A mixing-and-matching method for an optical environment group is disclosed in this invention. The optical environment group has at least a primary optical environment having a first numerical aperture (NA) and a first off-axis illumination (OAI) mode and at least one backup optical environment having...http://www.google.com/patents/US7493588?utm_source=gb-gplus-sharePatent US7493588 - Mixing and matching method and integration system for providing backup strategries for optical environments and method for operating the same
