High-NA EUV projection lens with central obscuration

摘要

EUV projection lens consisting of four coaxial mirrors with a Numerical Aperture of 0.485 and a twelve-fold demagnification has been developed. According to the computation the circuit features at 10 nm in center and 20 nm on the edge of 12.4 mm field of view can be imaged. The scheme of the projection lens with such demagnification promotes the production of the defect-less masks and reduction of their cost.