PATTERN-DEPENDENT CHARGING IN PLASMAS - ELECTRON-TEMPERATURE EFFECTS

The differential charging of high-aspect-ratio dense structures during plasma etching is studied by two-dimensional Monte Carlo simulations. Enhanced electron shadowing at large electron temperatures is found t o reduce the electron current density to the bottom of narrow trenches , causing buildup of large charging potentials on dielectric surfaces. These potentials alter the local ion dynamics, increase the flux of d eflected ions towards the sidewalls, and result in distorted profiles. The simulation results capture reported experimental trends and revea l the physics of charging damage.