JPH04122589A - Articulated conveyor device in vacuum - Google Patents

Abstract

PURPOSE:To suppress the scattering of dust generated from a sliding part to a minimum by providing a cover to transmission mechanism that can be the dust generating source. CONSTITUTION:Transmission mechanisms 14, 15 provided between a pair of driven arms 12, 13 and a carrier base 18 is covered with a cover 19. The dust that may be generated in these transmission mechanisms 14, 15 is closed into this cover 19 so as to be substantially prevented from being scattered onto a processed article on the carrier base 18 or into a vacuum processing chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a multi-joint transport device used to transport a workpiece within a vacuum processing apparatus.

[Prior Art] Conventional examples of multi-joint transfer devices in vacuum include, for example, Japanese Patent Laid-Open No. 60-183738 and Japanese Patent Laid-Open No. 61180.
One example is the one described in Japanese Patent No. 949.1 In the examples disclosed in these publications, one end of each of two pairs of arms is connected to each other, and a segment gear is attached to the other end of one pair of arms. and the other ends of the other pair of arms are coupled to gears rotatably mounted in engagement with each other on the support which is rotatably adapted to rotate. A conveyor connected to a drive source separate from the rotational drive source and attached to the other end of one pair of arms by driving each gear connected to the other end of the other pair of arms by its drive source. Move the table linearly towards the support stand or away from the support stand,
Furthermore, by rotationally driving the support base, the conveyance base is configured to be able to pivot around the rotation axis of the support base.

However, in such a multi-joint transport device, the mechanism for moving the transport platform in a straight line and the mechanism for rotating the transport platform are independent.
The structure is complicated, and it is difficult to position the workpiece on the conveyor table with good reproducibility and high precision.Furthermore, when used in a vacuum atmosphere, there are many parts that need to be vacuum sealed, making the equipment itself expensive. There were drawbacks such as.

Therefore, the present inventors previously proposed in Japanese Patent Application No. 2-80064 a pair of drive arms, each of which has one end rotatably attached to a coaxial drive shaft connected to a separate drive source via a transmission mechanism. One end of a pair of driven arms is attached to each side so that they can rotate freely relative to each other, and a conveyance platform is attached to the other end of the driven arm via a transmission mechanism, and by controlling the rotational drive of the coaxial drive shaft, the conveyance platform can move straightly. We proposed a so-called frog-leg articulated transfer device that can be used in vacuum processing equipment configured to be able to rotate.

With this proposal, the number of shaft seals can be reduced, the transmission mechanism can be simplified, the cost of the device can be lowered, and the movement of the conveyor table can be easily controlled with high precision.

[Problems to be Solved by the Invention] By the way, in the previously proposed frog-leg multi-joint transfer device, the transmission mechanism provided between the transfer table and the pair of arms slides to remove dust during operation. Occur. In other words, since the transmission mechanism in this part is a sliding motion based on line contact, dust is easily generated, and the generated dust scatters over a wide area and contaminates the walls of the vacuum chamber and the objects to be processed (e.g., wafers) on the carrier table. As a result, there are problems such as a decrease in yield.

Regarding the problem of dust, even if shielded type bearings are used in the bearings of coaxial drive shafts, dust with extremely small particle diameters will scatter and become a problem. Particularly in this part, since the two drive shafts rotate in opposite directions, the relative rotational speed is high, and since there is a moment load from the arms attached to these drive shafts, dust is likely to be generated.

Further, since there are sliding parts in the gear parts used in the transmission mechanism provided between the coaxial drive shaft and each drive source, there is a problem that dust generated from these parts becomes a source of contamination.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multi-joint transfer device in a vacuum that can solve the above-mentioned problems and substantially prevent the influence of dust.

Another object of the present invention is to provide a multi-joint transfer device in a vacuum that can eliminate sources of dust that affect the processing process within the vacuum processing device.

