holding thin plate 12
Since one surface is formed with the concavities and convexities 11a and 12a, the section modulus becomes larger than that in the case of a simple flat plate. As a result, the bending rigidity of the main thin plate 11 and the auxiliary thin plate 12 can be kept high. As a result, the finger 10 is secured while ensuring the rigidity of the finger 10.
It is possible to effectively prevent an increase in thickness.

As described above, since the finger 10 can have the damping characteristic with a simple structure, the excessive vibration of the finger 10 causes the wafer 1 to drop off or the wafer 1 to be damaged. Can be effectively prevented. Further, since the vibration of the finger 10 can be suppressed, the finger 10 can be driven and positioned at a higher speed, and the productivity of the semiconductor device can be improved.

The present invention is not limited to the above-mentioned one embodiment, but can be variously modified without changing the gist of the invention. For example, although the finger 10 has a two-layer structure in the one embodiment, the finger 10 is not limited to this and may have a structure of three or more layers. A finger having a three-layer structure can increase the sliding area between the layers as compared with the finger 10 having a two-layer structure.

In the above embodiment, the finger 10 is used.
The main thin plate 11 and the auxiliary thin plate 12 are not bonded to each other and are made slidable so that frictional heat is generated in this sliding portion. However, the present invention is not limited to this and, for example, The thin plate 11 and the auxiliary thin plate 12 may be bonded to each other with an adhesive having elasticity to heat the adhesive. Even with such a configuration, the vibration energy can be converted into the heat energy as in the above-described embodiment, so that the vibration can be similarly suppressed.

Further, in the above-described embodiment, only the main thin plate 11 is fixed to the moving body 9, but the present invention is not limited to this, and the auxiliary thin plate 12 is also moved to the moving body 9.
It may be fixed to. Even with such a configuration, since displacement occurs between the two plates 11 and 12, the same effect as that of the above-described embodiment can be obtained.

[0035]

As described above, according to the present invention, the fingers for holding the wafer are constituted by a plurality of laminated plates, and when the fingers are vibrated, displacement is caused between the plurality of plates. Heat is generated in this portion due to friction or the like, and the vibration energy is converted into heat energy.

According to this structure, the finger can have the vibration damping characteristic without taking measures such as increasing the thickness of the finger to improve the rigidity. Therefore, it is possible to effectively prevent the occurrence of resonance with the vibration from the driving side, so that it is possible to effectively prevent the problem that the wafer is displaced or dropped during the transfer. Also,
It is possible to increase the contact area of each plate by forming the unevenness on each plate of the finger and stacking the plates by combining the unevenness. As a result, the thermal energy is generated more effectively, and the damping effect is increased. Also, by providing unevenness, without increasing the thickness,
It also has the effect of improving the bending rigidity of each plate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a plan view and a side view showing an enlarged main part of the same.

FIG. 3 is an enlarged vertical sectional view taken along line AA of FIG.

FIG. 4 is an explanatory diagram showing vibration modes of fingers.

[Explanation of symbols]

1 ... Wafer, 3 ... Wafer transfer device, 10 ... Finger, 1
1 ... Main thin plate (plate), 11a ... Unevenness, 12 ... Auxiliary thin plate (plate), 12a ... Unevenness.

Claims (2)

[Claims] 1. A wafer transfer apparatus for holding a wafer on a finger and transferring the wafer, wherein the finger is composed of a plurality of stacked plates, and when the finger is vibrated, the finger is displaced between the plurality of plates. The wafer transfer device is characterized in that the vibration of the finger is attenuated by causing 2. The wafer transfer apparatus according to claim 1, wherein each plate of the fingers is formed with concavities and convexities, and the respective plates are stacked by combining the concavities and convexities. Mounting device.