Li Xianling

Key technology progress of optomechanical systems in 193 nm projection objective

Combined with double/multiple exposure 193 nm immersion lithography will be the main method of industrial production of large scale integrated circuits in the next 5 to 10 years. As a core subsystem in lithography, research progress of key technologies of the projection objective opto-mechanical systems affects its performance directly. The current demand for 193 nm immersion projection objective in integrated circuit manufacturing is analyzed in the paper. Research status of objective key technologies are elaborated which including exposure system design, lens mount, lens displacement adjustment, active lens, exchangeable elements and numerical aperture (NA) regulation methods. The key scientific issues that hinder the future development of objective lenses are refined. Currently, the mechanism and correction strategy of high-order thermal aberrations need further clarify in 193 nm immersion lithography. The multi-DOF position and orientation calibration problem should be resolved. To guide the manufacture of high image quality objective lenses, an integrated research method of projection objectives should be achieved.