Effect of H/sub 2/O partial pressure and temperature during Ti sputtering on texture and electromigration in AlSiCu-Ti-TiN-Ti metallization

The effect of residual gas constituents and substrate temperature during Ti sputtering on the texture of TiN/Ti films deposited on SiO/sub 2//Si substrates has been investigated. The Ti(002) and TiN(111) preferred texture of the films deposited at 350°C was improved drastically by increasing the H/sub 2/O partial pressure from lxl0-9 to 3xi0-8 Torr. Both the Ti(002) and TiN(lll) texture showed a similar H/sub 2/O partial pressure and substrate temperature dependence because of the epitaxial transfer between these planes. The improved Ti(002) texture was attributed to the self-assembly of Ti atoms on the SiO/sub 2/ surface, which had a low surface free energy due to the formation of surface OH groups. The AlSiCu/Ti/TiN/Ti film fabricated with the highly-textured TiN/Ti film showed a strong Al(111) texture and had a smooth surface. Moreover, interconnects from this improved film had longer EM lifetimes.