Inductively Coupled Hydrogen Plasma-Assisted Cu ALD on Metallic and Dielectric Surfaces

Plasma-assisted atomic layer deposition (ALD) of Cu, via CuII(tmhd)2 (tmhd = tetramethyl-3,5-heptanedionate) and an inductively coupled hydrogen plasma, is shown on metallic and dielectric surfaces. Nonselective deposition was achieved on SiO2, Au, and TaNx in a temperature range between 60 and 400DGC. Deposition was self-limiting from ~90 to 250DGC. A novel method to determine self-limiting behavior of the first half-reaction is presented; it is determined by pulsing the precursor once, for a long time, and the resulting growth is measured by Rutherford backscattering spectrometry. Further, saturation curves for plasmaassisted ALD of each half-reaction and as a function of purging time were also determined. In contrast, thermal ALD via CuII(tmhd)2 and H2 was attempted and was very slow within the self-limiting temperature range. These experiments were undertaken on all the metallic and dielectric surfaces studied here including a plasma-assisted atomic layer deposited Cu seed.