EFFECTS OF SIDE WALL ION REFLECTION ON MASKLESS PHYSICAL ETCHING.

The effects due to the reflection of the beam on the groove wall during maskless ion milling of a surface are quantified by a tri-dimensional model, based on an analytical theory developed by Smith and Walls. The model incorporates the effect of the main secondary processes that place during etching, such as redeposition, resputtering and ion reflection at side walls. Two simplified models have been used depending upon the assumption that a single or a multiple elastic collision process is responsible for ion reflection. For a simple collision event between the incoming ion and a surface atom, we assume that the ions are reflected with an average scattering angle.