METHOD FOR MODIFYING OPTICAL MATERIAL PROPERTIES

摘要

The present invention provides a method for increasing the usable lifetime of a photomask that includes directing electromagnetic radiation towards a photomask substrate on which a partially absorbing thin film is disposed, generating a thermal increase in the photomask substrate and recovering at least a portion of the phase delay loss of the thin film. The electromagnetic radiation has a wavelength that substantially coincides with a high absorption coefficient of the photomask substrate.