Overview of Key Technologies for Optical Manufacturing of Lithographic Projection Lens

Abstract

Currently the projection lens manufacturing represents the frontier of ultra-precision optical machining,which demands nanometer and even sub-nanometer machining accuracy.To meet the high quality requirements,such as nanometer-precision manufacturing,the production of ultra-smoothing surface and the machining of special material,the key theories and technologies for projection lens machining are proposed.Based on Sigmund sputtering theory,the controllability of efficient material removal capability at atomic scale is investigated,and it provides technology foundation for nanometer-precision machining.A combined figuring technology for high-precision optical surfaces using ion beam material adding and material removal methods is proposed to realize nanometer-precision and ultra-smoothing machining,which enriches and develops the current optical figuring mechanism that dedicating to removing local protuberances on optical surfaces.Aiming to overcome the poor adaptability for machining anisotropic material existing in conventional figuring methods,the controllable compliant figuring method is studied to build the uniform material removal technology for single crystal CaF2.Relational experiments are carried out in self-developed equipments,and the experimental results show that ultra-high precision optical components are obtained,which indicate that the theory is mastered,including technique process and machine tool technology for manufacturing 193 nm lithographic projection lens.