[Means for Solving the Problems] In order to achieve the above first object, according to the present invention,
One end of each drive arm is rotatably attached to a coaxial drive shaft connected to a separate drive source via a transmission mechanism, and one end of each driven arm is rotatably attached to the other end of the pair of drive arms. In a vacuum multi-joint transfer device in which a transfer platform is attached to the other end of the driven arm via a transmission mechanism so that it can move straight and rotate, a cover is attached to the transmission mechanism provided between the pair of driven arms and the transfer platform. It is characterized by being provided.

Preferably, each transmission mechanism provided between each drive source and the coaxial drive shaft is also covered with a cover.

In order to achieve the above-mentioned other object, the present invention provides a pair of drive arms each having one end rotatably attached to a coaxial drive shaft coupled to a separate drive source via a transmission mechanism. In a multi-joint transfer device in vacuum, one end of a pair of driven arms is attached to each end so that they can rotate freely relative to each other, and a transfer platform is attached to the other end of the driven arm via a transmission mechanism so that it can move straight and rotate. The transmission mechanism provided between the driven arm and the conveyance table is characterized by being composed of magnetic gears.

In order to achieve this other objective, the bearing of the coaxial drive shaft is preferably a repulsive passive magnetic bearing.

[Operation] In the multi-joint transfer device in vacuum according to the present invention configured as described above, the transmission mechanism provided between the pair of driven arms and the transfer table is covered with a cover, so that the transmission mechanism Any dust that may be generated is confined within the cover, and can be substantially prevented from scattering into the workpiece on the conveyor table or into the vacuum processing chamber.

In addition, if each transmission mechanism provided between each drive source and the coaxial drive shaft is covered with a cover, the dust that may be generated in these transmission mechanisms is also prevented from scattering, thereby further reducing the influence of dust. can be reduced.

On the other hand, when the transmission mechanism provided between the pair of driven arms and the transfer platform is constructed of magnetic gears, the magnetic gears have a non-contact structure, so there are no sliding parts in the transmission mechanism, and therefore dust is generated. can be avoided. Furthermore, in this case, by configuring the bearing of the coaxial drive shaft with a repulsion type passive magnetic bearing, the bearing portion of the coaxial drive shaft also becomes non-contact, so that dust generation from this portion can also be eliminated.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically shows the configuration of the main parts of an example of a multi-joint conveyance device that is a target of the present invention. In FIG. 4 and a lower bearing 5, and are coaxial drive shafts that can rotate concentrically independently of each other, and the solid shaft 2 protrudes and extends from both ends of the hollow shaft 3. The lower ends of the solid shaft 2 and the hollow shaft 3 are each connected via a gear transmission 6.7 to a separate drive motor 8.9. These drive motors 8.9 can be comprised of reversible motors, pulse motors, etc., and are configured to be able to control the rotation direction, rotation, or amount of rotation of the solid shaft 2 and the hollow shaft 3.

Further, one end of a pair of drive arms 10111 is fixed to the upper ends of the solid shaft 2 and the hollow shaft 3, respectively, and the other ends of these drive arms 10 and 11 are rotatably attached to one end of a pair of driven arms 12 and 13, respectively. is connected to. At the other end of this driven arm 12.13 are gears 14.1 that engage with each other.
5 are attached to the shafts 16.15 of these gears 14.15.
17 is a transport table 18 for the object to be processed (for example, a semiconductor wafer).
is installed. Gear 14.15 is connected to shaft 16.17
It is designed to rotate around the center. Therefore, when the solid shaft 2 and the hollow shaft 3 are rotated in the same direction, the transport platform 1
8 is pivoted around a coaxial drive shaft 1 and also has a solid shaft 2
When the hollow shaft 3 is rotated in the opposite direction, the multiple pairs of arms move toward each other in the direction of opening or closing, thereby moving the carrier 18 toward or away from the coaxial drive shaft 1. Move in a straight line.

