ZYGO Coherence Scanning Interferometry (CSI)
When specifying a 3D optical metrology solution, it is important to appreciate
that not all tools are the same, and users should look for solutions characterized
by their speed, superior measurement precision, magnification range, and the
ability to measure a broad spectrum of surfaces from the super-smooth to the
extremely rough.
ZYGO’s Coherence Scanning Interferometry (CSI) based 3D Optical Profilers
deliver best in class performance in all of these categories.
These systems use the principle of optical interference to measure a sample.
As shown in the image, illumination is divided into two paths where one travels
to a precision reference surface, and the other travels to the test surface.
The reflections from these two surfaces combine at a camera detector where they
interfere with each other, and a pattern of light and dark intensities is created.
That interference pattern represents the surface topography of the test surface.
In ZYGO’s systems, interferometer is contained in the microscope objective,
which provides both magnification as well as the integrated reference; and a filtered
white light source is used to illuminate the surface through the objective.