Micro Angle Measurement for a Scanning Stage

Abstract

Long range scanning stages with very small positioning errors are the key elements in the nano-CMM that is used to determine the sizes and coordinates of micromachines and parts in three dimensions to realize MEMS/nano technology. A transmission stage needs six degree-of-freedom precision motion controls. A compact critical angle sensor (CAS) can be mounted on the base or frame to be used to monitor the orientation parameters of the scanning/transmission stage along the 3 axes and feedback the error signal of the sensor output to maintain the stage moving performance. By calibration with an autocollimator, the resolution is better than 0.1 arcsec with a measurement range above 600 arcsec.