JPH06120320A - Carrier - Google Patents

Abstract

PURPOSE:To perform the smooth operation of a carry arm by optimizing the positional relation between a drive magnet and a driven magnet used for a magnetic coupling at all times when transmitting not only the torque but also the axial force in the axial direction perpendicular to this rotational direction. CONSTITUTION:This is a magnetic coupling structure, where the rotation and expansion and contraction parts of a carry arm using a multijoint arm is composed of driven parts 26 and 30 positioned inside airtight space and drivers 32 and 34 positioned outside of the airtight space, and this is equipped with a structure 22 which shifts the rotation, extension, and contraction parts axially, putting the interval between the opposed fellow driven parts and drivers in the same condition. Accordingly, even after the shifting in axial direction for lifting up the carry arm, the magnetic attraction between the driven parts and the drivers at the rotation, extension, and contraction parts is maintained at maximum, and accurate and quick operation can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device, and more particularly to a transfer device having a transfer arm composed of multi-joint arms used in a reduced pressure atmosphere such as a semiconductor device manufacturing apparatus.

[0002]

2. Description of the Related Art Generally, when a film to be processed such as a semiconductor wafer or a depressurization process such as an etching process is carried out, the processed object is carried into or out of a load lock chamber into a process chamber. Is used. As the transfer device, a transfer robot having a multi-function arm such as a frog leg arm having a well-known structure in this technical field is used, and is located on the first fulcrum side of the frog leg arm. The object to be processed can be loaded or unloaded by rotating the base or expanding / contracting the transfer arm itself.

By the way, such a frog leg arm realizes the rotation of the base and the extension / contraction of the arm by the rotation of a plurality of drive transmission shafts. The rotary drive source is usually arranged outside the chamber from the viewpoint of preventing contamination inside the chamber. Therefore, it is necessary that the rotary shaft that transmits the driving force penetrates between the atmosphere side and the vacuum atmosphere side and maintains airtightness at the atmosphere-vacuum boundary.

For this reason, conventionally, for example, a magnetic fluid containing magnetic powder in oil is filled in the support portion of the rotary shaft and the housing located at the boundary between the atmosphere side and the vacuum atmosphere side. In some cases, a magnetic seal structure for

However, when the magnetic fluid is used, if the differential pressure increases more than the pressure resistance of the seal portion when the pressure increase to the atmospheric pressure and the pressure reduction to the vacuum atmosphere are repeated, the pressure inside the seal portion increases. The magnetic fluid may be destroyed, flow out, and float in the load lock chamber. Therefore,
If the floating magnetic fluid drops and adheres to the surface of the semiconductor wafer as particles, it may lead to the destruction of the circuit formed on the object to be processed and the poor quality.

Therefore, the rotary shaft of the transfer arm is located in an airtight space set in a vacuum atmosphere, and the driven magnet is arranged so as to oppose the driven magnet outside the airtight space. Has been proposed (for example, Japanese Patent Laid-Open No. 3-136779). According to the proposed structure, the driving force can be transmitted to the transfer arm by magnetic coupling inside and outside the airtight space without using a magnetic fluid seal or the like.

[0007]

In the above-described conventional magnetic coupling drive type transfer device, the drive direction is only the rotational direction. That is, the drive of the conventional transfer arm is
This is because there are only the drive for expanding and contracting the arm in the horizontal plane and the drive for rotating the arm, and both of these drives are achieved by the rotary drive.

The present inventor has found that in addition to the above-described driving of the transfer arm, by varying the horizontal height of the transfer arm, various added values can be obtained in the transfer of the semiconductor wafer. At this time, the elevating and lowering drive of the transfer arm is performed by moving the sliding shaft in the axial direction, which can minimize the number of constituent parts and can perform the efficient drive.

However, when the rotational driving is performed by the magnetic coupling to enable transmission of the driving force from the atmosphere side without using a magnetic fluid seal or the like, the sliding shaft is also driven in the axial direction. The positional relationship between the drive-side magnet and the driven-side magnet for rotation in the axial direction is not always constant, and driving by proper magnetic coupling becomes impossible.

