The precision optical system design represented by the lithographic projection lens is a collaborative design process that combines optical, thermal, and mechanical analysis. The optical design comprehensively considers various links such as component materials, processing and detection, optical filming, mechanical structure, lens integration and the like, and optimizes the optical path on the premise of manufacturability through such means as recalculation optimization, computer-aided assembly and adjustment, system-level component finishing and the like so as to realize strict indexes of image quality. The thermal design aims at the irradiation working condition, which refers that under the specific thermal load, the ideal diversion effect is realized through the optimized design of the lens support structure, and the image quality compensation element is arranged at a suitable position to make forward/feedback compensation to the aberration so as to ensure the imaging quality under working conditions. The mechanical design evaluates the dynamic response of the support unit of the element or the overall structure of the lens through finite element simulation and other methods so as to make targeted improvement and maintain the stability of image quality under certain external interference.
Based on the development of lithography projection lens for IC manufacturing, the team has established a collaborative development model and tolerance system for complex optical and mechanical system and has built a optical / thermal / mechanical collaboration design and simulation platform and has accumulated rich experience in the development of ultra-precision optical and mechanical system. Based on the current manufacturing capability, the team developed the first set of NA0.75 - ArF lithography projection lens in China, achieving the core indexes that average wave aberration of full field is higher than 4 nm and the average distortion of that than 5.7 nm.