An optical measurement system is disclosed for evaluating samples with
multi-layer thin film stacks. The optical measurement system includes a
reference ellipsometer and one or more non-contact optical measurement
devices. The reference ellipsometer is used to calibrate the other optical
measurement devices. Once calibration is completed, the system can be used
to analyze multi-layer thin film stacks. In particular, the reference
ellipsometer provides a measurement which can be used to determine the
total optical thickness of the stack. Using that information coupled with
the measurements made by the other optical measurement devices, more
accurate information about individual layers can be obtained.
