Enhancing Nano-Structure Stability in Sublimation Drying: Practical Insights into Solidified Film Morphology

The purpose of this study is to clarify the correlation between the solidification film formation behavior and pattern collapse during the sublimation drying process in order to suppress pattern collapse during the drying process associated with semiconductor scaling. In the experiment, low-molecular-weight organic sublimating agent (LOSA) was dropped onto a Peltier device, and the solidification process was photographed and analyzed while changing the temperature and film thickness, and the pattern collapse rate after drying was evaluated by SEM observation. As a result, it was found that the solidified film morphology (cloudy film, transparent film, etc.) determines the presence or absence of pattern collapse and the collapse mode, and that there is a high correlation with video features (solidification time, interface growth rate, brightness, low frequency component, etc.) that indicate solidified film formation behavior. Furthermore, it was suggested that the collapse inhibition effect could be achieved over existing IPA drying and SMT drying by optimizing the process conditions.