Optical performance of extreme-ultraviolet lithography for 50 nm generation

Extreme-ultraviolet lithography (EUVL) is one of the promising technologies for the fabrication of critical dimension of 100 - 32 nm. The optical performance of projection optics is most important to realize the fabrication of high-resolution pattern. The design of 6-mirror projection optics of extremes-ultraviolet lithography is presented and the optical performance is analysed by using optical design software CODE V. The resolution can reach 50 nm and the exposure area is 26 mm × 1 mm. The performance of optics depends on the field points of the exposure area. The optical evaluation of optics is completed at full exposure area. The maximum distortion of 3.77 nm and the maximum wavefront error of 0.031λ (root-mean-square) can be reached. This projection optics can fully meet the requirements of EUVL for next generation.