Method and apparatus for monitoring and controlling imaging in immersion lithography systems

摘要

A method of monitoring an immersion lithography system in which a wafer can be immersed in a liquid immersion medium. The method detects an index of refraction of the immersion medium in a volume of the immersion medium through which an exposure pattern is configured to traverse and determines if the index of refraction is acceptable for exposing the wafer with the exposure pattern. Also disclosed is a monitoring and control system for an immersion lithography system.