Apparatus for Measuring Aerial Images Produced by an Optical Lithography System

Abstract

At least one exemplary embodiment is directed to detection aperture array which includes a shield layer; and a plurality of apertures, where the plurality of apertures are formed in the shield layer and filled with a first medium having an effective index of refraction, wherein the plurality of apertures includes at least two apertures separated by a pitch, wherein the plurality of apertures has a measurement value wherein the measurement value includes at least one of the effective refractive index and a pitch value, wherein the measurement value is changed so that TM and TE modes in incident image light passes through the plurality of apertures with about the same transmittance level, wherein when the measurement value is the pitch value then the TM and TE transmittance level are about the same when an angle of incidence of an image light varies.

Dependencies are inferred from the claim text.