In situ ellipsometry study of atomic hydrogen etching of extreme ultraviolet induced carbon layers

► In situ spectroscopic ellipsometry was applied to investigate the etch rate of EUV-induced carbon. ► The high etch rate of the EUV-induced carbon is related to the large hydrogen content. ► A hydrogenating process precedes the removal of carbon by atomic hydrogen. ► Strongest temperature dependence of the etch rate observed on EUV-induced carbon.