CLEANING OF MULTI-LAYER MIRRORS

摘要

A method of controlling carbonaceous contamination of the surface of a mirror coated with a metal layer comprises the steps of supplying to the mirror a source of carbon for forming carbonaceous deposits on the mirror surface, and a source of a reactant for reacting with the deposits either reductively or by incorporation of hetero-atoms other than oxygen to produce a volatile product, and exposing the mirror to extreme ultra violet (EUV) radiation to activate the reaction. Controlling to the partial pressure ratio of the carbon source and the reactant source can enable the level of contamination of the mirror surface to be actively controlled. ® KIPO & WIPO 2007