Characterizing aberrations in an imaging lens and applications to visual testing and integrated circuit mask analysis

Abstract

Aberrations in a lens and lens system are identified by projecting an optical beam through a mask having an opening (probe) and a surrounding open geometry (pattern) and through the lens to an image plane. Lens aberrations are identified from the combined intensity of the beam in the image plane. In one embodiment the pattern is a plurality of rings concentric with the probe. Spillover between the probe and the geometry becomes intermixed in passing through the lens and alters the light intensity in the image plane. Vision of a patient can be tested by providing a plurality of probe openings and surrounding geometries that are illuminated. The patient then compares the images for brighter and darker probes as a measure of pupil aberrations. Areas in an integrated circuit mask layout impacted by aberrations in projection printing can be identified by sequentially comparing an aberration function to a mask layout, which can then be used to modify the mask layout.