Modeling and Optimization of Wet ALE Process

Wet ALE (atomic layer etch) processes are emerging as an important alternative to standard ALE processes in semiconductor manufacturing. Here we present a model for simulating an idealized wet ALE process that includes both chemical reactions and liquid flow in order to predict the amount of material etch, how much of the etching is true ALE vs continuous etch, and its uniformity across the wafer. This model is applied to both a simple test flow cell and flow across a spinning wafer in a typical wet single wafer process. Results show that etch amount and uniformity depends on timing of the dispense steps, flow parameters, and the kinetics of the specific chemical reactions.