圧電素子アクチュエータ微動機構を備えた超精密X-Y移動台

抄録

A precision X-Y stage has been developed for step and repeat type lithography systems, such as optical reduction projection exposure and electronbeam writing systems. To achieve both high-speed and high-precision, the stage incorporates a dual stage system consisting of coarse-and fine-tables. The coarse-table has a unique mechanical structure utilizing a PTFE slide-bearing guide. To reduce the moving mass of a table, it is designed that only a table moves on an X-Y plane. The table is driven by DC servomotors and ball-screws. These X and Y-axis drive mechanisms are both fixed to the same base. The coarse-table moves at a maximum velocity of 100 mm/s, and is positioned within ±5 μm of a desired position. The fine-table is driven by three piezo-electric actuators, and moves precisely along the X, Y, and θ-axes so as to correct X and Y-axis positioning errors and yaw with the coarse-table. Positioning of these tables is carried out with a closed-loop control system using a 3-axes (X, Y and yaw) laser interferometer measurement system. A ±0.05 μm positioning accuracy, a yaw of less than ±1 μrad, and a 200 ms move time for a 10 mm step is achieved.