空気圧ベローズにより駆動する微動ステージの制御方法とナノ位置決め

抄録

The semiconductor industry requires accurate stage positioning with nanometer-order, for many fabrication processes. In addition, the demand for precision positioning of nanometer-order is increasing with the progress of nanotechnology. Currently, such precise positioning is realized using a stage driven by a piezoelectric element. However, the piezo-electric element has disadvantages of low durability and short stroke. These disadvantages can be removed by the use of a pneumatic bellow actuator instead of a piezoelectric element. Previously we developed the new micro motion stage with elastic hinges driven by pneumatic bellows. The developed stage has precise positioning accuracy with 10nm or more. The accuracy is decided by the resolution of the capacitance sensor which is the position detector. In this study, the capacitance sensor changes to the laser interferometer with resolution of 38 pm for a position detector and the positioning control technique to realize the higher accuracy has been examined. The vibration caused by the fluid noise reduced by estimating velocity and acceleration of stage using observer and velocity and acceleration feedback. As a result, the positioning accuracy is e±3σ=0.7±10nm, where e is a deviation and σ is a dispersion at center position of the stage. The resolution improved to less than 1nm. We confirmed that pneumatic bellows drive can achieve ultra-precise positioning of nanometer-order which is the research goal.