Visible-laser repair of clear defects in photomasks

A method for repairing clear defects in photomasks is demonstrated. A visible (514.5-nm) laser beam focused on a defect area drives a pyrolytic reaction which leaves a metal film on the defect area. Defects as small as 1.6 µm have been successfully repaired. Using currently available laser trimming systems, submicrometer repair resolution can be achieved.