Patent ID: 11929277
Assignee: YASKAWA AMERICA, INC.
Field: Measurement (Instruments)
Classification: CPC H  G | IPC G  H

Claim 12:
13. A method comprising:
providing a wafer on a wafer platform having a wafer receiving surface, the wafer having a notch on an outer peripheral edge thereof;
rotating the wafer on the wafer platform from a start position at which the wafer is initially received on the wafer receiving surface until a detector detects a notch location of the notch in relation to the start position, the start position corresponding to a sensing area of the detector;
storing the notch location in a memory;
repeating the providing, rotating, and storing for one or more successive wafers to gather and store notch location data in the memory;
setting a notch window using the notch location data, the notch window defining a range of angles in which a subsequent notch of a subsequent wafer is predicted to be located in relation to the start position at which the subsequent wafer is initially received on the wafer receiving surface; and
performing a pre-alignment operation on the subsequent wafer in which the subsequent wafer is rotated from the start position to a notch location of the subsequent wafer in a first minimum period of time using the notch window.