Spatial Resolution of a Wavelength-Dispersive Electron Probe Microanalyzer Equipped with a Thermal Field Emission Gun

In this study, a prototype WDS-EPMA equipped with a thermal field emitter (TFE) was used. By using X-ray mapping technique with this instrument, we analyzed sub-micron inclusions in highly pure copper compounds used for manufacturing electronic devices. The analytical conditions of the accelerating voltages were 10 keV and 15 keV; the measured elements were Ni and Si. We measured 160000 points (400 × 400 points) within a couple of hours (1.5 hours at 10 keV, 0.5 hour at 15 keV). The analysis of the X-ray mapping data revealed very small inclusions with diameters estimated to be less than 100 nm. The new EPMA could be used for the elemental analysis of various materials including very light elements in a wide area with a spatial resolution of 100 nm.