Electrode material and geometry effects on the electrical properties of particle traps in a parallel plate plasma etch reactor

Abstract

A newly designed Langmuir probe has been evaluated and was used to map the plasma potential near the powered electrode of a plasma etch chamber in 2 dimensions. Various electrode materials and geometries were used in order to investigate the relationship between electrode design and the presence of localized regions of elevated plasma potential. These regions of elevated plasma potential were known to be responsible for the presence of particle clouds suspended in the plasma during operation. A relationship was established between sharp edges on the powered electrode, insulating materials on the electrode and localized elevation in plasma potential. A thin layer of raised plasma potential has also been discovered at the plasma-sheath boundary. Suggestions for electrode design to reduce the presence of particles suspended in the plasma are made.