Optimization of damascene feature fill for copper electroplating process

Abstract

A copper electroplating process suitable for routine IC manufacturing use must deliver Cu films that reproducibly fill deep, narrow damascene features. In this paper, several important factors such as seed layer coverage, plating waveform (DC, reversed-pulse), and additive chemistry formulation were examined in terms of their effect on the elimination of localized void defects within filled structures. A combination of two-step DC plating and custom additive chemistry enabling complete fill of 9:1 aspect ratio (AR), 0.13 /spl mu/m trenches and 5:1 AR, 0.18 /spl mu/m vias was accomplished.