Effects of ion energy distribution on topography dependent charging

A new mode of plasma charging which depends on the aspect ratio has recently been observed during poly-Si etching in the form of notching and oxide damage. The mechanism behind this charging appears to be the directionality difference between ions and electrons bombarding the surface. A simulator which considers the roles of the ion and electron energy distributions on topography related charging is shown and verified by application to experimental results. The general results are that the charging voltages due to the directionality difference of ions and electrons are controlled by the population of low energy ions and that anything that increases this population reduces charging.