On the fly center-finding during substrate handling in a processing system

A substrate center-finding apparatus for a substrate processing system having a substrate handler for moving a substrate, the substrate center-finding apparatus comprising:

• at least one sensor disposed in the substrate processing system;
• and
• a controller connected to receive signals from the at least one sensor and to control the substrate handler, the controller configured to perform a substrate center-finding method comprising:
• moving the substrate in a non-uniform path to trigger the at least one sensor;
• determining at least three data points relative to a reference point of the substrate handler;
• and
• calculating a center of the substrate relative to the reference point.

An apparatus for transferring a substrate in a processing system having a robot and at least on sensor disposed in the processing system, comprising:

• a computer-readable medium containing instructions of a computer program for performing a method comprising:
• moving the substrate in a non-uniform path to trigger the at least one sensor disposed in the processing system;
• determining at least three data points in relation to a reference point, each data point representing coordinates of a point on a substrate perimeter as the at least one sensor is triggered;
• determining a center of the substrate in relation to the reference point utilizing the at least three data points;
• and
• moving the substrate to position the center of the substrate in a desired location in the processing system.