Development of a small ultraprecision positioning device with 5 nm resolution

This study describes the development of an ultraprecision positioning device with positioning resolution of 5 nm. The device uses a stepping motor and ball screw without a piezoelectric actuator for fine positioning. Here, the stepping motor is driven at high speed with an open loop control, at medium speed with a closed loop control and a low-speed drive with a closed loop control using the feedback-loop displacement sensor of 5 nm resolution. With the step responses repeated we achieved a positioning accuracy equal to or less than 5 nm. Since this ultraprecision positioning device is very small, the stage has a high resonance frequency of 670 Hz for external forces, and we made sure that the positioning device was very resilient to vibrations from the outside.