System and Method Producing Data For Correcting Autofocus Error in An Imaging Optical System

Abstract

A new and useful system and method is provided, for correcting autofocus errors in an imaging optical system. In a system or method according to the present invention (a) an optical test assembly with an input portion directs light at a wafer surface under conditions described by ellipsometric input beam conditioning parameters, and an output/detection portion receives reflected light from the wafer under conditions described by ellipsometric output beam conditioning parameters, and produces output based on the received reflected light; and (b) a processing control circuit processes the output of the optical test assembly, and produces autofocus correction data based on ellipsometric analysis of (i) the ellipsometric input and output beam conditioning parameters and (ii) the output of the optical test assembly.

Dependencies are inferred from the claim text.