Simulation tool design for the two-axis nano stage of lithography systems

For advanced electron beam lithography systems, a simulation tool for a two-axis nano stage is developed in this paper. The stage is equipped with piezo-actuators and flexure guides. Even if piezo-actuators are believed to be feasible for realizing nano scale motions, it is difficult to predict their characteristics due to their nonlinearities such as hysteresis and creep. In this paper, the nonlinear properties are modeled considering the input conditions. In detail, the hysteresis is described as a first order differential equation with 24 sets of the hysteresis parameters and the creep is modeled as a time-dependent logarithmic function with two sets of creep parameters. The characteristics of the flexure guides are analyzed using the finite element method and are embodied into a multi-body-dynamics simulation tool. The dynamic behavior of the simulation tool is compared with the experimental data.