Step height evaluation in the vibrating condition based on microscopic interferometry

Microscopic interferometry can be applied in the step height evaluation with sub-nanometer vertical resolution. This paper describes the effect of outside vibration on the evaluation process through many experiments. A micro actuator with high accuracy is used as the simulation of outside vibration. Experiments are done on the system with different vibration amplitudes, vibration frequencies and phase extracting algorithms. The experimental results show that different phase extracting algorithms have different responses to the outside vibration; low frequency has a strong effect on the measurement values when the vibration amplitude is below a threshold value; however, the effect on the step height evaluation is small by averaging many profiles.