PULSE REVERSE COPPER ELECTRODEPOSITION IN HIGH-ASPECT-RATIO TRENCHES AND VIAS

A theoretical model, based on a one-dimensional approximation, for the filling of high-aspect ratio trenches and vias with copper by pulse r everse electrodeposition is presented. The dependence of void size on the pulse waveform is demonstrated for submicron features. It is shown that the off-time should be on the order of the diffusion-time consta nt and that the deposition time should be smaller than the diffusion t ime constant. Reverse current, i.e., dissolution, is shown to play an important role in diminishing void size. Comparison with two-dimension al calculations indicates that the theory is an adequate yet efficient means of simulating shape change.