Film properties and surface profile after gap fill of electrochemically deposited Cu films by DC and pulse reverse processes

The self-annealing and the surface reflectivity of Cu films prepared by electrochemical deposition (ECD) are obtained for the DC and pulse reverse processes. They show different behaviors for these two processes, and their behaviors can be well correlated with the grain size of the films. The mechanism of gap fill is discussed according to the surface profile after gap fill for these two processes. It is proposed that the gap filling is mainly controlled by the additive diffusion for the DC process, while it is mainly controlled by the additive adsorption for the pulse reverse process.