Material or article handling – Horizontally swinging load support – Swinging about pivot
Reexamination Certificate
2002-04-11
2003-09-23
Underwood, Donald W. (Department: 3652)
Material or article handling
Horizontally swinging load support
Swinging about pivot
C294S099100, C901S039000
Reexamination Certificate
active
06623235
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
N/A
BACKGROUND OF THE INVENTION
In semiconductor fabrication, circuits are formed on wafers of a semiconductor material such as silicon. A single crystal of the semiconductor material is sliced into thin wafers and the wafers are transported between various stations, such as processing stations, storage stations, or queuing stations, in the fabrication plant. The fabrication plant must be kept clean to prevent contamination of the semiconductor wafers. The wafers are accordingly handled very carefully in sealed cleanroom environments.
Robots are often used to transport the wafers between processing, storage, queuing or other stations. A typical robot includes an arm movable vertically and in a horizontal plane. An end effector on the end of the arm picks up and places the wafer. The end effector may include a mechanism for holding onto the wafer to prevent the wafer from slipping or otherwise becoming damaged while the robot arm is carrying it.
In certain semiconductor applications, the wafer includes an alignment feature, such as a notch or flat, along one edge that is used to align the wafer in a desired orientation prior to delivering the wafer to a processing station. A pre-aligner device is often used to accomplish this alignment. Before delivering the wafer to the processing station, the robot arm deposits the wafer at the pre-aligner device, which rotates the wafer until the notch or flat is properly oriented. The robot arm then picks the wafer up again, in the proper orientation, and delivers the wafer to the processing station.
SUMMARY OF THE INVENTION
The present invention relates to an edge gripping device for a robot that grips the edges of a substrate, such as a semiconductor wafer. The edge gripping device provides proximal and distal points of substrate contact that move in synchronized motion toward a substrate to grip it and away from the substrate to ungrip it. The motion is achieved via two four-bar linkages that move the proximal contact(s) in a substantially horizontal plane and the distal contact(s) both vertically and horizontally. Preferably, at least three contact locations are provided to securely hold the substrate.
More particularly, the edge gripping device includes a base fixed to an end of the robot arm. A distally extending blade and a proximal pusher bar are movably mounted to the base. A linkage mechanism movably mounting the blade and the pusher bar to the base is formed of two four-bar linkages that share a stationary link plate and a movable link arm. The first four-bar linkage has a stationary link fixed with respect to the base and three movable links connected in a parallelogram configuration. The proximal member is fixed to one of the movable links of the first linkage for movement therewith. The second four-bar linkage has a stationary link fixed with respect to the base and three movable links connected in a trapezoidal configuration. The blade is fixed to one of the movable links of the second linkage for movement therewith. The trapezoidal configuration provides both horizontal and vertical components of motion for the distal contact(s).
An actuator is fixed at one end with respect to a moving link of the first linkage and at an opposite end with respect to a moving link of the second linkage. The actuator is operative to move the first linkage and the second linkage to effect movement of the proximal and distal contacts between a closed position in which a substrate is gripped between the distal and proximal contact members and an open or ungripped position.
The linkage mechanism of the present invention eliminates the need for separate actuators to accomplish horizontal and vertical motion of the distal contact(s). Similarly, the need for small motions of the robot is minimized during substrate gripping and ungripping.
REFERENCES:
patent: 3807029 (1974-04-01), Troeger
patent: 3811665 (1974-05-01), Seelig
patent: 3813089 (1974-05-01), Troeger
patent: 3825992 (1974-07-01), Troegar
patent: 5702228 (1997-12-01), Tamai et al.
patent: 5810935 (1998-09-01), Lee et al.
patent: 6155773 (2000-12-01), Ebbing et al.
Charif Malek
Hwang Ted
Mann Joseph
Rouland Jean-Pascal
Yokota Chuckson
PRI Automation, Inc.
Underwood Donald W.
Weingarten Schurgin, Gagnebin & Lebovici LLP
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