Identification of Surface Contaminants Using Infrared Micro-Profiling

Abstract

Infrared micro-profiling is the combination of infrared microspectroscopy with precise microscope stage movements. It can provide molecular and spatial information for a variety of samples as small as 10 μn in diameter. To illustrate the technique, different contaminant materials, including a cellulose acetate fiber, oils deposited from a fingerprint, and a thin film of solder flux residue, were infrared micro-profiled. An integrated absorbance data reduction technique commonly used in gas chromatography/FT-IR applications was applied to the micro-profiling data. This technique organizes the vast amount of data generated, enabling the user to plot the results in 3-dimensional projections, allowing extraction of relevant spatial information. A method of coadding spectra from different pixel elements is presented, providing higher quality spectra without increasing data acquisition time. This procedure improves spectral signal-to-noise which aids in the identification of unknown contaminants.

This work was performed at Sandia National Laboratories supported by the U.S. Department of Energy under Contract Number DE-AC04–76-DP00789.