At the 65 nm node, silicide faces formidable challenges. Co is the current process of record for most integrated circuit manufacturers and thus becomes baseline silicide for 65 nm. However, Ni is the likely replacement. Both silicides are challenged to meet the requirements at the 65 nm node. This manuscript reviews the current CoSi2challenges (dopant interactions, Ge interactions, linewidth extendibility, impurity effects, agglomeration issues, etc). Ni consumes less Si but has its own challenges, including issues with contact leakage and thermal budget, excessive diffusion and oxidation, interactions with dopant and impurities. Both silicides have formation and stability issues in the presence of Ge. Additions of Ge increase the temperature at which a low resistance CoSi2is formed due to film segregation into CoSi2and Ge-rich Si-Ge grains. With Ni, additions of Ge decrease the temperature at which NiSi converts to a NiSi2, lead to agglomeration at a lower temperature and lead to germanosilicide formation.

Front End-of-Line (FEOL) front side and back side defect investigations revealed a previously unknown back side defect mechanism that may negatively affected die sort yields. Using the AMAT SEMVision TM and Compass TM tools, the KLA-Tencor AIT TM and SP1 BSIM TM tools, and the JEOL SEM TM a detailed FEOL front side and back side defect partition showed that several defect mechanisms were operating in the FEOL and a previously unknown back side defect mechanism was newly identified. These new defects were large gouge/scratch type defects greater than 100 um and were found, prior to processing in our facility, on every incoming silicon wafer from several silicon substrate suppliers. The new back side defect data enabled the Si suppliers to identify the root cause to be a marginal furnace anneal process and marginal boat configuration at their various manufacturing sites. This FEOL back side defect characterization revealed a previously unknown defect mechanism that affected every production starting Si wafer from those suppliers and corrective actions are in place at each supplier sites to reduce and eliminate them.

No abstract

No abstract