Therefore, an object of the present invention is that not only the rotary shaft for expanding and contracting the transfer arm rotates independently, but also the drive that is always used for the magnetic coupling even after the transfer arm is moved up and down. It is an object of the present invention to provide a transfer device capable of smoothly operating the transfer arm while maintaining the positional relationship between the magnet and the driven magnet.

[0011]

In order to achieve this object, a first aspect of the present invention provides a transfer arm arranged in a load lock chamber of a semiconductor manufacturing apparatus, and a rotation for driving the transfer arm to extend and contract. A shaft, a sliding shaft for moving up and down the transfer arm, an outer housing having an airtight space that communicates with the inside of the load lock chamber around the rotating shaft and the sliding shaft, the rotating shaft and the sliding shaft First and second driven magnets fixed respectively to the first and second driven magnets, which are arranged to face the first and second driven magnets while sandwiching the wall surface outside the outer housing. It is characterized in that a magnet, a rotation driving means for rotating the first driving magnet, and an axial moving means for moving both the first and second driving magnets in the axial direction are provided.

According to a second aspect of the present invention, there is further provided a rotation driving means for rotating and driving the second magnet independently of the first magnet, and the sliding shaft is provided through the second driven magnet. Is rotated to rotate the transfer arm in a horizontal plane.

According to a third aspect of the present invention, there is provided means for magnetically separating the first drive and driven magnet arrangement area from the second drive and driven magnet arrangement area. To do.

[0014]

In order to favorably perform the rotation operation by the magnetic coupling using the drive magnet and the driven magnet, the facing distance between the drive magnet and the driven magnet is set to a state where a constant magnetic attraction force is always obtained. It is necessary to. Therefore, in the present invention, when the transfer arm is moved up and down, the first and second drive magnets are both moved in the axial direction to form a pair of first and second drive magnets.
The magnetic attraction force by the magnetic coupling with the second driven magnet is always constant regardless of the ascending / descending position.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings.

FIG. 1 is a layout diagram showing the overall construction of a vacuum processing apparatus to which the carrying apparatus of the present invention is applied.

That is, the vacuum processing apparatus 100 is configured to convey a semiconductor wafer (which will be described below in the case of a semiconductor wafer), which is an example of an object to be processed, in a conveying direction (direction indicated by an arrow A in the drawing).
A load-side lock chamber 102 and a process chamber 104 that can be replaced with an atmospheric pressure-vacuum atmosphere, and a load-lock chamber 106 that can be replaced with a vacuum atmosphere-atmospheric pressure are arranged in this order from the upstream side. . Then, an opening for carrying the semiconductor wafer W is formed at the connecting portion between these chambers, and this opening is opened and closed by the gate valve 108.

Of the load lock chambers described above,
For example, the load lock chamber 102 on the loading side has a space in which the semiconductor wafer W loaded into the process chamber 104 is temporarily stored and a pressure reduction process is performed from atmospheric pressure to a vacuum state. In the case of the vacuum processing apparatus shown in FIG. 1, the transfer robot 110 provided inside
For example, some semiconductor wafers W are sequentially taken out from a sender cassette 120 capable of storing 25 semiconductor wafers W, and are placed in a buffer 130 provided therein at intervals in the vertical direction.

Thus, the load lock chamber 10
The reason for accommodating a plurality of semiconductor wafers W temporarily in 2 is to reduce the chance of entering the atmosphere as compared with the case where the pressure reduction process from atmospheric pressure is performed for each semiconductor wafer W. This is to reduce the time required for decompression by avoiding repeated decompression from atmospheric pressure.

On the other hand, as a method of mounting the semiconductor wafer W on the buffer 130, for example, as shown in FIG.
When the buffer 130 having the two-stage mounting portions is installed, the transfer robot 1 has a height that does not interfere with the upper-stage mounting portions.
The transfer arm 10 of 10 is positioned (see FIG. 2 (A)), and the transfer arm 10 is lowered from this position toward the mounting portion to place the semiconductor wafer W (see FIG. 2 (B)). Next, the semiconductor wafer W is placed on each of the upper and lower stages by repeating the above-described order on the mounting portion on the lower stage (see FIGS. 2C and 2D). According to this method, it is possible to prevent impurities such as particles from falling and adhering to the surface of the semiconductor wafer W placed on the mounting portion.

