As the semiconductor industry further shrinks feature sizes, new analytical solutions are required for elemental composition analysis. Conventional EDX analysis is limited by the obtainable energy resolution. In order to analyze extremely small impurity particles, material doping, interdiffusion effects or small chip structures, the diameter of the area hit by an electron beam and particularly the volume of electron-surface interaction has to be reduced accordingly. This can be achieved by reducing the electron beam energy.

X-ray spectroscopy is most frequently used for damage free material testing. Nowadays, semiconductor based energy dispersive X-ray spectrometers (EDS) are employed on a routine basis and are frequently used in combination with scanning electron microscopes (SEMs). But performance is limited by their rather poor energy resolution, which is typically in the 130eV range for a 6keV X-ray line, and their limited capability of resolving X-ray lines within short spectral ranges. Further, overlaps of spectral lines are most critical in the low energy range.