CVD TaN barrier for copper metallization and DRAM bottom electrode

The extendibility of PVD barriers is expected to become a limiting factor for 0.13 /spl mu/m copper metallization, and an MOCVD barrier is likely to be indispensable due to its superior conformality. A 400/spl deg/C process for deposition of a nanocrystalline conformal (>85%) MOCVD TaN layer in high aspect ratio (AR>5) trenches/vias with barrier properties equivalent to c-PVD TaN has been developed using a liquid organometallic precursor. This enables barrier thickness to be scaled to <125 /spl Aring/ compared to >250 /spl Aring/ for i-PVD TaN. Resistivity of /spl sim/1000 /spl mu//spl Omega/-cm has been achieved, which can be further reduced through barrier engineering. MOCVD TaN is a key enabler for extendibility of copper metallization to the sub-0.13 /spl mu/m technology node.