Prediction of electroplated copper protrusion profiles in trench patterns using an empirical equation

We propose a simple model to describe the electroplated topography over trench patterns of line widths and spacing ranging up to 30 μm. Excellent agreement between model predictions and measured protrusion heights was observed. This was especially true for the cases of narrow line widths and spacing below 4 μm. The model suggests the existence of a critical spacing for each line width above which the protrusion height becomes positive. It also shows that an increasing film thickness on electroplated copper leads to a decrease in critical spacing.