Transient thermal and structural deformation and its impact on optical performance of projection optics for extreme ultraviolet lithography

For extreme ultraviolet lithography (EUVL) targeting 45 nm technology generation and beyond, thermal absorption is the main source of multilayer-coated mirror structural deformation, which will finally cause degradation of lithographic performance. It becomes necessary to consider thermal absorption issue in the design phase of volume production tool. Utilizing several commercial and in-house software packages, we have performed a complete transient thermo-mechanical analysis of such effects and its impact on optical performance for volume production of EUVL. This article presents the simulation results based on wafer throughput model of 100 300mm wafers per hour for the 32nm technology generation.