Hydrogen plasma-enhanced atomic layer deposition of copper thin films

The growth of plasma-enhanced atomic layer deposition (PEALD) grown copper films appropriate for nanoscale electronics applications is reported. Self-limiting PEALD copper growth behavior, employing copper(II) acetylacetonate and atomic hydrogen as reactants, was observed. Deposition of continuous layers as thin as 10 nm was achieved on TaN, Ru, and SiO2 substrates in a temperature range between 85 and 135 °C. A copper purity greater than 95 at. %, as measured by Auger electron spectroscopy, was observed. For a 30 nm thick film, PEALD copper resistivity was 5.3 μΩ cm on TaN and 8.8 μΩ cm on Ru. Conformal depositions have been achieved over high aspect ratio (∼5:1) structures.