Axcelis Technologies, Inc.
Shallow angle, multi-wavelength, multi-receiver, adjustable sensitivity aligner sensor for semiconductor manufacturing equipment

Abstract:

A workpiece alignment system is provided has a light emission apparatus that directs a light beam at a plurality of wavelengths along a path at a shallow angle toward a first side of a workpiece plane at a peripheral region. A light receiver apparatus, receives the light beam on a second side opposite the first side. A rotation device selectively rotates a workpiece support. According controller determines a position of the workpiece based on an amount of the light beam received through the workpiece when the workpiece intersects the path. A sensitivity of the light receiver apparatus is controlled based on a transmissivity of the workpiece. A position of the workpiece is determined when the workpiece is rotated based on the rotational position, an amount of the light beam received, the transmissivity of the workpiece, detection of a workpiece edge, and the controlled sensitivity of the light receiver apparatus.