Presence sensing and position correction for wafer on a carrier ring

摘要

Embodiments of the invention include apparatuses and systems for determining the position of a carrier ring assembly supported by an end effector. In an embodiment, the position of the carrier ring assembly is determined by passing the carrier ring assembly through a plurality of through beam sensors. As the carrier ring passes through the sensors, a plurality of sensor transitions along points on the carrier ring assembly are detected. Each sensor transition indicates that one of the through beam sensors changed from an unblocked state to a blocked state, or changed from an blocked state to an unblocked state. The position of the end effector is recorded at each sensor transition and is associated with the sensor transition that caused the end effector position to be recorded. A position of the carrier ring assembly is then calculated from the plurality of sensor transitions and their associated end effector positions.

主权项

1. A method of determining a position of a carrier ring assembly supported by an end effector, comprising:
passing the carrier ring assembly through a plurality of through beam sensors; detecting a plurality of sensor transitions along points on the carrier ring assembly, wherein each sensor transition indicates that one of the plurality of through beam sensors changed from an unblocked state to a blocked state, or changed from a blocked state to an unblocked state; recording a position of the end effector at each sensor transition and associating the recorded end effector position with the sensor transition that caused the end effector position to be recorded; and calculating a position of the carrier ring assembly with the plurality of sensor transitions and their associated end effector positions.