Three Examples of Surface Contamination Investigations:
Classic surface contamination residue left by the evaporation of a solvent on a surface. The circular shape of the evaporating solvent becomes smaller in diameter as the solvent evaporates and the circumference concentrations of salts or dissolved materials become higher with most of the precipitation of contamination occurring there. A ring structure in the contamination is left. The residue material was analyzed with XPS to determine its elemental and chemical species composition.
A scratch in an anti-reflective coating on a lens allowed an interior layer to react with water vapor and produce contamination. The image was made using the Nomarski phase interference contrast method on our metallographic microscope. The residue material was analyzed with XPS to determine that a particular underlayer of the many layer film was being attacked corrosively. The attacking agent was also identified as water.
This contamination on a printed circuit board was analyzed with XPS and identified.