In addition, when it is necessary to prevent the particles from adhering to the surface of the semiconductor wafer, the semiconductor wafer may be taken out of the buffer 130. In this case, the semiconductor wafer is taken from the lower side of the buffer 130. Are taken out and placed on the susceptor in the process chamber 104.

Therefore, the transfer arm 10 of the transfer robot 110 can be expanded and contracted, and the arm base 12 supporting the transfer arm 10 can be rotated and moved up and down for loading and unloading the semiconductor wafer on the buffer 130 and the susceptor. It has a structure that can be done.

FIGS. 3 and 4 show a case where the first embodiment of the transfer device according to the present invention is applied to the drive unit of the transfer arm 10 arranged in the above-mentioned load lock chamber. In the embodiment, the frog leg method described above is used as the structure of the transfer arm 10.

That is, the transfer arm 10 is provided with, for example, as shown in FIG. 4, an arm base 12 for rotating the entire arm, and the arm base 12 serves as a base forming a base portion of the load lock chamber. A drive unit is disposed inside the portion 14 for rotating the expansion and contraction fulcrum shaft of the frog leg arm.

An outer housing 16 is arranged on the lower surface of the base portion 14. This outer housing 1
6 is arranged with its upper surface separated from the lower surface of the base portion 14 to form a space capable of surrounding the outer side and the lower end in the axial direction of the drive shaft 18 which drives the expansion and contraction fulcrum shaft of the frog leg arm. It is composed of a bottomed member. Further, between the upper surface of the outer housing 16 and the lower surface of the base portion 14, metal welded bellows 20 that are expandable and contractible partition walls that are integrated with both ends in the extension direction are provided on these surfaces, respectively. The inner space of is sealed airtight by the metal welded bellows 20 and the outer housing 16 can be displaced in the axial direction.

In order to perform such displacement of the outer housing 16, a piston 22A of an air cylinder 22, for example, is connected to the lower end of the outer housing 16.

The outer housing 16 described above is the drive shaft 1
2 large diameter parts 16A, 16B along the axial direction of 8
And the small diameter portions 16A1 and 1A1 which face each other across the large diameter portions 16A and 16B along the axial direction of the drive shaft 18, respectively.
The shape provided with 6B1 is set. Then, one of the small diameter portions, in FIG. 3, the bearing 24 is arranged along the axial direction on the inner peripheral surface of the small diameter portion 16B1 at a position corresponding to the vicinity of the shaft end portion of the drive shaft 18, and the large diameter portion 16B A first driven magnet 26 fixed to the outer peripheral surface of the drive shaft 18 is inserted in the inner peripheral surface.

A cylindrical shaft 28 is concentrically and independently rotatably supported by a bearing 24 on the inner peripheral surface of the other small diameter portion 16A1 so as to be rotatable. Is fixed to the arm base 12. Then, the second driven magnet 30 fixed to the outer peripheral surface of the cylindrical shaft 28 is inserted into the inner peripheral surface of the other large diameter portion 16A.

Therefore, the drive shaft 18 and the cylinder shaft 28 are both located inside the outer housing 16 and independently rotated, whereby the telescopic drive of the transfer arm 10 and the arm base 1 are performed.
2 is driven to rotate and the cylinder shaft 28 is moved up and down to move the arm base 1
2 can be raised and lowered.

On the other hand, first and second drive magnets 32 and 34 are arranged at positions facing the first and second driven magnets 26 and 30 with the outer housing 16 interposed therebetween. Figure 3
Then, below the first and second driven magnets 26, 30, the first,
The second drive magnets 32, 34 are arranged, and these drive magnets 32, 34 are rotatably supported by the outer housing 16 via bearings 36. Each of the first and second drive magnets 32 and 34 has a structure in which it is rotated by its own rotation drive mechanism (not shown). The rotary drive mechanism can be configured by, for example, engaging an output gear of a servo motor with gears formed on the first and second drive magnets 32 and 34, and the rotary drive mechanism is moved up and down by an air cylinder 22.

