Nano-Motion X-Y Stage by Pneumatic Servo Spherical Bearing Actuators

Abstract

With the development of IC technology, ultraprecise positioning actuators with nanometre-order resolution are in demand, especially for semiconductor stepper equipment. A prototype X-Y stage for ultraprecise positioning composed of six pneumatic servo spherical bearing actuators (PSSBAs) was developed and its specifications were evaluated especially focusing on the step response and its minimum resolution. The minimum positioning resolution of the prototype was 3 nm under the best conditions, and the positioning resolution as a practical specification was approximately 10 nm for all conditions, even without feedback controls. With a simple feedback control, the minimum resolution was improved to 1 nm, which is enough to meet the demands of current ultraprecise positioning technology.