Method and apparatus for repairing a defect of a lithographic mask

A method for repairing at least one defective pattern element of a lithographic mask, the method comprising the steps of:

• a. determining at least one repair element of the lithographic mask which does not image the lithographic mask during the exposure thereof, wherein the at least one repair element is configured to change an imaging behavior of the at least one defective pattern element, and wherein determining the at least one repair element comprises recording at least one aerial image of the at least one defective pattern element;
• and
• b. producing the at least one repair element on the lithographic mask by use of at least one focused particle beam and at least one precursor gas.

An apparatus for repairing at least one of a lithographic mask, comprising:

• means for ascertaining parameters of at least one repair shape for the at least one defect, wherein the means for ascertaining parameters comprises:
• means for allocating a numerical value to at least one parameter which deviates from the numerical value predefined by the at least one defect for said parameter, and wherein the deviation of the numerical value of the at least one parameter is selected from a range whose lower limit is greater than zero and less than a resolution limit of the lithographic mask;
• and means for recording at least one aerial image of the at least one defect.