Cobalt bottom-up contact and via prefill enabling advanced logic and DRAM technologies

This work introduces two new metallization schemes using the electroless deposition (ELD) technique; one based on contact fill and one based on via prefill. One of the key features of the electroless process is its selective deposition, which can be used for bottom-up fill of high aspect ratio features. The feasibility of this Co ELD process is demonstrated on contacts landing on W and vias landing on Cu. Our simulation of the Co via resistance shows that it can serve as alternative to Cu with lower via resistance below 15nm dimension. The results from a planar capacitor study show that there is no degraded reliability in an organo-silicate glass low-k film when Co is in direct contact with this dielectric. Therefore, selective Co ELD process for contact and via prefill has the potential to enable future scaling of advanced logic and DRAM technologies.