Handling: hand and hoist-line implements – Grapple – Fixed and moveable jaw
Reexamination Certificate
1999-08-31
2001-11-27
Underwood, Donald W. (Department: 3652)
Handling: hand and hoist-line implements
Grapple
Fixed and moveable jaw
C414S744800, C901S039000, C901S047000, C294S907000
Reexamination Certificate
active
06322119
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
BACKGROUND OF THE INVENTION
There are a wide range of apparatus types for processing workpieces that ultimately become microelectronic devices. As the microelectronics industry advances toward efficient and economical mass production of the devices, the demands on the apparatus used in processing of the workpieces have increased. Increasingly, automation of the apparatus is being used to meet these ever-increasing demands. More particularly, many of the increased demands relate to automated devices for handling the microelectronic workpieces during processing.
An automated apparatus used for processing a microelectronic workpiece, such as a semiconductor workpiece, is disclosed in U.S. Ser. No. 08/991,062, filed Dec. 15, 1997, and titled “Semiconductor Processing Apparatus Having Lift and Tilt Mechanism”, which is hereby incorporated by reference. This apparatus utilizes a plurality of workpiece processing modules or stations for performing various processing steps. Workpiece transport units are used to access workpiece cassettes and transfer workpieces throughout the processing apparatus. A workpiece conveyor supports and guides the workpiece transport units for transferring individual workpieces between workpiece interface modules and the workpiece processing modules or stations. The workpiece conveyor also includes a transport unit guide, such as an elongated rail, which defines a path for one or more workpiece transport units within the apparatus. The workpiece transport units which move along the rail are configured to have a workpiece transfer arm assembly having an end with a vacuum effector for holding a workpiece. The transfer arm assembly can be adjusted in vertical elevation and can be rotated about the vertical axis for precise positioning of the effector and the workpiece.
Workpieces are typically handled and stored with the face to be processed (the “front” face) oriented facing upwardly. This orientation avoids contact on the front face by the supporting structure. Some processing modules, on the other hand, require the workpiece to be oriented with the face to be processed facing downwardly. To accommodate such requirements, some processing modules such as electroplating reactors, utilize a processing head which can be “flipped”, i.e., rotated, between a first position in which the processing head is positioned to receive the workpiece with a front side of the workpiece facing up and a second positioned in which the front side of the workpiece faces down for processing.
Making provision for each processing module or station to “flip” the workpiece for processing requires complicated head operator mechanisms for rotating the processing heads. Such operator mechanisms can require substantially heavy or large structures for rotating the processing heads, and can require significant overhead operating room for the rotational movement.
The present inventors have recognized that reducing or eliminating the requirement for processing modules to turn over or flip a workpiece for processing would simplify the overall workpiece apparatus. The present inventors have also recognized that cost savings and process simplicities would be enhanced by eliminating the requirement for flipping the workpiece. Still further, the inventors have recognized that a wider range of processing stations of different types may be integrated into a single processing tool. Such processing stations may have varying wafer orientation requirements, one station requiring a front-face up orientation for processing while another station requires a front-face down orientation for processing. An apparatus that addresses each of these recognized problems is set forth.
Additionally, the present inventors have recognized that it would be advantageous to provide a workpiece conveyor with transport unit slidable thereon which minimizes the required working space or “footprint” of the conveyor and transport units operating between laterally disposed process units. An apparatus which provides this advantage is set forth.
SUMMARY OF THE INVENTION
The present invention is directed to a workpiece conveyor system that is used for transporting individual workpieces between workpiece processing stations and the/or interface modules in a workpiece processing apparatus. The workpiece conveyor system includes an improved workpiece transport unit that carries the workpieces within the apparatus on, for example, a conveyor rail or the like. The transport unit includes a vertical member extending from a housing. An arm member extends from the vertical member at a base end of the arm member. A workpiece-holding end effector is disposed at a distal end of the arm member and is selectively driven in rotation about a horizontal axis to “flip” the workpiece between a face-up orientation and a face-down orientation. The effector is preferably configured to grip an edge of a workpiece, such as a semiconductor wafer, and can have a workpiece presence sensor for informing a control unit that a workpiece is present on the effector.
In accordance with one embodiment of the present invention, the workpiece transport unit provides five “axes” of movement. To this end, the transport unit can be driven linearly on the rail along a horizontal axis (Y). The vertical member can be raised or lowered vertically along a vertical axis (Z
1
). The arm member can be rotated about the vertical axis (Z
1
) and a distal portion of the arm member can be rotated about the vertical axis (Z
2
). The end effector can rotate or “flip” about a horizontal axis (R), for example, to orient the workpiece in either the front-face up or front face down orientation. To execute such rotation, the arm member preferably includes a rotary actuator mounted within the arm member to turn the end effector about the horizontal axis.
By providing a workpiece transport unit with increased flexibility of movement, including a rotation about a horizontal axis, more expensive, heavy and complicated mechanisms for flipping workpieces at a plurality of process modules is avoided. Additionally, it becomes possible to integrate processing stations having different workpiece orientation requirements into a single processing apparatus.
In a further aspect of the invention, a workpiece transport unit is provided having a vacuum gripping mechanism for holding a workpiece to the end effector. The vacuum gripping mechanism includes a plurality of raised pads for pressing against an edge region of the workpiece, and vacuum ports through the pads for urging the workpiece onto the pads.
In a still further aspect of the invention, two workpiece transport units are slidable on opposite lateral sides of a guide rail structure. At least one of the transport units includes a first end effector which is elevated above an adjacent section of its respective first robot arm, providing a vertical space therebetween. The vertical space is sufficiently projected in a horizontal direction for the respective other end effector of the other transport unit, operating at a lower elevation, to pass under the first end effector and over the first robot arm. Thus, wafers held by the two end effectors can be overlapped in plan, and the two transport units can be moved longitudinally along the conveyor rail, together, or individually with respect to each other, without interference between end effectors or wafers held thereby. This arrangement minimizes the lateral footprint needed between opposing process units of the tool.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings in which details of the invention are fully and completely disclosed as part of this specification.
REFERENCES:
patent: 4451197 (1984-05-01), Lange
patent: 4639028 (1987-01-01), Olson
patent: 4670126 (1987-06-01), Messer et al.
patent: 4770590 (1988-09-01), Hughes et al.
patent: 49
Oberlitner Thomas H.
Schmidt Wayne J.
Perkins Coie LLP
Semitool Inc.
Underwood Donald W.
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