Development of a Sensor for Layered Micro-component Measurement Using White Light Interferometry

In this work, a white light interferometry technique has been developed for measuring the thickness of a multi-layer structure. Essentially, the method utilizes a white light source, which illuminates a test object mounted on a translation stage, using a modified Michelson interferometer configuration. Images of the object are recorded at certain prescribed vertical movements of the translation stage via a PZT. Tests are conducted on a dual layer semi-conductor wafer and a micro-gear. The results obtained show that the thickness and profile of a micro-gear fabricated from a polymer can be determined with good accuracy.