Copper Oxide Films Grown by Atomic Layer Deposition from Bis(tri-n-butylphosphane)copper(I)acetylacetonate on Ta, TaN, Ru, and SiO[sub 2]

The thermal atomic layer deposition (ALD) of copper oxide films from the nonfluorinated yet liquid precursor bis(tri- -butylphosphane)copper(I)acetylacetonate, , and wet on Ta, TaN, Ru, and substrates at temperatures of is reported. Typical temperature-independent growth was observed at least up to with a growth-per-cycle of for the metallic substrates and an ALD window extending down to for Ru. On and TaN, the ALD window was observed between 110 and , with saturated growth shown on TaN still at . Precursor self-decomposition in a chemical vapor deposition mode led to bimodal growth on Ta, resulting in the parallel formation of continuous films and isolated clusters. This effect was not observed on TaN up to and neither on Ru or for any processing temperature. The degree of nitridation of the tantalum nitride underlayers considerably influenced the film growth. With excellent adhesion of the ALD films on all substrates studied, the results are a promising basis for Cu seed layer ALD applicable to electrochemical Cu metallization in interconnects of ultralarge-scale integrated circuits.