Influence of SiH4 process step on physical and electrical properties of advanced copper interconnects

Model for the barrier diffusion into Cu interconnects at high temperatures

“…It is assumed that the resistance increase and the increase in MTTF are due to a thermally activated diffusion of Ta out of the Ta(N) barrier into the Cu/SiN-cap interface (leading to a change of this weak interface) and potentially into the Cu line. Ta diffusion into Cu has been previously reported [7]. Due to this diffusion, vacancies at the Cu/SiN interfaces are blocked.…”

“…fail at the Cu/SiN interface) is still occurring at the site of the fail mode B in the wide line, but no longer in the narrow line. Structural changes at the interface between interconnect and barrier have been observed [7] and are used in the presented model to explain the bimodal electromigration behavior. Table 1 Calculated MTTF and r for failure modes A and B (P(A) -probability of failure type A) …”

Integration of Low‐ k Dielectric Films in Damascene Processes

“…It can be easily understood that a Cu/metal interface will demonstrate stronger adhesion properties than at the Cu/dielectric barrier interface. SAB techniques based on selective CVD [69,70], electroless deposition [71][72][73][74][75][76], or copper surface modifi cation [77,78] have been studied. However, when SABs are integrated as a stand-alone process above the Cu lines prior the SiOC dielectric deposition, i.e., without any low-k dielectric liner, via over-etching cannot be prevented for misaligned vias.…”

Investigation of the influence of thermal treatment on interconnect-barrier interfaces in copper metallization systems

“…This means, the performed SIMS analysis gives a strong evidence for Ta diffusion into the Cu layer, but a measurement artifact cannot be definitely excluded. Chhun et al [12] showed tantalum diffusion dependant on the capinterconnect quality. These results clearly support our analysis even though there are several differences in the process of both investigations.…”

“…The main difference is the interconnect surface treatment prior to the cap deposition as well as the cap material itself. In [12] CuSiN is used (which provides a better performance due to the better adhesion) in contrast to our SiN.…”