Dyanmic Modeling And Simulation Of The Extreme Ultra Violet Lithography Wafer Stage

Wafer stage is a key subsystem in the extreme ultra violet lithography (EUV). Step-scan exposure is used in EUV, the image quality depends on not only the quality of the optical system, but also the dynamic performance of the wafer stage. Therefore the dynamic performance and the quality of the mechanical structure are as important as the optical system. The positioning accuracy, speed, acceleration and machine dy-namic are the key factors to the image quality, overlay accuracy and productivity. Therefore, dynamic analysis of the stage is especially important in the R & D stage.This paper introduced the key technology on the wafer stage by analyzing the ad-vanced ultra-precision positioning stage developed at home and abroad. An wafer stage is designed based on gas-lubricated bearing and linear motor driving. The theory of the vacuum cushion was analyzed. Motion analysis with the geometric analysis was car-ried out to explain the role of micro-motion compensation.Static analysis, modal analysis and transient analysis are used to study the stage performance with finite element analysis software ANSYS. Static analysis is the basic analysis for the structural simulation,which mainly shows the static characteristics,such as stiffness,strain and stress of the stage. Modal analysis is carried out to iden-tify structural weaknesses in the design. The dynamic characteristics are analyzed by transient analysis. Dynamic response is compared under different damping and differ-ent load time.The topology optimization and parametric modeling technology are introduced into the structural design. Topology optimization is applied based on static stiffness and dynamic stiffness of the stage. The finite element analysis is parameterized with the APDL language of ANSYS. The dissertation analyzed the sensitivity of the stage, and then the stage is optimized based on the subproblem approximation method of ANSYS. At last we compared the static characteristics, dynamic characteristics before and after optimization.