Study of nanocrystalline Ta(N,O) diffusion barriers for use in Cu metallization

In this study, the film properties and the barrier behaviour of 50 nm thin reactively sputtered Ta(N,O) diffusion barriers between Cu and Si were investigated. Auger electron microscopy, glancing-angle x-ray diffractometry and atomic force microscopy revealed that the Ta(N,O) films exhibit quasi-amorphous/nanocrystalline properties. Using sheet resistance measurements, scanning electron microscopy, Auger electron spectroscopy depth profiling and conventional x-ray diffractometry the 50 nm thin Ta(N,O) films were found to be effective diffusion barriers between Cu overlayers and Si substrates even after 1 h annealing at 600 degrees C.