In the area between the first driven magnet 26 and the second drive magnet 34, a magnetic shielding member 38 made of a magnetic material such as permalloy is provided in the outer housing 16.
It is provided so as to project inside and outside. The shield member 38 prevents the first driven magnet 26 and the second drive magnet 34 from affecting each other.

Next, the operation will be described.

The transfer arm 10 in this transfer device is
The cylindrical shaft 28 located on the lower surface of the arm base 12 and the drive shaft 18 located inside thereof are both located inside the outer housing 16, and the bottom of the outer housing 20 and the metal welded bellows 26 fixed to the upper surface thereof. By shutting off the formed internal space from the outside air, the rotating / extending / contracting motion part and the elevating / lowering motion part are sealed from the outside air.

On the other hand, the transfer arm 10 in the transfer device
Performs rotation, expansion / contraction, and elevating / lowering operations in order to transfer the semiconductor wafer between the chambers and to mount / unload the semiconductor wafer on / from the buffer and the susceptor. Therefore, the rotation operation is obtained by rotating the arm shaft 12 by rotating the cylinder shaft 28, and the expansion and contraction operation is obtained by rotating the drive shaft 18 that drives the rotation fulcrum shaft of the transfer arm 10. On the other hand, in the lifting operation, the lifting force of the outer housing 16 when the piston 24A of the air cylinder 24 is driven is transmitted to the cylinder shaft 28 via the second drive and driven magnets 34 and 30. realizable.

Therefore, the rotation of the arm base 12 via the cylindrical shaft 28 causes the second drive magnet 3 to rotate with respect to the second driven magnet 30.
This is done by causing the magnetic poles to attract each other when the 4 is rotated. Further, the rotation of the drive shaft 18 is performed by attracting the magnetic poles of each other when the first drive magnet 26 is rotated with respect to the first driven magnet 26. At this time, the driving of both is prevented from exerting a magnetic adverse effect on the other pair of magnets by the magnetic shield member 38 such as a permalloy material.

On the other hand, the raising and lowering operation of the arm base 12 is performed by integrally raising and lowering the cylinder shaft 28 according to the displacement of the outer shell housing 16. At this time, the shaft portion 18 is also moved in the same manner as the cylinder shaft 28. It will be integrally moved up and down via the drive and driven magnets 32 and 26 of FIG. Therefore, the first and second driven magnets 26 and 30 can be moved up and down by following up and down movements of the first and second drive magnets 32 and 34 that are integrated with the outer housing.

Therefore, even if the position on the drive magnet side changes due to the displacement of the outer housing 16, the positional relationship between the drive magnet side and the driven magnet side facing the drive magnet side is always set to the same relationship. When the arm base 12 or the drive shaft 18 is independently rotated at the displaced position, the position of the drive magnet with respect to the driven magnet can be set to the same state as before the displacement, thereby changing the attraction force between the magnetic poles. It can be executed without being allowed.

Next, another embodiment of the present invention will be described with reference to FIG.

In the embodiment shown in FIG. 5, as in the example shown in FIG. 3, the outer shell housing 40 is provided on the lower surface of the base portion 14.
Is arranged, which is different from the above embodiment in that the upper surface is directly fastened to and integrated with the lower surface of the base portion 14. The outer housing 40 has a cup-shaped cross section, and hermetically seals a space that can surround the outer side and the shaft end of the drive shaft 50 that drives the rotation fulcrum shaft of the transfer arm 10.

On the other hand, inside the outer housing 40 and around the drive shaft 50, a cylindrical shaft 60 whose upper surface is fastened to the lower surface of the arm base 12 is arranged concentrically with the drive shaft 50. The cylindrical shaft 60 is movably supported in the rotational direction and the axial direction with respect to the outer housing 40 by a bearing 62 provided on the outer peripheral surface at a position facing the base portion 14 and a position corresponding to the vicinity of the lower end in the axial direction. Has been done. This bearing 6
No. 2 does not describe the details of the structure, but for example, one having a structure that allows rotation and sliding in the axial direction of the cylinder shaft 60 using spline coupling or the like is used.

