Method for repairing lithographic transmission masks

Abstract

The invention concerns a method for repairing transmission masks. After the mask has been inspected and the position coordinates of the mask openings have been stored, these position coordinates are compared with the position coordinates of the desired mask pattern to determine the location of defects. The mask to be repaired is then blanket coated on its front side with a photoresist. Particular photoresist regions overlying the mask defects to be repaired are exposed by non-optical or optical radiation for cross-linking the photoresist, the dose required for cross-linking depending upon the respective resist employed. The non-crosslinked portions of the photoresist are subsequently removed. Gold is then applied to the rear of the mask, with the cross-linked photoresist regions acting as a substrate. After the gold has been applied, the cross-linked photoresist regions are removed, typically by plasma etching. Since, after comparison of the position coordinates of mask defects with stored structural mask data, the exposure system exposes and cross-links only the photoresist regions necessary to correct mask defects, mask correction can be carried out within milliseconds.

Dependencies are inferred from the claim text.