Single-Wafer Sublimation Drying Process Achieves Damage-Free Results for Ultra-HAR Structures

Of all the emerging drying technologies to mitigate pattern collapse, sublimation drying is particularly promising due to its simple process conditions and low cost of ownership. In this work, we developed a single wafer sublimation drying process using a custom-formulated sublimation chemical. Process optimization is mainly achieved by fine-tuning the film thickness through wafer rotation and optimizing the chemical concentrations. The optimized sublimation drying process demonstrated damage-free results on ultra-HAR fin structures, significantly outperforming conventional drying techniques such as IPA, hot IPA, and SMT drying.