Application of Energy Filtered TEM on Failure Analysis of Sub-Half Micron IC Devices

摘要

High resolution TEM becomes more powerful when coupled with a Gatan imaging filter (GIF) and is called energy filtering TEM (EFTEM). It gives both structural and compositional information simultaneously with sub-nanometer and nanometer resolution, respectively. In this paper, we show examples to demonstrate the application of this technique on failure analysis and characterization ULSI device. ONO (silicon oxide/silicon nitride/silicon oxide) structure is difficult to define high spatial composition profile using electron energy dispersive spectrometer (EDS) after electron damage or sample drifting but EFTEM can get 3-nanometer sharp nitrogen ratio image. Investigation of phase transformation in the TiN/Al/Ti/Si/SiO_2 film in Si substrate due to a local arcing during metallization processing is also shown. From analyses of the phase formation, the arcing temperature can be estimated. The copper metallization process is next generation semiconductor technoogy. Tantalum is good material to be the diffusion barrier layer. The structure of Ta is #beta#-Ta under ion metallization plasma process (IMP). The Ta oxide layer can form between Cu and Td during 500 thermal vacuum (10~(-4) torr) annealing. It proves the eFTEM is a valuable characterization tool for the development of sub-half micron device processing.