Ocean Optics ElliCalc - Manual (Page 4)

Ocean Optics Germany GmbH Thin Film Metrology
3
1 Introduction
ElliCalc is an ellipsometric software to extract thickness and optical data from thin, transparent layers on
different substrates. ElliCalc uses Ocean Optics microspectrometers.
ElliCalc offers a lot of different options like:
• Simulation and measurement of multilayer systems (weakly absorbing or transparent)
• A powerful software engine in the background (“SCOUT”)
• Additionally: an easy-to-use “internal “ mode for thickness extraction and/or Cauchy dispersion
• A graphical user interface that is very easy to use (recipes)
• Simulation of up to 10 layers (weakly absorbing or transparent)
• Highly accurate thickness measurements between some nanometers up to about 25 µm.
• Extraction of dispersion n(λ) and k(λ), roughness, EMA-fractions and other layer parameters, if
using SCOUT add-on (and Cauchy models in internal mode)
• 3D - mapping mode with a motor driven xy(z)-stage (=function of position)
• Online/multipoint measurements (=function of time)
• Remote control via OLE-commands from external software
• Video
• Combination with reflectometry (“NanoCalc”)
Measurement principle
A thin layer is illuminated with white light via a collimating optics and a spectrometer measures the change
of polarization (that occurs after reflection) as a function of wavelength. ElliCalc software determines
thickness (and optical parameters) of the layer.
The mathematics to extract useful data about the film is quite ambitious, but the user is separated from
these problems. The internally measured properties are called “Psi” and “Delta” (in degrees) or sometimes
tan(Psi) and cos(Delta). Of course in spectroscopic ellipsometry these 2 properties are measured as a
function of wavelength (in contrast to single wavelength ellipsometry)
ElliCalc has 2 different modes of operation:
1. data extraction via an optional software tool called “SCOUT”. This SCOUT software is very powerful
and works more or less in the background. SCOUT is able to handle very complicated dispersion
curves, but needs some experience with optical modeling. ElliCalc acts as a user interface to simplify
the data extraction process. Even without deep understanding of the underlying physics it is possible to
measure complex layer systems by using a recipe concept. A layer recipe has to be loaded and the
rest is a “one-button-solution” (of course there must be an expert in the beginning to establish this
recipe. Ask your software supplier…)
2. data extraction by ElliCalc itself (without SCOUT). In this “internal mode” it is very easy to extract
thicknesses and –to some extent- dispersion values without optical modeling. Recipes may be used,
but even without recipes it is extremely simple to get results. This “internal mode” does not need an
expert, but it is not as powerful as the “SCOUT mode”.