A new method for deposition of cubic Ta diffusion barrier for Cu metallization

Fabrication and diffusion barrier properties of nanoscale Ta/Ta-N bi-layer

“…Refractory metal and its compounds with N, C, Si doping were widely studied because they have high melting point, low resistance and good adhesion strength with Cu thin-films (Yin et al, 2001). Recently, some research groups focused the research on the Ta, Ta-N and ternary amorphous structures such as Ta-Si-N, Zr-Si-N (Hecker et al, 2002;Khin et al, 2001;Song et al, 2004;Yuan et al, 2003). The main problem to improve the barrier properties is to decrease the micro-cracks and grain boundaries.…”

Comparative investigation of TaN and SiCN barrier layer for Cu/ultra low k integration

“…However, for the amorphous TaN barrier, Latt et al [11] reported that TaN transits from amorphous phase to a mixture of TaN and Ta 2 N up on thermal annealing and Ta 2 N is unstable and dissociates into body center cubic (a-phase) Ta and a Ta 2 N phase [12]. The a-phase Ta promotes Cu (111) orientation [3]. This can explain why the intensity of Cu (111) increases with annealing time.…”

“…Generally, the grain boundaries in Cu and TaN are thought as fast diffusion paths. Because TaN grain size is around 4.6 nm [3], it can easily enter the underlying porous ULK with pore sizes around 10 nm. On the other hand, C, H, O atoms with smaller volume and lower mass in the ULK can also easily out-diffused into TaN barrier layer along the grain boundary defects, even penetrate the barrier layer and reach the Cu film.…”

“…As copper is a faster diffuser in Si and SiO 2 , barrier layer will play a crucial role in Cu metallization. Recently, tantalum and tantalum based films are accepted as the most promising diffusion barriers to prevent copper from reacting with the underlying Si and SiO 2 , and has been successfully applied in deep submicron integration circuit [1][2][3][4][5][6][7]. However, when low k or ULK dielectrics replaced the conventional interlayer dielectric (ILD), SiO 2 , to reduce the RC delay, Ta was found not favorable for ULK dielectrics because of its poor step coverage and significant coefficient thermal expansion (CTE) mismatch.…”

Growth of nano crystalline near α phase tantalum thin films at room temperature using cylindrical magnetron cathode

“…A considerable amount of work has been done on the tantalum (Ta) thin films, mainly because of its varied properties and variety of applications: print head heater [1], semiconductor electronics [2,3], photo catalyst [4], biomedical stents [5,6] and hard coatings on tools [7,8] etc. The Ta thin films, as is known, exist in two phases: β (tetragonal) and α (bcc).…”