Axcelis Technologies, Inc.
System and method for aligning light-transmitting birefringent workpieces

Abstract:

A workpiece alignment system has a light emission apparatus to direct a beam of light toward a first side of a workpiece through a first polarizer apparatus. A light receiver apparatus positioned on a second side of the workpiece receives the beam of light through a second polarizer apparatus between the workpiece and the light receiver apparatus. A workpiece support supports the workpiece. A rotation device selectively supports and rotates the workpiece support about a support axis. A controller determines a position of the workpiece based on an amount of the beam of light received by the light receiver apparatus. The controller determines a position of the workpiece when the workpiece is supported and rotated based, at least in part, on a rotational position of the workpiece support and at least a portion of the beam of light received by the light receiver apparatus.