Quick estimation of physical etching of SiO2 among etchers with decoupled plasma sources

A quick estimation method of physical etching was studied among three etchers with decoupled plasma sources and high plasma densities. Experiments performed in three types of decoupled plasma source (DPS) chambers suggest a rough estimation rule: if the same top source and bottom bias powers are applied, SiO2 physical etch rate (ER)×wafer area (A) are comparable for 200 and 300 mm wafers among these DPS chambers. This implies that the recipes from these chambers could be readily scaled up from 200 mm DPS to 300 mm DPS chambers. In addition, experimental results corresponded closely with results predicted by an energy balance model specifically developed for DPS. Beyond a certain threshold, physical etch rates in DPS chambers increase linearly with the bias power. The threshold depends more on source power than on chamber geometry. Both the simple estimation and the model are directly useful for experimental engineers in evaluating physical etching during development of new DPS chambers or in process transfer and optimization.