Characteristics of Pulse-Reverse Electrodeposited Cu Thin Films: I. Effects of the Anodic Step in the Absence of an Organic Additive

Abstract

One of the main concerns in fabricating Cu interconnections is a significant increase in resistivity. Thus, pulse-reverse electrodeposition was implemented in an attempt to improve the properties of Cu films. The influences of the anodic step in pulse-reverse electrodeposition were intensively investigated by varying the anodic potential and time (the amount of anodic charge). It was confirmed that the anodic step affected the grain size as well as surface roughness and the change rates of these properties were determined by the anodic potential. The conflicting effects between grain size and surface roughness resulted in the lowest resistivity at an optimum amount of anodic charge. The contributions of the grain size and surface roughness were taken into account to explain the resistivity behavior depending on the anodic charge. A theoretical approach was applied to complement the qualitative findings and it was well-matched with the experimental results.