Patent Number: 
Section: abstract

A cost-effective method for repairing reflective optical elements for EUV lithography. These optical elements (60) have a substrate (61) and a coating (62) that reflects at a working wavelength in the range between 5 nm and 20 nm and is damaged as a result of formation of hydrogen bubbles. The method includes: localizing a damaged area (63, 64, 65, 66) in the coating (62) and covering the damaged area (63, 64, 65, 66) with one or more materials having low hydrogen permeability by applying a cover element to the damaged area. The cover element is formed of a surface structure, a convex or concave surface, or a coating corresponding to the coating of the reflective optical element, or a combination thereof. The method is particularly suitable for collector mirrors (70) for EUV lithography. After the repair, the optical elements have cover elements (71, 72, 73).