EFFECTS OF INSULATOR SURFACE-ROUGHNESS ON AL-ALLOY FILM CRYSTALLOGRAPHIC ORIENTATION IN AL-ALLOY TI INSULATOR STRUCTURE

Effects of insulator surface roughness on the overlying aluminum-alloy film crystallographic orientation in Al-alloy/Ti/insulator layered structures have been studied. Tetra-ethyl-ortho-silicate-O-3 (TEOS-O-3) based SiO2 and its chemical-mechanical-polished (CMP) films have been used in order to change the surface roughness of underlying insulators. Ti(002) and (011) peak intensities in X-ray diffraction (XRD) spectra increase when the underlying insulator has a smooth surface, and this orientation change in Ti causes Al(111) peak intensity more than two orders higher on a very smooth surface of CMP TEOS-O-3 SiO2 film, particularly in Al high-temperature sputtering, compared to that on non-CMP TEOS-O-3 SiO2 film. This crystallographic orientation change results in a large difference in the electromigration performance in high-temperature-sputtered Al alloy/Ti layered metal line.