METALLURGICAL MODES OF FAILURE IN THE SI/TIN/AL METALLIZATION STRUCTURE

Reactively sputtered titanium nitride diffusion barrier films were prepared with an increasing nitrogen content in argon, the working gas. This process affected the microstructure and stoichiometry of the films. The metallurgical modes of failure in the Si/TiN/Al metallization structure were characterized by annealing temperatures ranging from 300 to 600-degrees-C for 30 min. The TiN films performed their barrier function in temperatures up to 567-degrees-C. However, in the temperature range 400-567-degrees-C, residual and thermal stresses caused the top Al film to crack. At 600-degrees-C, Auger depth profiling indicated that a diffusion of both Al and Si occurred through the TiN film. Lesser contributions to the barrier failure were attributed to stoichiometry and the structural distortion for the annealing routines.