Abstract: A small internal volume cell having fluid entry, and exit ports wherein at least one bubble trap is present in a fluid pathway which is continuous with the fluid exit port. There further being present an input/output aperture, for entering and exiting electromagnetic radiation, positioned to allow causing an input beam of electromagnetic radiation to impinge on a sample substrate at a location thereon at which, during use, fluid contacts; and a mirror for directing electromagnetic radiation which reflects from said sample substrate, toward and out of said input/output aperture; as well as methodology of its use.

Abstract: A method of determining a starting value for thickness of the most influential layer in a mathematical model of a sample for use in a data fitting routine, supplemented by the use of ordinary or B-spline polynomials to represent at least one of the real and imaginary parts of optical constants in the mathematical model.

Abstract: Disclosed is application of oblique angle of incidence, reflection and/or transmission mode spectroscopic ellipsometry PSI and/or DELTA, (including combinations thereof and/or mathematical equivalents), vs. wavelength data over an intermediate wavelength band range around a pass or reject band, to monitor and/or control fabrication of multiple layer high/low refractive index band-pass, band-reject and varied attenuation vs. wavelength thin film interference filters, either alone or in combination with transmissive non-ellipsometric electromagnetic beam turning point vs. layer data obtained at an essentially normal angle of incidence.