A method and apparatus that may comprise an EUV light producing mechanism utilizing an EUV plasma source material comprising a material that will form an etching compound, which plasma source material produces EUV light in a band around a selected center wavelength comprising: an EUV plasma generation chamber; an EUV light collector contained within the chamber having a reflective surface containing at least one layer comprising a material that does not form an etching compound and/or forms a compound layer that does not significantly reduce the reflectivity of the reflective surface in the band; an etchant source gas contained within the chamber comprising an etchant source material with which the plasma source material forms an etching compound, which etching compound has a vapor pressure that will allow etching of the etching compound from the reflective surface. The etchant source material may comprises a halogen or halogen compound. The etchant source material may be selected based upon the etching being stimulated in the presence of photons of EUV light and/or DUV light and/or any excited energetic photons with sufficient energy to stimulate the etching of the plasma source material. The apparatus may further comprise an etching stimulation plasma generator providing an etching stimulation plasma in the working vicinity of the reflective surface; and the etchant source material may be selected based upon the etching being stimulated by an etching stimulation plasma. There may also be an ion accelerator accelerating ions toward the reflective surface. The ions may comprise etchant source material. The apparatus and method may comprise a part of an EUV production subsystem with an optical element to be etched of plasma source material.
