Selective Filling and Sintering of Copper Nanoclusters for Interconnect

Abstract—In copper interconnect technology, dielectric trenches are patterned, filled with copper, and polished. We report a cluster-based deposition technology that provides efficient trench filling and excellent selectivity between trenches and plateaus on damascene structures. The selectivity arises due to the propen-sity for reflection of clusters from the planar surfaces between trenches. Trenches of sub-200 nm widths, with various diffusion barriers and seed layers, and up to 5: 1 aspect ratios have been completely filled with copper clusters. We also show that copper clusters can be sintered into a seed layer using hydrogen an-nealing. Thus, dense copper films within trenches are obtained. Preliminary results from planar samples show that the resistivity is around 2.3 10 8 m Index Terms—Cluster deposition, copper, damascene trench filling, integrated circuit interconnections, integrated circuit metallization, materials science and technology. I