Simulation Study For High-NA EUV Lithography

Abstract: One of the main challenges of EUV lithography is low numerical aperture of the exposure systems. This problem arises from geometrical design limitations. Anamorphic imaging is one unconventional way to solve the problem of the low NA. The consequences of using high NA imaging systems on the most relevant lithography metrics and process characteristics are investigated. Simulation results for isomorphic imaging systems are shown. The impact of both imaging systems on the lithography metrics is inspected.

The large NA achieved by anamorphic imaging increases the importance of investigating 3D mask effects in EUV lithography. It is not known, which of these 3D mask effects can be addressed to the absorber or the multilayer respectively. A hybrid mask simulation approach addresses this question. Simulations results for a hybrid of real and ideal mask elements are shown in an attempt to try to understand their individual effects of the mask elements and which mask element cases these effects.