DETAILED MEASUREMENTS AND SIMPLIFIED MODELING OF WAFER CHARGING IN DIFFERENT BARREL REACTOR CONFIGURATIONS

The detailed profiles of the wafer charging in different barrel reactor configurations have been obtained by using the electrically erasable-programmable read-only memory devices. Charging profile in a parallel electrode system depends strongly on the wafer orientation with respect to the rf electric field, while minor changes are observed by the use of floating Al etch tunnel and by the reduction of the wafer-to-wafer separation. On the other hand, no wafer charging is detected in a co-axial electrode system. A simplified equivalent circuit model, which represents the potential in 2-dimensional rf plasma-wafer system, has been proposed. The charging profile derived from the simplified model coincides with the experimental results. This model gives an analytical explanation of the gate charging.