Geometrical instruments – Indicator of direction of force traversing natural media – Level or plumb – terrestrial gravitation responsive
Reexamination Certificate
2000-03-08
2003-03-04
Bennett, G. Bradley (Department: 2859)
Geometrical instruments
Indicator of direction of force traversing natural media
Level or plumb, terrestrial gravitation responsive
C033S371000
Reexamination Certificate
active
06526668
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of levels and more particularly to an electronic level designed for the semiconductor industry.
BACKGROUND OF THE INVENTION
Semiconductor wafers are moved into and out of cassettes and processing stations by automated handling devices (robots) as part of the semiconductor manufacturing process. These automated tools need to be properly setup to pick up wafers and to properly return wafers to set positions. When the tools, cassettes and processing stations are not level, semiconductor wafers may be damaged, broken or scratched. This results in yield losses that can have a significant financial impact. The present method of leveling uses either an “eye-ball” approach or mechanical bubble levels. These techniques are not accurate enough and do not properly address leveling one device relative to another.
Thus there exists a need for a leveling device that overcomes these and other problems.
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Beckhart Gordon Haggott
Conarro Patrick Rooney
Farivar-Sadri Kamran Michael
Harrell Kevin James
Krause Michael Charles
Bennett G. Bradley
Halling Dale B.
Microtool, Inc.
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