We have proposed and developed a design method of a freeform surfaces （FFSs） based hyper-numerical-aperture deep ultraviolet （DUV） projection objective （PO） with low aberration. With an aspheric initial configur...We have proposed and developed a design method of a freeform surfaces （FFSs） based hyper-numerical-aperture deep ultraviolet （DUV） projection objective （PO） with low aberration. With an aspheric initial configuration, lens-form parameters were used to determine the best position to remove elements and insert FFSs. The designed FFSs PO reduced two elements without increasing the total thickness of the glass materials. Compared with aspheric initial configuration, the wavefront error of the FFSs PO decreased from 0.006λ to 0.005λ, the distortion reduced from 1 to 0.5 nm, and the aspheric departure decreased from 1.7 to 1.35 mm. The results show that the design method of the FFSs PO is efficient and has improved the imaging performance of PO. The design method of FFSs PO provides potential solutions for DUV lithography with low aberrations at 10–5 nm nodes.展开更多
基金the Major Scientific Instrument Development Project of the National Natural Science Foundation of China (Nos. 11627808 and 61675026)the National Science and Technology Major Project for their financial support
文摘We have proposed and developed a design method of a freeform surfaces （FFSs） based hyper-numerical-aperture deep ultraviolet （DUV） projection objective （PO） with low aberration. With an aspheric initial configuration, lens-form parameters were used to determine the best position to remove elements and insert FFSs. The designed FFSs PO reduced two elements without increasing the total thickness of the glass materials. Compared with aspheric initial configuration, the wavefront error of the FFSs PO decreased from 0.006λ to 0.005λ, the distortion reduced from 1 to 0.5 nm, and the aspheric departure decreased from 1.7 to 1.35 mm. The results show that the design method of the FFSs PO is efficient and has improved the imaging performance of PO. The design method of FFSs PO provides potential solutions for DUV lithography with low aberrations at 10–5 nm nodes.