The drive shaft 50 described above has a pair of bearings 64 arranged between it and the inner peripheral surface of the cylinder shaft 60.
It is movably supported only in the rotational direction with respect to 0, and a first driven magnet 66 is fixed to the outer peripheral surface near the shaft end.

A second member is also provided on the outer peripheral surface of the cylinder shaft 60 described above.
Driven magnet 68 is provided, and the second driven magnet 68 is fixed to the outer peripheral surface of the cylinder shaft 60 between the bearings 62.

Therefore, the drive shaft 50 and the cylinder shaft 60 are driven in a state of being shielded from the outside by the outer housing 40 whose upper surface is integrated with the lower surface of the base portion 14. On the other hand, outside the outer housing 40, first and second drive magnets 70 and 72 are respectively arranged facing the first and second driven magnets 66 and 68. In the case of the present embodiment, the first and second drive magnets 70, 72 are located at a predetermined distance from the side wall of the outer housing 40, and
The magnets are arranged at positions corresponding to the distance between the driven magnets facing each other, and the same positional relationship is always set even when the driven magnets are displaced in the axial direction.

Therefore, the first and second drive magnets 70, 7
As the support mechanism of 2, a structure having a function of rotating independently of each other and a function of displacing in the axial direction of the drive shaft in a state of being integrated with each other is used. The support part is connected by a clutch mechanism to enable independent rotation, and the clutch mechanism is connected to the elevating mechanism to displace the clutch mechanism itself up and down along the axial direction of the drive shaft 50 to interlock the drive magnets. There is a structure to make it.

Next, the operation will be described.

In the transfer arm of the transfer device, the cylindrical shaft 60 located on the lower surface of the arm base 12 and the drive shaft 50 located inside thereof are both located inside the outer housing 40, and the bottom and upper surface of the outer housing 40 are By shutting off the internal space formed by the fastened base part 14 from the outside air, the rotation / extension operation part and the elevating operation part are sealed from the outside air.

On the other hand, the transfer arm rotates, expands and contracts, and moves up and down in order to transfer the semiconductor wafer between the chambers and to place and take out the semiconductor wafer to and from the buffer and the susceptor. Therefore, the rotation operation is performed by the cylinder shaft 60.
The arm base 12 is rotated via the, and the expansion and contraction operation is obtained by rotating the drive shaft 50 that drives the rotation fulcrum shaft of the transfer arm. Further, the lifting operation is obtained by displacing both the cylinder shaft 40 and the drive shaft 50 in the vertical direction.

Therefore, the rotation of the arm base 12 and the extension / contraction operation of the arm 10 are similar to those in the example shown in FIG. 3, and the first and second driven magnets 66, 66 having the drive shaft 50 and the cylindrical shaft 40 are provided.
By rotating either of the first and second drive magnets 70, 72 with respect to any of 68, the magnetic poles attract each other according to the movement of the magnetic poles.

On the other hand, in order to raise / lower the arm base 12, it is sufficient to transmit the raising / lowering force to at least the cylinder shaft 40. In this embodiment, both the cylinder shaft 40 and the drive shaft 50 are also moved up / down. The vertical movement of the cylinder shaft 40 and the drive shaft 50 is performed by displacing the first and second drive magnets 70 and 72 so that the magnetic poles attract each other as the magnetic poles move. Then, the driven magnets and the drive magnets are displaced while maintaining the same interval during the lifting operation.

Therefore, the first and second drive magnets 70, 72
Is displaced, the spacing between the drive magnets and the spacing between the first and second driven magnets 66 and 68 that are displaced accordingly are always maintained at the same state. When the drive shaft 50 is rotated, the position of the drive magnet with respect to the driven magnet can be set to the same state as before the displacement, and this can be performed without changing the attraction force between the magnetic poles.

According to this embodiment, since the arm base 12 and the drive shaft 50 can be moved up and down through the cylinder shaft 60 by using the drive magnets for the rotation and expansion and contraction of these members as well, the constituent parts can be constructed. It is possible to suppress the increase in size of the structure by reducing the number of.

