A method is provided for repairing a phase shift mask. The phase shift mask has
a substrate and a shifter containing a defect and disposed on the substrate. An
ion beam is irradiated onto the defect while a region of the shifter that includes
the defect is supplied with a first gas containing silicon, an oxidizing second
gas, and a third gas for controlling an amount of ions from the ion beam which
penetrate the region of the shifter to form a silicon thin film on the defect and
thereby repair the phase shift mask.
