MASK CLEANING METHOD, MASK CLEANING APPARATUS, AND PELLICLE

摘要

Embodiments disclose a method for cleaning a mask having a mask film that is of a surface to which a foreign substance containing silicon oxide adheres. In the method, the mask is retained in a cleaning gas containing diluted hydrofluoric acid vapor at a temperature at which an etching rate to the foreign substance becomes higher than an etching rate to the mask film. Further, in the method, the cleaning gas is supplied to the surface of the mask to etch the foreign substance.