An edge gripping device grips and ungrips a substrate, such as a semiconductor
wafer. A blade extends in a distal direction from a base of the device. At least
one distal contact member is provided at the tip of the blade. Two proximal lever
arms are pivotally coupled for synchronized, oppositely directed rotation to the
base. Each lever arm has at least one proximal contact member at an outer end.
A biasing member is coupled to the two proximal lever arms and to an actuator to
effect pivoting movement of the lever arms. The pivoting motion moves the ends
of the arms generally radially toward and away from the center of the substrate
to be gripped or ungripped, thereby minimizing sliding of the substrate. The biasing
member is biased to retain the lever arms in a closed position in the event of
a power failure. Ramps are provided next to each contact member. The contact members
and ramps are profiled to minimize the zone of the substrate edge that is contacted.
The lever arms are pivotally mounted with flexural pivot members having no sliding
motion, to minimize particle generation.
