An optical metrology method is disclosed for evaluating the uniformity of
characteristics within a semiconductor region having repeating features
such a memory die. The method includes obtaining measurements with a
probe laser beam having a spot size on the order of micron. These
measurements are compared to calibration information obtained from
calibration measurements. The calibration information is derived by
measuring calibration samples with the probe laser beam and at least one
other technology having added information content. In the preferred
embodiment, the other technology includes at least one of spectroscopic
reflectometry or spectroscopic ellipsometry.