AbstractCollapsing nanostructures due to the surface tension of cleaning solutions pose a significant problem during the drying process in semiconductor manufacturing. The sublimation drying method has been proposed as a potential solution, but achieving collapse-free drying has been challenging. This study investigated the correlation between the mechanical properties of sublimation agent thin films and the collapse rate of nanostructures during sublimation drying. First, various mechanical properties — such as Young’s modulus, viscosity coefficient, plateau stress, and rupture stress — of eight sublimation agent thin films were determined by conducting indentation tests using a spherical indenter. Next, sublimation drying of Si substrates with nanostructures was conducted using these sublimation agents, and the pattern collapse rate of the nanostructures was assessed. The study found a correlation between the rate of viscous change during the phase transition of the sublimation agent from liquid to solid and the collapse rate of nanostructures. However, no correlation was found between other mechanical properties and the collapse rate. These results suggest that the viscous change during the solidification of the sublimation agent exerts stress on the nanostructures, leading to pattern collapse. This study highlights the importance of considering the viscous change during sublimation agent solidification for enhancing nanostructure stability in semiconductor manufacturing.