The present invention provides dust countermeasures for each sliding portion in such a multi-joint conveyance device, and one embodiment thereof is shown in FIGS. 2 and 3. In the following description of each embodiment, parts corresponding to those in FIG. 1 are designated by the same reference numerals as in FIG. 1.

In FIGS. 2 and 3, the distal ends of the driven arms 12 and 13 are bent approximately vertically on the lower side of the conveyance table 18, and gears 14 and 5 are respectively attached to the distal ends. A cover 19 is attached surrounding these gears 14 and 15. As shown in FIG. 3, this cover 19 has a peripheral edge 20 of an opening through which the bent end of each driven arm 12.13 passes, and is bent upward along each arm.
This prevents dust generated from the sliding parts of the gears 14, 15 and the bearings from falling out of these openings due to the movement of the arms 12, 13. Also, the driven arm 12
．． By bending the tip of the cover 13 almost vertically, the movement of the driven arm relative to the opening of the cover 19 during operation is only a rotational movement, thereby minimizing the size of the opening, and the generated dust is removed from the cover 19. The probability of it jumping out is minimized.

FIG. 4 shows another embodiment, in which the lower ends of the solid shaft 2 and the hollow shaft 3 of the coaxial drive shaft 1 and the respective drive motors 8.9
A cover 21 is provided which covers the transmission mechanism 6.7 between. The cover 21 surrounds the lower end of the hollow shaft 3 as shown, and the opening edge 22 between the lower end of the hollow shaft 3 and the lower end is bent downward, and the sliding part of the transmission mechanism 6.7 and the lower bearing 5 occurs. Even if dust is thrown up, it is difficult to escape from the edge of the opening.

FIG. 5 shows yet another embodiment, which is constructed to eliminate dust sources.

That is, magnetic gears 24.25 are used in place of the mutually engaging gears 14.15 provided at the ends of the driven arms 12.13 in FIG. In order to minimize the amount of
Alternatively, a Ni-plated gear, a magnetized 5US440C, or a permanent magnet coated with C or Ni plating is used, and the teeth of each magnetic gear are magnetized as shown in the figure, or a permanent magnet is used. When used, the permanent magnets are bonded to the teeth and formed into a gear shape.Thereby, the magnetic gears 24, 25 rotate without contacting each other due to the effect of magnetic repulsion.

The magnetic gears 24, 25 may be magnetized as shown in FIGS. 6 and 7.

FIG. 8 shows a modified embodiment, in which rotating wheels 26 and 27 are attached to the tips of a pair of driven arms, respectively.
These rotating wheels 26, 27 are configured to overlap each other without partially contacting each other, and the peripheral edge of each rotating wheel 26, 27 is magnetized as shown.

Accordingly, in accordance with the movement of the driven arm 12.13, the rotary wheels 26.27 can be rotated without contacting each other due to the effect of magnetic attraction.

FIG. 9 shows yet another embodiment of the present invention, in which the upper bearing 4 of the coaxial drive shaft 1 shown in FIG. 1 is constituted by a magnetic bearing. That is, a magnetic pole 28 is provided around the solid shaft 2, and a magnetic pole 29 is provided on the inner circumferential wall of the hollow shaft 3 at a position facing the magnetic pole 28, and these magnetic poles 28, 29 have mutually opposing surfaces. They are magnetized to have the same poles, that is, N or S poles, thereby forming a repulsive passive magnetic bearing that can be held without contacting each other by repulsive force.

In this case, since the lower bearing 5 is held using the normal bearing shown in FIG. 1, there is no need to provide a control circuit for these magnetic poles.

With this configuration, the bearing on the side closer to the transfer table has a non-contact structure, and generation of dust due to sliding can be avoided.

By the way, in the above explanation, the embodiment related to the multi-joint transport device shown in FIG. Any type of multi-joint transport device can be used as long as it is equipped with a sliding part that is a source of dust generation.

