Improved methodology for monitoring deposition or removal of material to
or from a process and/or wittness substrate which demonstrates a negative
e1 at some wavelength. The method involves detection of changes in
P-polarized electromagnetism ellipsometric DELTA at SPR Resonance
Angle-of-Incidence (AOI) to monitor deposition of and/or removal of
minute amounts of materials onto, or from, said process and/or witness
substrate. The methodology can optionally monitor ellipsometric PSI, and
involves simultaneously or sequentially applying non-P-polarized
electromagnetism at the same angle of incidence, or electromagnetic
radiation of any polarization at a different angle-of-incidence and
wavelength to the process or wittness substrate and application of
conventional ellipsometric analysis.