Self-forming Mn-based diffusion barriers on low-k substrates

In this work, we report on a self-forming barrier process in Cu-Mn alloys. Cu-Mn alloy films were directly deposited onto low-k substrates by co-sputtering and then subjected to an annealing treatment at various temperatures. X-ray diffraction patterns obtained for the Cu-Mn alloys showed Cu(111), Cu(200), and Cu(220) peaks, while transmission electron microscopy images revealed that a uniform Mn-based interlayer self-formed at the Cu-Mn/low-k interface after annealing. In order to evaluate the barrier properties of the Mn-based interlayer, thermal stability measurements were carried out with the low-k dielectrics. The Cu-Mn alloy showed improved thermal stability when compared to a pure Cu reference sample. The chemical composition of the self-formed interlayers on the low-k substrates was ultimately investigated by X-ray photoelectron spectroscopy analysis. Our results show that the composition of the self-formed interlayers depends on the oxide and carbon concentrations in the low-k material. (C) 2014 The Japan Society of Applied PhysicsThis work was performed with the support of the Samsung Electronics Co. The authors would also like to acknowledgethe operators at the Industry?University Cooperation Foundation of Hanyang University for their assistance in TEManalysis