[Effects of the Invention] As explained above, according to the first feature of the present invention, since a cover is provided on the transmission mechanism that can be a source of dust generation, scattering of dust generated from sliding parts can be minimized. As a result, contamination by dust inside the vacuum processing chamber and the objects to be processed can be reduced, and the yield can be improved.

According to another feature of the present invention, non-contact magnetic gears and magnetic bearings are used instead of transmission mechanisms and bearings with sliding parts that can be sources of dust, so that the sources of dust can be virtually eliminated. Therefore, the influence of dust can be avoided, and the yield of the vacuum process can be further improved.

Furthermore, since no gas is generated due to sliding, it can be used at lower atmospheric pressures.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an example of a multi-joint transfer device in which the present invention will be implemented, and FIGS. FIG. 4 is a schematic partial cross-sectional view showing an example in which the present invention is implemented in a transmission mechanism between a coaxial drive shaft and a drive motor of the device shown in FIG. 5 is a schematic partial view showing another example in which the present invention is implemented in the driven arm and conveyance table portion of the device shown in FIG. 1, and FIG. 6 is a schematic partial view showing a modification of the embodiment shown in FIG. 5. FIG. 7 is a schematic enlarged partial view showing another modification of the embodiment shown in FIG. 5; FIG. 8 is a schematic enlarged partial side view showing still another modification of the embodiment shown in FIG. 5;
1 is a schematic enlarged partial cross-sectional perspective view showing an example in which the present invention is implemented in a bearing portion of a coaxial drive shaft of the apparatus shown in FIG. 1. FIG. Figure Middle 1: Coaxial drive shaft 2: Solid shaft 3: Hollow shaft 4, upper bearing 6.7: Transmission mechanism 12.13: Followed arm ■4.15: Transmission mechanism 19.21: Cover 24.25: Magnetic gear 26.27: Rotating wheel 28.29: Magnetic bearing Fig. 1 Fig. 2 Fig. 3 Fig. 4 Blank Fig. 9 Fig. 5 Fig. 6 Fig. 7 Fig. 8

Claims (1)

[Claims] 1. One end of a pair of drive arms is rotatably attached to a coaxial drive shaft connected to a separate drive source via a transmission mechanism, and one end of a pair of driven arms is connected to the other end of each drive arm. In a multi-joint transfer device in a vacuum, in which the driven arms are attached to each other so that they can rotate freely, and the conveyance table is attached to the other end of the driven arm via a transmission mechanism so that it can move straight and rotate, there is a A multi-joint transfer device in vacuum, characterized in that a cover is provided on the provided transmission mechanism. 2. One end of each drive arm is rotatably attached to a coaxial drive shaft connected to a separate drive source via a transmission mechanism, and one end of each of the pair of driven arms is rotatably attached to the other end of each drive arm. In a multi-joint transfer device in vacuum, in which a transfer platform is attached to the other end of the driven arm via a transmission mechanism so that it can move straight and rotate, each transmission mechanism installed between each drive source and the coaxial drive shaft is installed. A multi-joint transfer device in a vacuum characterized by being covered with a cover. 3. One end of each drive arm is rotatably attached to a coaxial drive shaft connected to a separate drive source via a transmission mechanism, and one end of each of the pair of driven arms is rotatably attached to the other end of each drive arm. At the other end of the driven arm, a transmission mechanism is attached to the other end of the driven arm so that it can move straight and rotate in a multi-joint conveyor system in vacuum. A multi-joint transfer device in vacuum characterized by being composed of gears. 4. One end of each drive arm is rotatably attached to a coaxial drive shaft connected to a separate drive source via a transmission mechanism, and one end of a pair of driven arms is rotatably attached to the other end of each drive arm. A multi-joint transfer device in a vacuum in which a transfer platform is attached to the other end of the driven arm via a transmission mechanism so that it can move straight and rotate, is characterized in that the bearing of the coaxial drive shaft is configured with a repulsion type passive magnetic bearing. Multi-joint transfer device in vacuum.