Microcalorimeter Energy Dispersive X-Ray Spectroscopy in Routine Semiconductor Failure Analysis

摘要

Microcalorimeter based energy dispersive X-ray analysis (EDS) combines in a revolutionary way resolution of wavelength dispersive spectroscopy (WDS) with the ease of use of conventional EDS. The necessary operating temperatures (～100mK) for the superconducting sensor are supplied by a mechanical, maintenance free and fully automated cooling system, allowing the integration of the system not only in a traditional F/A environment, but also as an inline (cleanroom) installation. Typical examples of material analysis in everyday F/A work show that the detector exhibits an energy resolution of about 10 eV. With this performance, the solution of well known overlap problems existing for element combinations commonly used in semiconductor technology (peak separation of Ti/N, Ta/Si, W/Si) is possible. Structures of small volume can be investigated successfully, since the tool is optimized for work in the low energy range. The case of a failing TiN-layer showed that μ-calorimeter EDS allows also thin film analysis: oxide layers with a thickness difference of a few nm can be distinguished; subsequent depth-profiling with Auger electron spectroscopy confirmed the results.