Abstract
This paper describes a micro-topography measurement system using a Mirau interferometric microscope objective. Such
system is a non-invasive, full-field, economical, and compact. The interferometer device consists of a beam splitter that
permits send a portion of the light to the sample surface and other part to a reference surface. Reflected light from these
surfaces are combined to form interference fringes which are captured by a CCD camera. For each local point on the
surface target, there is a distance from the Mirau microscope objective lens. Then, each fringe provides the locus of
points of equal phase in the interferogram image. Contour lines corresponding to the surface target topography are
extracted from the interferograms using digital image processing. Phase-stepping technique have been used in order to
have a phase map which is unwrapped and mapped to a full-field microscopic data topography of the surface target.
Object target is mounted on computer controlled stage with capability of linear movements of the order of nanometers.
With this, the phase-stepping technique was done. For calibrating, a step-in-shape made of thin film on a glass substrate
is built up. The obtained depth resolution is of 15 ± 4 nm, employing the interferometric system. Experimental results
were compared with an Atomic Force Microscope, (AFM) giving an overall error of 17 nm on a 33μm × 45μm field of
view. An application for integrated optics on-chip quality control is suggested.
