The effects of hydrogen plasma substrate pretreatments on the subsequent material and integration properties of a previously developed plasma-enhanced atomic layer deposition Cu process have been investigated. Plasma treatments were observed to improve Cu nucleation and enable lower Cu resistivity, which have important technological implications with respect to the use of copper in nanoelectronic interconnect structures. The observed results can be explained by the removal of substrate surface hydroxyl groups achieved by the hydrogen plasma pretreatments. The removal of hydroxyl groups and subsequent H-termination of the substrate is favorable for the initial Cu nucleation, which results in higher nucleation density, a smoother surface, and lower resistivity. (c) 2008 The Electrochemical Society.