Interferometer mechanical reference plane offset calibration

摘要

The present development relates to interferometer systems. Interferometer systems are known, for example in the field of lithography machines, and may be used to accurately measure the position of a reflective surface, such as mirrors attached to a moving stage and a mirror or lens of projection optics elements. Some types of interferometer systems are capable of measuring an absolute distance. This absolute distance must be measured relative to a known reference.