Characterization of Mn-Based Self-Forming Barriers on Low-k Samples With or Without UV Curing Treatment

In the present work, we report a Cu-Mn alloy as a material for the self-forming barrier process, and we investigated the diffusion barrier properties of the self-formed layer on low-k dielectrics with or without UV curing treatment. Cu alloy films with 3.8 at% Mn were directly deposited onto low-k dielectrics by co-sputtering followed by annealing at various temperatures. The self-formed layers were investigated by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). In order to compare barrier properties between the Mn-based self-formed layer on low-k dielectric with UV curing and the interlayer on low-k dielectric without UV curing, thermal stability was measured at various thermal stress temperatures. Our results indicated that the formation of the barrier at the interface of Cu-Mn alloy/low-k dielectric was enhanced by UV curing due to changes in the porosity and C concentration in the dielectric layer.