Method for cleaning photo mask

摘要

The present invention provides a method for cleaning a photo mask without the need for removal of the pellicle mounted on the photo mask, without the large scale equipment for washing with a solution, with a small number of steps for cleaning and inspection, and without the increase of the production cost. The method for cleaning a photo mask with a pellicle mounted, in which the pellicle frame has a gas introducing hole and a gas discharging hole, comprises: a step of introducing a gaseous substituting substance from the gas introducing hole in a pellicle inner space surrounded by the photo mask and the pellicle, substituting foreign substances on the photo mask, and discharging the foreign substances from the gas discharging hole; and a step of irradiating an ultraviolet ray to the photo mask, while an air or a nitrogen gas or a rare gas is introduced from the gas introducing hole, for degrading the substituted substituting substance so as to be gaseous, and discharging the same from the gas discharging hole.