Although the structure of the transfer arm described as the embodiment of the present invention is intended for the case where there is a single drive shaft for driving the rotation support shaft for the expansion and contraction operation, a plurality of drive shafts are provided. It is also possible to target the structure, and preferably the axes can be concentrically arranged.

Further, the present invention is not only applied to the transfer arm constituted by the fleg lock arm mounted in the load lock chamber described above, but also rotated by using the transfer arm having the structure of the multi-joint arm. It is of course possible to apply the present invention to a carrying device for raising and lowering. Further, the driving magnets and the driven magnets arranged inside and outside the outer housing may be arranged in multiple stages along the axial direction in order to secure a desired driving force.

Further, one transfer device having the above-mentioned transfer arm is installed, and the transfer device carries in and out the objects to be processed into a plurality of chambers or other materials to be processed under a reduced pressure atmosphere. Of course, the present invention can be applied to a so-called multi-chamber type when the transfer arm is rotated, expanded and contracted, and moved up and down.

Further, in the above embodiment, the buffer 1 capable of accommodating semiconductor wafers in multiple stages by moving the arm 12 up and down.
Although it is possible to transfer the wafer to and from the wafer 30, the present invention is not limited to this, and the wafer can be used for various purposes such as the transfer to the susceptor in the process chamber 104.

According to the embodiment of the present invention, since the magnetic seal used in the transfer device of the vacuum device is eliminated, a transfer device in a clean vacuum device in which the magnetic seal does not contaminate the process chamber or the load lock chamber is provided. Can be provided.

[0057]

As described above, according to the present invention, at least the telescopic operation part and the axial movement operation part of the transfer arm can be operated in the airtight space by using the magnetic coupling structure. Even after the axial movement, the positional relationship between the drive-side magnet and the driven-side magnet with respect to the operation unit for performing the expansion / contraction operation can be matched. Therefore, when the drive-side magnet for the expansion / contraction operation is operated after the movement in the axial direction, the attraction force between the magnetic poles between the driven-side magnet and the driven-side magnet can always be set to a constant state. The expansion and contraction operation can be performed quickly and smoothly.

[Brief description of drawings]

FIG. 1 is a layout diagram for explaining an overall configuration of a vacuum processing apparatus which is an example of an apparatus to which a carrying apparatus according to the present invention is applied.

2A to 2D are schematic views for explaining a procedure for mounting a semiconductor element in a load lock chamber of the vacuum processing apparatus shown in FIG.

FIG. 3 is a cross-sectional view schematically showing the structure of a drive unit of a carrying device to which the present invention is applied.

4 is a partial cross-sectional view for explaining a main part structure of a transfer arm to which the drive unit of the transfer device shown in FIG. 3 is applied.

FIG. 5 is a cross-sectional view schematically showing the structure of a drive unit of a carrying device to which another embodiment of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Transfer arm 12 Arm base 14 Base part 16,40 Outer housing 18,50 Drive shaft 20 Metal welded bellows forming a partition wall 22 Air cylinder 28,60 Cylindrical shaft 30,66 First driven magnet 26,68 Second Driven magnet 32,70 First drive magnet 34,72 Second drive magnet

Claims (3)

[Claims] 1. A transfer arm disposed in a load lock chamber of a semiconductor manufacturing apparatus, a rotary shaft for driving the transfer arm to extend and retract, a slide shaft for raising and lowering the transfer arm, and the rotary shaft. And an outer housing having a periphery of the sliding shaft as an airtight space communicating with the inside of the load lock chamber, first and second driven magnets fixed to the rotary shaft and the sliding shaft, respectively, First and second drive magnets that are arranged to face the first and second driven magnets and sandwich the wall surface on the outer side; rotation drive means for rotating the first drive magnet; A transport device, comprising: an axial moving means for moving both the first and second drive magnets in the axial direction. 2. The rotary drive means according to claim 1, further comprising a rotation drive means for rotating and driving the second magnet independently of the first magnet, and the sliding shaft is connected via the second driven magnet. A carrier device, wherein the carrier arm is rotated to rotate in a horizontal plane. 3. The means for magnetically separating the first drive and driven magnet arrangement area from the second drive and driven magnet arrangement area according to claim 1 or 2. A transport device characterized by.