Film thickness measurement and contamination layer correction for quantitative XPS

In order to determine the most appropriate method of measuring film thickness using imaging XPS, a series of thin polymer films have been prepared and analysed using spectroscopy. The thickness of these thin polymer films has been determined using peak shape analysis and by using photoelectron peak areas compared with a bulk reference and by using relative sensitivity factors. These results have been compared with values obtained using ellipsometry. The values obtained by measuring photoelectron peak areas were seen to be influenced by the chemistry of the film, so that a bulk reference of similar chemistry to the film is required for accurate thickness measurement. The values obtained using peak shape analysis, both interactive and non-interactive, were not dependent on the chemistry of the film and showed good agreement with ellipsometry. Imaging of a patterned polymer film was successfully carried out, and the polymer cross section was shown to provide a reasonable description of the inelastic background from the carbonaceous contamination layer. An image of the substrate photoelectron intensity was successfully corrected for attenuation in both the carbonaceous contamination layer and the polymer film simultaneously using an image of the film thickness determined by non-interactive peak shape analysis. This procedure is suitable for automated film thickness measurement and correction for attenuation in the carbonaceous contamination layer in both spectroscopy and imaging. Copyright (c) 2016 John Wiley & Sons, Ltd.