Long working distance interference microscope

The present invention relates generally to the fields of microscopy and metrology, and more specifically to interference microscopes used for non-contact, ultra-high resolution optical profiling and metrology of integrated circuits and MEMS devices. Disclosed is a long working distance interference microscope suitable for three-dimensional imaging and metrology of MEMS devices and test structures on a standard microelectronics probe station. The long working distance of 10-30 mm allows standard probes or probe cards to be used. This enables nanometer-scale 3-D height profiles of MEMS test structures to be acquired across an entire wafer. A well-matched pair of reference/sample objectives is not required, significantly reducing the cost of this microscope, as compared to a Linnik microinterferometer.