Patent ID: 7746479
Filing Date: 2010-06-29
Classification: G03F

Abstract:
1. A measuring device for measuring a wavefront aberration of an optical system, the measuring device comprising: a first mask for defining light that enters the optical system; a second mask including a first opening and a plurality of further openings, the first opening transmitting a component of the light passing through the optical system including information about the wavefront aberration of the optical system, and the further openings transmitting components of the light passing through the optical system having the information about the wavefront aberration of the optical system removed; a detector for detecting a first interference pattern formed by interference between the light component passing through the first opening and the light component passing through one of the plurality of further openings and detecting a second interference pattern formed by interference between the light components passing through two of the plurality of further openings; and a controller for subtracting a wavefront aberration calculated from the detected second interference pattern from a wavefront aberration calculated from the detected first interference pattern wherein the further openings are slits, and the first opening is larger than the slits.