Computational Study of Extreme Ultraviolet Vote-Taking Lithography for Defect Repair.

Extreme ultraviolet (EUV) lithography is a prospective technology for the fabrication of integrated chips with critical dimensions (CDs) under 10-nm. However, since chips with similar CDs have similar defect sizes, one of the most critical problems in extreme ultraviolet lithography (EUVL) is mask defect and repair. Defects cause local areas of undesired absorption, reflectivity, or phase change, which ultimately lead to imperfections in the printed image. For example, phase defects may cause substantial changes in image anomalies with different focuses. In this paper, the results of EUV vote-taking lithography are calculated and compared with other repair methods using the scattering matrix (S-matrix) method. Vote-taking lithography with the assumed perfect defect-free masks (N = 4) can maximize 90% and 91% repair improvements at pit defect and dump defect, respectively.